Total noob. Small plywood sailboat questions.

Speaking for myself, I put my boats in the water for a few hours at a time, freshwater lakes only, I store them insde most of the time, or upside-down on the beach for a couple of weeks at a time on vacation. If this also describes your intended usage then my methods may be applicable.

I dislike glass fiber and minimise use of epoxy. Titebond III is an alternative see http://www.boatdesign.net/forums/wooden-boat-building-restoration/titebond-iii-testing-27019.html. I use marine ply for all planks. For a simple flat-bottomed boat I fasten the chines using chine logs which are narrow wood battens about 4 times the thickness of the ply: these are first glued to the side (sheer) planks while flat using Titebond. When the bottom is glued on I use epoxy as this joint alone is exposed to water and the paint can wear at the chine exposing the wood and glue line; in addition this joint is difficult to fit without at least a small gap, and epoxy can handle gaps whereas Titebond cannot.

I do not glass or epoxy coat my boats, I find paint/varnish is sufficient protection given the conditions they work in. I make sure they are exterior grade: I use house paint sometimes, it lasts for years on a house exposed to far worse conditions than my boats run into. I check for and patch scratches about once a month, don't usually find anything. My first boat ws left outside for an entire Ontario winter; it had only Titebond III, no epoxy, and was fine in the Spring, except the pressure of the snow on top of the boat which was stored on its side caused slight distortion of the gunnel. I protect the "wear locations" on my boats, using brass stem bands on all stems and small skids (skegs) to absorb impacts at corners and edges.

This is not the construction of an heirloom quality boat of course, but they seem to last quite well. And of course, the time saved by not coating with epoxy and glass fiber, with the interminable sanding required for a decent finish, is considerable.

 

AK, I know what you mean. I used titebond II for the crib and it worked great. (the short open time makes glue ups quite frantic though). I'm just worried about getting water into the end grain of the plywood and epoxy seems like the ideal solution. But yeah, I'll probably only be sailing a few hours at a time, or maybe if we like it a lot, we might cruise along the shore and camp out overnight (we'll see).

I have another question now, one that's less stupid than the former ones. Since I'm not gonna be mooring this, I'd like to get the simplest rig to set up and take down in the fastest amount of time possible. I don't want to spend a long time messing with riggings, I want to get off the ramp and sail! Is the bermuda rig practical for me? Or should I maybe think about something else? I kinda like the lug rig for the fact that you can leave the sail attached to the top and bottom spars and just connect those to the mast, right?

If I do build the Falcon, I assume that I would be highly advised not to change the rig setup without getting a designer involved, because that would mess up the aero/hydrodynamic interactions stuff, right?

Anyway, what rig do you guys recommend for fastest/easiest setup and takedown and trailerability?

 

The free standing, sprit boomed, Bermudian with a sock luff (sound familiar Terry) is about as easy as they come. The sail can be rolled up around the mast. Of course some will argue in favor of the free standing lug or other arrangements, but the rig I've proposed needs the least amount of rigging and spars, plus produces the best sail plan form to maximize performance potential.

Placing a new sail plan on this design would present no major challenges, but it would require some skill to get it right. You could use the rather imprecise method of installing an adjustable mast step and partners, knowing it will need adjustment come launch day. If you place the CE of the new rig, 8' aft of the stem/deck joint, you'll be close enough to adjust after launch.

This also gives you the option of lopping off the bow sprit, which is a good thing too.

 

I am just starting a small sailboat myself (a tiny perfect design from PAR, actually). That is a catboat, one sail, unstayed mast, two mast step locations for small and large sails, initially I will use a spritsail but later ... well, we'll see I don't have a lot of experience yet in this field but I can pass on what I have learned so far.

Generally if you don't understand the theory you will be advised not to mess with the existing rig. I would suggest as a general rule, keep the center of sail area at the same location fore and aft, and don't increase the sail area or rig height until you have tried the boat and have a feel for it.

Earlier you asked about stainless steel vs silicon bronze screws and bolts. SB is appropriate for top of the line sea-going boats. I think SS is OK for your purposes. Lots of people have used ordinary galvanized steel screws. I personally prefer brass for appearance, it's much weaker but for me the fasteners are to hold the boat together while the glue is setting. I pay a lot of attention to good joints and you clearly have the skills to do that.

I have noted that an overstressed glue joint, once it has started to open up, can fail catestrophically, virtually unzipping, which could cause a massive leak. I had one start to fail like that on my first boat, a canoe, but when I stopped kicking it the water pressure virtually sealed it again. While that might happen on a canoe it might be a different story on a sailboat, which is stressed more. I believe leaving the screws iin place will limit that to a manageable/survivable leak but it's only a theory. What I do before each new build is to make samples of every critical joint in the boat using proposed materials and test it to ensure that the ply breaks (across the thickness, not just delaminating).

 

Wombat, the problem with these free or low cost plans are many fold. First off is the plans are usually quite dated. This doesn't mean they're not good, but it does mean the methods and particularly the materials may be difficult if not imposable to find today. It also means newer products, especially adhesives and sealants aren't incorporated into the design. You also don't have a person to call or email if you have specific questions about the plans.

For example, if that was a modern design, one say done by me or other contemporary. It would likely be taped seam construction. This would eliminate the frames, floors and most of the interior structural elements of the design. That's a lot less building to do, not to mention materials to buy.

If it wasn't a taped seam build, it would probably be a longitudinally stiffened build. Using plywood to best advantage you can still have a fairly traditional build, meaning little to no epoxy, but still have no frames. Just bulkheads, partitions and stringers, which the plywood is fastened to.

In this size range there are lots of plans available. Taped seam, plank on frame, whatever build style you'd like to try.

For your uses, stainless steel fasteners will be fine. It'll be dry sailed and on fresh water, so you're okay.

A lighter boat doesn't mean it's less stable. A simple analogy would be to ask if a Mini Cooper is less stable then a big Chevy Impala. The Chevy weighs twice as much, but it's not more stable because of it. Boats are similar. Small boats by their very nature, rely on crew placement to gain needed stability. Some are better at this then others, but nothing by the numbers I see for Falcon would suggest she's a tender craft. In fact she appears quite the opposite.

http://www.bateau.com/studyplans/CR13_study.htm?prod=CR13

This design is much better.

You may also want to look at Glen-L 13, 14 or 15 (www.glen-l.com)

Then again maybe one of mine.

 

Is that what they call the leg-of-mutton rig? or do you mean a sprit rig?

As I've been looking around at different plans, I really do like the catboat style. It looks pretty easy to sail and I like the wide hull. That's probably why I liked the Falcon, since it was kinda similar to that. I looked at the "Instant Catboat" and I may end up going with that one, I like it so much. The Gaff rig looks kinda complicated, but if I install the mast on a tabernacle, do you think I could just leave the sail rigged while I transport it? I also like the gaff rig because if I'm about to capsize I can just release the peak halyard and I hear that will right her every time.

That's good news! That'll probably save me a few hundred dollars in fasteners.

Whoa, sounds like there wasn't enough glue on that joint. That's good you test them now to be sure joint is stronger than the wood around it. The worst thing that ever happened to me like that is a molding came off a cabinet. My wife wouldn't be happy though if a seam just opened up while we were out on the lake.

Yeah, I figured that when they suggested covering the deck with canvas and painting it.

I definitely do like the stitch and glue method, mostly because it saves on weight. It'll be a lot easier for me and two women to wrestle with a 200 lb boat than one that weighs a quarter ton. That's how big my planer/molder is and it's a monster to move around the shop, even on wheels. The decrease in materials is nice too, but I like working with white oak anyway. It will save money though, which is a really good thing.

I see. I just wondered, because a mini-cooper doesn't have several hundred foot pounds of overturning moment trying to flip it on its roof when the wind is blowing at its side. LOL

I agree. That is better. You know, I did look at the Glen-l boats and I liked their shape a lot, but I couldn't figure out if they were traditional construction or stitch and glue.

Yours is nice too. Can that center board be raised though? And what about the rudder. Beaching will probably be something I want to do, if say we go to an island for a picnic or something.

Looking at the sections, I think I may be warming up to the flat-bottom style. I liked the V bottom at first, because I think it probably sails better, (is that even right?), but the flat bottom would sure be easier to walk around on without having to build a floor.

 

Chine joints are unlikely to open up using the taped seams construction because they flex a little. Use of screws in the chines does not apply to taped seam construction. Using chine logs provides me with a stiffer hull and lets me use less frames, but can lead to stress concentration at the chines. The seam that failed was on my first boat which was made with door skin, very cheap ($10/sheet) luan ply that I no longer use. I didn't anticipate the seam would react like that to stomping inside it; that put a peeling force on the joint, a glued joint's worst enemy. Everyone told me to use marine ply and I do these days, but back then I wanted to build boats for as few $$ as possible until I learned the craft. I also wanted to design my own boats so I didn't expect my first boats to be much use. Experience, embarrassment and pain have been patient teachers.

Speaking of covering the deck with canvas and painting it, there is an article on that in the current issue May/June 2009 (#208) of Wooden Boat Magazine, so it is still being done.

There are a lot if advantages to the flat-bottom skiff. As you noted, it comes with a built-in floor. It has to be the easiest way to build a boat, although you may get arguments about that from the skin-on-frame faculty members. Stability is a given of course, and I understand skiffs sail respectably since they shed skin area as they heel, and there is more usable internal space than other boats of the same overall size. I have done stability analysis for the tiny 10 ft long skiff I am starting, and that indicates that theoretically I can stand anywhere within the boat without overturning it, except possibly the extreme bow but the deck will make it impossible to stand there anyway.

I have decided to install buoyancy tanks along each side which will double as seats, so in practice I won't be able to stand right at the gunnel, so she should not move underfoot very much at all. The tanks can go all the way up to the sheerline on such a small boat eliminating the need for side decks, they will stiffen the lightly-built hull and prevent me stomping too close to the chine joints.

 

Hi Wombat, if you still interested, take a look at http://www.dinghy.pl/ there are a few free plans easy to build, and they are light weight, you can contact the designer by mail if you do have any questions.
Good luck on your project.