Making an Engine Bracket

[strick]

Go easy on me boys as this is my first time. I decided to give a try at building a engine bracket for my 23CC. I have a yamaha 250 that is supposed to hang off the back of this thing. I may or may not put a kicker on it as well. The bracket has a 48 inch wide flotation chamber and a 30 inch set back. The swim platform will be 84 inches long by 27 inches wide.

I started by making a 1 off mold out of 1/2 inch MDF for the flotation chamber. After cutting the mold pieces I tacked them together with finish nails and put some fiberglass tape around the edges to hold the mold together. I used bondo to make the rounded courners on the inside of the mold. Bondo hardens fast so you dont have to wait a long time for it to dry because there is a lot of sanding needed to make the corners smooth. Two coats of epoxy on the inside of the mold and sanding with fine grit over each coat helped to make it smooth. I put 4-5 coats of wax over the entire mold buffing out each coat.

For the lay up I used System 3's 2/1 epoxy. They have different hardeners that you can mix together to get the right working time for your lay up. I put three coats of Duratec sanding primer over the inside of the mold. I used 1808 biaxial cloth for the entire lay up. I overlapped all the corners and then reinforced the corners with 8 inch tape. The layup was hard for me because of the thickness of the bracket and I needed to pay attention to structural detail. The finished shell of the flotation chamber has a 1/2 inch thick lay up on the front, back, bottom and sides. The corners are 1 inch thick lay up.
I glassed a core transom into place with a 1/4 inch thick lay up on the inside of the bracket. Next I glassed in some stringers made out of 2 pieces of 5/8 inch corecell glued together.

I'm currently working on the mold for the swim platform and will start the lay up of that this week. The swim platform will be bonded to the flotation chamber with cabosil. I am glassing in a lip that goes around the inner edge of the flotation chamber for the swim platform to adhere to. I have two 8 inch armstrong round hatch plates for access to the inside of the bracket.

The bracket is still a long ways off from being finished. Like I said I still need to make the swim platform. Also there is some fairing and sanding that needs to happen due to some imperfections of the inside of the mold. It will have to be painted as well.

I wanted to thank some of the fellas on Classic SeaCraft who helped me by sending pictures of their brackets. I would not have had a clue as to were to start. Here are a few pics of the project and a link with a photo gallery of all of the pictures I have so far. I will post again when it is all finished.













http://www.casdvm.com/photos/Bracket/index.htm

Strick