Attaching a frame to older boat

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Attaching a frame to older boat

Post by SFWilliams » 06 Apr 2015, 16:11

This may ramble a bit but I'm in the planning stages for my new project and realized I may not have all the knowledge I need to make a long lasting boat:

Last fall I purchased an old 14 foot starcraft taken down to the brackets.
I plan on using 3/16 rivets to attach angle to the sides which will then have a piece run across to the other side. I'm wondering how if it will improperly stress the boat. What kind of spacing should I have between them. From what I've read 1"x1"x.125" should be strong enough? Or do I need to step up to either thicker or wider Al.

I'm hoping I can get away with having only attachment points at where the old seats were but more might be better? Every two or three ribs possibly? At some point I'll be picking a 9.9hp motor up but for now a 55lb bow mount will be my primary propulsion. It will be mounted to the deck frame.

I'll make a project thread when I have more planned out, but right now I'm planning on having the deck about 6 to 8 inches bellow the gunwale. Along the starboard section of the there will be a raised platform that is slightly above the gunwale for a trolling motor mount, hoping to be able to store tackle drawers underneath it. On the starboard side I'm hoping to squeeze in a small rod locker level with the gunwales as well. Will this be too much weight for the side of the boat to support or will I need to find some way for the bottom of the boat to take some load. I'm worried the added ridgity might be bad for longevity.

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Attaching a frame to older boat

Post by Johnny » 07 Apr 2015, 08:53


what you envision will work. . . . make adjustments as you go
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Attaching a frame to older boat

Post by minuteman62-64 » 07 Apr 2015, 14:16

If you are asking about the rivet spacing - you can go on-line and find data on the shear strength of different types of rivets. Make a conservative assumption about the load on the bracket, divide by the shear strength of one rivet and the result is the minimum number of rivets needed (its going to show as pretty low - maybe even 1; I'd at least double or triple the number.

Are you thinking a 1x1x1/8 angle going across your boat? I did some calculations awhile back, based on a 200 pounder (me) standing in the middle of my small add-on deck. Again, being conservative, ended up using 1 1/2 x 1 1/2 x 1/8 angle of a structural grade. Would cost a little more, but, compared to the labor you'll put in, won't amount to much in consideration of the entire project.

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