Substantial Cracks in Gelcoat

[sphelps]

Something is weak there I would think because it is cracked ... I would just stick with poly . But that's just me ..
DB is right do some exploration to tell just what you have .. Then move on to the fix ...

 

[Yacht Dr.]

Hey guys..mind if I chime in..

IMO the cracks split from the holes drilled for the screws and the bolts like dry fingernails. Most of these cracks can be dremeled out and filled with gelpaste. Ill bet if you take the hardware off you will see they just drilled and bolted/screwed. Gelcoat needs to be camphored (sp) or 'countersunk' or it will leave a hard edge that will start to crack out. I also dont think you have wood core either. As far as bedding..well the last time I talked to 3m tech support they said the basic difference with 4000 and 4200 is its UV protection ( 4000 has more ).

Take the hardware off..die grind and repair the cracks with gelpaste ( IE repair kit )..sand and buff. Countersink the holes a little ( bevel the edges of the holes ) and install with 4200/4000/5200..your choice.

Good luck.

 

[MikeDobbs]

Wow- thank you so much to all of you for the detailed responses!

The boat is used in saltwater, so rot should not be an issue. On your scale of perfection to just wanting to go boating, I'm pretty close to the want to go boating side

I figure if it bothers me I can always redo the repair in the off season when I'm not missing time on the water.

On that note, I'm going boating today :joyous:, will keep an eye on the area while we're out. Tomorrow morning I'll pull the ladder off and, assuming there's no wood core weirdness back there, I'll probably grind out the scratches and patch with gelcoat repair. Then, reinstall the ladder with plywood backing and 4200/4000 adhesive.

Thanks again for all the help, I'll post back with more questions, or pics if I can finish the job on my own

Any suggestions on the best way to campher/countersink the screw holes? Is there a special tool/bit for this? Or can I just widen the hole a bit with a dremel?

 

[DeepBlue2010]

Just use a file to flare the edges, this should do. You goal is to smooth any cracks that might have developed during drilling and prevent them from extending to the rest of the gel


BTW, please don't take for granted that saltwater means no chance of rot. Boats gets washed with fresh water all the time, rain, etc. So, any leaks needs to be addressed immediately

 

[Woodonglass]

Not sure of your hole size but Lowe's or Home Depot sells countersinks...

 

[sphelps]

Dremel works good also . Use one of the cone shaped bits ...

 

[Yacht Dr.]

Not sure of your hole size but Lowe's or Home Depot sells countersinks...

This is what I use..quick.

You dont want to 'widen' the hole..just remove the gelcoat around the hole. You can do this whenever suits you. The cracks not gonna get much worse anytime soon. Do your thing then bang it out

 

[MikeDobbs]

No Title

Hey everyone-

So, I finally got around to getting the ladder off and making the repair. No wonder it was leaking- I'm surprised it wasn't leaking more. In the first picture you will see the holes in the boat were large, and had absolutely no sealant in them at all

So, we reinforced the inside with exterior plywood and reinstalled the ladder with lots and lots of 4200 to take up all the extra space in the mounting holes. I also used a Dremel to widen all the cracks in the gelcoat and (you're gonna hate this part) in the interest of getting back on the water filled the gaps with 4200. It's a bit messy looking, but it's an old boat and I only lost one day on the water. Depending on how much it bothers me I will cut/grind it all back out once the season ends and do a proper gelcoat repair.

We've been out on the water several days since the repair was made and there's absolutely no leaking

Thanks again for all the help

 

[gm280]

Hey everyone-

So, I finally got around to getting the ladder off and making the repair. No wonder it was leaking- I'm surprised it wasn't leaking more. In the first picture you will see the holes in the boat were large, and had absolutely no sealant in them at all

So, we reinforced the inside with exterior plywood and reinstalled the ladder with lots and lots of 4200 to take up all the extra space in the mounting holes. I also used a Dremel to widen all the cracks in the gelcoat and (you're gonna hate this part) in the interest of getting back on the water filled the gaps with 4200. It's a bit messy looking, but it's an old boat and I only lost one day on the water. Depending on how much it bothers me I will cut/grind it all back out once the season ends and do a proper gelcoat repair.

We've been out on the water several days since the repair was made and there's absolutely no leaking

Thanks again for all the help

Okay, My suggestions, when you get to it again, is to obviously grind out all the 4200 and/or 5200 sealant and even remove the inside plywood plate. Then do a little investigation work to see if your transom has suffered any water damage in those areas by drilling some sample drillings to see if dark rotted or wet shavings comes out. If so, you're in for a lot more effort. If they come out light color dry wood shavings then enlarge the holes and fill them with a mixture of polyester resin and Cabisol and fiberglass clippings and allow it to cure. Then sand those areas smooth and re-drill them for the proper size bolts and reattach everything with your 5200 sealer again and happy boating... JMHO!

 

[MikeDobbs]

Thanks gm280 - when I had the bolts out I did poke around the inside of the holes with an awl, and everything seemed really solid and dry. I will definitely take it under advisement though

 

[Woodonglass]

The goo thing is...That is NOT your transom. The design of your boat is quite unique an those "Wings" are separate to the structural transom so if there is wood in them, (was there???) it's not as critical as it would be where the outdrive is. I would advice protecting the plywood backer with some kind of coating.

 

[MikeDobbs]

Yup- I was thinking the same thing. Not really sure if there was wood in there or not- There were many layers of material- kind of like a sandwich. All seemed dry and solid to me though, so I'm not too worried about that.

As for the plywood, any suggestions for what to coat with? I know you mentioned resin and glass in an earlier comment, but it's a rather difficult spot to work on and in, so I'm not sure I want to go through the trouble. I figure it should stay dry with all the holes filled in with 4200, and if not I can always replace it down the road with some starboard or something...

 

[Woodonglass]

It doesn't have to be much of nuttin'. Just somethun to help preserve it a bit. I like the Oldtimers Recipe and it works really well and is easy to make and pretty cheap too!!!...

Adjust the ratios accordingly and just mix up a quart. 1/2 cup of BLO, 1 cup MS, 1/2 cup Poly. = 1/2 qt That should be enuf to coat the plywood. Then a couple full coats of the Poly after it dries. Or heck Just a couple coats of Oil Based Rustoleum Paint will make it last a long time in that location. I doubt much water gets there. If you got some 4200 in the drilled holes it should last a long time.

 

[BillP]

Yup- I was thinking the same thing. Not really sure if there was wood in there or not- There were many layers of material- kind of like a sandwich. All seemed dry and solid to me though, so I'm not too worried about that.

As for the plywood, any suggestions for what to coat with? I know you mentioned resin and glass in an earlier comment, but it's a rather difficult spot to work on and in, so I'm not sure I want to go through the trouble. I figure it should stay dry with all the holes filled in with 4200, and if not I can always replace it down the road with some starboard or something...

Next time use a piece of pressure treated wood and rot/sealing won't be an issue. 3/4 pt ply or 1x4 pt pine. SS fender washers are also a larger diameter and an improvement to spread the load. I back my ob motors installations up that way and no problems ever...

Let me add that hot dipped galvanized dock building washers are also a large diameter, heavy duty and can be used if massive strength is desired for a backkup.

bp