Reattach cap to hull

[Jack2048]

What do people use when re-attaching the cap to the hull?
3M 4200?

This is for a 23' 1994 bow rider.
There is a 3/4" plywood strip screwed to the bottom half of the hull, see picture.
Then the cap was screwed to the hull/plywood strip combo.
Then there is the rubber bumper line that was screwed into this too.
So you had two screw binding the two halves together.
It looks like they used silicon to glue the two halves together.

 

[jimmbo]

That sounds a lot more solid than a lot of hulls on the water

 

[stresspoint]

use silicone , roof and gutter will be fine as that area requires a sealant not a glue..

 

[Scott Danforth]

4000UV would be my go-to

 

[Jack2048]

4000UV would be my go-to

There seems to be some issues w/the 3M 4000 UV.
I have some concern about this product, lots of people who successfully use the product, but also too many negative reviews after searching and some product failure issues:
https://www.practical-sailor.com/blog/ps-seeking-reports-of-3m-4000-uv-failure

 

[alldodge]

It's very doubtful the top cap will ever need to be removed again, but if it did it would be better with silicone

 

[todhunter]

I just used some clear silicone caulk I got from Home Depot. My cap was originally put together with it, so that's what I went back with.

 

[alldodge]

...

 

[Jack2048]

I just used some clear silicone caulk I got from Home Depot. My cap was originally put together with it, so that's what I went back with.

Well, that's two votes for silicone and that is how my cap was attached. I was just thinking there might be something better.

Looking at Sika 291

 

[zool]

I used Lexel from lowes/hd on my sea ray 33 between the cap and hull, and under the rub rail. No more water stains on the hull liner where i cleaned previous stains after one season. I did stuff the bow some going thru the inlet, but it held up fine.

 

[mickyryan]

i use a polyester caulk usually the roofing caulk only because i try to keep silicone away from any boat i ever wanna paint **** just travels

 

[tpenfield]

The 4000UV or the 5000 would be fine IMO. I did find that on my swim platform project, the 4000UV shrunk up a bit after the first year and needed some re-chaulking. Of course the bond on a shoe-box joint would be different.

Maybe . . . Plexus structural adhesive. I know that Formula boats (and probably some others) use it for the hull joint bonding.

 

[Scott Danforth]

plexus would be permenant, however you would need a crew of people to drive in the screws before it sets.

 

[tpenfield]

plexus would be permanent, however you would need a crew of people to drive in the screws before it sets.

I know . . . . . . maybe that's why we don't see folks taking the cap off any of those boats.

Of course on a re-build, assuming done right, maybe permanent is OK

 

[Scott Danforth]

I know . . . . . . maybe that's why we don't see folks taking the cap off any of those boats.

Of course on a re-build, assuming done right, maybe permanent is OK

if it was done right, there wouldnt be a rebuild. however as an engineer, you understand design life.

 

[froggy1150]

I tried that lexel and it never cures completely. After a year it's still sticky. I went with it cuz it was crystal clear but now wish I didnt use it. In a hidden joint with lots of flex might be fine. Just not exposed where you might touch it

 

[zool]

I tried that lexel and it never cures completely. After a year it's still sticky. I went with it cuz it was crystal clear but now wish I didnt use it. In a hidden joint with lots of flex might be fine. Just not exposed where you might touch it

Its a little tacky, yea, but thats a plus for this purpose, it retains its adhesive properties in wet areas for years because its moisture cured, as opposed to getting brittle and having to be dug out and replaced. The fasteners keep the parts together, the lexel keeps the water out without delamination.

I dont really use appearance caulk on boats because I think caulking makes it look like a quick fix leak repair

 

[froggy1150]

I used it on a plexiglass window. I went thru at least a dozen seal samples and took the best one I could find and wanted a little help. It did work but if I touch it .....

 

[Jack2048]

I have a rather large gap between the hull transom and the cap.
I am wondering how to fill this gap?

The picture below shows the gap. The view is looking from the ground upwards to the sky at the back end / corner of the boat.

 

[Scott Danforth]

Take a picture from further back so we can get some perspective