[Paddlewise] fitting foam seat into boat

A few notes on taking the curve from the boat's bottom, so a new foam seat 
will fit, and on setting the seat into the boat:

First, the very obvious fact that the inside of the seat will be much 
easier to carve if you do that part **first** and then fit your blank into 
the boat.

There are several ways to fit the newly carved seat into the boat. It's 
easy with a hard chine boat, a bit more difficult for a rounded chine.

For the hard chine, just set a piece of wood or cardboard inside the boat 
from one chine to the other and measure the "deadrise", the distance from 
the chine-line to the keelson line, vertically. Draw these on cardboard and 
you should have a perfect fit. Don't forget to cut out little curves at the 
chine edges of your template and at the keel, to accomodate for the fillets.

A variation of the same technique can be used to take the curve from a 
round chine boat, though a "Draftsman's curve" works well enough in my 
experience. I haven't tried solder for this. Anyway, if the solder or 
draftsman's curve isn't working, use a "lofting technique": Set a stiff 
piece of something inside the boat so it runs from one side to the other, 
at the level where you want your seat to fit into the boat's bottom. Now 
take vertical measurements, or as near to vertical as you can manage (use a 
90 degree level if you're really compulsive, but it's not necessary), at 
intervals from your transverse baseline to the bottom of the boat from one 
side to the other. Intervals of 1 inch would be wonderful, but 1.5 inches 
or maybe even 2 inch intervals would probably be good enough. Now transfer 
those dimensions to your cardboard template. Draw your transverse line on 
the template, drop your verticals, make dots at each dimension, then draw 
the resulting curve. Obviously if the boat's bottom curves more toward the 
chines, make your intervals more frequent at those points, less frequent 
toward the keel.

For most boats - Don't forget that you'll probably need to take a curve 
from the place where the forward edge of the seat goes, and another curve 
from the point where the rear (aft) edge of the seat will go.

Make your templates, try them in the boat (be careful to mark *left* and 
*right* sides as you measure, again as you mark, etc). If they're not as 
exact as you like, shave tiny bits from the template or tape a sliver of 
cardboard to the template, as needed. I don't think the fit needs to be 
exact, but it shouldn't be hard to get it nearly exact.

When you're satisfied with the fit of your templates, mark the front and 
rear edges of your minicell blank (==>keep track of L and R, front and 
back, both on your templates and on your minicell !!) and cut along the 
resulting lines at the front and back of your template. Draw lines along 
the sides of your minicell joining your front and back cuts, and cut along 
those lines too. If you're not confident of your carving ability, angle 
your cuts outward a little, then use one of the carving techniques 
described elsewhere on this list to join the two cuts.

This whole procedure is a lot more complicated to read than it is to do. It 
does not take a lot of time, or a lot of skill. If it did, I couldn't do 
it. But I can do it.

Finally, my preference has been to set the new seat in the boat with Velcro 
and then paddle the boat for a while. That way I can move the seat forward 
or back, to get the best balance and therefore the best handling from the 
boat. Probably the ideal thing would be eventually to glue the seat in 
place permanently. In practice I've found that the Velcro, if properly 
cemented in place in the begining, will last for at least a few years, and 
I just leave the seat fixed with that.

Bill Hansen

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