Temporary hole repairs below waterline

[MachSchnell]

I have removed the remnants of the swim ladder that was destroyed by the former owner of our boat. The screw holes below the waterline are my biggest concern, but there are also some holes on the top deck where rain intrudes into the hull and trickles down onto my batteries. The boat is on dry dock right now.

I have JB-Quik epoxy or regular silicone caulk on hand but I'm not sure which could be the best repair for this summer. I even wondered if acrylic interior/exterior caulk could do the trick. These are small screw holes (max 3/8" diameter) that only need to endure a minimal amount of hydrostatic pressure. There isn't much time and I'd consider any sensible temporary repair until it can be done properly next winter. I also looked at PowerPoxy or maybe 3M Fast Cure Marine Adhesive/Sealant

Does anyone have any suggestions for which (or which other) way is the best to tackle this problem? Thanks!

 

[oops!]

Re: Temporary hole repairs below waterline

hi bud.....3m 4200 will be fine till you want to fix it...

the 5200 is the better way to go and permanant, however it soulds like you want to get in there and fix it corectly soon....so the 4200 is the quick, easy, and totally acceptable fox for that.

cheers
oops

 

[MachSchnell]

Re: Temporary hole repairs below waterline

Thanks, oops! Glad to have you aboard!

 

[saildan]

Re: Temporary hole repairs below waterline

I have removed the remnants of the swim ladder... The screw holes below the waterline are my biggest concern

Epoxy is your most solid hole filler. It adheres with 400,000 psi tensile strength and covered with a drop of paint or clearcoat to give it UV protection will last the life of the boat. Want to reuse the hole, just drill it to size.

Marine-Tex is all the rage. An epoxy with hardening filler added to make a paste or putty. Your JB is the same generic epoxy as anyone's with JB's own magic filler. Their regular formula uses metal powder as a filler, that's why it looks metallic gray.

​

Caulks are a distant runner-up. Popular right now are the Polysulfide and Polyurethanes, BoatLife or 3M XX00. Notice in the data sheets, caulks only have 300 to 700 psi tensile (pull-apart) strength compared to epoxy's 400,000 psi. Depending on the job this may or may not be a good thing.

​

3M 4000 would be the basic caulk, 4200 for a fast cure variety of 4000, or 5200 for extra adhesive stickiness for tacking things together. You do have to read the cure time needed before immersing, but once fully cured they are rated for below the waterline.

Click on an image to read the data sheet for prep and cure information.

4000 UV


4200


5200


3M Sealant Brochure​

 

[oops!]

Re: Temporary hole repairs below waterline

the problem with those type of products is that they are permanant.
the poster wants to do a proper repair in a while, and does not want a permanant fix.

the only way to remove the products you describe are to grind them off.
that means fairing and re-gellcoating the spots after the proper repair is done. if the hull is a white.....matching that color of white may be a special order from the manufacturer (if they are still in business)

thats why the 4200 and not the 5200....
we use it in boat yards for that exact purpose all the time.

 

[saildan]

Re: Temporary hole repairs below waterline

the problem with those type of products is that they are permanant.
the poster wants to do a proper repair in a while, and does not want a permanant fix.

the only way to remove the products you describe are to grind them off.
that means fairing and re-gellcoating the spots after the proper repair is done. if the hull is a white.....matching that color of white may be a special order from the manufacturer (if they are still in business)

thats why the 4200 and not the 5200....
we use it in boat yards for that exact purpose all the time.

Oh, I concur. I'm not advocating any one product, only speaking to the level of durability. An attempt to show a comparison for an informed decision on his part.

Like I said, some qualities may or may not be desirable for the application. It's his call.

 

[Yacht Dr.]

Re: Temporary hole repairs below waterline

Hello Mach..

The " The screw holes below the waterline are my biggest concern " issue.. Im assuming thats were you have your 3/8" holes..

Quick fix instead of grind and glass ? okies.. get some though bolts that fit the holes..fender washers and then bed them down with 5200 ( you did say there below the waterline eh ? ).

When your ready to do it the right way ( which would not take you very much more time in this summer heat ) .. post again..

The other small holes .. above waterline..clean and fill with your leftover 5200..

YD.

 

[MachSchnell]

Re: Temporary hole repairs below waterline

This is awesome and you fellows are great with a wealth of info. I'm liking the idea of putting screws in the holes and bedding them down with 4200. The holes below the water line are in black gel coat. Some of these come in black and could also make a fine fix without too much effort and I'm not sure that anyone would notice but me. This boat's not a trailer queen, but sometimes I dream.... It's a Cobalt and they're still in business and they've offered me great support. I called them once to inquire about it and they sent me the build sheet. They still had it after 20 years.

Could I epoxy the holes in deep and leave enough room over top to redo the gel coat at a later date? Would it be better to gel coat later over the 3M products?

Please keep your comments coming.

 

[109jb]

Re: Temporary hole repairs below waterline

Epoxy is your most solid hole filler. It adheres with 400,000 psi tensile strength ...

More like 4,000 psi if that.

 

[Yacht Dr.]

Re: Temporary hole repairs below waterline

This is awesome and you fellows are great with a wealth of info. I'm liking the idea of putting screws in the holes and bedding them down with 4200. The holes below the water line are in black gel coat. Some of these come in black and could also make a fine fix without too much effort and I'm not sure that anyone would notice but me. This boat's not a trailer queen, but sometimes I dream.... It's a Cobalt and they're still in business and they've offered me great support. I called them once to inquire about it and they sent me the build sheet. They still had it after 20 years.

Could I epoxy the holes in deep and leave enough room over top to redo the gel coat at a later date? Would it be better to gel coat later over the 3M products?

Please keep your comments coming.

No.

5200 under waterline..

I dont understand these " hole repairs " in the summer.. man.. grind it bevel like 2".. put 3 layers of mat.. block and apply gel ( you can finish/polish when you can ) .

Holes in the transom would take like 2 hrs ( total time without cure ). One day..finished and polished..

YD.

 

[saildan]

Re: Temporary hole repairs below waterline

More like 4,000 psi if that.

I guess that's "modulus", 7,800 psi tensile, at least according to WEST - my error and apologies. Still far beyond 5200's 600 psi when a real adhesive is called for. I'm no epoxy engineer, just trying to have a solid basis for comparison rather than the usual 3rd, 4th, 5th hand smoke so often tossed around.

WEST Typical Physical Properties Sheet​

_

 

[flakeys2005]

Re: Temporary hole repairs below waterline

My swim ladder is still attached but with two loose screws. The previous owner did a repair but it was not a good one. I have noticed since his repair failed, I do take on quite a bit of water in a relatively short time. I bought the boat life stuff, but have yet to make the repair. I will let you know how it works if I get her back in the water in the next couple of days.

 

[MachSchnell]

Re: Temporary hole repairs below waterline

No.

5200 under waterline..

I dont understand these " hole repairs " in the summer.. man.. grind it bevel like 2".. put 3 layers of mat.. block and apply gel ( you can finish/polish when you can ) .

Holes in the transom would take like 2 hrs ( total time without cure ). One day..finished and polished..

YD.

Thanks, Yacht Dr. I guess it's summer when we learn about the faults in our boats.. I wish I had the experience to perform these repairs so readily, but I'm just learning. I did choose the 5200 in black, btw, as suggested below the water line. I'm getting the 4000UV for the top holes to try to keep them whiter and give myself a fighting chance one day if another remedy is necessary.

The advice I'm getting here is tremendous. Thanks, everyone-