Added Strength Under Cap

[LandscapeSavannah]

I’m not a new boat owner, but I’m a newer SeaCraft owner. I have a 1976 20’ and someone began a transformation by adding an Armstrong bracket and closing the transom. I was wondering if there was a way to strengthen the space up under the cap? There is a large amount of flex when a passenger steps onto the side of the boat when boarding and I figured this would be a good area to practice working with fiberglass. Any recommendations?

[rcoster38]

are we talking the original cap, or the new part that was added when the transom was closed? is the new cap cored?

[castnetcracker]

depends if you plan on pulling the cap off or not. I tore out all the old core, laid down a layer of 1708, 3/4" divinycell, sealed up with another layer of 1708, and its solid as a rock now.

[LandscapeSavannah]

There is foam, or is that coring? I have not done anything with the cap, but I am wanting to replace the non skid and do something to prevent so much flex. If someone leans or sits on the side it’ll give a great deal- it just worries me.

[crsavage1]

I am interested to see what advice you get. Have a similar issue where my cap needs some added strength in the corners. I have included the underside of mine which is in the aft corners where my enclosed transom is. Curious if yours look anything like this?

For reference, this is a picture of the underside of my cap. This is the corner of the transom and port side with the open hole being one of the thru-hulls that I took out. There is serious spider cracking in the corners that will need ground out and fixed, but I think the real issue is the lack of support for the cap in the first place.

[GreyGhost]

Originally Posted by LandscapeSavannah

I’m not a new boat owner, but I’m a newer SeaCraft owner. I have a 1976 20’ and someone began a transformation by adding an Armstrong bracket and closing the transom. I was wondering if there was a way to strengthen the space up under the cap? There is a large amount of flex when a passenger steps onto the side of the boat when boarding and I figured this would be a good area to practice working with fiberglass. Any recommendations?

The below video is what you need to do. I could not type enough to explain as well as this video does.

Watch "Installing The Coosa Support Knees On The Bertram Moppie 25" on YouTube
https://youtu.be/q_uRrpVmsjA

[Oldboat]

I did mine in one inch coosa solid as a rock. I also cored cap with coosa. I had my cap on and off quit a bit when I was rebuilding it. I template the braces with door skin and hot glue so they fit perfect. I bonded them in with expoxy butter and glassed the joints. Also drilled 1/2 nah hole while they were being made for wires.

[Glosta23]

Great info... THX

[rcoster38]

Originally Posted by castnetcracker

depends if you plan on pulling the cap off or not. I tore out all the old core, laid down a layer of 1708, 3/4" divinycell, sealed up with another layer of 1708, and its solid as a rock now.

i did this as well, plus a layer of 1808 on the forward area and now i could park a truck on it. the old core was GNARLY. however i only took the cap off as far aft as the side storage cubbies to save myself a lot of fairing. the coring was fine aft of there and its such a small span i wonder if it even really needs coring at all

[Oldboat]

Nice job. I did one thing a little different when I core the coosa in cap. After I ground it out I cut and fitted all the Cossa and screw in to cap with temporary screws then I took all the cossa out put the cap back on boat with temporary screws and used epoxy butter and put coosa back in with temporary screws and after it was set pulled cap off and glassed. Reason why is I wanted my gunnels to line up perfect with the crown on the new transom and to fit really tight it worked perfect