Introduction: Designing and Building a Light, Car-top-able Outrigger Sailing Canoe [March 2016 Update]
[ UPDATED MARCH 2016, SEE LAST STEP -- WT ]
(Comment on the Photos: Short Dragon is a good boat, but it started rather heavy and gained weight as I added new features such as watertight compartments. He has undergone many revisions, but the revision to very light kayak-replacement and car-top-carried sailing canoe is impossible.)
There is an ancient saying: "You need a boat for everyday of the week." I am not so sure about that anymore, because you can be spread thin, as in, too much bread, too little butter, sort of the way Frodo felt after carrying The One Ring for too long. Apt metaphor. Our things can weigh us down and thin out our attention span. Buddhism is good for that trouble. But anyway, here I am thinking about another boat.
I have my reasons. Now, I already have a trailerable outrigger sailing canoe (you have seen "Short Dragon" here on Instructables). That will be retired as I build a longer one (a Gary Dierking design, Tamanu), but I suddenly noted something: I was often driving by scenic locations on visit back home, where I have always wanted to launch a boat for a day -- but these places were not trailer-boat friendly, or at least trailer-friendly. Therefore I needed a boat to go on the roof of my small car.
Don't you dare say "kayak." I have one, they are OK, but they are too ubiquitous and limited. I need something better -- which means of course, an outrigger canoe. This new concept would replace my kayak because the new outrigger would be light and paddleable. But what is a boat if it cannot raise sail? It is nothing. So now you get it: this is another chasing of the ideal of "the perfect boat."
Yes, it is an unattainable ideal, but I have figured out that if you have two or three "perfect boats" you have gotten as close as is feasible, unless you can sail in Plato's World of the Ideal Forms, and sadly, once there, you cannot move, because perfection implies that any movement in the Land of the Ideal is a movement away from perfection. The wind would be forever fresh but held in stasis, so too the wave, and you and your thoughts.... That world is just plain static, gleaming like a variegated crystal, no doubt, but motionless just the same. Good news! Our sad, imperfect mortal world is the only place to get things done.
I intend to get a little done. This instructable will show the entire process, from rough sketches, to finished product. I will be pissing off a few people because I will build this instructable in stages; my thought process and physical attainments will be posted bit by bit. Viewers may even influence the process with thoughtful comments along the way.
Step 1: Step 1: Dream, Talk, Sketch, Write, Reiterate.... Until a Vision Forms
(Comment on the sketches: The current in a series of increasingly more precise sketches, which tells you how rough the previous ones were! The two important ones are (1) the profile with bottom rocker curve (influences how the water flows around the bottom and where the center of displacement will be, and how much displacement), and (2) the cross-sectional profile setting the maximum beam at waterline and the character of the edges -- flat bottom to rounded bottom, which influences things such as lateral resistance, displacement, and surface friction = paddling efficiency).
I have nothing against having a new Instructable appear fully formed for the public delectation like Athena from Zeus's mind. I just do not want this one to go like that. I seem to think best when I think the public is eavesdropping. Self-serving, ego-driven? May be. And yet isn't it also another kind of method? One method, call it the "Athena is Born" method. Pretend the doer/thinker/writer lives a charmed life, linear, logical, efficient. Another method: show the dirty process, stop pretending it was ever just-so; leran a lesson from the genre of stream-of-consciousness. Well.
The dream started as a light boat to bring to the sailing/paddling/rowing expedition race known as The Everglades Challenge (www.watertribe.org). The contestants must be able to drag their boats from beyond the high tide mark to the water unassisted. They can have no shore support or resupply. They have eight days at the start of each March to get from St Petersburg to Key Largo, about 300 miles. (There is also a shorter event in North Carolina in September). Even for a "I am not a leader and not a follower" type like me, it is an inspirational event. I never win anything, ever. But I do experience. I wanted the experience, and to meet like-minded people and out-there people.
I started dreaming about a boat designed just for the race a few years ago -- fast and light, and able to survive being swamped and capsized, sailable and paddleable if the wind died. Outrigger canoes fit the need.
In 2009 I was invited to crew, but our boat sank after several hours from a leaky fitting. I thought my current boat would work OK, and towed Short Dragon there in 2011. I lost my rudder blade after 22 hours, and thought I was disqualified because I could not make the first checkpoint by deadline (wind in our face that first day, took that long to go 30 miles -- but I was wrong about the disqualification; note to self: read the manual better next time). But I learned something: having dragged my nearly 350 pound loaded boat to the water, and having had to recover after the abort, I knew that Short Dragon was not an EC boat.
The dream melded into the other requirement mentioned in the introduction: why not have a boat proper for an EC, but also good for those places where I cannot bring a trailer boat? I spent a few afternoons at my local bar (which is, the Barnes & Noble cafe), drinking skim lattes and doodling in my daybook. This "mission" emerged:
(1) light and plug-and-play -- a car-toppable, sailing single-outrigger to permit home-territory sailing and paddling from certain lovely shore parking areas that are not trailer-friendly (thus it does not replace any current trailer outrigger I will have); the parts must easily lift out of the cockpit, deploy, "plug" into the hull, and be quickly attached by lashings and cleats; similarly, the rig must be drop-in -- no stay or shrouds. Repeat: this boat must not replace the planned 20 foot outrigger with its larger rig.
(2) EC-adapted -- as the name implies, a boat I can bring to a North Carolina Challenge and/or an Everglades Challenge. For this purpose the light, car-toppable design permits easy beach-launching and recovery (and transport back to start-line parking area) whether things go well or ill;
(3) storable -- elegantly storable: the cockpit of the main hull must accommodate the ama (outrigger float) and akas (crossbeams), leeboard, and the sail on its spars (right now planned to be a 113 square foot lug and 10 square foot mizzen). Given the need for permanent stiffening bulkheads (which intuitively I thought should have no more than 10 feet of separation), that would limit the ama to 9 or 10 feet (also to be a glassed foam construction). For the EC, of course two inflatable 16 foot amas used during the 2011 Everglades Challenge are an option.
Now free the mind: sketch. Much must be planned: length (16 feet), width (19 inches amidships), depth (15 inches for the wooden hull, and some inches of shaped and fiberglassed closed-cell foam on the bottom: this provides efficient bottom shape and also flotation to permit a self-bailing cockpit).
To be continued.....
Step 2: Talk to Betters and Peers; Modify the Vision As Needed, But Do Not Lose Important Things
Step 2 in precise directions for people who are the movers and doers of the world:
Step 2.1 -- Talk to friends and colleagues who know your hobby/lifestyle.
Step 2.2 -- Take their good advice, be diplomatic with any advice that went awry in the telling.
Step 2.3 -- Reject some advice to remain in control of your project. Rejection should not be arbitrary, though it may not always accord with the strictest of linear science. But since the testing of alternative hypotheses is in the highest of scientific tradition (what philosophers call "abduction"), your final decisions sort of do take the best of many ideas (synthesis).
Step 2.4 -- Despite what I said in 2.3, formulate an honest apology + explanation to your colleagues,because you will be coming to them again, and they must NOT be discouraged.
Step 2 in a more relaxed and wandering mode for people like me:
I began on a "Noble Lie." That is, of course I already talked to people! We constantly stand on other people's shoulders. I've been talking for years. No doubt much of my new design incorporates the ideas of others already. I know the origin of my foam bottom right now -- it was gotten from John Wright aboard the sailing sharpie 'Laguna Tres' somewhere off the Texas coast, inside the Laguna Madre, during the Texas 200 cruising event, in summer 2012. I did not press the "mark" button on my GPS at the time, but I hope this attribution is good enough.
John was my skipper and boat-host for this 5 day sailing cruise, and you will not be surprised to know that we talked about boats sometimes. He has an idea for a new boat that will be a little like a scaled down racing boat he once owned, albeit with a modified keel that can kick up in shallow water, and an encapsulated foam bottom to insure self-bailing. That idea immediately went into my "EC Outrigger" scheme. In fact, he had incorporated the idea into a previous boat and found it good.
Eventually I post my plans to my outrigger canoe (proa) discussion forum. I am mostly worried about the bottom shape, but they were worried about all the other things too, as is right. In those days (months back from current date of ~April 2013) I was considering a 24 inch wide main hull, 16 feet long. This is what we call in the trade, "a fat outrigger," though ethnographic precedent does exist in Indonesia (checkout Tim Anderson's website "Tim Anderson's Home Away from Home," where one of his links documents his visit to a 'jukung' on the island of Madura).
I was trading speed, and a little weight, for comfort. I slept one night aboard my current outrigger, where my space (subtracting for intrusions such as ribs and hull curvature) was about 15 inches wide. I slept because I was destroyed after over 20 hours straight at the helm or paddling, and two previous nights of vastly reduced sleep at the public campsite at Ft Desoto -- I am still angry about that, you noisy drunk people!). In short, I learned I want more than 15 inches for a sleep deck.
If you say "fat" among proa-people, you might as well go all the way and say other offensive words. They want hulls with 15 to 1 length/beam ratios (so a 2 foot wide hull must have a 30 foot length). In fact, if you could have a 4 inch wide hull a 100 feet long, they would like that better. :-) ). So I had no bargaining position with my colleagues at all.
They talked me down to a 19 inch width -- just wide enough for my shoulders when I sleep inside, which is also a good snugnessness for when the boat rolls -- but maybe 18 or 20 feet long. I hung my head for two weeks over these changes. They are good changes -- that is a proper boat. But proper canbe problem. Paradox destroys comouter logic, but we humans do just fine with it. If you are going to have two boats to average out and approximate "The Perfect Boat," then one of them has to be worse than the other. And that is natural law.
I plan on having a 20 foot outrigger, kept on a trailer, and with a more serious (time-intensive set up) sailing rig -- therefore, my "light cartop-able sailing outrigger" must not be almost as good as the trailer boat. I hope you see the sense in that. A light 18-20 foot outrigger would not make me want to sail the other boat much. The other heavier boat will have certain advantages once rigged and in the water. Must keep those.
So by now you get that this step 3 is actually a long apology to my colleagues, since I have had ignore their good advice and keep to the 16-foot length -- but you convinced me with the 19 inches. Not so bad? The "important thing" I needed to preserve really was this sense of a minimalist outrigger that would give me a slightly different delight than the trailered outrigger.
(I'm sorry, I could not think of attractive and/or useful graphics for this step, but I may think of something later).
Step 3: Step 3, Continue to Obsess About the Shape of the Bottom
Efficient Step-by-Step Summary of Step 3:
(1) The bottom shape is important, so continue to obsess about it.
(2) Summarize the advice of various friends and colleagues on a sheet of paper. Cross out the outliers, discover the consensus.
(3) Un-cross-out the outliers, because the majority is not always right (also the problem of Democracy).
(4) Bring in the considered responses of professionals.
(5) After discovering you are no closer to the solution than you were before (engineering trade-offs mean there are many paths to the peak of the mountain), at least be happy that you are now better educated. Restate all the positions in a considered way.
(6) Consult the Cylons (or hull design software).
Wandering Detailed Version:
There's something about a good bottom, on both people and boats. It is an essential contact with reality. It is a plane whose relative position to other materials defines Time itself (for we need to see two things moving relative to each other to define Difference, which is Time). But be careful! As an instructive anecdote, I once slapped the wrong bottom. There was this girl, you know, in the college dormitory, her head stuck in one of those water fountains designed like a little cave, her head concealed but her bottom looking just like one from a girl with whom I had mutual bottom-slapping privileges. It was the start of the fall semester, I was glad to see her after the summer break, and yada yada, I made a pleasant and entirely supportive comment about her bottom and slapped it affectionately, and -- you have guessed this long ago -- it was the wrong girl. "Why thank you," she said, with an expression of surprise and curiosity. I turned green, she said, and the look on my face was reportedly worth the awkwardness. Gracefully she accepted my explanation and profuse apologies, and we would become platonic friends. That just goes to show....something. But bottom curves are critical in a boat, and you may generally run your hand along them, and should so do after asking the owner. .
Advice on the (hull) bottom has been difficult to interpret. Theories vary -- which will turn out to be the strongest? Designing a boat is a lesson in the scientific method. Here are some theories: (1) The curve of the bottom assists maneuvering; the hump of the curve is a "pivot of buoyancy." (2) On the other hand, if steering is too easy, the pilot is constantly trimming to the point of annoyance, especially if the hull keeps on turning from an initial disturbance, and the pilot over-compensates, and the boat leaves behind a long S-shaped wake. (3) A flat rocker assists tracking; an initial disturbance hardly disturbs the hull from its straight course. But when you really have to turn, as in tacking through the wind, then the hull is grumpy, slow to move, it “gripes,” (old sea-slang from the meaning, “to grasp” -- yes, the flat narrow hull does grasp the sea). (4) Efficiency must not be left out: surface friction, wave-making length and size (the length of the wave the boat makes at its top speed, the angle and size of the wake, things I will not much talk about because the wave length is set by the limit I set to my hull length, and a skinny hulls makes the least size (volume) of water in the water the hull pushes aside, and I don't know a lot of the angle of the two wakes except that it the wake of the main hull interferes badly with the wake of the outrigger hull, that sucks). (5) Summary: We must attain the balance of the sacred trade-off.
The efficiency is important, but our skinny hull is already reasonably efficient. Perhaps the fine points of hull efficiency will disappear when we are sailing in a good wind -- free energy frees us from obsessing. Yet it is more of a concern if the wind is light, and a definite concern if you have to paddle for long hours in a calm. The rounded bottom -- for me, at least good radiuses on the edges -- reduce the surface friction of water against hull (“wetted surface”) (the hull will sink more, though, than a square bottom, which has other effects). As well, the water must closely follow the hull and not break away in turbulent eddies -- these eddies (which you could see if you injected dye in the water at different points as the hull moved through the water) affect the pressure of the water on the hull (Mr. Long will speak more on that, below), and also represent energy expended in making the water swirl rather than just flow straight. Another thing to worry about is water crossing laterally (side to side), around the keel. So much to worry about! Blessed are they who just enjoy the day(sail)!
So we have to worry about water breaking away from the hull in all its dimensions, but I will simplify and divide it into the hull sides and the hull bottom. I think it was Phil Bolger who thought that, if the curve of the planform of the hull (the lines as seen from above the boat) were similar to the rocker (bottom) curve of the hull, then the pressure was more likely to be equal on all sides (water less likely to divert laterally across the bottom and mess up the straight flow; as Bolger might say in his charming technical-humor style: “No doubt in Paradise water flows in ideal lines around a boat and stays attached, but here on Earth...”).
Now, if we just worry about the water flowing longitudinally, we want to encourage the water to not break free and cause eddies. Sharp turns in the hull make eddies likely -- flowing water has momentum as well as pressure, so the momentum of water can carry it beyond a sudden curve -- just like when you are driving your car in a high-speed chase in San Francisco, and as the hill drops suddenly, the car leaves the ground. Good for people watching Steve McQueen, good for automobile repair shops, bad for everybody else. A skinny hull is least likely to have this problem in planform, but one with a flat bottom could be at risk. Bottom water must also leave the bottom of the hull with as little disturbance as possible as it slides off the aft. That’s why you are here seeing me obsess about the rocker curve -- who is worse: me, or you, dear reader, patiently experiencing my obsession? Anyway, have a look at the cartoons offered below.
The final thing about the effect of water flowing along a skinny hull is the fact that the crew’s placement of body weight (and cargo) on the hull can suddenly change many behaviors -- crew/cargo weight shifts instantly alter center of gravity and center of lateral resistance (not necessarily bad -- this is how you can steer a rudderless proa or a rudderless St. Lawrence skiff). Also affected somewhat, the nicely planned water-flow lines. To avoid despair we must assume that our weight will usually be distributed “just so,” thus the flow will at least 51% of the time be about how you wanted it when you planned the hull form.
I do not pretend to have a handle on all this, so let’s add the words of someone who knows stuff. Here is Roger Long, contributing to a thread on hull design in the on-line Wooden Boat Forum (sub-forum, “designs and plans”) May 2010:
“...Water is incompressible and somewhat thick so, when a boat moves forward, it pushes up a hump in the water around the bow. The water level is higher in this hump so water pressure on the hull under the hump is higher than normal and is pushing back on the hull. This is a major component in wave making resistance.
“The hump, as it falls back down due to gravity, turns into a wave. When operating near hull speed, the next crest of this wave is at the quarters. The water level around the stern is higher so water pressure on the run is elevated. In crude terms, the boat’s own wave system is pushing forwards on the stern. A more elegant way to say it is that the hull is recovering some of the energy it expended making the waves at the stern. It’s only getting back a small portion of the effort expended in getting the wave moving but it is enough to be a significant factor in overall resistance.
“Now consider the flow of water over the hull. It follows the hull fairly closely along the bow lines and around the midsection. Aft of the midsection, the water has to close in around the hull again and, if the flow lines are too steep, it can’t do this. The flow will then separate and kind of design a new “hull” for itself, leaving a space of turbulent water between the main flow and the hull that is largely moving along with the hull.
“Why should this separation be a problem? In the air, separation is often promoted as in the dimple on golf balls to reduce resistance. If the water isn’t flowing over the hull, there is less frictional resistance. The answer is in the wave train and the energy recovery from it.
“The wave train cannot “push” on the stern and energy cannot be recovered from it through a zone of separation. The stagnant and turbulent water under the separated flow insulates the hull from the higher water pressure of the wave train. Waterline length is such a significant factor in boat speed because of how it is related to the dynamics of wave making resistance. The boat’s length essentially ends at the point where a significant degree of separation begins. A 30 foot waterline vessel with a full stern and steep flow lines might then actually be only a 25 foot waterline craft. This is why double enders are often slow....” [I think he means here, the large monohull double-ended sailboats, with a squat curve to the stern lines.]
OK, let’s move on to what a computer program suggests about the bottom shape.
Step 4: Step 4, Consult Some Machine Intelligence
I hope you are as worried as I am about the way increasingly more complex and capable technology removes something from the human. I understand the daily hypocrisy I engage in, by the bye. I gladly take in all the Novocain my dentist cares to pump in, I happily mix batches of epoxy to enable my low-skill boat-building projects, and I love as much as anyone the way I can climb aboard an airliner and get to a foreign country quickly. But we humans must ever be paradoxical and hold contrary ideas in our minds: here we must admit too, that for every labor-saving device, short-cut, or computer-driven idea, the human has one less thing to do, one less thing we need to do, and one less thing we eventually can do. How to balance the convenience of technology and some desirable level of capability of the human, is one of our most pressing questions, second only to killer asteroids, and I hope someone does an instructable about that.
So I gladly downloaded the free version of "Delftship" software to consult it (really, its human designers, abstracted from reality) to see what it thought about the bottom shape. I'm not very computer-savvy but like the rest of you can generally make something work if it has drop-down menus (which subtracts our ability to know how to tell computers what to do, but what the hell, death to DOS!). I told it my hull dimensions and among many other pieces of information it gave me the shape in the first picture below. The curves (some toward the stem, and a greater sweeping curve up to the stern) form a common hull shape for modern small outrigger craft, especially trimarans, which you can glean from looking at a lot of them. Thus this rocker must be pretty much the recommended form.
The computer-generated bottom shape takes away more displacement than I had envisioned -- for day-sailing, not a problem, but for the Everglades Challenge gear-carrying requirement, maybe a small problem. I messed with the recommended lines (see the second picture) to add more displacement while maintaining the "spirit of the curves" but what do I know? I got back ~ 40 pounds of displacement but at the cost of screwing with somebody's formula for best bottom shape. As I said in the previous step, maybe the placement of crew weight overrides the finer points of these issues.
I may not lose as much displacement as I fear because the software produced a round bottom (see the third picture), and the form I sketched in my first step has a flatter bottom with large edge-radiuses, and also straight sides (the computer drew a very slight flare). I do not yet know how to ask the software to draw and calculate exactly what I want. I may not expend the time to learn how unless the manual makes it easy (yes, I did the first stuff here without reading the manual -- a bad habit I know, especially as I used to make a living as a technical writer). The rocker curve is more what I was seeking -- yet how would that be affected if the design were set to a flatter bottom cross-section?).
Here I remain at present. The workshop is now clear of the last small project (a kitchen utility bench), and now I can start making the workbench for the new boat, and get it into the garage, which is becoming warmer as the days go by. There is still time to think about that bottom as I set up the plywood topsides and get the basic planform of the wooden part of the hull (remember that the bottom will be stacked layers of closed-cell foam, epoxied and shaped, and glassed over). [I left this off at approximately April 2013, returned to it June 2013]
Step 5: Step 5, Re-Think Bottom Shape One Last Time; Get to Work
(Step 5, June 21, 2013) At the year's longest day we celebrate the highest point of the sun in its perceived travels and ultimate triumph over darkness, and brace ourselves for the next solstice when the predatory creature comes to swallow it down again. That is, if your myths stem from the high latitudes -- for others the sun is mostly just there with vague strolling wanderings. Anyway, this is a good day to continue this instructable. (And in this program I find suddenly my Enter Key does not function, so I have to shift to MS Word where it does -- why is that? Back in a moment....)
Executive Summary for Executives with deficit attention from too much social networking on web-phones:
(1) The design settled for has rocker moved a little aft, and a transom carrying full beam aft.
(2) Latest proposed dimensions (unless someone convinces me with logic otherwise within the next few days) are: 16 feet length (same), ~23 inches maximum depth of hull (15 inches depth plywood hull, 8 inches depth foam bottom), 22 inches max. interior beam at gunwales (carried through to transom), 20 inches beam at sole (now fully comfy for sleeping), 7 foot clear cockpit space.
(3) Keeping cockpit clear means thicker than usual gunwales to take leeboard stress.
(4) Bow and stern to be decked and watertight; some kind of scupper/bailer to be installed in the center open cockpit area.
(5) Still intend to have a cat-yawl rig. I love the mizzen on my current outrigger “Short Dragon.” I just got through a short but intense squall on my mizzen (was sailing 9 knots on it after dropping the mainsail, whose reefing system failed) with good control -- I love my mizzen! I could be convinced to drop mizzen sail area to about 15 square feet, but no smaller than 10.
(6) The aka/ama system (crossbeams/float) will probably be a permanently installed folding system rather than the plug-and-play I first envisioned.
Many Other Details:
OK, in the intervening months I have considered more advice about the canoe hull. As ever, advice from smart people often conflicts, the central irony for the intelligent creature. But I trust Gary most of all, who has thought that a rocker somewhat like a Farrier F22 is good (see photo below) and further, to carry the beam all the way aft. That is, the boat is to have a transom, which will help dampen pitching. I was convinced further that a 22 inch beam at the gunwales and 20 inches beam at the sole will ensure comfortable sleeping. The F22 rocker curve seems close to the one I modified intuitively from the Delftship model. The 22 inch beam is a compromise with the 24 inches I originally posited, so the hull evolves to the average. The first photo of my hand-drawn scheme reflects the current goals.
I assume that the hull will still be skinny enough to not have a broaching problem (when a following wave lifts up a high-volume (=high buoyancy) stern, pushes the lower-volume (+ sharp) bow down, and might make the bow catch water, spin the boat, end in a few variations of unpleasantness. I also hope that the transom will not drag, which will be mostly a function of where I sit and stow the heaviest cargo.
By myself I resolved to make the foam bottom 8 inches thick at the thickest -- depth at bow a bit less, and depth at transom curving up (due to rocker) being 15 inches, or the depth of the plywood part of this hull. This desire comes from my experience that an outrigger with 24 inches or slightly under depth amidships is fairly seaworthy, drier at least than the kayak-outrigger-sailers (all due respect to the very effective Hobie Adventure- and Tandem Islands), and still able to be paddled well enough from that height.
One final change, is that I think a folding-aka system will be better than a system wherein all the ama and aka parts stow inside the hull. This concept now allows the ama to be longer = better for the speeds and style at which I will sail. I didn’t think I could well stow an 8-foot ama in the cockpit with the bracing needed. A folding aka system (and I like the one on the Brown/Marples Seaclipper 20) will allow a 10 or 11 foot ama to fold alongside the canoe hull. The folded beam should be about 4 feet, maintaining the car-topping requirement. In any event, the ama-akas can change far more easily than the hull itself, if I don’t like.
But enough! “The job never started takes the longest to finish.” I have to commit or never get this boat done and tested by march 2014 (when I hope I can attend the Everglades Challenge). Time to live with results rather than worry about them.
This week I cut the bow angle (shallower angle than Short Dragon’s -- I can increase it if I change mind, but not after I add the bottom panel (sole) to which the foam bottom will be bonded). I also cut a form to bend the topsides around, and a transom form to eyeball the hull. (See crappy photos below; the in-garage perspective is not great). I used brace-sticks to stick-out the hull forward a little.
My next step should be to:
(1) Use the mock-up bulkhead form (center in photos) to create the permanent transom and the two bulkheads that will be set where the akas (cross-beams) will rest. The transom and aft bulkhead would remain at the current dimension of 15 inches deep, 22 inches wide at top, 20 inches wide at bottom. The bulkhead under the forward aka will have to be considered again -- I am not sure how the lines converging toward the bow will look when a bulkhead is set there. And,
(2) Make gunwales and chinelogs from scarfed pine strips, and glue to topsides. (the gunwales will eventually be thicker so that I can have a clear cockpit -- wider gunwales will take the place of the ribs this kind of hull cannot have, and will take the strain of the leeboard as well. People who are familiar with the gunwales on the mostly clear open hull of the Bolger/Payson “Windsprint” will know what I mean).
(3) Now spread out the hull sides again with the bulkhead forms to check the lines. Adjust as necessary.
(4) Drill holes to wire sides together at the bow; figure a way to clamp on the transom (might have to screw it on), insert permanent bulkheads; epoxy them on.
(5) Scarf plywood into the bottom, trace the planform, cut it, glue on the bottom.
(6) Move on to finding high-density extruded polystyrene foam slabs (3 pounds per square inch capacity, says Surfer Steve’s website), laminate with a center plywood web cut to the rocker curve, and shape the foam into a nice bottom to be bonded to the plywood part of the hull. I had better practice this on a quick-and dirty-safety-ama for Short Dragon -- have never done this before.
But will the design still be coming in under 100 pounds (minus the rig)? We'll see.
Step 6: Some Progress, Some Changes to Original Plan (8/20/2015)
Hello -- Apologies to people who expected much more from me. I am lazy or distracted with too many other projects (a job, a novel, a novella, fieldwork notes from folklore studies, and my girlfriend's adorable grandson whom I love like my own kin), not sure what ratio of which, but it all ends up the same (and laziness is a kind of hobby when done properly). This boat is alive and well, but like breach birth, is taking some time to be born.
Changes to the last idea I had:
I reasoned that the most miserable times I had in Everglades Challenge 2011 were when I had to paddle in the calms. My current outrigger "Short Dragon" is just too massive for this, attaining 1.7 knots a rate that could be carried on for hours. I have explained why in other places, but to save you time searching them out, (1) that outrigger started as an open hull built with cheap heavy materials (Douglas Fir), then I glassed the hull over in 9 oz glass, added two more layers to the bottom, and glassed the inside bottom and up to waterline also -- very rugged, and very heavy. I had chines, two stringers, and gunwales = more solid wood. In later years I added three watertight compartments (with decks of course) and more glass, and you know what that means (good seaworthiness and more weight). The ama was heavy because it started as a proa ama (where weight is not too bad of an idea) but I sailed it as a tacker, so I ought to have made a lighter ama. The main hull is flat-bottomed, the ama is a deep-V, which add some inefficiency against human power (not so noticeable when sailing in a good wind, and inertia (weight) can be good in a chop).
OK, so when I was designing this light outrigger, I was solving some of these problems, but also I was going with a transom for volume aft, which is good for a powerful outrigger or trimaran that is expected to go fast. Then I thought, I am not really a performance-obsessed sailor! I attain satisfaction at 5 knots, happiness at 6-7 knots, and excitement at 8-9 knots (and some nervousness at more than 9 knots in a 16 foot boat alone at sea -- I have to admit, I am nearing 60 years old and do not react or recover as quickly as I used to). I will not be putting a huge rig on this new boat (a 16 foot Hobiecat catamaran has over 200 square feet of rig!). When the wind is good, I know I will be happy, and this will be a much lighter boat than "Short Dragon" so I ought to attain satisfaction/happiness speeds a bit more often. Therefore, it will be for the light winds and the paddling times I will want the boat to offer least resistance.
Keeping other aforementioned dimensions the same, I made the stern plumb and pointy. The bottom will still have the foam-and-glass bottom with 6 inch radii on the edges, and a total of 6 inches of thickness (down from the previously planned 8 inches) though of course this will mean less volume aft and less overall safety buoyancy. I think the safety factor will be enough, however, because 5 feet of the bow and 4 feet of the stern will be decked over as watertight compartments besides the foam bottom. I should be able to open a bailing device on the aft-side of the cockpit and sail out from under a lot of water that might get inside, besides pumping/bailing.
The basic hull is done (~16 feet long, 15 inches deep amidships, 22 inches wide at top, 20 inches wide near waterline). I have just cut the sheer web with the rocker curve in it, and must now glue on the foam slabs, glue the unit to the plywood bottom, shape the foam, and glass the entire hull over on the outside (multiple layers over the foam).
The rocker curve gave me much anxiety. I worried overlong about it, perhaps. I relied on advice from expert friends as well as people on the Wooden Boat Forum. I settled on a 5 inch rocker curve aft, 4 inches toward the stem, favoring full depth one station aft of amidships. I got a method to draw this curve that involved drawing two curves with a very long batten (which I did not have, you really need a table saw and prime quality wood to make a good batten), and then fairing those two curves together to attain that differential rocker. I confess I finagled that a bit. Perhaps the result will be OK given that a small skinny hull is much affected by weight distribution -- put your peanut butter sandwich down to do something and the attitude of the hull and water flow over the bottom changes a lot :-) Anyway, it is settled.
Not worrying about the rig ovemuch yet. Short Dragon's cat-yawl set-up could transfer right over (though would also carry over shrouds and forestay, which I may not be happy about). I also have a 113 square foot balanced lug -- a bit big maybe -- I could have a ~85 foot one built (we do get a lot of light air in New England). I gave away Short Dragon's old 56 square foot standing lug mainsail (in thanks to the man who loaned me his Puddle Duck boat for the 2014 Texas 200 -- check out my write-up about this trip in Duckworks Magazine on-line; it should be out in Fall 2015) but I could buy another one, and it might be enough for this lighter boat along with the 20 sf marconi mizzen. I really love the sail that Meade Gougeon uses on his "Voyageur" sailing trimaran-canoe; so far the one sailmaker I asked about building such a thing never responded, but I will try again.
I am still keeping with the plan to build the folding crossbeams. Whether I go to a trimaran configuration is a question I will address later. The boat will start as a single outrigger with a modest sail plan, and I will see how often it almost capsizes -- then sail plan can change, or configuration. I will make a safety ama but will probably test without it at first. A safety ama tends to become a quasi trimaran -- it has on Short Dragon -- unless you raise the safety ama far over the water, as you see done on the Hawaiian outriggers. I wonder what that does to windage? How will I enable early tests and decisions? I will leave enough crossbeam opposite the single-outrigger configuration so that I can add a full-folding-trimaran option, or just go with a safety ama. It is easier to saw off than add on; anyway, the protruding crossbeam (about 18-20 inches I'd guess) is still useful to put a pole across to take a side seat (or last least a place to hold on to and lean out), and leaves just barely enough room to paddle.
Pictures of the hull and sheer web (rocker curve are shown in this step. The basic hull (without the sheer web or the foam bottom that will be glued to it, and without the fiberglassing) is about 70 pounds -- a little heavier than anticipated. It has to get heavier -- not just because of the bottom and glass, but also bracing to take the leeboard stress (double gunwale? laminated frame or two?), the decks over bow and stern, mast steps, and what else?. And the 7 foot long open cockpit is flexy (glass the inside? frames and double gunwales for both sides?). The basic hull simply will not be under 100 pounds, I suppose. Oh well. The ama will be foam and glass and I hope not over 25 pounds. The cross beams must be as light as possible -- maybe spruce or sitka spruce, or box beams. 150 pounds total? But the rudder and leeboard and rig must be added then. Ah! Such is life.
That's it for now. Back to work.
[UPDATE, MARCH 2016] -- The project continues, slowly as ever. I thought I should get some practice building foam-and-glass things for boats, so I took a side trip to build a safety ama for my current outrigger "Short Dragon" (which already as a v-hull safety ama added last year, about 40 pounds of additional weight :-( ). This ama will also be used as a safety ama for the "light car-top (?) outrigger" being shown here.
Now that I have made enough mistakes on my first foam-and-glass ama (one of them was using paint thinner to clean it: DO NOT USE PAINT THINNER TO CLEAN FOAM -- IT WILL HISS AND MELT THE FOAM! I HAD HOURS OF REPAIR WORK TO DO AFTER THAT. DENATURED ALCOHOL SEEMS TO BE OK THOUGH), I am about ready to install the foam bottom on the main hull of the new boat.
After a simple experiment with scrap foam, I decided to do this: lay the slabs of foam on the bottom without the sheer-web (which defines the rocker curve and adds a keel-like strength to the foam bottom), epoxy it on, do the rough shaping, and THEN cut a slot down the centerline with a saw, hog it out with a bastard file (the same width of the plywood sheer-web), clean out the slow, and finally slide in the panel and epoxy in place. That seems a little simpler (despite what it sounds like) than trying to bond the foam slabs on either side of the panel (use your imagination for what can go wrong).
I have rethought the cross beams and folding system. I think I will spring for T6 aluminum tubes (Dwyer Mast Co.), 2.5 inch diameter for the hull-mounted ones, about 3.5 feet long, and 5 foot long 2.25 inch tubes for the cross-beams. These can then telescope inside the hull-mounted tubes to produce a width of 5 feet, which I think is acceptable for car-topping on a rack as long as the boat is light enough for that. That width makes better sense for trailering, too: I am pretty anxious when I tow my current outrigger (8.5 feet wide with the safety ama telescoped in) through city traffic to get to the ramp at New Haven.
Now that I am clearly getting too many boats for my tiny and inconvenient laid-out yard, I will need a separate trailer for the light-outrigger -- perhaps an aluminum Castle Craft type, making the whole system easy to move around and up the incline of my front lawn (this is a back-breaking effort for the current boat on its LoadRite trailer when I stow boat on front lawn for the winter).
And that's the update for now -- WT