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

[PipeDreamsMarine]

As always... nice work.

[pogden]

Strick,
I should have known you would be the one to do this, the quality of your glass work is phenomenal. I can't wait to see the end result. I am going to try to do this on my MA, I can only hope it comes out half as nice. Keep the pic's coming.

Pat

[Bigshrimpin]

Looks great!! What's the transom core material on either side of the marine ply?

[Capt Chuck]

Outstanding Strick [img]/images/graemlins/cool.gif[/img]

Maybe a built-in insulted 12 pack size box type cooler in each chamber before you seal the platform on would be a thought??? Access through the top port holes. Keep bait, beer or even small dry storage or whatever, drain them to the main chamber drain.... [img]/images/graemlins/grin.gif[/img]

[FELLOW-SHIP]

Again looks great, I know AFTER I did my transom I started thinking “I wonder if one could build a intergraded bracket WHILE you are redoing your transom”??? Sooner or later some one probably on this board will try to do that but in the mean time your approach looks great.
FellowShip [img]/images/graemlins/grin.gif[/img]

[Trayder]

Looks good-

Only issue I can see is water getting trapped in between the stringers?

[strick]

Thanks fellas

I guess well see if it works when I that engine on the back of it [img]/images/graemlins/confused.gif[/img] The transom core is 3/4 inch plywood sandwiched between two layers of 5/8 corecell. After I did it it thought that I should have done it the other way around and sandwiched a piece of corecell between two pieces of plywood. I have a drain in the center stringer but Trayder is right and I need to add one on each of the outside stringers before I close it all up. Here are a couple more pics.

Strick

[Trayder]

Strick-

I leaned the hard way, I forgot to put drain holes in my outer stringers and let me tell you much of a pain it has been finding a fix after the deck was in...... I did fix the issue but trust me I will never forget again.

All the water that accumulated in my outer stringer area was Condensation but after a few months of vastly differing temps that condensation accumulates very rapidly.

One drain hole in the aft corner of each stringer is all you will need.

Your bracket looks great, and oddly familiar [img]/images/graemlins/wink.gif[/img]

[strick]

I'll drill a couple one inch holes and seal with cabosil and that should do the trick.

Today one our fellow SeaCrafters Tim Barber aka Bigshrimpin paid me a visit. It was great to see Tim and talk with him about SeaCraft's and boats in general. Tim not only stopped by to shoot the $h#t but was kind enough to roll up his sleeves and dig right in. Here are a few pics of what we did today. We applied 3 coats of wax over the swim platform mold and applied two layers of 1808. We then cut some corecell to fit and glued it in place. Tomorrow I hope to finish the paltform pop it off the mold and see if it fits the bracket [img]/images/graemlins/confused.gif[/img]

Strick