Cider Weekend 2023: Cranking Up Again

After a 2-year pause and a small ‘trial run’ last year, we cranked up some cider in Five Islands on the weekend of October 21 this fall. The cabins were once again full, the forecast threatened rain but it mostly held off, the kids ran around in a delightful unruly herd, and the juice flowed freely. In the end we handily polished off about 3 bins (~1800lb), producing 150 gallons of cider and finishing in time to tear down and clean up before a big dinner.

For me the week started on Monday with an interesting full-circle experience; I was invited by my grade-school friend Philip Francis to give a talk to the students at his Seguinland Institute alternative gap-year program on the other side of Georgetown island, sharing my experience growing up on an off-grid homestead and subsequently working in clean energy startups. In preparation for this my folks and I dug through old picture albums from the pre-electricity days to put together a slideshow for the morning, and after lunch the class re-located to Joanna and Jed’s for a tour of a homestead-in-progress and a demonstration of small-scale grain milling. The demo used the same multipurpose pedal-power stand that runs the hydraulic cider press, with the heavy duty aluminum grain mill bolted to a sliding platform on top and belt-driven from the flywheel. To add a modern twist, I assembled two cast-off PV modules (about 350W total) reclaimed from the Kaufmans’ catamaran, mounted on a pallet with an MPPT charge controller and a small deep-cycle battery, and bolted a salami-sized surplus 12VDC brushed motor to the pedal stand (the specific motor is apparently intended for use in a truck-bed salt/sand spreader). So the students were able to experience how much elbow-grease is required to hand-crank corn into flour, then observe how much easier it was to grind using pedal-power and gearing, and finally flip a switch and let solar-plus-storage do the same thing, faster and more quietly, while we carried on a conversation. It was a good time, both in preparation and in talking with Philip and the students, who were mostly late-teens and suburban/urban in background; I got the sense that any kind of hands-on rural living was a pretty foreign concept for them, let alone building your own house and growing/milling your own grain.

The middle part of the week was given over to fiddly hardware details, cleaning and organizing cabin space, gathering food, and schlepping bins of apples for the event. We got a nice mixed bin from Brackett’s in Limington, and I had an errand in northern MA so for old time’s sake I also got a bin from Autumn Hills, which is under energetic new management since Anne retired; they always have a great variety and apparently have a new block of cider apples that is coming into production soon. With Dave’s help I also cleared out and re-energized the pop-up kitchen that we built in the big barn using Craigslist appliances back when Ummy and Poppy’s house was rented out.

On Friday morning we attempted an ambitious tarp setup spanning between the two barns, but the wind was too strong and we retreated to a sturdier and more modest setup that worked well. On toward evening we made the customary giant skillet of refried black beans for asynchronous burritos as families arrived, ate, and got set up in cabins, followed by a campfire with s’mores.

One big change we piloted last year was shifting the pedal-powered cider equipment from the original big barn to the slightly smaller sugarhouse/cider barn that my folks subsequently built so they could (hypothetically) put livestock in the big barn at some future date. We replicated the original counterclockwise flow from washing to grinding to pressing to tank, and most of the equipment just sits on the floor, so relocating wasn’t a big deal. The exception was the dunk tank/apple elevator/tumble washer setup, which was previously attached to and stabilized by one of the 6×6 posts of the big barn. The space in the sugar barn is a bit narrower, and it lacks both the post and the floor drain that we previously took advantage of, so we decided to set it up just outside the door of the barn, under a heavy-duty tarp awning we stretched above the wide doorway.

Last year the apples were pretty clean and the crew was smaller, so we didn’t set up the elevator/washer, but this year we made a morning-of decision to set it up. This ended up being a near-run thing, since the various pieces that connect at precise distances via belts and bike-chains normally sit on a nice flat slab, and were now standing on a sloping gravel driveway, but in the end worked out fine with the help of sawhorses, blocks, and plenty of cedar shims. I’m glad we set it up; besides making for cleaner cider it’s a cool visual spectacle and a reliable kid-pleaser.

Despite setting up the washer, we got started before 10AM on Saturday. Sadly the crop from Five Islands was a complete bust; as with many other orchards in New England this year, the hard freezes in the spring and strange weather all but eliminated fruit production on the North End. But other trees in other parts of the island escaped the damage; besides the two bins from Brackett’s and Autumn Hills, my folks managed to scrump an impressive quantity of apples around town, amounting to probably a third full bin’s worth that were arrayed in the ubiquitous reclaimed Tidy Cat buckets. Given the large, energetic labor pool we set a high standard of quality; each apple was individually inspected and any bad spots cut out with paring knives before rolling down a ramp into the rinse tank. From there, enthusiastic small children encouraged the floating apples into the elevator, which steadily raised them in ranks to tumble into the spinning tumbler (made from a plastic culvert lined with green astroturf), where a combination of mechanical scrubbing and a fine mist of clean water got them tolerably clean.

The tumble washer delivered apples and rinse water into a laundry basket below the outlet of the drum; this part of the setup could use some refinement, as a fraction of the apples managed to bounce out and escape, where they had to be fed back into the washer. The laundry baskets were also marginal for the task; given that they probably came from the Georgetown Mall, and in any case weren’t spec’d for 50lb of wet apples in the first place. If I have time ahead of next year, the support and containment aspects of the washer could use a thorough going-over.

From there the baskets were emptied into sturdier tubs which were lugged over to the pedal-grinder setup, which was little-changed from previous years. Eerik being in Sweden with a new baby, we didn’t make another attempt to couple his erg to the grinder this year, though if it had been sunny I would have been sorely tempted to bolt on a DC motor and attempt to augment the pedaling effort with 350W of direct-fed PV power (as prototyped on the grain grinder for the Seguinland demo). The grinder delivered finely-shredded apple pulp into flexible plastic tubs below, which when full were lugged to the press on the other side of the barn for loading into the cheese frame as usual. Once four cheeses were stacked with wooden grates between, the assembled stack was slid under the press and carefully squeezed down to extract the cider.

Unlike the grinder, the amount of gross shaft work needed to press out a stack of cheeses is not huge (a medium-sized kid can easily do it with the right technique), but there are a couple of tricks to it. First, the cheeses should be made up carefully in an aligned vertical stack, and not too full (five thinner ones is better than four stuffed to the gills). Second, for the initial pressing that extracts the majority of the juice, it’s important to pedal very slowly; while the pulp is still soft, the stack can get squirrelly and the grates can go out of parallel in a way that reduces pressing efficiency, and in extreme cases can require the stack to be torn down and re-equilibrated. Then, once the flow of juice starts to slow, pressure is steadily ramped up to get the extraction rate above 70%.

This is where skillful manipulation of the control valve in conjunction with the heavy flywheel on the jackshaft of the pedal stand is important; the log splitter pump has an ‘automatic transmission’ effect; internally it’s really two hydraulic pumps in parallel, and the faster one is automatically disabled (via internal fluidic logic) once the ram encounters resistance and the outlet pressure rises above 600psi. In the intended application on a log splitter, this advances the ram quickly to engage the log, then slows down and increases the pressure-generating ability of the power source as necessary to split a tough log. In our application the same effect is convenient; just as the pedaling gets difficult, the resistance drops off noticeably and a short burst of vigorous pedaling easily gets the cylinder pressure up to ~1500psi – above which we see diminishing returns in juice flow. Even a small kid can manage to hit the target pressure by setting the hydraulic control in neutral, spinning up the flywheel while the pump is isolated from the press, and then throwing the lever to the ‘down’ position, which reconnects the pump to the cylinder, so the energy stored in the flywheel kicks the dual-speed pump over into the low-flow, high-pressure mode, and the residual energy in the flywheel (combined with modest pedaling) readily attains the target pressure.

All in all, the application of these hydraulic system components – designed for high-speed, high-power applications with a multi-horsepower engine – to lower-speed, limited-power pedal-driven use has been surprisingly effective and satisfying. One important detail is that the internal check valve in the log splitter pump leaks at a high enough rate to cause the cylinder to lose pressure at a noticeable rate when pressing down on the cheeses, leading to an annoying need to pedal steadily against high resistance just to hold a constant pressure on the stack for final extraction. So years ago we installed a soft-seat hydraulic check valve in line with the down-pressing end of the cylinder, with a bypass valve in parallel; this completely eliminated the leakage, such that the pressure only decays slowly as the last of the juice seeps out of the pomace.

The juice gushes out of a hole cut in the formed polyethylene press pan and falls into a modest-sized stock pot on the floor; from there it is slurped up by a hand-pumped diaphragm-type bilge pump (Bosworth model 500) and deposited in the elevated 100-gallon conical-bottom tank that we have used for many years. From there the accumulated cider output is portioned into gallons, half-gallons, carboys, mugs, etc.

Operating the hand pump is a popular job for the smaller children, though quite satisfying for anybody who tries it; wielding the wooden crusher that mashes the apples down against the spinning primary grinder drum is another popular kid task. All told, more and more of the operation of the cidermaking process is run by the next generation, some of whom have become quite skilled at certain tasks (e.g. operating the pedal-hydraulic press for efficient juice extraction).

With Eerik attending to family matters across the Atlantic, Holly gamely took on the task of bottling the small batch of hard cider from last year’s pressing – despite being bleary-eyed from his very recent return from an extended work trip to China. These 3 carboys had been mellowing in the root cellar since last fall; he and a team of helpers cleaned out a number of Cornelius kegs, racked the cider into them, chilled and carbonated them, re-assembled the complex double-barreled counterpressure filler setup, and packed several cases of 750ml crown-cap bottles for the crowd to take home.

We had an ample crew for the work even though the threatening weather kept the usual large crowd of Georgetown locals to a minimum; this was just as well given that packing the usual crowd into the limited space under cover would have been a challenge. By the middle of the afternoon we had pressed the last of the apples; the rain mostly held off though an increasing drizzle kept things damp outside. All hands transitioned smoothly to taking apart the cider equipment for cleaning, packing it for storage, and swabbing the accumulated apple muck out of the barn. The equipment has its own place in the sugar barn, packed into a corner, which is a big improvement over hoisting everything into the lofts of the big barn. Cleanup and packing has been significantly streamlined since most of the equipment (excepting the grinder assembly itself) is palletized and can be schlepped around the barn with a pallet jack. The pallet jack has been a surprisingly great addition, not least because the smaller kids think it’s the best toy ever – they pump it (and various payload items ranging from other kids to empty 15-bushel apple bins) up and down, roll it around, crash it into things, etc. Sometimes they can even be recruited to do something useful with it, or convinced to lend it to an adult for a couple minutes.

I had pre-made several lasagnas which went in the barn oven while the crisps that Holly engineered went in the house, and we set up the four long church-supper tables donated by the Jones family for dinner, together with a large, motley assortment of plastic lawn chairs salvaged from the transfer station and the high tide line. Together with assorted pot-luck dishes from the crew, we had a fine dinner in the big barn, after which the remaining day trippers got on the road and the rest of the tired crew retired to the cabins for the night.

Rain had let up by Sunday morning for blueberry pancakes in the giant skillet, followed by the usual wrapping-up tasks including transfer of cider into four 6-gallon carboys, final sweet cider bottling, more sundry cleanup, and goodbyes. We loaded the pedal-hydraulic power stand (which is used for milling whole-grain flour at home), the PV rack pallet from the Seguinland demo, and various tools and oddments into our small trailer, and made it home comfortably before dark. All in all, a fine re-launching of the pedal-powered cider tradition. A number of refinements suggest themselves for next year, particularly a more ergonomic jug-filling station, a stronger and more adjustable modular support frame for the elevator/washer assembly, and possibly a palletized rebuild of the grinder frame, addressing the sporadic clogging issue in the post-crusher, and also potentially incorporating shifters for the grinder bikes (finally!) and a motor mount for optional solar power boost. Hearty thanks to everyone who helped make it happen, and here’s hoping for a better crop and even more familiar faces next year!

The last cucumber and tomato sandwich of the year

When I was a kid, cucumber and tomato sandwiches on sturdy homemade bread were a staple of summer, and in these last few years of more serious gardening I’ve marked the turning of the fall season by mentally noting the last cucumber and tomato sandwich of the year – today was the day for 2023. We still have plenty of tomatoes, but only put in one batch of cukes, which moldered on the vine in the constant humidity of this summer. They don’t last long in the fridge, so this is the end of the line.

The summer squash are long gone, the last of the butternuts and spaghetti squash are cured and stashed in the basement, and in fact a large strip of the garden is given over to a newly-sprouted cover crop of white clover. It’s time to focus on cider and winter preparations.

Reflections on another year of serious gardening (2023)

Hello again world! With more time on my hands this summer (but operating solo now that KFK is afloat), I’ve been wrestling with the strange weather of this year to grow vegetables. Here are some notes so far:

• After a seriously dry spell in the spring, June and July turned stubbornly rainy and humid; this is the headline impact on Maine gardening for the year. The river which usually shrinks to the size of a small stream for most of the summer remained in spring-like torrent mode, with occasional bursts out of its bank in response to 2-3″ rainstorms. The grass was brown briefly in May, but has been as green as Ireland for the entire summer since.
• Naturally I was worried about the strawberries, especially since I didn’t manage to get straw under them in the spring, but somehow they put out a decent crop with only a bit more mold and mud than usual; we froze maybe ~20 quarts and jammed most of the frozen remainder from 2022, which was a more prolific year. With more time for diligence, I did manage to police the beds for weeds a few times, so they look pretty good for next year.
• Given family enthusiasm, this year I planted 3 different maturities of shell peas in addition to the usual sugarsnaps. Unsurprisingly given the weather they did well; we had fresh peas from late June right into August. Most went right down the hatch before even being cooked, including a consistent dose shelled fresh in preschool lunch every day, but I froze maybe a quart. We ate the sugarsnaps fresh as usual; I haven’t found that blanching and freezing them results in an appetizing product.
• Beyond the weather my biggest antagonist was a family of woodchucks; they hopped right through the holes in the cattle panel fencing on a bee-line and devastated the peas and brassicas early in the season. I fought a running battle stapling up 1″ chicken wire (“poultry netting”) over the lower half of the cattle panels; while I didn’t entirely encircle the garden, I started closest to their den, and it seemed to dissuade them – or other stuff sprouted in the woods that they like better. I am still working to gradually upgrade the entire perimeter by applying the chicken wire to each panel, such that if the panel is removed, the netting comes with it and the whole assembly can be transported/reapplied easily.
  • In the process of doing this fencing work I discovered hog ring pliers which take strips like an Arrow stapler; can’t believe I made it this many decades without realizing these were so handy.
• Given the damage from the woodchucks, my broccoli and brussels sprouts were a sad affair; I ended up buying a couple of six-packs from a nursery to patch in the ones that were too badly chomped. Finally here in September I’m getting some broccoli; it remains to be seen how far the brussels sprouts will get before the snow flies. I started fall broccoli which has hit the fast part of its growth cycle, so hoping to freeze a couple more gallon bags of florets for pizza before the season ends.
• Alliums were so/so. Garlic did its usual thing, producing scapes and then dying back for harvest in time for its bed to be given over to late broccoli and lettuce. I doubled down on leeks, planting approximately 70 row feet of a couple of varieties; they did fine but haven’t sized up that impressively given that I started them in the greenhouse early and gave them a couple rounds of compost. Onions were more disappointing. After a tremendous harvest of prime softball-sized storage onions last year that carried us right into the summer, I thought I had the recipe down: I planted individual seeds of a couple varieties (yellow and red) in individual 200-cell plastic trays, nursed them in the greenhouse with organic liquid fertilizer, and planted healthy starts on 8″ centers in a well-fertilized bed. I even collared each one with cut-up toilet paper roll tubes that I’d been diligently saving all winter, to keep the cutworms at bay. They appeared to grow OK, but didn’t size up nearly so well as last year – baseballs at best, which I suspect is just down to the weather. I think commercial onions are grown in the sunny parts of the northwest, suggesting that the cloudy summer may be to blame.
• Summer-bearing raspberries were OK; nothing spectacular, but Z ate plenty fresh, and I managed to freeze 2-3 quarts. I gave them a ton of composted manure and buried it with fresh sawdust from the bandsaw mill that we hired for a day this spring; next year’s canes are a good 18″ taller than this year’s, which may be related and a good sign. Fall-bearers are just starting now and look normal.
• Tomatoes have suffered badly. They appeared to grow normally, but were extremely slow to set fruit, and likewise slow to ripen. The tomatoes in the greenhouse have been marginally healthier/earlier, but not by any significant margin. This makes me think that they need sun more than heat. As of the first week of September I have perhaps only harvested 15-20lb total; they are starting to come in heavier now that the sun and heat have come on; we’ll see how much we get before it turns cold. Fortunately I overdid it last year and still have several quarts of diced in reserve.
  • Peppers and eggplants were likewise slow to grow and miserly with fruit (even in the greenhouse and hoophouse), again making me think that sunlight was the missing factor.
• Continuing in the theme of hot-weather annuals, basil is a commodity crop for us, and it did pretty well. I plant ~8 sq feet in the greenhouse and ~30 sq feet outdoors, and as usual the greenhouse patch was more rampant, but both produced respectably. I make large batches of pesto, freeze it in ice cube trays, and pop the frozen cubes loose into plastic bags, aiming to put up 2 or 3 gallons to make it through the winter. Often it starts to brown and dry up by now, but the late burst of heat and humidity seem to suit its continued growth.
• Squash family crops did relatively poorly; we got a good run of pattypans early, but the plants fizzled out (though that’s not unusual). I planted a couple hills of spaghetti squash, and they set and sized fruit impressively, but then the vines died before the fruit could ripen – we’ll get maybe a half-dozen big ones, and it’s not clear if they really matured. Waltham butternut did better; the vines still look OK, some fruit is mature, and some are still coming. I planted a couple of hills of Connecticut field pumpkins, and they made a good showing with several respectable jack-o-lanterns turning orange now.
  • The real standout of the squash family was the ‘Zephyr’ summer squash variety; it’s a yellow summer squash with a mildly crook-ed neck and a light green blossom end. Those plants are still kicking out fruits long after everything else has turned mildew-y and dried out. The flavor is fine and they are plenty tender if picked at a reasonable size.
  • I was able to grow a handful of really nice cantaloupes, mostly in the greenhouse. The eggplants and peppers I planted in there didn’t do much, so I let the cantaloupe vines run rampant to the point where they started to take on even the tomato plants.
  • Cucumbers produced respectably; we don’t make pickles so there’s only so much to be done with them.
• Potatoes look OK; they are taking their time dying back, but I don’t know if this will translate into high yield. The couple of hills of white potatoes that Z and I have dug up had some with internal voids (not rotten); hopefully this doesn’t extend to the other varieties.
• Carrots and beets have done their thing; nothing apparently unusual. I have tried to keep successions of carrots going, though the ones I overwintered last year ended up small and tough. I did get a good crop of parsnips this spring which lasted us for muffins most of the summer; this year germination wasn’t as good so I expect a smaller number of monsters come next spring.
• Greens were sufficient to our needs; by sporadic succession plantings there was always something to make salad out of. I had quite a bit of overwintered spinach that did well enough that we ate a ton of Greek omelets and and was able to freeze some early in the season; will try for this again by planting repeatedly as the fall progresses.
• Asparagus produced nicely, and put up a very strong stand of fronds, to the point where I wonder if I should be dividing the clumps or something – need to look that up.
• It wasn’t a big year for grain staples; we didn’t do field or sweet corn, and planted fewer potatoes. I did have about 1000 sq feet of fedco winter wheat I planted (with red clover) last fall on the patch that had grown potatoes last summer; the stand wasn’t particularly thick, and the wet weather of the spring didn’t seem to agree with it. I did harvest it (with scissors, not the grain cradle I improvised for rye the previous year, as it was thin and weedy) – it’s drying in the attic, and we’ll see if I ‘make my seed corn back’. I have heard that spring wheat is more common in Maine, so at some point I should try that, but so far corn and rye have been much more successful. The red clover has subsequently put up a nice stand so at least there’s the nitrogen gain from that.
• Total fertility input at this point has stabilized to 3cy of ‘Surf and Turf’ from Odonals each spring, plus the compost output from kitchen, yard, and garden. I spread finished compost and S&T by pailfuls onto the beds, fluff it in with a Johnny’s broadfork, and rake the beds smooth before planting. The small rear-tine gas tiller we bought used died years ago, and for the established beds I don’t miss it, though I don’t have a ready solution if it came time to turn over some stout sod.
• Weed control is fairly refined at this point between the BMX-bike-derived oscillating wheel-hoe, a long-handled Eliot Coleman collinear hoe with a 7″ blade, and a small Japanese hand hoe.
• Pest control consists of I’ve settled on 1, occasionally 2 applications of spinosad on the potatoes to control beetles when I first see the nasty grubs feeding, which this seems to do the trick, and 2-3 mistings of Bt on the brassicas, which keeps the green worms pretty much in check.

New Year’s 2022; composting diapers

It’s been an indifferent winter so far, with just a day or two of snow suitable for skiing on the north side trails and a warm inter-holiday week, but a cold spell was forecast so I took advantage on the Sunday after New Year’s Day to string out the hoses and compost diapers.

Diaper consumption is gradually decreasing in preference to use of the potty, but still the compostable liners accumulate, and I have made a habit of slurrying them (yellow ones only) and mixing with diverse organic matter to make very nice compost for the garden. In the photo above, the right bin holds the last fall batch that has cooked down nicely, while I am layering and mixing fresh material on the left. I had to dig off a few inches of snow to get at the pile of leaves and garden waste behind the bins.

Building a kinematic solar chicken tractor (A Philosophy of Outbuildings, 2nd worked example)

In late 2019 I wrote a post called A Philosophy of Outbuildings, attempting to capture the lessons from 40 years of making and using utility structures on the land in Five Islands, and now a bit here in Gorham. In the summer of 2020, as part of our garden expansion I took down our oldest, smallest ground-mount PV array of four modules, which was mounted on a rack of untreated 2×4 that was rotting up from the ground. We needed a new rack for the PV, and we have also talked for a long time about eventually getting chickens here. I had already worked up a mostly-effective technique for using quality aluminum foil tape to weathershed the seams between modules on a ground-mount array, making a pretty nice garden shed that might become a third essay in this series. So a solar chickenhouse seemed like a decent idea.

One of the principles of the philosophy is that Small Outbuildings Should be Portable – because they can be, because it increases the value of the time put into building them, and because otherwise they often get in the way of bigger plans that come along later. In the case of grazing livestock, portability is a primary requirement, to expose the critters to fresh pasture, and the Chicken Tractor is at this point a classic DIY project. My parents have taken that concept to the extreme in Five Islands with two small barns for laying hens, built on the four-wheeled frames of retired haywagons from the Holbrook dairy operation in Woolwich. These are truly impressive structures, complete with large winch-up flyways, and those hens get moved every 2-3 days, but a conventional stick-frame rectangular building on a long, spindly four-wheel wagon will come under some pretty intense wracking strains when pulled over uneven ground, and indeed the first iteration ended up somewhat diagonal due to this fundamental challenge of kinematics.

The wracking of the four-wheel chicken tractors offended my engineer’s sense of propriety, much as an out-of-plumb outhouse grates on a carpenter’s, so I resolved that our portable solar chicken house would be kinematically correct, with a three-point stance to avoid wrenching when transported. This complicated things significantly, but the end result was satisfying enough to document in this post, with some lessons learned that could be useful in designing similar buildings.

The size of the building was roughly set by the four PV panels to be mounted, older 185W Chinese mono modules that measure a bit over 2×5′ each. To minimize footprint and provide a bit of standing headroom inside, I arranged them 2×2 in portrait format, leading to a collector a bit over 5’wx10’h, set at 45 degrees (we’re at 44 degrees north here), giving a right-triangular wedge for the main mass of the structure.

When tilted up, the run of the collector array fell just short of 8′. But for efficient use of materials, and to provide a bit more floorspace, I went for a full 8′ in the north-south dimension. To cover the gap at the north end I put in a small north-facing roof facet which I covered with twinwall polycarbonate to let in a bit of light; this also echoes the design of the (decidedly non-portable) solar garden shed that sits just to the north. In the end this resulted in a lot of picky carpentry; it might have been best to tilt the array slightly flatter than 45 degrees and deal with the reduced headroom, but I am happy with the result. With our without the north-facing rooflet, the north wall is the only one big enough to receive a door, and is also a convenient place to implement daylight/ventilation.

Inspired by a coop Gerry Carroll built in NJ, I was keen to try accessing the laying boxes from outside, and the building could use a bit more width to give it stance against blowing over, so I slung two rows of laying boxes on either side running north-south, designed to have hinged access hatches on the side walls and de minimis shed roofs to cover. I clad the laying box sheds with salvaged mobile-home skirting in a nice gray-brown faux woodgrain color, scored from Dave’s salvage collection. We’ll see how the external-access laying boxes work out if we ever get around to populating it with chickens.

The kinematic foundation is the most unique element of the structure, and fortunately I have some decent pictures. Because the shed would be located within our large fenced garden area, it would probably move relatively infrequently (on an annual or slower-than-annual rotation) to allow the chickens to fertilize a fallow area, so I decided to use skids rather than wheels. The kinematic principle could (and I would say should) be applied to a wheeled structure with minor variations. Like the portable tractor shed I built upriver, the skids are made of ordinary treated lumber, 4×6 flatwise in this case. Here are some shots of the substructure under construction, showing how the floor can pivot freely and be adjusted independent of the base:

Built upward from the skids are a front crossbeam (2×10, sculpted top and bottom to increase clearance) and a back crossbeam (C-channel construction of PT decking, similarly sculpted below for ground clearance), plus 2×6 diagonal braces to keep the substructure square. The front crossbeam has metal plates sandwiching it fore and aft, through-bolted (in this case the plates happen to be leftover tail vanes from a prototype wind turbine). The curved metal plates project well above the crossbeam, and form a trunnion that accepts one of the joists of the floor deck with a large pivot bolt. This gives the superstructure a roll degree of freedom relative to the substructure, which is key to preventing the building from wracking as the skids move semi-independently to conform to the surface contour of the soil. Additionally, the flex in the metal plates, the wooden joists, and general slop in the system allows sufficient pitch degree of freedom such that the floor can be leveled.

The ability to level the floor is not necessary to the fundamental goal of a kinematically appropriate structure, and the chickens probably won’t care, but as the son of a carpenter I feel that certain standards must be upheld. So the north end of the structure is supported off the rear crossbeam by two salvaged scissor screw jacks from light cars, which allows the floor attitude to be adjusted, taking advantage of the roll and (modest) pitch degrees of freedom of the front pivot point described above.

Between the solar panel roof and the specialized kinematic base, I tried hard to keep the structure from getting too heavy. The floor is 1/2″ PT plywood framed with a 2×6 perimeter, but joisted with 5/4 decking. The wall framing is similarly light, mostly decking ripped in half lengthwise, and the side walls of the structure are diagonally planked with Hammond Lumber’s thinner, nicer-grade shiplap that is rough one side but measures an actual 3/4″ thick (where regular shiplap is actual 7/8″ thick). I also incorporated some hardware cloth and twinwall polycarbonate for light and ventilation. Here are some photos of construction:

We got an early snow in the fall of 2020 that then melted, and I took the opportunity to skid it into the garden to its final (for now) home:

The structure moved nicely, and it was almost a letdown how trivial it was to level it in place with a couple cranks of the screw jacks. Because the superstructure is intentionally built light, it is secured downward to the skids and the jacks with light chain and preloaded by turnbuckles left over from a fencing project. I bolted on the PV modules, and it sat through the winter and spring while other projects took priority, including growing and harvesting a nice crop of rye (which deserves a post of its own):

I finally got to ‘finishing’ it, roofing the laying box sheds with the trailer skirting and building a door on the north wall this summer. All in all, a satisfying project, currently storing gardening sundries and awaiting a shipment of chicks someday.

Naturally in the course of this type of exploratory project, I came up with some things I’d do differently next time. Most basically, the construction makes the superstructure a few inches taller than I think is necessary, and fitting the kinematic degrees of freedom into a shallower package would be cool. This might be accomplished by dispensing with the metal trunnion plates and fitting the front crossbeam between two closely-spaced floor joists. This would also require a more compact arrangement for the adjustable elevation on the north end, and while the scissor screw jacks were free from Dave’s dump collection and well-suited, they have a temporary, inelegant feel about them; in building another one I might try to substitute some stumpy homemade turnbuckles with welded end plates, fabricated from a couple large-diameter left-hand threaded nuts and bolts. This would obviously also provide downforce, eliminating the need for the turnbuckle/chain.

Reflections on another year of serious gardening (2021)

A post to capture findings from another year of trying to do a good job in the vegetable garden (last year’s post).

The weather was odd; spring seemed ordinary, then June was absurdly dry, then July was ridiculously wet right into August. then things seemed to even out, but I can’t remember a late summer period that seemed this green. We irrigated steadily early in the year, but never once after it started to rain in July.

Made an effort to drive up fertility with good effect; got the usual 3 yards of surf-and-turf in the spring from O’Donal’s, and probably made and spread nearly that much of our own compost.

Weed control was OK through most of the summer thanks to the hacked BMX-bike wheelhoe and a spiffy collinear hoe I bought from Johnny’s. Got sloppier late in the year as things turned rampant and other projects intervened.

Fencing is in good shape, thanks to big investment last year. No woodchucks in the squash this time; deer only got in when we left the gate open.

By crop:

• Brassicas: did pretty well in general; planted all in one row and sprayed 2 gallons of BT (organic-listed bacterium that parasitizes moth larvae) on the row 3, maybe 4 times over the course of the summer, which made a major difference – e.g. the Brussels sprout tops were getting skeletonized and recovered immediately right after I sprayed.
  • Broccoli: direct-seeded 2-3 fedco varieties, one or two failed so got a dozen starts from O’Donals. Couldn’t tell the difference between varieties; froze several gallon bags’ worth on cookie sheets, since we always use a lot. Kept producing off side shoots well into the fall.
  • Kohlrabi – grew for the first time after being inspired by a picture of Holly’s son with a huge one. His description was pretty accurate – like a giant hunk of broccoli stem. The root is functionally similar to jicama but a bit zippy instead of sweet, and makes pleasant fresh eating as a low-cal snack, or grated into a salad; I blanched and froze a few quarts to try in soup. Surprisingly good stir-fried with sesame oil and salt, per HG advice. Next year: attempt to succession-plant; start some late for fall.
  • Purple cabbage – I direct-seeded this early, and thinned/transplanted in the rows. They did well, but ripened while there was a ton of more compelling food in the garden. Plant late for fall/storage
  • Kale: didn’t plant kale early, and didn’t miss it much. Planted some late which is doing well now; seems like the right move. get some other varieties next year besides Russian
  • Brussels sprouts: still coming along – look pretty good.
• Cucurbits – very satisfactory this year. We experimented training cucurbits and tomatoes on the garden perimeter fence; the tomatoes did great but the squash got munched by deer – so in the future we should either string electric fence outboard or confine the squash to the interior of the garden.
  • For summer squash I started some early in the greenhouse in 4″ pots – Yellow crooknecks, the same anonymous green pattypans I bought in the spring of 2020 at O’Donal’s, and a green zucchini variety I bought from fedco without reading the description very carefully. These latter turned out to be zucchini rampicante, which are in the moschata family, and they worked really well – resistant to the bugs that eat the stems of other squash, long-lived, and prolific. They would have been even more impressive if the deer hadn’t decimated them where they climbed the fence, and if I hadn’t planted them over mowed red clover that came up pretty think and competed for light. The pattypans were OK but nothing like last year (maybe try a different variety next year), and the yellow squash faded fast but I planted a succession probably around July 4 that did well (and is still fruiting in late Sept, while just starting to get mildewed).
  • Cucumbers likewise we planted along the perimeter fence (as well as in the greenhouse). The deer got them, but still got plenty for salad and sandwiches (not sure if Kelsey pickled; I think we’ve had more in past years…) – Plant fewer next year, and succession-plant them
  • I grew a few pots of honeydew, cantaloupe, and watermelon. Got a few of each that were pretty good. They got a bit lost under the tomatoes that were also planted on the fence; in general I have a sense that if we committed space and babied them, we could grow some serious melons.
  • For winter squash I planted 3-4 hills of waltham butternut, and got about 120lb of fruits. This grew in an area about 15×20′; this represents a pretty decent people-feeding rate of around 4.5 people per acre, although at 200 calories per pound it would be tough to live on butternut squash…
• Tomatoes: did OK, planted mostly along the perimeter fence, and the deer didn’t touch them. Didn’t pay enough attention to varieties, and ended up with a bunch of sungold and small red cherries, and not so many large eating/canning tomatoes. The elongated red cherries were pretty nice for fresh eating, and overall we got plenty of fruit – I canned over 6 gallons of diced tomatoes in enriched sauce made by reducing mass quantities of the little ones in a crockpot and running them through Kelsey’s squeezo. The ones in the greenhouse did OK but actually came in later than the outdoor plants; the greenhouse seems less necessary for them than for peppers and eggplants. Plant more large ones next year.
• Basil: planted around 12 row-feet in the greenhouse, and similar outdoors. Both did great, made several ~quart batches of pesto and froze in ice cube trays. The outdoor planting started to brown pretty early in September; it definitely seems to be among the most sensitive to cold of the stuff we grow.
• Eggplants: did great in the greenhouse. Didn’t bother outdoors based on last year
• Peppers: bought some starts at O’Donal’s, mostly planted in the greenhouse where they did OK. Two plants outdoors kinda fizzled; not clear why
• Carrots: did a good job of planting successions, mostly of Yaya. Frustrating since the cutworms really like them, but still got plenty. Carrots seem happy in our soil; I definitely see the potential to grow an absurd amount by refining practices. Mark Fulford has done some experiments with intense organic cultivation of carrots that seem pretty impressive, yielding 54-65,000lb/acre in 70 days – equivalent to a feeding power of approximately 15 people/acre.
• Beets: got a couple meals from an early planting, but goldfinches have taken a liking to them and skeletonize the leaves (likewise of chard). Plant small successions of beets under floating row cover next year.
• Chard: Grew some; goldfinches ate most of it. Kelsey feeds it to her family and they seem to like it. One of those things where by the time it’s ready to eat, there are a lot of other tasty things to eat.
• Spinach: overwintered some and it was great to have in the spring. Got a good long row planted early, and ate heavily of it (plus froze some) despite heavy predation by cutworms. Later plantings bolted in the heat; Kelsey got in another good long row for fall that’s doing well.
• Alliums: not a fantastic year. I planted some yellow onion sets, and they got heavily munched by cutworms; the ones that made it looked good but started to rot quickly after harvest. Kelsey transplanted a small patch from seed that seemed to do better though they also got cutwormed. Maybe BT spray would help. We also planted leeks that she started from seed; it too got cutworms and struggled to get going. Definitely not as good as last year.
• Green beans: Kelsey planted a couple rows and they kept going all summer – seems like they liked the rainy weather.
• Peas: snap peas did OK as usual – great fresh eating right in the garden; I haven’t figured a way to freeze them that’s actually tasty. Also grew a couple types of shell peas, but they are a lot of work – seems marginal for to grow and shell them for storage. I did look online and it appears that one can make a homemade tumbler out of wood and hardware cloth to shell them automatically.
• Potatoes: did fine; crop seemed not-especially-heavy but quality was good. Picked a lot of beetles, plus one whack of spinosad when the picking got behind.

Topo vs. Graph

As a kid, I got my introduction to hiking in a particularly spectacular setting, the Wind River mountains of Wyoming. As soon as my sister and I were old enough, my parents would prepare us with local hikes, and drive us west in a marathon road trip – sometimes straight through, sometimes with a night in a motel in Grand Island, Nebraska – and we’d disappear into the wilderness.

In most peoples’ imagination, trails are an integral part of hiking. But one striking thing about the western mountains is that above a magical elevation, trees thin out and trails became optional. We could pick a particularly remote and interesting-looking spot and just go directly there, navigating through the landscape visually, with greater or looser precision as dictated by the terrain and our haste or leisure. The glacier-scoured contours of those mountains seem custom-configured to encourage this sort of loose-jointed bushwhacking or aimful wandering, with open glades, bold ridges, and frequent grassy benches to offer a path down even quite steep slopes.

I didn’t fully appreciate the freedom of travel and freedom of thought that this sort of terrain encourages until much later, when I started hiking and backpacking in the White Mountains as an escape from city life in college. Hiking in the east is all about trails. Off-trail travel in the eastern mountains is difficult to impossible given the heavy growth of trees and underbrush – and unethical above treeline, given the fragile soil and heavy traffic. Views are limited, and navigation is a matter of keeping track of which trail you are on and not missing the junctions. When the rigidity of trails is combined with infrequent vistas, humidity, crowds, and restricted camping locations, the overall comparison isn’t favorable.

I think these two modes of navigation are actually quite general. The first, western version I’ll call Topo, after the special color-printed topographical maps that we would order in preparation for those Rocky Mountain trips. A topo map offers comprehensive, uniform fine-grained knowledge of the entire landscape, down to the resolution of the contour interval and scale. A Topo landscape facilitates broad freedom of travel (albeit with natural obstacles and salients), and trails are of secondary importance or non-existent. The eastern version might uncharitably be called ‘Maze’ but more neutrally I’ll call it Graph, since in a mathematical sense that’s basically what the AMC’s hiking maps are, with thick lines representing trails and segment mileage printed on, the scale relatively broad and the contour lines recessive. The idea of Graph is that getting from place to place is less about the details of the landscape, and more about the paths through it (which are discrete and relatively few), the quality of those paths, and the logic of linkages among them.

These two ways of thinking about a landscape don’t depend on holding a map of one type or other. The broad meaning of Topo is to have an actual overall layout in your head at some fidelity, and a sense of your physical position on it to some accuracy. I came to appreciate it in the wilderness, but it’s just as useful in cities: ‘I’ll just head south until it gets kind of downtown-ish, then go east until I hit the river.’ Graph means discrete knowledge that you’re on trail X between point A and point B, combined with a finite list of instructions for getting certain places: ‘go out the door, you’re on Prospect St. Turn left, then walk until you hit Mass Ave. Take another left and walk to #77.’

Some landscapes (open, legible) lend themselves to Topo, while others (cluttered, opaque) lend themselves to Graph. A train on a railroad is the ultimate Graph – there are only so many tracks, and you are either on a track or you are in very bad shape. The ultimate Topo is the sky for a bird, or perhaps the ocean for a fish, though given a chart and GPS the ocean is Topo for a boat. With their orderly grids, some cities encourage Topo-type facility (e.g. Salt Lake), while in others (Boston) perhaps only particularly-talented natives eventually achieve Topo, and everyone else operates in Graph. When I first moved to Portland, the cluster of roads around PWM was an impenetrable tangle in my mind, and I had the barest Graph-based proficiency in how to get to a few places. As time has passed I am gradually approaching an overall Topo sense of the layout, and a facility with back-streets and connections.

I believe that the ideas of Graph and Topo extend usefully to the contours of landscapes that are not geographical. Topo is broad confidence, legibility, and freedom to ramble through the terrain of the solution space. Graph is narrow efficiency, stick-to-known-paths, and so tends fragile. Speaking of fragile, in my amateur attempts to learn and play fiddle tunes, I am almost purely Graph – the line of the melody might as well be a railroad track. If I am lucky, my mind and fingers can stay on the rails and keep the tempo. If I fall off the track I must back up, retrace my steps, and attempt to navigate the junctions until I make it correctly twice around the A part. Then the B part traverses what is dimly recognizable as the same landscape, albeit at higher or lower altitude – the exact relationship between the two is obscured by dense thickets of wrong notes. But it’s obvious that talented musicians navigate the same musical landscape in Topo. They see not just the single set track of the melody but rather the entire terrain of chords and harmony, and while they follow the cycles by instinct, they can just as easily jump the rails and ramble freely over the entire glorious landscape – and even take flight, to improvise and soar ecstatically like an acrobatic bird, then land back on the rails without missing a beat.

The same modes of thought apply in engineering realms as well. When I was a kid I had one of those Radio Shack ‘200-in-one’ electronics project kits with the little springs and jumper wires for making connections, and to me the projects were literally Graph – use wires to make connections following a sequence of numbers, then throw the switch and see if it works. While the manual also had narrative descriptions of how each circuit functioned, maddeningly they were written at a level suitable for a competent analog electrical engineer, not an elementary school kid. So my knowledge remained Graph, and in analog electronics I never got much beyond that, while the best engineers I know operate in pure and glorious Topo, flipping effortlessly between digital and analog, frequency and time domain, with a gut feel for every nonlinearity of a magnetic core or an insulated gate semiconductor. If only those old kits shipped with a copy of The Art of Electronics, I might not be a mechanical engineer.

Being invisible and mostly insensible, electricity is by nature hard to grasp, but chemistry is probably worse. My knowledge of aluminum alloys is strictly Graph: ‘Use 6061 for structural, 6063 for cosmetic. Use 7075 for airplanes.’ But I am sure that a skilled metallurgist has Topo knowledge of aluminum alloys – understands intuitively what the copper, zinc, silicon, etc. are doing in there, and I bet in a pinch they could whip up something pretty good in a crucible the way a skilled cook improvises in the kitchen. Chemistry might be where Topo knowledge is most impressive – while mortals scan an impenetrable text for clues and pray that nothing explodes, like Harry Potter on the first day of Potions class, the master seems to have an intuitive feel for what molecules want.

Cooking is domestic chemistry, and in the kitchen some people are strictly Graph, and wouldn’t dare make something without a recipe, while others are casually Topo, adding a dash of this and a sprinkle of that. I fall somewhere in between – when making soup or yeast bread I operate in Topo, while in quickbreads I’m more cautious and hew close to a recipe (Graph). To me the distinction feels inherent in the landscape/solution space of those foods, but perhaps there are others who see them oppositely?

While I’m firmly Graph in music, analog electronics, chemistry, and countless other areas (literature, small engine repair), and transitional in cooking, I enjoy solid Topo facility when working with wood, metal, and manufacturing technologies. I’ve got pretty good familiarity with rough and finish carpentry and working knowledge of many adjacent trades, and can play with the techniques to solve unique problems. I know what most ordinary kinds of wood are good for, and I can fell a tree, get out a bolt, slice it up with a bandsaw, dry it, join, plane, saw, assemble, and finish, and make something nice out of it. In metal I can MIG, TIG, stick, solder, and braze, and could mill and turn with decent precision when I was in practice. In manufacturing I know how most things are made and why they’re made that way, and can mix and match to come up with something new. Alex Slocum who taught the famous 2.70/2.007 design class used the metaphor of Legos – each material, technique, structure, or mechanism you learn is like having another Lego piece in your toy box. The more pieces you collect, the more freedom you have to solve problems efficiently, and once you collect enough, you transition from ‘I know A way to solve this problem’ (Graph) to ‘Which of the Many ways to solve this problem do I feel like using in this instance?’ (Topo)

Skill in prediction seems central to having a Topo understanding of a landscape: “There will likely be an annoying boulder field under that cliff face.” “If the screws are too short they are likely to pull out of the end grain.” Professor Slocum also talked usefully of having a ‘Mental FEA Module’ – a good engineer should work to build, exercise, and test their intuition for predicting how their designs will behave, so they can mentally iterate through potential solutions, rather than ‘guessing and checking’ experimentally or relying heavily on closed-form math or computer simulation. A big box of mental design Legos is like a good topo map, providing fine-grained coverage of the landscape, and a well-tuned Mental FEA module provides advance judgment about what parts of that landscape will make for easy walking. Design then starts as a playful mental exercise of trying to sense what physics will work well, what reality is struggling to communicate to us – in the words of the Indigo Girls, ‘trying to feel what’s coming next’.

Beyond any one person’s knowledge, I have the sense that the human scientific project started off groping in darkness with the barest fragments of Graph knowledge and has rapidly built out an ever-more-detailed Topo map of big chunks of reality. The alchemists could see very little of the landscape of Chemistry, and fumbled around hoping to find One Weird Trick for turning dross into gold; now the physicist Sean Carroll has provocatively claimed that the laws of physics underlying everyday phenomena are completely explained. That’s not to say we understand emergent phenomena, or the Big Bang or dark matter, but rather that essentially there are no blank spaces on the Topo map of forces and particles that make up our everyday lives. Fortunately or unfortunately, that still leaves plenty of work to do – e.g. Prevent Pandemics. Cure Cancer. Build a Sustainable Global Economy.

A philosophy of outbuildings: first worked example

In late 2019 I wrote a post called A Philosophy of Outbuildings, attempting to capture the lessons from 40 years of making and using utility structures ranging from outhouses to the awesome barn my parents built that we’ve been making cider in. One of the fundamental principles was that small outbuildings should be portable, so they can be moved to a more useful spot (or to get them out of the way of some other project). Since then I’ve built a couple examples of this, and thought I’d capture the results in case they are of any use to the greater internet community.

The purpose of the first was simple: to shelter a small diesel tractor that came to us from Five Islands. The tractor gets used for bushhogging, harvesting firewood, and moving mulch/gravel around the yard, and sits idle through the winter; it is approximately as old as I am and would deteriorate rapidly if left in the sun/rain, so it needed some protection. My model was the very successful open-front pole-barn that my father and grandfather built in the early 1980s that we used to keep the cider operation out of the rain in Cider Year Five, but I didn’t have firm plans for the land where I built it, so I wanted to be able to move the shed later if I needed to.

Expanding slightly on the dimensions of a single bay of that pole barn, I settled on a footprint 10′ wide and 14′ long, with about four feet of overhang on the open west end. The building would be floorless, open on one end, and sit on two 16′ 6×6 PT skids with chamfered ends, blocked up level on pads of coarse crushed stone. The closed back end of the building is built on a 4×4 cross-beam set on top of the skids and lagged down. The walls are framed with rough-sawed 2x4s from Five Islands, and diagonally sheathed with Hammond Lumber shiplap. I used a chevron pattern for the sheathing on the side walls, in hopes of providing the long 6×6 skids some structural support to prevent sagging. I did the project in a hurry with the winter of 2019-2020 closing in, so I don’t have great construction pictures; here’s the walls framed up at the end of the first long day:

Rafters were cut from 2x6x8′ rough-sawn, with something like a 6-pitch. Collars were likewise 2×6; 2×4 would do but I had thoughts of hanging a boat from them. The roof is strapped with 1x and dried in with dark green five-rib steel sheet. The overhang on the open end is supported by 4×4 diagonal braces, and the roof structure is tied together by a 20′ PT 2×8 ridgebeam. It got dark inside, so I used a large piece of salvaged plexiglass on the closed gable end up high to let in a bit of light. Here’s the ‘finished’ shed, with happy tractor inside:

The most obvious miss was that I should have extended the diagonal siding to tie in with the 4×4 brace poles that hold up the overhang; this was not obvious because I built the wall sections before fully thinking through the overhangs, but it would have made the structure stouter and also helped to keep weather out. The gable end of the overhang could also be sheathed to keep rain/leaves out, at the cost of some light.

At least until I further perfect the art of portable buildings, this was as large as I was prepared to go on a floorless open structure that I would hope to move with come-a-longs, pulleys, and small tractors/vehicles. My biggest concern was wracking/distortion, both from natural ground settling and also during any future move. To prevent in-plane wracking of the open end I added a pair of a-frame type diagonal braces that can be seen in the photo above, to tie the side walls and end collar tie to the ridgebeam; not sure how well they will work, but they look cool. There is also some small chance of a tornado or derecho-type event picking it up and blowing it over; it’s surrounded by mature trees so it feels fairly protected, but at some point when I put the last few boards on the gable end I should probably also cable it down to the bases of a couple trees for extra security.

In order to skid the building I would plan to temporarily add structure to tie together the skids at the open end, and also temporary internal cross-bracing or cabling to keep the footprint square. With just 5″ of undercarriage clearance, it would be interesting to see what it can skid over; I have a feeling that I should have done something to elevate the bottom of the back wall more – e.g. bandsaw an arch into the underside of a 4×8.

From an ecological perspective, other than the steel roofing (approximately 2lb/CO2 per square foot as calculated in the post linked above) and a handful of pieces of PT trucked up from the Southeast, the building is made from untreated locally milled lumber. The overhangs are decent, the skids sit on crushed stone and/or blocks, and the site is reasonably airy for being in the woods, so I am optimistic it will hold up well over time.

The next building in the series is smaller but more exotic – a kinematically-correct portable solar chicken coop.

A box of tools – then and now

At some point over the winter I stumbled onto a mention of the Mastermyr chest on the web, and marveled at the similarity of thousand-year-old Viking tools to hand tools today:

Not long after, I was puttering in the workshop with Z, who was fascinated by and kept pulling tools out of my own wooden toolbox, so I decided to pull everything out, dump the sawdust and drywall screws, and take my own version:

It appears that the Mastermyr box owner was a locksmith, and I imagine folks in that trade as being clever, thoughtful, and handy. It’s fun to imagine a Viking craftsman time-traveling into the present and wondering at 21st century tools; most I imagine they’d figure out quickly, even if they weren’t a thing back then (bubble level, chalk line, hex wrenches). The stud finder and the digital multimeter might take some explaining. Just imagine the fascination of the Mastermyr craftsman on figuring out a staple gun – or a pneumatic framing nailer!

I’ve been enjoying a trove of practical history blog posts by a classical historian named Bret Devereaux (here’s a series about iron and ironworking). In some ways technology is surprisingly stable (e.g. pliers, hammers); in others it changes very quickly. It seems that one of the blacksmith’s most time-consuming tasks back in the day was making nails, and when I was growing up a big part of carpentry was driving large galvanized nails. Then along came pneumatics and high-quality structural screws, and recently my dad has been trying to figure out what to do with hundreds of pounds of leftover nails and spikes that it may never make sense to drive.

Richard Scarry innovation – more on hydraulics

The recent Richard Scarry post gives an example of disruptive innovation that can be enjoyed by a 2-year-old. But for a professional innovator it’s interesting to think about how it happened and why it happened then.

Christensen described how hydraulics burst on the scene in the middle of the last century and quickly displaced cable-driven equipment to dominate the market for excavation equipment. But hydraulics in some form had existed for thousands of years. Beyond the obvious dams, irrigation ditches, grist-mills, and the like, according to Wikipedia the Romans had piston pumps and used them for e.g. firefighting. Pascal figured out hydrostatics in the 1600s, and a fellow named Joseph Bramah invented the hydraulic press in the late 1700s (Bramah also invented the flush toilet). In the 1900s hydraulic power distribution briefly became a thing in the UK, before being eclipsed by electricity. The famous Tower Bridge in London built in the late 1800s was hydraulic-powered (literally – the working fluid was water), and apparently that system operated into the 1970s.

Mechanical power transmitted by cables and pulleys is also thousands of years old, dating back to at least ancient Egypt. Ships made extensive use of pulleys, blocks, and tackle, to the extent that the British navy’s need for blocks led to one of the earliest forms of mechanized manufacturing. On land, the human-powered treadwheel was used to build cathedrals and other works, and presaged the digging machines that Christensen wrote about.

I haven’t dug deeply into the history of manufactured hydraulics, but I suspect that the sudden breakout of hydraulic technology in excavation has more to do with the pumps than the pistons. It stands to reason that piston-cylinder setups that can seal properly and take significant pressure would arrive at around the time as piston-based engines, based on the necessary precision of boring machines and sophistication of oil seals and the like. But in order to make practical use of hydraulics for digging machinery, you have to be able to deliver significant energy to the hydraulic cylinders, and to do it in a mobile machine (as opposed to stationary works where you can tap pressure off a dam or something) you need compact, robust, high-pressure pumps. Most of these seem to be some form of gearpump, which in turn requires precision in machining the complex meshing surfaces, an art and science that surely advanced massively in the 20th century due to automotive transmissions, aircraft, and general engine-engineering. As we have learned the hard way in pedal cider experiments, high shaft speeds are important to getting decent efficiency in hydraulic pumps and motors, given that leakage flows are driven by pressure, so engines had to speed up to a certain point, and gears had to get precise enough to allow that to happen.

By comparison, larger, cruder open-gearing systems driving drums and cables seem more compatible with older, lower-speed engines, and generally requiring of a lot less precision – not to mention that when all this was getting started, lubricating oil was harvested by hand-hunting whales on the open ocean, so it would not be attractive to use it as the working fluid for large, crude, leaky piston systems.

Putting all this together, it doesn’t seem surprising that cable-driven machinery dominated in the age of steam and early internal-combustion engines, but within a few decades after high-speed engines came of age an entire industry would spring up around compact, high-pressure hydraulic drive systems. And in the time since Christensen wrote that chapter, hydraulics have continued their run to the point where many small tractors and other light construction machinery – where smoothness and durability are more important than pure energy transmission efficiency – have no direct drive mechanisms at all. I remember first being struck when looking ‘under the hood’ of Dave’s small bobcat excavator and realizing the whole thing was run by one big pump.

The cables-to-hydraulics story is an easily-visualized and personally interesting example of a larger set of phenomena in technology and innovation, where a certain technology platform dominates for a long time, despite the presence of minor competitors, and then some other technology platform goes on a tear and displaces both the previously-dominant platform and all other competitors to become the new incumbent. It’s pretty clear to me that the key to understanding this is positive feedback, or virtuous cycles of economies of scale, cost reduction, profit, and reinvestment in innovation. I hope to write a post or two about these virtuous cycles soon, specifically on the striking recent growth in silicon solar cells and lithium batteries.