Foam for corner form?

[Buz]

My buddy tells me yesterday he wants a removable cabin for the bow of his Maycraft. About 6ftx6ftx6tx4ft and 30" or so high. The boat has a 4"x4" lip along that part of the gunnel inside the rails that he intends to fit it over. He plans tabs with in-hull bolts jutting up. I'm gonna suggest toggle-latches and maybe a hook in front much like an outboard cover.

The forward corners of his bow lip have about 220' of a 6" radius we'd like to match. Rather than kerfing very thin ply, can a foam tube be used as a corner form and ground out after glassing? How many layers of what glass would those glass-only corners need to catch a stumble at the railing?

[fallguy1000]

You need to do a drawing because 'catch a stumble' does not compute.

But, if you want it to be removable, it needs to be strong enough not to crack in handling; maybe this is what you mean?

1708 is fast build and builds about 0.040" per layer. The solid glass flanges would need to be about 6 layers to avoid breaking. This gets transistioned into the top. So say a flange is 4" wide. You make each piece 1" longer. So the first piece is 10" wide with 6" on the cabin side, then 9",8,7,6,5. All of the ends can match, but this is hard to do while glassing; so you typically add an inch to all of them and then cut it for a nice edge later. So the pieces would be 11,10,9,8,7,6 laid longest first. You never lay air into a laminate...unless not a pro.

My picture shows 4 layers for finger sketch.

[Buz]

"Catch a stumble", means not break when someone going around the rail leans onto it. Same as what you said. Thanks.

And I guess what Im wondering is a 6" or so gap between wood core at those corners ok? Haven't noticed it done in any threads Ive read.

[fallguy1000]

"Catch a stumble", means not break when someone going around the rail leans onto it. Same as what you said. Thanks.

And I guess what Im wondering is a 6" or so gap between wood core at those corners ok? Haven't noticed it done in any threads Ive read.

Need some help trying to understand what you mean better...

[Buz]

Your drawing shows the cores at the corner are "touching" and taped/covered with 1708. What if there were 6 or 8 inches between the pieces of core at the corner?

[fallguy1000]

You need to provide a napkin sketch. Otherwise, I am guessing.

In order to not have a wood core for 6" vertically; the laminate must be solid. A solid laminate must transistion from a wood core in a special way.

But I'm not gonna guess. If you want to avoid a core on the bottom for water concerns; this would not be the approach. What is done is the bottom of the cabinsides is filled with a waterproof epoxy slurry and glassed all around. Or, you can use M200 foam core or plascore or coosa on the bottom edge.