First boat: chine fill question

Does anyone have a suggestion for a better design?
Personally I have not tried ply on frame and don't have a clue.

Something known to work might keep the OP interested, although he seems pretty resilient.

 

Another question: I'm familiar with Luan plywood. Is it the same as 1/4" mahogany plywood? The local DIY centers sell Luan: one face is mahogany; the other is something I would classify as masonite. It's not 1/4" thick. More like 3/16".

 

Luan - sometimes called Phillipine Mahogany but no relation - is an OK wood for plywood but is often used for poor quality plywood because it is relatively cheap.

Always inspect plywood from a hardware store. Look at both sides for checking and look around the edges for evidence of voids in the middle ply or plies. There'll almost certainly be some but small ones (1/4" or less) can be ignored. Since luan is often referred to as mahogany the "mahogany" ply may well be luan of a more decorative cut. If you are planning to paint your boat instead of varnishing it, repairs in the outer face plies are OK.

Okoume is a common ply for use on boats as it is light, strong for its weight and takes a good finish. It is more expensive. Meranti is a bit more expensive too: I understand it is our old friend luan, but generally good quality if carried by a store catering to boat builders. Plywood with the stamp BS1088 or BS1066 is supposed to be built to British specifications but the standard is voluntary and the stamp no longer means much unless from a first-class supplier like Joubert or if it carries Lloyds approval. As in all things you will pay more for quality; for a first boat it probably isn't worth the extra just take a good look at what you buy.

Wood and plywood is sometimes sold in murky, ill-lit warehouses where you can't really inspect it properly; that's a recipe for a bad buy, been there and done that, move on to another source.

Masonite has no place on a boat.

 

Thinking of starting over

So, I've been taking my time thinking about the remedial work I have to do to get this first build ready for ply skin. Competing against this is the thought that I should start over...there's a lot of problems with the chines & sheer clamps & stems. Run the photos please....

This is a pretty simple boat that won't last many years. Is it worth the efforts to correct all these errors. I've gained enough from this and your inputs to know what to do on the next attempt. I think I will cut out the keelson and use it for the next frames. And use something besides OSB to make a strongback, and make the strongback higher, and more stable. Again, I'm just starting out, so what do you think of a start over for this? Has anyone gone this way? I have enough lumber on hand that the costs would only be time and effort.

 

As an exercise, I think its been valuable for you to undertake. It will help in so many ways with the next projects.

What you are facing is another 300% of time/money investment with the skin and finishing - lets not forget the finishing

This design, as me and a few others have hinted, will leave you unhappy to use after the first half dozen times on the water. It will be hard to paddle, slow to go anywhere, awkward to maneuver - because the dimensions and shape are far from optimal.

The trick with boats is to make sure that what you end up with something that will be a joy for many years, to use and to admire.

I would suggest that you do a careful evaluation of what sort of boat you will get the most use out of, then locate a proven performer, and buy the design.

New builders often mistake a full and competent design as a cost. For every dollar you spend on the design, you save 4 dollars in wasted effort and materials.

Welcome to the wide world of choices,.



PS - do nesting sail/power boats appeal. Check out
http://www.boatdesign.net/forums/boat-design/dave-gerrs-nester-dinghy-design-42213.html

http://www.duckworksmagazine.com/04/s/designs/greene/cham/index.cfm


or maybe

http://www.duckworksbbs.com/ProductDetails.asp?ProductCode=oz-GIS-p

 

One of the hardest things to recognise is when you're pursuing failure with more resources in an attempt to break even.

If you treat what you've done as a learning experience, none of it is a loss.

Salvage what you can and start afresh. I've done this many times myself.

PDW

 

Now all we need are some suggestions from people who have made boats similar to what the OP wants.
I am really surprised not to have seen a dozen suggestions.

Hint, Hint.

 

The keelson is already too short so there would be no sense in saving any of it to use on another attempt at the same plans.

I think you can resurrect what you have, though the boat would be like 6" shorter. It couldn't hurt to try if you're going to throw it away anyways.

In the middle photo where it's looking down the stem from the bottom, the reference point is the line drawn on the edge of the stem. The point of the chine is set back maybe an inch and the point on the sheer is set forward maybe an inch from the line on the stem. That is not right, the points should theoretically meet on that line. That's where the apparent twist comes from. It's hard to tell exactly how the joint between the stem and the chine and sheer is to be done, but the point is they should meet and the ends be both in plane with that line which is set by the 42 degree cut.

So, if you cut and shorten the sheer clamps to where they will join and be in line with the chines on the 42 degree angle, that should bring the faces of the chine and sheer in line so ply will lay flat on them. The stem will be have to be cut and will end up narrower, but if it is too narrow, you could just glue and screw a piece on to bring it back to it's original 3 1/2" width. Of course you'd also have to shorten the strong back too.

Another thing is that 42 degree cut. The plans are somewhat strange in the way they give measurements and angles. The stem is to be cut 42 degrees, but when it's attached to the keelson, the rocker of the keelson will add a degree or two. They give a measurement of 3 3/8" cut on the end of the strongback to give you the angle to cut it, which is bogus, they should just give the angle of 44 degrees or whatever it is and be done with it because any variation in the width of the 2x4 strongback will give a different angle with a 3 3/8" length cut. So since you used particle board for the strongback, maybe you just cut a 42 degree angle on the ends of it and that would also tend to throw off all the joints of the stem/chine/sheer.