Saturday, July 9, 2016

Progress Report

Much of the design work has been completed over the past few months. The 3D model, drafted in Rhino 3D, is largely complete. Construction techniques, including materials selection, joinery techniques and order of assembly have been largely worked out.


The cockpit design, the deck arches, the tiller linkage, tanks and lockers and many other details have been worked out in detail. We have designed a very strong structure for stepping the mast tabernacles, constructed out of 4x4 hardwood timbers glued and bolted together.


This structure, fastened and glued to the deck, bottom and sides of the hull, will also provide plenty of resistance to torsional loads, side loads when docked and strengthen the foredeck.


We are still working out such minor details as tiller design, hatches, interior cabinetry, wiring and plumbing, and running rigging.


The model has been hydrostatically tested using Orca3D software. (We are very grateful that Orca3D has agreed to sponsor our project, and has donated two seats of their excellent software for our use.) Hydrodynamic tests will have to wait until we build a 1:12 scale model, and conduct towing tests and other types of in-the-water testing.


The good news is: there are no surprises at all. The hydrostatic tests have confirmed the initial calculations: QUIDNON, ballasted as initially designed, is going to be seaworthy and reasonably fast.


Moreover, it will be able to carry considerable freight. Here is a table of draft (with centerboards and rudder blades retracted) vs. load.

Load Draft
0 12.9 inches
10 tons 25.3 inches
20 tons 34.6 inches


Shown above is the aft amidships section: two 20 lb. propane cylinders in an ABYC-compliant propane locker with an overboard drain, a 100-gallon gasoline tank below it, and a 40 hp outboard engine forward of it in an inboard outboard well.


According to results from Orca3D analysis, fuel consumption and speed will be as expected. As the above chart shows, even when loaded with 20 tons of freight, QUIDNON will do a comfortable 7 knots with a 40hp outboard at half-throttle, burning 2 gallons per hour, for a 350 nm cruising range. Without freight, its cruising range increases to over 600 nm.

It is interesting to note that when QUIDNON isn't loaded, as speed increases from 7 kt, power requirement shoots up. This is because the hull form is a compromise, and at 0 load the transom bogs down faster than when loaded. But this effect will be pronounced mostly when motoring; when sailing the center of force will be further forward, keeping the bow down and presenting a smaller profile to the water.

And so it is safe to conclude that QUIDNON will work very well as a live-aboard boat. You pay for a 36-foot slip and you get around 540 square feet of interior living space, plus just as much space on deck, which is plenty of space for living aboard and for throwing dockside parties. It is fast and economical enough to make a good canal boat, and with a 20-ton cargo capacity it can be used to bring back a year’s worth of harvest from wherever you hunt, gather or grow it back to your winter quarters.

But is it seaworthy?


But, you probably still want to know, Is it seaworthy? To an engineer, this is a fairly annoying question, because there is no technical definition of seaworthiness. And so I will apply my own definition. Seaworthiness is the ability to survive arbitrary conditions at sea. By “arbitrary conditions” I mean something that includes arbitrarily high, almost vertical walls of very angry water, with spindrift blowing from the wave tops at well over 100 miles an hour.

By this standard, few boats are actually seaworthy. We can immediately rule out all catamarans and trimarans: they are more stable floating upside-down than right-side-up, and once a rogue wave flips them over, it’s game over every time.

We can also rule out most yachts, large and small, with tall masts: once the masts hit the water, more often than not they snap off, and, again, it’s game over, every time. So masts have to kept quite stubby. In QUIDNON’s case, the masts measure exactly 36 feet from the mast tabernacle hinges, because they can’t overhang the bow or the transom when the masts are dropped and secured to the deck arches (for canal work, to pass under bridges). And the reason they can’t overhang is because that would increase QUIDNON’s overall length (LOA), incurring increased slip fees at marinas, and we can’t have that.

Secondly, we can rule out all large commercial ships: tankers, cruise ships, dry bulk carriers, container ships, etc. All of them are designed for a maximum wave height, and a big enough wave will capsize them, break them in half, or both. Over a hundred ships are lost every year in just this manner. But “fixing” this problem would be too expensive, and rogue waves are rare enough to keep marine insurers in business.

But we who sail around in small boats do like them to be able to survive almost arbitrary sea conditions. And if you try to design something that is completely seaworthy, by this definition, you end up with a coconut every time. But who wants to sail around in a coconut? (Actually, QUIDNON’s hull shape comes pretty close.)


Hydrostatic analysis shows that QUIDNON is self-righting up to 130º. It is very tender when level, and just walking across the deck is enough to make it list a few degrees. But beyond 10º it puts up a very serious fight. In fact, while sailing, it is probably not possible to make it list more than about 25º, in any sort of useful wind. It continues to put up a very serious fight until about 70º. Thus, any sort of sudden squall will lay it over for a bit, but with no serious consequences (unless you fall overboard, but that's verboten).

At around 90º, it gets ready for Round Two, because at that point the masts are in the water, and they are buoyant because they are filled with foam, weighing in at negative 8.5 lb. per foot of length, with a huge lever arm. Only beyond 130º does QUIDNON develop a propensity to turn turtle and settle.


When inverted, it is only about half as stable as when it is floating right-side-up, and if it lists by more than 50º it will right itself. Thus, if a big enough wave flips it over, leaving it floating at some arbitrary angle, there is only a 27% chance that it will be left floating upside-down. And if a wave big enough to capsize it comes along, there is about a 50% chance that the following wave will be at least half as big, enough to lean it over by at least 65º, and since 65>50, QUIDNON will then right itself. And so the chance of QUIDNON remaining bottoms-up after a rogue wave event is no more than 15%.


This, I would think, is quite seaworthy—for a houseboat. However, we must keep in mind that it is a houseboat, and even though we can take it out on the Big Wobbly with quite a lot of confidence, we should still remember that we are just moving house, not embarking on an extreme survivalist adventure at sea. And so, we should take certain precautions. These are divided into strategy and tactics.

The strategy is to avoid storms by carefully picking weather windows. For longer passages, on which storms are impossible to avoid completely, the strategy is to carefully pick weather windows for getting away from land, and for making landfall. The idea is to be nowhere near anything at all when bad weather hits. Rocks and shoals kill boats; wind and water—not so much. This is the sort of advice you can get from any number of books.

Another part of the strategy is preparing QUIDNON for bad weather, and it is QUIDNON-specific. QUIDNON can sail just fine with unstayed masts, but when making ready for the open ocean a bit of standing rigging makes a lot of sense. A triatic line is connected between the mast-tops, and two running stays are connected to each of the mast-tops and tensioned, the two from the foremast running forward, and the two from the mainmast running back. This set-up is traditional; Tom Colvin had lots of luck with this arrangement. Also, obviously, anything that could possibly shift in a capsize should be secured, both above and below deck.

The tactic is simply to ride out the weather, in the usual sequence: heave to, lie ahull, lie to a drogue, scud off under bare poles. Make a pot of stew, batten down the hatches and hunker down. Again, you can get this sort of advice from any number of books. Unless you are particularly unlucky, seriously bad weather generally passes in 2-3 days, and so with QUIDNON drifting at about 1 knot you’ll need about a 100 nautical mile offing from the nearest hard object to drift safely.

Since this is much more seaworthiness than one has any right to expect from a houseboat, and since it comes at very little additional expense (filling the masts with foam and rigging some running stays is pretty cheap) we will consider this aspect of the design handled.

56 comments:

  1. Glad to see a new Quidnon post! I like the idea of foam filled masts a lot. I imagine it will add a little bit of stiffness too.

    We just completed the Great American Loop in a 34' fiberglass sloop. We had a 49' keel stepped mast that we had to carry around in locks. Having that big jousting pole made turbulent locks a bit more of a challenge, but it was OK. We didn't stay in marina's often, but 90%+ of Canadian and US marinas charged us for 34' and not for the 49' stick we were carrying horizontally. I think you could get away with taller masts and not really increase your docking fees.

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    1. Yes, slip fees are somewhat negotiable, especially for transients. But keeping the masts short has more advantages than disadvantages for this design.

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  2. I'm impressed.. I am also curious. Is there an historic counter part to this general design?

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    1. Yes, you should research barges, scows and cargo lighters.

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  3. Great progress since we were last in touch Dmitry. I'm impressed!

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  4. Constantly fascinating developments. Go well, Dmitry! NOM

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  5. Impressive. Very thorough as to be expected. I must admit I'm sceptical around departures from "traditional" forms of boat design and building. Not that I have anywhere near the experience or training to be critical. So I am eager to see how well Quidnon performs as you put her through her paces in wind and wave. I have to take exception to your statement that when a multihull is rolled it's "game over" when in fact it's rather a "game changer". It is still afloat, affords shelter from the elements and retains its comtents. Not comfortable, but survivable. A ballasted monohull is history within minutes of being flooded, taking virtually everything with it to the bottom leaving former occupants with only a Life raft and emergency supplies for survival. Take your pick. Game over?

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    1. Since QUIDNON is a houseboat, it is in competition mainly with other houseboats. All the indications are that it will motor and sail acceptably and be reasonably stable out on the ocean.

      When a multihull is rolled over, the occupants spend some time getting knocked about in an upside-down cabin, soaking in diesel fuel and battery acid and eventually suffocating because they have run out of breathable air. In that situation, people become desperate and dive their way to freedom, never to be heard from again. If you like that sort of thing—go for it! (I've learned from experience that arguing about safety with multihull fans is a waste of time.)

      But you do bring up an interesting point: how will QUIDNON float when flooded? You see, most of the ballast (5 tons of it) is water, and there is a substantial amount of buoyancy in the plywood core. This is a test we can run. My expectation is that when holed QUIDNON will sit low in the water, allowing the crew to await rescue on deck. Thanks for the suggestion!



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    2. Since your ballast will be in 'air-tight' tanks low in the hull, if you needed to lift her when flooded you could consider having a couple of modest CO2 cylinders on board, or utilise the LPG tanks. Couple these to the ballast tanks. Open a drain cock, open the gas cylinder and do what submarines do - Blow All Tanks! Up you go. Then you can drain the cabin, and re-flood the ballast tanks - being careful to vent the gas outside. That could get the re-floating underway quite quickly.

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    3. Adding air pumps to "blow the tanks" might be an interesting bit of optional safety equipment. Blowing the tanks using propane would make the boat into a bomb, though, and probably land the designer in jail, so it seems inadvisable to say the least.

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  6. When can I buy one and how much will it cost? :) Seriously though...

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    1. At this rate the entire design will be done in about a year, and the cost of materials is likely to be under $50k. This will get you something that floats and that you can live on; to outfit it for various adventures would require a bit more time and money.

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  7. Despite my ignorance of boats, sailing, and nautical design, I am impressed by your work. This thing you are conceiving is quite beautiful, in its homespun way.

    I have a question. I have heard you mention that you will move to Russia later this year. Will that move impact the progress on the project?

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    1. The design is actually very traditional—just not in the tradition most people are acquainted with, since it has nothing to do with imperialism (tall ships) or ostentation (luxury yachts). The world of sharpies, dhows, bateaus, junks, cargo lighters and sailing barges is a huge and ancient one. Homespun? No, just traditional, but adapted to the circumstances and making use of the best of current technology.

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    2. To answer your other question, I am always moving, back and forth mostly. Russia has 101,600,000 km of navigable inland waterways and 38,808,000 km of coastline, so I don't see a problem.

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    4. Russian inland waterways are closed to foreign-flagged vessels. Since you'd have to hire a Russian vessel, captain and crew, you wouldn't need a guide. There are plenty of tours of the Volga. Another option is to go engineless, by yourself or with a small group, in small boats, and hire locals to tow you as needed.

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    6. Yes, I believe so, based on the stories I've heard. But as with all things Russian, you don't know what's true until you've read the specific chapter and verse of the law. It's all online and relatively straightforward (for those who can understand Russian bureaucratese) but I don't have time to research the question right now. In general, small non-motorized craft are "grandfathered" everywhere, but details vary between jurisdictions.

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  8. While I'm not a sailor, I have friends who are. One of them opined that a boat designed to be sailed by a single person should come about if that person goes overboard. This assumes some things, of course, like the autopilot is off. Any thoughts on this?

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    1. I am not sure what would make a person feel worse after falling overboard: watching his boat swiftly sail away and disappear beyond the horizon, or having the boat come about, get off course and perhaps hit some rocks a distance away. In any case, falling overboard is verboten. That's what harnesses and lifelines are there to prevent.

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    2. It's called "weather helm", and is quite normal. Release the rudder, and boat points into the wind.

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    3. Remember; Slocum was treading water watching his sloop Spray disappear in the distance when he felt the fishing line he had trailed off the stern brush his leg. Probably not silly to trail a line behind, just in case.

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    4. Least silly of all is to not fall overboard in the first place.

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  9. A few thoughts on seaworthiness. I am a kayak builder and kayaker and have much experience with capsizing and capsize recovery as do many kayakers. Kayaks differ from most other boats in that most of the mass in a kayak is the crew, i.e., the kayaker who is also the source of propulsion power and is essential to capsize recovery.
    One thing I've discovered is that a swamped upside down kayak is easier to roll back upright than an empty one. On the other hand, a swamped upright kayak also rolls back upside down more easily than an empty one. I don't know whether any of this applies to larger boats.
    As for model testing, I wonder if anyone ever does model testing of larger boats in a wave tank to see how they handle inversion by large waves.

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    1. Unlike kayakers, sailors have very little experience in capsizing big boats, and houseboat sailors even less. Generally, the procedure recovery involves holding your breath and praying. Tank testing is good for hydrodynamics; stability testing is done using hydrostatic testing, which we have already done.

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  10. I got to have lunch with a Cajun who builds 400 foot boats that service oil wells worldwide. I wonder if a boat like this a couple of guys could buy together and make a living making deliveries to oil wells of low priority stuff.

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    1. If you sell the movie rights to your brilliant idea, I will build some props for it. I imagine your heroes being paid in oil, taking clay pots of it back to the base, to distill into vaseline, of course.

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  11. There is a previous post (in the comments) where you mention no one should take Quidnon into the ocean with a lot of heavy stuff on deck. If Quidnon was being used to carry tons of cargo (I suppose including salvage materials pulled from the water), would all of this need to be stowed inside?

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    1. For use as a cargo vessel, the entire front section of the cabin, from the 2nd bulkhead forward, would be blocked off for cargo. The crew would still have the use of the two aft cabins, the galley and the heads. Cargo would be loaded through the large main hatch, and secured in the passageway between the two water tanks (with the settees and the table folded away). Heavier cargo would have to sit low—no higher than the tops of the water tanks. Very light cargo—bales of hay, for instance—could be packed up to the gunwales, and even be carried on deck. This arrangement would not affect stability too much.

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  12. I love it. I do have two new questions, though. First, would a pair of 30# or 40# propane tanks fit in that propane locker, or is that as snug as it looks? Also, does your testing program adjust it's fuel consumption estimates with the engine size as a consideration? Because I know that a lower power outboard with the correct prop is typically more fuel efficient than twice the engine running at half throttle. Since the outboard motor is a modular part, I was wondering if choosing a 20hp or smaller outboard and cruising at 80% to 100% throttle would result in usefully more cruising range than a 40hp outboard at reduced throttle.

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    1. We picked 20# propane tanks because that's the only size stocked in the US. But for 20# tanks there are Blue Rhino exchanges at many gas stations and supermarkets. But these are rarely accessible on foot. When cruising around, people usually don't have access to a car (unless they stop at a marine which has a courtesy car). Taxis are also problematic, since it's against the law to carry a compressed gas cylinders in an enclosed vehicle. But a 20# tank in a milk crate (fits perfectly) can be carried on the back of a bicycle.

      The engine size is an independent variable. 20 hp is probably the smallest size I'd go with, and 40 hp is safer for maneuvering because there is reserve power for quick starting and stopping. A low-pitch prop is definitely needed for this application. I am not totally sure about the fuel efficiency, but I don't have the relevant tables in front of me. In any case, the choice of motor is somewhat arbitrary.

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  13. Why gasoline instead of Diesel fuel?
    Diesel engine (IDI type) are old-perfected tech, the fuel is less explosive (almost non-explosive), more available, and has more available power per weight & volume. I really like the small Honda gensets (1000W inverter), but a 300cc Kubota Diesel is a capable engine to spin a 2KW generator (either a DC rotary charger or AC generator) at about a pint of fuel per hour. Right-sized battery bank + solar pv will run your refrigeration (most relentless load, esp. in warm waters) and an inverter for AC loads (could include hot water heater: luxury!). Propane for cooking gas is okay, but propane is heavier than air and leaks will accumulate low without venting blowers. Kerosene or alcohol are safer fuels for cooking, in addition to a microwave oven when power is available.

    Thanks for sharing the progress of your ideas.

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    1. Your questions are answered in detail here:

      http://quidnon.blogspot.com/2015/01/the-engine.html

      QUIDNON is a houseboat. It can do lots of other things, but what I supply is plans for a live-aboard boat that is easy to construct and affordable. And the most affordable option is to live at the dock, plug into shore power and skip the motor altogether (borrow a dinghy motor and drop it in if you have to shift berth).

      I house-sat an off-grid place once where my morning routine involved firing up a 300cc Kubota Diesel, because the clapped out lead-acid batteries would run down during the night, so that I could turn on the VHF radio and get updates. Couldn't hear the radio over the bang and clatter of damn diesel half the time.

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    2. Different priorities for living and parking than a primarily-working boat with high duty-cycle, makes sense. Thanks for the link.

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    3. That seems like a distinction without a difference. For a number of reasons, QUIDNON would have to be documented as recreation/coastwise, so it is not a workboat by definition. But it is not very different from a workboat, and similar in many ways, such as the use of an outboard engine. Most workboats, from marina pumpout boats to coast guard launches to motorized barges used for maintenance work use outboard engines. Diesels only make sense on ships. If they are used on luxury yachts, that's because luxury yachts make no sense. And building a diesel engine into a houseboat would be a very strange thing indeed.

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  14. Hey Dmitri, what was your reasoning behind choosing a centerboard instead of lee boards? Also, great design! Will you be making plans available once they are completed?

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    1. Leeboards are difficult to mount in a way that makes them useful for maneuvering. They are also noisy and collect floating debris, and many people find them less than optimal from an aesthetic point of view.

      Here's the full write-up on the centerboards:

      http://quidnon.blogspot.com/2015/01/the-centerboards.html

      I will make available designs, tool paths and milled kits ready for assembly; milled kits will obviously be the best value, but if somebody wants to buy or rent a ShopBot and do their own NC milling, there is nothing to stop them. In fact, if the build is happening in Tasmania or Tierra Del Fuego, that would be the way to go.

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    2. Thanks for the reply Dmitry. Reading through the linked post was really interesting and shows how much time and thought you are putting into making this a rock solid design. I like your idea of using durable plastic strips affixed to the centerboard to cut down on banging. You're dead on in that seemingly small sounds can be nerve wracking when trying to sleep while underway. I look forward to following your progress and seeing the finished product!

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  15. Pdxr13 & Andrew A-J; your questions were answered in the preceding articles & commentary. The short versions are as follows... Since Quidnon is primarily a sailing vessel, the engine is auxilary power anyway & outboard motors are mass produced in volume, and are thus cheaper and easier to replace than a marine diesel. Lee boards have their issues, and Quidnon's off-centered centerboards are both tilted so that one will be vertical when heeled, the board box also forms one watertight side of the two freshwater ballast tanks.

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    1. Good answer! One more: with the inboard-outboard, there is one type of transportation fuel on board (gasoline) and one engine, which can be used to move the big boat and can also be pulled out and used on a dinghy, saving lots of money and avoiding quite a bit of fuss.

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  16. Also, another advantage of using an outboard on a displacement sailboat. If you are concerned about reliability, it's trivial to keep a small (4hp) outboard on the boat; in the event that your engine and *both* rigs are damaged. As the chart shows, even a 4hp kicker would get you there.

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    1. That's correct. If your inboard diesel dies, you pretty much have to pay for dockage and then look for a diesel mechanic. The total expense usually runs into many thousands of dollars. I know well the helpless look of a person with a dead diesel who's stuck at some random marine (that's gouging him for transient rates). It's pathetic.

      But if your inboard outboard dies, you pick a place to anchor, break out a wad of emergency cash, row yourself to the nearest dock and then go talk to the local fishermen. Some time later you row yourself back on board, having just purchased a used outboard of some sort, spend an hour messing about with the throttle and shifter linkages, the starter button and the kill switch, and then off you go again.

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  17. Impressive design/sophisticated simplicity. TY Mr. Orlov

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  18. Regarding your masts in a knock down.

    As shown in your 3Ds it looks to me that the point of maximum strain from top to keel would be in the mast post (tabernacle) at the junction with the upper frame. A failure at this most likely yield point could see a dis-masting cause serious damage to the deck and make recovery difficult.

    I presume (since you have already thought of everything) you are making the mast supports from the hinge down to the keel stronger than the mast above the hinge (so that the post/tabernacle will survive the knock down break undamaged), and that you are contriving a failure point in the mast just above the hinge so that you can swap the hinge hardware to the spare mast or trim the mast and re-fit it, again leaving the hinge and tabernacle without damage.

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    1. The primary point of failure in a dismasting would be the running stays. The secondary point of failure would be the mast directly above the mast heel/upper tabernacle hinge, where the aluminum mast is mated to the thicker-walled steel mast hinge. The part that would need replacement is the mast, which is an aluminum pipe. The old aluminum would be ground off the steel mast heel, and a new pipe epoxied on. If the masthead fitting (also steel) went swimming, a new one would have to be welded up out of a piece of pipe and some steel plate. There could still be serious damage from the broken mast flailing about, of course, because it would still be connected by all the running rigging, but most of the lines can be released from the relative safety of the cockpit.

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    1. Why on Earth would I want to do that? Suggestion makes no sense at all.

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  20. Your design makes me think of Pete and Annie Hill and the 34' junk schooner they built from a Phil Bolger design, Badger. Badger is almost a floating box. Pete and Annie spent years living aboard and sailed all over including the high latitudes. When a box heels over it has a v-shaped hull - on both sides!

    I've had several engines and by far the best is a Honda 9.9 long shaft outboard running on gas. It behaves as you would hope, is simple to fix and inexpensive to replace. Small inboard boat engines are crap and turn your home into an engine room.

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    1. I am familiar with those two. Badger wasn't a Bolger design, though. I recall it was a bateau hull with concrete ballast.

      I've owned two 9.9's, and you are right that they are quite excellent. I also hate small inboard diesels. Stinky, noisy, expensive, hard to fix... the list goes on.

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  21. This is a very interesting concept...Have you examined use of aluminum,or better yet steel,as your hull material?{the long swept curves would be cake to fabricate}...snuffy

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    1. The problem with aluminum and steel is that they require welding expertise, whereas QUIDNON is designed to be built by handy amateurs using basic carpentry tools. The fiberglass-over-plywood solution is a proven one, resulting in a cheap and very durable hull. Aluminum and steel are not thermally insulating; insulation would have to be added, at extra expense. Metals have greater embodied energy than plywood, resulting in greater environmental damage. For all these reasons, and a few others, metal is not a good choice for this project.

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  22. Even under the engine, this would be a rather efficient of moving cargo. I figure that it would be about 100 ton-miles per gallon; when fully loaded & ballasted, and running 5 knots per hour consuming a gallon per hour (10 horsepower). Not as good as a train, but not limited to tracks, either.

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  23. As a dentist my battles for longevity of my work have similar enemies to a boat: immersion in liquid, temperature shifts, impacts and pressure forces, organisms looking for habitat and food. Here are some of the questions that come to mind.

    If you are using copper cladding, will you use solder joints or some other way to seal out leakage? Will the plywood underneath the copper have its own protective coating? How will the copper attach to the wood underneath? Will different areas of the hull use different guages?

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    1. We are planning to use roofing copper. The thickness is determined based on a 30-year expected lifetime of a QUIDNON continuously in salt water. (We need better ways to calculate that; right now we are working off a few data points from people who have tried this approach before.) The plywood will be protected by a generous layer of fiberglass, thick enough to classify the boat as a FRP (fiberglass) boat rather than a wooden boat (which nobody would certify as safe or insure). The attachment will be using glue and either annular bronze nails or bronze screws driven into epoxy plugs. It is also traditional to user an underlayment of tarred felt. The edges will not be soldered, since that would introduce dissimilar metals into the mix, and galvanic effects.

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