My little wooden boat project... by a complete novice

[cameron.d.mm]

Hello,

I'm new around here - having just bumped into the forum this evening - but want to share something. I have a little project going that might be appreciated around here - or, quite possibly, picked to pieces!. (Not that that would be a bad thing, necessarily.)

The story so far: starting out from complete scratch, I've started building myself a very small wooden boat. Really, there is nothing in my past to indicate I'm capable of doing such a thing, but, being a little bull-headed when it comes to looking things up like a responsible person would, I've just plowed ahead at pretty much full steam. So far it seems to be going acceptably well... But I guess I won't really know until I drop the thing in the water!

Below I've included some pictures of my progress, as well as my 'plans', which are really just a quick sketch. I've actually got the entire haul planked over the frame (such as it is) and am now ready to do some finishing. Once the weather warms up around here, I'll drag it out the basement window and sand it/plane it outside. Then I can add seats and the other important bits still to do.

I plan to make matching oars for the boat, and possibly add an electric trawling motor, which should propel it at a good clip.

In terms of actual construction, I've used Spanish Cedar (Cedrela odorata) and African Mahogany (Khaya ivorensis). I'll probably use some white ash as well, as I can get it locally in long lengths and for a good price. Everything is glued, while the structural joints are also screwed with brass fasteners.

Anyway, I guess I've written a good bit, so I must be eager to share. But I'll can it now as we all know why you're here: for the pictures!

Thanks for taking the time to browse.

Some more pictures can be found here: http://www.camerondmm.com/studio.html

I'd love to hear if anyone has comments or questions, and I'll try to keep this thread up to date with any developments, but the weather is still a few weeks away from cooperating with me.

 

[timgoz]

Cameron,

Welcome to the forum. I have just got back on recently.

Looks as if you have a nice boat there. Hope she meets all your expectations.

Take care.

Tim

 

[lewisboats]

My question is....does the horizontal line represent the waterline? If so...you don't have much freeboard to play with...depending on the displacement of the boat at that waterline. With that reverse transom...you may have a problem adjusting the trolling motor angle to drive it properly. You might need to build a motor mount that is vertical or raked aft to get decent performance from the motor.

Steve

 

[PAR]

If that blue line does represent the immersed volume it would be in the 700 to 800 pound range which is so over loaded it'll swamp in anything other then a still swimming pool.

 

[cameron.d.mm]

Hey guys, thanks for the replies.

I guess I kind of forgot about that waterline indication (which is what it is). I'd done a very rough calculation (ignoring both the rake of the sides and the curve of the bottom) to determine the displacement. Instead of picking a reasonable weight and going from there, I picked about 1/2 way up the side of the boat, and calculated how much weight it would take to sink to that depth. I think I came up with about 600 lbs (so, you're pretty much right on the money there PARR - especially when you consider I ignored the fact the boat gets wider near the top).

I was pretty satisfied with the projected displacement - but ultimately have no experience. I certainly don't plan on operating the boat loaded with 600lb. I'm a pretty heavy guy at around 210lb, but even with another passenger and a bit of lunch (plus the boat, which is pretty light) it should be OK in calm water. I'll probably use it mostly in the canals and rivers near here (Ottawa, ON Canada). Who knows, maybe I did the math wrong.

About the transom; I have actually built the boat without the reverse rake. I decided to keep my first build super simple. Plus - if I do put a trawling motor on it, it'll be much simpler.

Sorry for all the confusion about the sketch. It is also misleading in that the actual boat is closer to 9 feet long, as that let me build without having to scarf any of the planks.

Thanks again, and I promise to put up some more photos as I finish it off.

 

[Landlubber]

What would make you think that a boat less than 10 feet, built of light wood, would weigh in over 600 lbs? I am not being critical, just curious.

 

[cameron.d.mm]

Oh, sorry if I wasn't clear enough.

I don't expect the boat to weigh 600lb (never did), and wouldn't have built it if I had. So far it is pretty light, as I can still move it and hold it over my head by myself. Once I add the ash gunnels and seats, doing so might be more of a chore. 600lb was the figure I came up with for how much weight (boat plus cargo) it would take to bring the waterline half way up the sides of the boat, not how much I projected the boat would weigh.

 

[PAR]

At 350 pounds of displacement (you, the boat and BoBo the wonder dog) your boat will be about 4" deep at midship, with the bow and transom slightly immersed. Of course this is based on the general scale and rocker show in your sketch.

If you plan on rowing this puppy, build as light as you can and trim the boat with the transom clear of the water.

 

[cameron.d.mm]

Thanks for the tip PAR. I'll keep in mind that I should trim so as to have the transom just out of the water. Does this advise remain the same when using an electric trawling motor, or is it specific to rowing?

There is only one problem: you're getting me all excited to try it out, and it isn't ready yet! (Heck, the water I want to lunch the boat is still frozen solid.)

 

[PAR]

Your trolling motor will only push the boat to about 4 knots which is within it's displacement speed envelop, meaning yep, the transom should just clear or be slightly kissing the water underway.

Basically it real depends on where her displacement is centered. Again going by the rough drawing, it appears it's a little forward of an ideal location and the forward section appear "fuller" then desired for good rowing and low power applications.

You will not really have an idea of how things will work until you splash her and preform some trials under power and oar.

 

[cameron.d.mm]

So...

The boat is now outside (has been for a week or two - hasn't turned into a mass of splinters due to humidity, either) and I've started all the messy stuff. Rough sanding of the bottom is now done, and I've started the inside too.

In the coming weeks I'll be adding trim, gunnels, etc., then flipping it over and doing seats and the like. All this will take a while, but I've started to think more seriously about how to finish the boat as well.

Currently I'm of a split mind. My inclination is to just polyurethane the bejeezus out of the thing and then go rowing. But I know I'll be fighting runs on the curved surface of the hull. It has also been suggested to me that I use spar varnish, as it will go on a lot thinner, won't run so bad and setup quicker too. What are your opinions?

Keep in mind that it'll be 'dry sailed' (only in the water a few hours at a time) and that I want to keep as much water as possible away from my adhesives.

Can the two approaches above be combined? Could I do a few thick coats of ploy, and then layer the spar varnish on top of that? If that were possible, would there by any advantage?

Also: I plan to make my own oars. As a general rule, does such a plan fall under the good, the bad or the ugly?

Anyway, thanks for looking and taking the time to read. I appreciate that knowledgeable people are willing to share their experiences.

 

[alan white]

Polyurethane, by your description, that which is used to cover floors, and which is clear rather than being a paint, is not thicker than varnish.
Assuming you want to get a clear finish, the varnish has a UV protective additive that won't be found in the polyurethane. or at least the polyurethane will not survive the same UV as the varnish.
You could lay down some plyurethane and protect it with varnish but why go to asll that trouble when varnish alone will do the job?
Then you'll have more protection from the sun, which quickly turns polyurethane to a yellow hazy powder.
If you start with spar varnish, (as it is properly called), you'll have to do at least 6 coats and probably 8.
I'd paint the boat instead. A novice will have enough on his hands just building that first boat. Almost no one varnishes a hull, let alone the interior. since it's damned hard to do it that way and even harder to maintain once it's done.
It's your boat, however, so varnish away if you must, but be aware you're making a purse from a sow's ear, which is fine, but you may want to know the truth, and save a few dozen hours of hard labor.

 

[PAR]

Polyurethanes cure much faster then traditional varnishes. Spar Varnish is regular varnish, but with more UV inhibitors, which makes it appear with a more amber glow on wood. Polyurethanes are generally superior to regular varnish in moisture protection (by a few percent), but are harder to repair or touch up when the time comes.

The word varnish is now commonly used for any type of clear coating on wood. You will see cans that say things like "acrylic spar varnish" or "polyurethane spar varnish", which if you knew how each was made, makes them clearly incorrect descriptions of the can's contents, but marketing is marketing.

If you coat with polyurethanes, thin about 20% on the first coat, but on subsequent coats just enough to make the poly "flow". Most polys can be used straight from the can with good results. Regular varnish is a different animal and application is more of an art form, subject to lots of debate, technique and methods.

Neither polyurethane nor varnish will keep out the moisture, just resist it for a while. The only really effective way to keep moisture out is epoxy.

 

[lewisboats]

Looking really nice! I am with PAR though... Get yourself a small kit of epoxy (Clark Craft has a decent 1:1 ratio in smaller amounts) and lay a coat on the outside and the inside bottom and up about 1" on the sides inside. The inside bottom will see a lot more water puddles and such than you think...then either Spar varnish or paint.

Steve

 

[cameron.d.mm]

Hey guys,

Taking another look at the can of spar 'varnish', it is instead spar 'urethane' - oops.

To be honest, I'd been trying to stay clear of epoxy, but I guess I'll be giving it another look now. I know someone who has built several stitch and glue kit boats, and am familiar with the basic principles of epoxying a boat. I'll investigate some more. I assume several coats would still be the norm?

I like the suggestion of epoxying the hull and inside bottom, and then finishing with another clear finish.

Thanks again, and I'l lkeep you all posted.