BUILDING A LAMINATED COAMING

If you buy a set of plans it come with patterns for a stacked plywood coaming. On my personal boats I prefer a laminated coaming that is sewn in place. This is how I build my coamings.

My first coamings were made using 3mm marine grade Okoume plywood cut itto 1.5" wide strips. It takes four or five, eight foot long strips. Recently I have have started using hardwood such as maple, walnut or cherry instead.

I start with a 1" thick (or thicker) board, cut it into 1.5" wide piece(s) and then resaw it into thin strips to use in the coaming.

I wrap the strips around a form made from from two pieces 1/2" plywood glued together. The form is the same size as the inside of a finished coaming. If your have the full size plans you can can cut out two from the patterns. I recommend cutting the forms oversized and once they are glued together then sand or plane them to size at the same time so they match. I drill a series of 1-1/4" holes for the clamps. The size is not important, just as long as your clamps will fit. Even with these holes sometime you find you need to clamp between the holes. I have started cutting a slot (see photo below) instead of all the holes. It gives you a better chance of lining up the clamps where you need.

I take a strip and I cut a long taper or a scarf on one end similar to what is shown in the photo below. I have a stationary belt sander and since this is not critical I just sand it down till it looks right. The idea is the taper will give you a smoother edge inside the coaming.

I clamp the tapered end of the strip to the form. Then you start wrapping it around. With the 3mm I find it bends around the large end no problem as long as I just go slow. But it will not bend around the small without breaking usually.

Most people heat the strips with steam, but I found that with the thin strips that all I need to do was get them hot with a heat gun. Not a hair dryer, but a cheap heat gun. The heat gun is hot enough it can actually blacken the wood. I have found that if I heat the strip as I bend it I can feel it loosen and it will form around the small end of the form with no problem. I just keep adding clamps as I work my way around.

Once the strips start to overlap I apply the glue. I like to use TiteBond III as I find it easy to work with and easy to clean up since it is water based. When I start a new strip I butt the ends together, clamp and start wrapping it around the form. You will find that your have to remove a clamp or two place the new strip on top of an old one. I have found that I can remove one of two, wrap it in place and remove the next clamp and move it back to hold what I just bent in place. Sort of 'hop-scotching' the clamps as I go around.

Here is with all the clamps in place. I use mostly spring clamps. IYou will often have a piece, especially in a curve where the spring clamp will not bring up tight. In those places you will need a C or F clamp to pull it tight.

Recently I made a new form and I used slots instead of holes. This gives me more options as to where to put my clamps and makes a better jig than just the holes drilled in it.

I made a simple jig from some scrap in shop to drill the stitching holes. There is a thin piece of wood on the back you can't see that keeps the coaming in place. I use a seamstress cloth measuring tape to layout the hole spacing. I put them every 1.5 inches. They rarely work out even so the last two or three will need to to be moved around to make it look even.