Hull cover leakage

Posted By: Arjan13

Hull cover leakage - 03/31/18 01:50 PM

Hello all,

Just a short question I know some of you can answer probably quite easy.

Untill the day we find ourselves a new Infusion we sail on our old Inter18. As the boat is getting old we have decided to do a larger service to the hulls. We will grind some damages and put in New gelcoat, waterfront the full gelcoat and polish and so on.

However we also have some leakage at the hull covers. We always found the leak with some soap and filled it with silicone, but that is not really a long lasting solution.

Is there something else we could use?
Posted By: JeffS

Re: Hull cover leakage - 04/01/18 09:47 AM

If you can get rid of all traces of silicone, Marine grade Sikaflex is awesome but it won't stick on top of silicone
Posted By: Mike Fahle

Re: Hull cover leakage - 04/03/18 06:52 PM

Here is a chart from 3M of marine sealants to make it easy to choose the best one for your application. This is just 3M but these are all good.

Posted By: samc99us

Re: Hull cover leakage - 04/04/18 03:32 PM

Remove and re-seat with 3M 4200. You want to use a removable sealant as eventually it will fail.
Posted By: Arjan13

Re: Hull cover leakage - 04/06/18 08:47 AM

Thanks, this is good help, I will start this weekend, the season is starting here ;-)
Posted By: _flatlander_

Re: Hull cover leakage - 04/11/18 05:32 PM

sikaflex 291 is what you want
It is a Swiss product, and what all boat builders are using these days
Less than half the cost of 3M

Unfortunately not available in small tubes, like 3M products
Posted By: samc99us

Re: Hull cover leakage - 04/12/18 01:28 PM


Does Sikaflex 291 harden in the tube after opening? I recently learned that freezing the 3M products prolongs their in-tube life indefinitely.

Posted By: _flatlander_

Re: Hull cover leakage - 05/01/18 05:23 PM


Yes, moisture and air are enemies.
Put in a storage bag in the freezer.
(the fridge is for gelcoat ;p)
Posted By: Arjan13

Re: Hull cover leakage - 05/08/18 12:24 PM

We have used the Sikaflex, and it seems it works well! So thanks for the advice.

We have now however arrived at another challenging step. The boat is 20 years old, and the result of that is that the parts which were once a rough surface, bacame slippery. (like e.g. the hull covers) In rough weather conditions, this sometimes causes interestiung situations!

I remember reading something about mixturing sand / silica with gelcoat to overcome this problem. I cannot find this however here on the forum anymore.

1) Is there anybody who has done this before?
2) What "sand" did you use?
3) Can you describe how you did it?

Or is there another manner of dealing with this challeng?
Posted By: samc99us

Re: Hull cover leakage - 05/08/18 12:51 PM

My recommendation is to apply the non-skid that you see on newer F18's/A-Cat's. There are several brands, Seadek and Raptor Decking come to mind. The other option is a strip of non-skid tape:

The final option is basically a strip of the 3-6mm non skid EVA decking along the side of the hull (where your feet go), the 505 guys use a sort of tire-like rubber for this that works quite well.

I applied a full EVA deck to my Infusion Mk. 1 and it was the best upgrade we made to the boat, much more comfortable in all positions and super grippy. I used the 3mm raptor decking.
Posted By: Arjan13

Re: Hull cover leakage - 05/08/18 05:43 PM

Yes I've thought of EVA. If you however want to cover the deck like e.g. on the infusion, it gets quite expensive. If you would use a strip I wonder if it sticks?

The tape we have used before, and it cost me my wetsuit within half a year. So that would not be my first thought.

From one side we want a good solution, from the other side we so not want to spent too much money as we will probably go to an infusion anyway within the next 2 years.
Posted By: JeffS

Re: Hull cover leakage - 05/09/18 10:44 AM

International has a granular additive to add to paint or gel coat, it's rounded so no sharp edges, I've done it to a few boats now, I apply it with a 4 inch high density roller. You mix it in the paint tray and go over the surface once, if that's not enough grip you go back over a second time straight away and it sticks a lot more grip on, it's very good and much cheaper than tape
Posted By: samc99us

Re: Hull cover leakage - 05/10/18 11:30 AM


A strip of EVA foam will stick if you use contact cement to fasten it, or super glue the edges. Paint works fine too I just find it messy and painful compared with EVA.

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