Boat weight question

I am building a small rowboat to hold at least two people. Im planning on using plywood for most of the boat but if I use different types of wood along with it would it disbalance the boat? Also, how do I determine how heavy or what shape my boat can be in order to float? In other words how would I find the load capacity of my boat?

 

You realy need to do more research into boatbuilding and design if you are going to build a decent boat. There are too many factors to cover here, factors that would affect the questions you're asking.
Boat balance has nothing to do with what woods are used. Anything can be made to float, just make high sides. But your first boat should be based on an existing design if you don't know how to design it yourself.
The boat must do many things at once; carry weight, keep water out, move efficiently, float level, be cost effective, and be simple to build.
To achieve all these parameters takes considerable skill. I would suggest you make a simple skiff (shaped like an iron, but with the bottom curving fore and aft). You can't go wrong with a good skiff design, and they are a real bargain when it comes to producing a decent boat in the simplest way possible. Designing a very good simple skiff, however, is a real art. Look around for something 10-12 ft long. A good boatbuilder could turn one out in a couple of days, and that tells you that such a boat is perfect for a first project.

Alan

 

Alan is right about going with an existing deiegn for your first boat. There are tons of plans out there. Fifty to one hundred dollars should be sufficient to obtain good plans.

Welcome & good luck.

Tim

 

Thank you and yes I agree I found some plans online which I plan to follow, they can be found here http://www.vintageprojects.com/boats/row-boat.pdf. Do you think this would be simple enough?

 

Thats one possibility. I'd do some looking before making a choice. Bolger, Payson, ect... may be of interest. Wooden Boat Magazine could prove very useful! Try them online to see what they may offer.

A marine ply & epoxy boat would be one of the simplest to build. The design you posted calls for "press board". Would not use that as a building material.

Good searching.

Tim

 

In fact, Tim, just a little while ago I paged through the new Woodenboat issue and saw a nice 12'- 1" skiff featured (grand prize winning design).
Pressboard... yech! Plywood is the way to go. Such a skiff could be built with taped seams by stitch-and-glue method, the simplest boat you could build. On a first boat, even exterior grade AB plywood would be fine. It will last a while, longer if kept after.
Another simple boat, a pirogue, is made with pine boards available off the shelf in any lumber yard.

Alan

 

I checked out that link you posted, and the material called for when that plan was drawn wouldn't exist any more in any case. Probably a 1945 design, and "hard-pressed wood" was most likely a war surplus material whose time has come and gone. Certainly, no boat I've ever heard of has been made with it, probably because it was quickly replaced by plywood, which was in every way superior.
The boat shown was indeed a skiff. But check out the Woodenboat magazine on the shelves now---- the boat featured weighed 100 lbs and was a bargain to build.

A.

 

Alan,

Don't pirouqes (sp?) use a transverse bottom planking? They remind me somewhat of the "six hour" canoes.

You guys get rid of all the snow up there yet?

Take care.

Tim

 

I think so, yes, Tim. Like dories, old method. Great starter project--- spread two boards with a stretcher til they look right add chine logs and cross-plank from both ends towards the middle, last board tapered to knock in tight.
As far as snow goes, it went, a month ago was it? Happens so fast.
Full blown Summer now, green and more green.

 

Stitch and glue or taped seam construction techniques, don't lend themselves well to the first time builder. The goo aspect can easily be overwhelming to the amateur. This coupled with the cost (probably doubling a small skiff build) and the necessary epoxy skills, to do a reliable job, just make me cringe.

The boat he has linked is a very old design. The planking calls for 12' sheets, which are extremely expensive today. The "Press Board" asked for in the materials list is plywood, not what we now call press board.

You'll have to use 8' sheets of plywood (unless you're made of money) and these can be joined with butt blocks or scarf joints.

Frankly, this is a heavy build for a 12' rowing skiff. This was common when this boat was drawn up. By current standards, the boat is twice as heavy and has twice the materials then is necessary for a 12' row boat. It will be a chore to lift out of the back of a pickup by yourself.

Yep, the plans are free and it shows. The battens are shown clenched to the planking, which is a poor way of fastening things. The building instructions leave considerable room for screwing up and much is unclear.

If you are interested in a skiff that is much easier to build, uses half the materials and specs out materials that are available today, drop me an email (click on my name). My plans include complete instructions and workable, clear drawings. You will not have to scrounge for odd pieces of expensive wood, in fact it's all available at your local building supply store. You don't even need epoxy, although it's a very fine glue and I recommend it on some joints.

If not my plans, then there are many other free or low cost plans, available on line, that reflect modern materials and techniques. Some of these also don't resort to using epoxy, but most will.

As to the question about weight, who knows, but a fair bit more then a more modern design. Heavy enough to want friends along to drag her up a beach or out of the pickup bed. Without doing a material masses calculation, speculation could only be offered, but well over 100 pounds is my guess.

Tim, lots of boats have used "file" planked bottoms. They were very common where I was raised on the Chesapeake. They fell out of favor when engines were put in boats, which tended to "rack" the bottom planks, in the cross planked versions of any particular type of craft. In sail or rowing craft it works fine, if not pressed too hard, repeatedly.

 

I can agree, Par, about the cost factor. I do however believe stitch and glue is very much suited to a first timer in terms of set-up. It also requires very few big tools--- a hand saw, block plane, random orbit sander, and a saber saw are about it. Not many fasteners ($), nor need for a table saw to rip long bevels.
Also, seam taping is limited to lengths of seam---- if a screw up occurs, rip it off and do it over again. One or two rolls of tape and a gallon of epoxy, and some filler for filleting.
Personally, I like the idea of a very low tech boat based on chine logs and sawn frames notched around the longitudinals. That one could get everything locally would be a huge bonus.
A few years ago, students in the Rockland, Maine area built greenland kayaks from luan 1/4" over pine stringers, glopped the seams with life caulk or somesuch, nailed the ply on, I think, with galvinized nails,and then toured the coast as a group. Wild paint schemes, heavy boats, but cheap and easy to build by the novice.
Interesting that the name pressed wood meant plywood. I have never heard that name before. So only the name got replaced.

 

Remember the first few times you used epoxy? How about the first fillets? You know the fillet that never dried or had the wrong reinforcement, so it sagged like crazy into a puddle of rock hard goo everywhere, except the place you wanted it. I don't think ripping off taped down seams is particularly productive and first builds should be.

Taped seam and stitch and glue boats almost solely rely on cloth sheathings too. Not all, but darned near all. Now there's a fun time, skinning a skiff with cloth, but not working fast enough or pouring on more then you can work, before it kicks.

Yes, setup can be quick, but the details are what consumes most of the time, not the hull shell (unless it sheathed). Fitting parts, making good joints, finishing, out fitting, etc. this is what eats up the time on a build. The planking is usually pretty quick, unless it needs a bunch of goo and fabric skin.

Don't get me wrong, I use epoxy all the time, love the stuff, but feel the first build should be goo free, as much as possible. It keeps the cost down, you don't need to learn how to use it and it forces you to use good materials and maintain the boat properly. Epoxy can hid a host of sins, which can be good once the new builder gets the "bug", but relying on it to have a boat isn't my idea of boat building for the beginner. As a builder gains experience, then employing different, more difficult concepts, materials, techniques and skills is natural.

I wasn't always of this opinion, but now do try to develop designs that have a minimum of epoxy requirements. Partly because people have nasty reactions to the stuff, it's not good for you and it adds so much, to what would other wise be a simple, inexpensive build.

 

PAR,

Do you have a website. I clicked some of your gallery images & it called for a password?

Tim

 

Par, I am trying to think about my first time with epoxy, and I think it was only about 18 years ago. Little stitch and glue tender, nutshell type. Microballoons...yeah. It went well, but I was already a builder of all kinds of things, and well read on epoxy and boatbuilding methods.
I see your point, however. I know some people (one who is a customer who constantly calls me to save a project he started before catastrophe struck), who aren't disciplined in the arts of constructing anything. It is amazing to me how they test Murphy's law in virtually everything they put their hand to.
If this particular customer were doing a stitch and glue boat I might get a call from his wife something like this: "Hey, can you get over here quick? He's stuck himself to the boat and it's sinking because he didn't pull it out of the water, and he drilled through the bottom and a storm's coming!"
And I would get there and that wasn't the half of it.
So, in answer to the question of whether or not, first project, etc., I guess I'd have to say depends on who's doing it, but when in doubt, err on the side of low tech and simplicity!
I think from now on, after thinking about this, I am stuck with seeing that customer's face on every soon-to-be boatbuilder, whether they like it or not.

 

Alan, you clearly have customers who are similar, if not directly related to mine. Most are the nicest bunch, but then there's the handful, that think you're plans package is reason to call, with every conceivable question, usually while they have goo on their fingers and have satisfied an eye itch.

You're right, it's the ability or more correctly, the common sense of the individual builder. Some just slide right in, naturally taking to the different skill requirements and performing research when they're stuck. Others leave me wondering, what their kitchen must look like, let alone their garage. God bless their wives and families . . .