Building a boat for the first time

[andrew_busch]

Hi guys,

I'm completely new to boat building, in fact I had to search wikipedia to figure out what "epoxy" and "port" (the left side of a boat) was today.

So now that you know more about me, I'm planning on building an extremely minimalistic boat - so much so that it could quite practically be called a "coffin", based on it's shape and... external impacts (hopefully not). It just needs to be able to float and drift around in a swimming pool, and if it ends up being a success, I may consider taking it with me when I move back to my home country, in which I can go sailing/rowing around the marina.

Now I have these nice sheets of plywood, particularly 3 0.7m X 2.5m ones - two 8mm and one 16mm. So I'm thinking that I could make a very basic two chine (bet I'm using that wrong) boat, like this: \_/ or: |_|. I think angled sides would be better, as it may lessen the claustrophobia of being in a boat that small. I was planning on chucking a piece of timber at the joints to beef it up a bit. Oh, and for the front, I'm going to keep it perpendicular to the water, and I got some other plywood planks and thin sheets that I could use there.

So as you can see, I got this down, except for most of it. Now for the joining, I was thinking that nails wood be good enough. But I realize that you can't just nail together pieces of wood and expect it to be sea worthy, so how do I seal it? I'd rather use something that hasn't got any health risks in both the construction and the usage, and is also cheap and easy. I heard paint can suffice.

So overall, how is my current design? And how do I do a simple job with sealing for a basic plywood frame boat?

[alan white]

Nailing the boat would work fine, but do you have access toi boat nails? Otherwise, galvanized nails will hold it together for a few years, and they are cheap.
the section you "drew" (cleverly, I might add) shows a dory shape, and in fact, a small rowing dory might be the perfect start for you. Google "banks dory" and you might even find a free plan or two. 3-4 meters would be about right for a small rowable dory, but if you want to go really small, you may need to go with a semi-dory to have enough volume to carry any weight. A semi-dory has a wider stern. Then 2 1/2 meters is possible.

[Rhinox]

try googling "South Haven Dory". I think you'll like what you find.

[andrew_busch]

I've had a look at the suggestions you've given, and yes, I do quite like the south haven dory. However, I've noticed that pretty much every boat design incorporates some sort of curved wood, which somewhat intimidates me, as I've never done any sort of woodwork like that. Is curved wood virtually a necessity, or can a boat with a side view like: |_________| or \_______| be ok? I don't really have ages to build this, as it's more just like a fun little project for a portion of a week off, so I'd rather a more simple design, but then again, having a good boat would be very nice.

[alan white]

I disagree with the idea that a highly comprimised shape like an oblong box has merit as a first boat. At a certain point, one might as well buy a boat. After all, what then is the purpose of the building process?
Most of the work involved in a curve-sided boat is in designing it. Purchase a design.
Otherwise, you will be stuck with a jon boat, which can be built without curves. Maybe that kind of a boat is satisfactory and it does have its uses. It is strictly a protected water boat. It has a dead flat bottom and somewhat (10 degree) flared sides, and the sides are generally parallel. The underside of the bow can be a simple 45 degree angle, and the transonm can be a 10 degree angle.
I encourage you to create a shape that has some curves. After all, that's what makes the project satisfying, which is the benefit of building something yourself. It's not to save time or money.
A dory is very easy to build, and its curves make the structure stronger. and compare rowing a dory and rowing a jon boat and you would choose the dory every time.

[andrew_busch]

Hmm... true, I suppose I can't really call it a boat if it doesn't go much further than a wooden crate.

But considering that this boat will probably spend most of it's time in a pool, stability is definitely favoured over speed in rowing. However, I wouldn't mind it being rather decent at rowing. So I think a mixture would be good, i.e. very stable, but quite decent regarding it's flow through the water.

Wait, I think I didn't fully understand the definition of a dory. It has the side view of \_____/ and a cross section of \____/ but a bird's eye view of <=> (more or less), right? I thought the bottom was curved, so it was like a banana... . Then in that case, I think I'll attempt at a simple dory. However, I'm not one to buy plans, and even getting a complete plan for free would make me feel not content. I'll probably try my hand at writing up a plan, hopefully I know enough trig and geometry to do it all. I'll still definitely get a lot of guiding here, as I'd rather it work than not.

For the sides, would a sheet of ply be ok, or should you do plank by plank? A sheet of ply would be harder to get right, but if you did, it'd be quick. On the other hand, I'd imagine that planks would be easier to plan but more work.

[alan white]

i don't know what you don't like about plans, at this stage in your aquaintance with boatbuilding; I won't judge your decision, but I'll tell you I don't recommend it.
I am building a dory this year and I will absolutely use Phil Bolger's plans, pay the $25.00 and know I'll be building one of the most refined rough water rowing machines ever designed.
Nevertheless... plywood is the way to go--- easier to build and own. If you must design your own boat, do a bit of research first and closely copy something that actually has been built.
Many of your questions are easily answered by your reading online or by getting a couple of books out of the library. Familiarize yourself with how dories go together, look up prices for materials, and generally bone up on the subject. I could certainly answer questions for you, but to be honest, it's much more efficient for both of us to deal with questions you can't easily find answers for.

[apex1]

Andrew
let me blow the same horn as Alan please.

I build some 18 to 30 boats per annum, and if I would build me a dory I would purchase some proven plans first, even if the boat would be built by one of my skilled shipwrights then.
You waste time and money trying to design it yourself.
Regards
Richard

[rasorinc]

Good posting Richard. I always tell them we will buy a proven hull and then topsides and interiors we can customize. Also can lengthen the hull within limits set forth by the N.A. Best, Stan

[PAR]

Andrew, considering you're extremely limited knowledge of building concepts, design principles and engineering applications, you'd be best advised to heed the notions of the other posters here.

In other words, if you have to look up which side of the boat is to port, then you are grossly unqualified to consider designing that which you clearly haven't a clue about.

Would you travel in an elevator that was designed by a person, who had to look up "retractable doors" before the process could begin?

[Ike]

I agree with Par to a certain extetn. You need to know more about what you are doing. But, a good way to learn is building a boat from plans you purchase that have good instructions and building notes. Actually from what you have said so far a dory sounds close to what you want. But why don't you go for a drift boat. It's very similar to a dory and simple to build. look here http://montana-riverboats.com/.

Once you know more about it then you can start kicking around ideas for your own design.

[andrew_busch]

I'll give it some thought wether I'll actually use plans or not. However, I'd like to point out once again that this boat is for my pool, so there isn't any risk in deaths, and I won't allow someone who can't swim to get in it.

But I think it would be best that I do some more research and reading into dory boat designs, as I think that would be the best design to go with. It's holidays for me right now, so I'm not sure if my school library is open, and if it even is open, I doubt it'd have that information. So I think the internet is the best way to go for me... . I'll do some research, and post again here if I need any more guidance.

Thanks for all the advice!

[Ike]

Not to be sarcastic but do you have any idea how many americans drown in pools every day? 6 every day. It happens to be the 4th leading cause of accidental death in the US.

My point is just, because you are going to use this only in your pool doesn't mean you shouldn't do it right. And you get the added benefit of being able to take the boat to the lake or river.

[andrew_busch]

I still don't think that I'm breaching moral code by making a rubbish boat, or being dangerous either, as I myself am on my school swim team, and once again, it's just for a pool and I'd make sure that everyone who goes in it can swim, unless I do actually make it well of course. Still, I'd be very cautious, so don't worry.

And I do want to do it right, it's just a question of how well. Like of course the ultimate would be to make a beautiful, large dory that I can bring back to Australia and use to row around in the sea, and lasts me decades, but there's no way that I'm going to require that level of quality. I simply want a boat that will be very hardy for calm waters like a pool and will last a bare minimum of a couple of months. I'll take it out of the pool when I'm not using it too, so yeah, I don't demand much at all for this boat.

Anyway, I've had a look online at methods of building dorys, and so far the most popular method seems to be the stitch and glue one, using epoxy and fiberglass strips as the sealant and also for strengthening. Is it necessary to do it this way? What are other methods with a similar or lower degree of simplicity for a plywood dory? I was thinking that screws could be used, and maybe something like silastic and a good oil-based paint...

[PAR]

Glued lap produces a prettier dory, uses much less epoxy, one the chine seam is taped and is lighter.

[andrew_busch]

What about the boat builders from the middle ages? What did boat builders use before epoxy wasn't around?

EDIT: Caulking was the method they used, right? And the modern day equivalent is still popular, right? How about using 3M 5200 as a sealant, then putting on some good oil-based paint all over the boat? Would that do?

[alan white]

Most recently, resourcinol was (and still is, but fits must be near perfect).
Middle ages? Tar and pitch I guess.
I've seen PAR (who appears the most experienced in this area) recommend polysulphide sealants for seams, and there are polyurethane formulations that are made for lap seams. It's no problem sealing seams with a non-hardening adhesive caulk, but epoxy makes a more rigid structure, and obviates the need for ribs.
If you use a caulk type adhesive, you may need to stiffen the hull with ribs to compensate for that loss of rigidity.
Often, changing the construction method entails a redesign, usually by a good designer who can analyze structures.

[PAR]

Up until relatively recently all wooden boat structures relied on a structural support system that permitted some "movement" of the various pieces. This movement allowed neighboring structural elements to share common loads and spread them throughout the framework.

This building method is tried and true, but not without good and bad points to consider (like everything else in yacht design). The good things are surprisingly light, strong and long lived boats can be built this way. The bad, all this movement eventually leads to leaks.

Leaks where a common aspect of all boats, from the day they were launched. Log books from the late middle ages, when Columbus debated crossing the ocean, clearly show how much leaking was accepted as "normal". A new boat, not yet over worked could be expected to have to have the "pumps manned" for 5 to 10 minutes every hour. A well worn boat could ask for 30 to 45 minutes per hour of pumping. This was noted in the log and was part of "ship's business". In fact, The Santa Maria required 30 minutes per hour during her crossing. The Pinta was a new boat, considered a fairly high tech departure from the current trends in caravel merchant vessels of the era. She required 5 to 10 minutes of pumping during the same crossing.

They used a number of things in the seams of these vessels, most less then satisfactory, by modern standards. In short, if you want a traditional build, then don't be surprised if you find you have to bail it out every so often.

With the advent of better glues in the later half of the 19th century, structures could be engineered differently. Molded hulls, strip planking and other construction methods took hold.

Once truly water proof glues came to be during WWII, everything changed. Now truly "homogeneous structures could be built with tremendous weight and frame member count savings. These types of builds rely on entirely different engineering methods and the two aren't very compatible. As a result, a design from the very start is determined to be one or the other.

Designing a small boat may seem a fairly easy prospect. It's deceptively not so. Small craft are very weight sensitive, even if just used in a swimming pool. Engineering structures strong enough to support itself, the folks sitting in it and the water pressure outside the hull from crushing it like an egg shell, can be an intimidating set of convoluted complexities, especially if you want to be able to lift it by hand.

It would be nice if it floated where you painted the waterline, for example or with the trim (bow up or down) as you hoped. Developing enough internal volume to carry the folks you want it to, without flipping over and getting everyone wet would be an extra nice feature as well. Even in a pool, all the hydrodynamic requirements apply. Will you be able to climb over the side or step on the rail, without being rewarded with a clunk on the head as it flips belly up and other stability questions should be a major consideration.

Do I think you can do this? Well, frankly no, at this point you're education on the various subjects isn't sufficient. Can you? Well of course you can, but you'll need to do some basics, possibly with the help of a designer.

The other option is to down load one of the public domain designs and staying very close to the shapes, modify it to suit your needs.

[andrew_busch]

Hmm... interesting. I definitely don't like the idea of constantly bailing out the boat.

I am beginning to realize that it's difficult to build even the most basic of boats, as things like wood rot, proper sealing, and structural strength must all be considered, even if it is just floating in a still pool. I'm still going to continue with aiming to build this boat without a complete set of instructions, but I guess I may choose otherwise if I find this too impossible. I am finding this very good for stretching my brain, and once again learning that things that seem simple are often far from it.

So, just to clarify, are the only two methods that would be suitable for this construction stitch and glue, and caulking the seams? I'm interested in the caulking of the seams, but I'm not sure how the rest of the wood would be water proofed. One would paint the entire boat with a latex or oil based paint, right? Is that actually sufficient waterproofing? I remember reading that moisture does actually seep through paint...

[PAR]

No paint will seal wood effectively from moisture penetration.

You can engineer a build method in any fashion you like. Lots of different methods have been employed, some better then others. Having a grasp of the engineering principles and the physical properties of the materials you'll use is another matter, which I don't feel you currently own. Without at least a fundamental understanding of the hydrodynamic concepts and basic engineering abilities, you're shooting in the dark.

[andrew_busch]

So what does properly waterproof wood, aside from epoxy?

I know this is a bit of a shot in the dark, but over the past couple of years I've managed to pick up a bit of a feel for overall engineering ideas (I think), and I'm looking at studying engineering in university, so I'm not completely clueless when it comes to designing structures. I guess we'll see if I actually do have a grasp for that stuff or not.

[andrew_busch]

I went to my local hardware shop, and of the things I saw, I found epoxy PC-7 and PC-11, which both look like very strong waterproof glues/sealants. I may go with PC-7 for sealing the cracks, as it's cheaper, but looks as if it'll still do the job. However, it's quite rock solid, so I'd be looking at a boat where all the parts hold tight and don't move, right?

I also saw some acrylic sealants, which advertised that they were waterproof, but said on the back that they shouldn't be used below the waterline, so I don't think they're truly waterproof.

I found Titebond II, would that be any good for sealing?

So I guess I only found stuff that would be useful for sealing the joints, but nothing that could coat the entire boat. Currently I'm thinking of joining the wood with the sealant, and probably screws for added strength (then covering the screws up with the sealant), and then coating the entire boat in some sort of waterproof paint.

So then, how are the products that I mentioned for sealing? And once again, what could I use to coat all the wood to properly waterproof it?

[alan white]

Those epoxy products are, I believe, repair formulations that are not at all useful for boat construction.
Your best bet on a first build would be to get a few cartridges (caulking tubes) of seam goo and build in plywood screwed to a skeleton frame in the traditional way. The right epoxy is often hard to obtain in some parts of the world, or at least it is very expensive.
A boat built that way will last for many years if well taken care of.
It's not a good idea to spend much on a first build. Epoxy is a messy thing to deal with, and it tends to take over so that you end up serving the epoxy rather than it serving you.
With plywood, you can epoxy/glass tape the seams and be done with it, and it won't leak at all. You might use a quart and some hardener of West System epoxy, available by contacting West Marine or Hamilton Marine or a lot of other suppliers.

[andrew_busch]

Yeah, I was thinking of something like that. So I'd make the wooden structure of the boat, and have it all solid using screws, and then I'd line the seams with seam goo? What stuff should I use? And then after I line the seams, what do I do about the rest of the plywood surface? It's not waterproof as is, right?

Oh, I'm in Indonesia by the way, so I have very limited access to things.

[andrew_busch]

I think I should actually go with epoxy for waterproofing the whole boat. Is there any variation in types of epoxy, other than ratios? I'd have to do a bit of a search around my city to see if they got it here. What would I coat the epoxy with, and once again, what would I seal the seams with?

[EDIT: I'm having a lot of trouble finding a polysulphide or polyurethane sealant here, so I'm thinking of just skipping on the sealant for the seams, and just using epoxy over the whole thing, and have nice, tight joins. Would that work?]

And just to kill 4 birds with one stone, is there any alternative to using epoxy for general waterproofing of the boat? The boat only really needs to last a couple of months, as I'm moving after that.

[alan white]

If you build a plywood boat using chine logs, seperate stem, etc., and you wish to omit epoxy, the seam compound should be applied to frames before the plywood is screwed on. Unlike carvel method, there is no crevice designed in to accept any caulking after the planking is hung.
You also want to have compound in any crevice down low, where frame parts join, such as where bottom, sides, and transom meet. The idea is to prevent places where rot can take hold by eliminating water traps.
I've used LifeCaulk form BoatLife, a polysulphide you can probably get anywhere boats are serviced.
If you want to epoxy the whole boat, there's a lot to know. A lot can go wrong. If you're going to use that volume of epoxy, it would be one suitable for laminating, like West System 5:1.
It would be best to add cloth for abrasion resistance and for reinforcing seams on the hull exterior. A lot more money to glass/epoxy the whole hull of course. The question is, is your first boat worth the expense?
For example, will it be used in salt or fresh water? Will it be trailered/carried or left in the water year round? Is the climate hot and humid, or cool and dry?
A boat left in the water all the time in a humid and warm climate, in fresh water, is most likely to suffer from rot.
If the climate is cool and dry, and a boat is only seeing four months of use in salt water, it will last a long time without the use of epoxy.
Good grief---- I am suddenly reading that you are building the boat to last for only three months?
Frankly, why not just build it out of cheap plywood with latex caulk for the seams and house paint? Why on Earth would you consider epoxy at all? For what? Even crumpled-up newspaper will float for a while.

[andrew_busch]

Ok, I'll remember to do that for my build.

Haha, yeah, that's nice to hear. I think I'll go with house paint for this boat. For the sealant, my three options are acrylic, silicon, and Titebond II. What would last me the longest? I'd love to use something better, but I just haven't found it.

I'm thinking that I'll build this boat just for a bit of fun, and won't expect a whole lot out of it, then maybe later on, when I move back to Australia, I may build a nice stitch-and-glue dory, or even a good-sized skiff.

Oh, and I think I'll use some cheap, ordinary 6mm ply. That'd be ok, right?

[PAR]

Don't go farther from shore then you can swim back to in this contrivance, Andrew.

[andrew_busch]

For sure, I doubt I'd even take it out to the ocean/sea, and a lake would also make me uncomfortable. Don't worry, I'm going to be completely safe in using it. To me, it feels as though it has the potential to sink at any moment, so I'd never rely upon it for being seaworthy.

[PAR]

I'm not talking about sea worthy, just common sense. Titebond II is a type II non-structural adhesive. It's not even close to waterproof. It'll melt after just a few minutes of emersion. Please do some research before you elect to use different techniques and materials for a boat. Silicon has only one use on a boat, to seal windows to their frames, that's it. Acrylics generally are worth a damn either.

[andrew_busch]

So none of those will hold then...

Once again, this only needs to hold for 2-3 months, with probably a couple of hours max each week. What materials could I use that are very common? Are my only options polyurethane, polysulphide, and epoxy? I have been doing research, and I know that polysuphide and polyurethane sealants are the ones I want, but I just can't find any here. They don't really have stuff like home depo here in Indonesia.

[andrew_busch]

So right now I'm planning on doing a very solid plywood on frame structure, sealing the seams with the hard epoxy glue I mentioned (PC-7 or PC-11), then painting it all with an oil based paint. Is this going to meet the requirements that I've stated for this boat? Considering 2 hours a week, how long do you think it'll last if I do a good job with the said method?

[alan white]

Andrew, why are you putting the boat in a swimming pool? Why build a boat instead of buying a used one? if you want to learn boatbuilding, why come here and ask for help while insisting on designing it yourself? Why abandon the boat after a couple of months?
Why not wait until you return home to build something? Why waste resources and time to build a poor design in a comprimised way so it can sit in clorinated water and leak?
Be uncomprimising in all that you do. Build it right or not at all.

[andrew_busch]

I'm doing this because I'm fond of the idea of making up a boat that I'll be able to float around in my swimming pool in. The ocean by Jakarta is quite gross, and I would want more than a sheet of plywood between me and it. I want to do it now, before I go back to Aus, because... I just want to. If the boat is good, I'll bring it back (I doubt it will be that good though).

Look, I'm leading up to my final high school exams, in which they will dictate what courses I'll be able to do in university, so it'd be foolish for me to take up a big, challenging project. I want the boat very soon, or at least have some time using it before I go back to Aus, so I figured that my only option is to do a quick, rough job. I soon realized that my knowledge was considerably lacking, so I came to these forums in hope of overall guidance for how to build my boat.

Also, I plan on using spare wood from a previous project of mine, and spare sealant, so it won't be a waste. Besides, I don't really see anything wrong with using a bit of wood to make up a boat for fun, even if the boat won't last that long.

However, through this project, I'll be able to get an idea whether or not I'd like to build a decent boat. I think I may consider it actually... . If I do though, it'll be back in Australia.


So I don't think you can really simplify it to building a boat very well, or not at all, because I want a boat, but I haven't the time to do it well. Does this answer your barrage?

[alan white]

Yes, thankyou. I see things very differently. I hope someone here can help you.
You know, regardless of the experience level of all the people on this forum, we do share one thing: a passion for an ineffable ideal, an escape, perhaps, from the mediocrity of today's make-a-profit culture.
It's born into all of us to seek a kind of geometric elegance in the way we apply our hands to our work.
Unfortunately, the modern world is structured in such a way as to turn us all into consumers of comprimised products. it's gotten to a point where we can't any longer open up food packaging or figure out how to use our answering machines.
Our "boats", or at least the ones the great majority of the population buys, are more likely to be designed by the shipping department or the marketing department than a good marine architect. They are emblazoned with graphics almost as large as the boat itself.
Not just boats, virtually everything available to most people is designed for reasons other than aesthetics, function, or longevity.
Mostly, design is about attracting the attention of a person who knows least about the product. The preceding sentence should cause you to take notice.
You see, to some, boat design and building is a high science. It is actually humbling to realize that here on this forum there are a few people who know as much as the best in the world about their craft.
Most of them have earned this knowledge without ever benefitting financially from it (at least to the degree that would reflect their vast knowledge of a trade).
I know that if I wanted to build a spaceship and sought advice from NASA, I would understand that they were puzzled if I told them I wanted to design it myself and then put it in my basement, then probably abandon it after a couple of months.

[andrew_busch]

That's good, I'm glad. I must say I share a version of that passion, particularly the "geometric elegance in the way we apply our hands to our work", and the whole principle of doing it yourself rather than just getting the finished product. That last point is part of the reason why I don't really want to just copy someone else's design, as I really want it to be a complete, do-it-yourself project.

Nevertheless, I do see why people don't agree with me making a quick build. Maybe I should have labelled this thread "building a quick, short-term boat" or something to that effect.

Anyway, I think I have some ideas for building the boat based on the materials available to me. I don't think I want to explain them, as I think they're pretty much sacrilegious in the boating world, and I'm sure the response will be something like "make sure you can swim back to the sure, because you're gonna sink". I'll make a post some time later if I've made progress, just to let you all know how it went/is going.

[alan white]

I'm sure you won't let yourself drown.
You already have enough advice to proceed if you read what's been written here. It's understood you're not trying to build a good boat. Whatever your reasons, good luck with the project.

[ancient kayaker]

Hannu Vartiala's site http://koti.kapsi.fi/hvartial/ has a section of free boat plans * that are very easy to make and has a lot of information about the design and construction of minimalist boats that would help you.

First decide what you want. A tiny boat that will barely hold you or a heavy and stable raft that you can haul yourself into from the water without tipping, or something between. Is the pool large enough to make it worthwhile building a rowboat and is it tough enough to withstand a boat and its occupant hitting its edge at speed?

From a safety point of view, it isn't just the risk of falling overboard; if you're in the water and pulling yourself into the boat and it flips over and comes down on your head, it can easily injure you or knock you unconscious. Since you are unlikely to be wearing a personal floatation device (life jacket) in a swimming pool there could then be serious risk of drowning. It is not always possible to anticipate a risk in an unfamiliar situation.

Building a boat is not difficult, especially with modern materials like plywood and glue. I don't know what's available in Indonesia but in North America we can get quite decent glues from a local hardware store. However, although they may be "waterproof", they are unlikely to withstand long soaking so the boat should always be removed from the water and dried out after use, and kept painted. House paint will do fine for such a boat.

One way would be to build a simple raft by constructing a simple box, filling it with foam, and covering it with ply. Screws or nails could then be used since it no longer has to be watertight as the foam will prevent it from filling. Screws and nails will not let the boat fall apart after a soaking, which could happen if you use the wrong glue. Plastic water bottles or an inflatable mattress would do the job as well as foam. If a few months life is all that is required there is no need to waterproof it or even paint it. However, it is not the sort of thing you would want to take back home and launch into a marina!

One type of boat that might suit you is a catamaran or pontoon. That would be 2 rather narrow hulls connected by cross members or a platform. Leaving the middle open allows it to be smaller, as you can pull yourself into the boat from the middle with no risk of it tipping.

However you proceed, enjoy the experience and may your efforts be crowned with success, or at least a feeling of accomplishment!

* The "Simbo" might suit you, it is made from one sheet of ply. Hannu's method uses screws through the ply into 2 x 2 x 2 inch wood blocks to hold it together while you add glass tape and epoxy, after which the screws and blocks are removed. That is because Hannu likes to get the entire boat from just the ply sheet, but you could leave the screws and blocks in place, maybe use a few more, and then apply an exterior grade caulk to the outside of the seams. Well protected with paint and stored out of the water, it should last for the few months you are looking for and be very quick to build. Most of the construction time will be waiting for the paint to dry.

[ancient kayaker]

Here's the web site for the PDRacer. That's PD as in Puddle Duck. It's one of the simplest boats there is, it is about 4' x 8' and perfectly square, with just a little curve on the bottom. http://homepage.mac.com/peterhyndman/Sites/PDRinfo/index.html

Here's a web page that will translate boating terms:
http://en.wikipedia.org/wiki/Glossary_of_nautical_terms#A

[rwatson]

I still don't think that I'm breaching moral code by making a rubbish boat,
Anyway, I've had a look online at methods of building dorys, and so far the most popular method seems to be the stitch and glue one, using epoxy and fiberglass strips as the sealant and also for strengthening. Is it necessary to do it this way? What are other methods with a similar or lower degree of simplicity for a plywood dory? I was thinking that screws could be used, and maybe something like silastic and a good oil-based paint...

You are 100% right - you are not breaching any moral code, and you will learn a lot building a rubbish boat.

Every rubbish boat I ever built (and there was a lot of work put into them) led me to the conclusion that I would have spent 1/4 of the time, 1/10 of the cost and 10% of the aggro by building a boat from plans, using a popular technique.

Even if you make a "fair" job from plans, you will get 300% more satisifaction, 400% more use and 500% more value from the final product.

Good luck on the project - and be assured you are cleverer than you think you are, and you can get a lot of good advice from this forum is you get confused or stuck on any plan or building problem.