Water in keel

[steffen]

Having my underwater scraped clear, i discovered a trickle of white substance along my keel. Further investigation revealed drops of water from the keel. I then drilled some holes that promptly ejected quit a lot of water and knocking the keel made a hollow sound at some spots, GRP delaminated form lead.
The keel is lead, not bolted on but laminated onto the hull by approx 15mm of GRP.
As an emergency -going wet in three weeks- i drained as much water as i could and then plugged the holes probably to find the keel filled with water when i go dry again by the end of the season.
The fluid is not acid, so probably no hydrolysis (yet).

Question: How to treat this problem next winter?

My own thoughts: drill open again and let dry during winter (some way to force drying?), fill with two comp PU foam .

All suggestion welcomed.

Happy sailing, Steffen

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[snowleopard]

not PU foam, it has no structural strength and even as little as 2 ft of water pressure will crush it. you could use aerosol foam (available from DIY shops) but it builds a lot of pressure if the exit hole gets blocked.

The safest material would be resin with added chopped strands (these are glass fibres around 2mm long which add structural strength, the resin is brittle on its own. with this method you need to drill a hole at the top to allow it to run down.

Another safe option is to use polyurethane mastic such as sikaflex (there are cheaper versions available from builders merchants which would be just as good. the advantage is that you can inject it.

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[steffen]

Had in mind to use 2-component; same stuff used for sandwich decks, seems pretty pressure resistant(?).
Mind you, i have to blow it into holes n the laminate to get it between the laminate and the lead keel core.

Happy sailing, Steffen

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[snowleopard]

yes, that's the stuff i meant: REPF (Rigid Expanded Polyurethane Foam). i use it for things like fridge insulation, dinghy buoyancy tanks etc. it is very weak and the cell integrity soon breaks down. the water is then sucked in like a sponge. a good quality sandwich deck will use PVC foam such as airex which has strength but can't be applied in liquid form.



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[oldsaltoz]

G'day Steffen,

I think you need to find the point of entry first, not much sense in spending a lot of time and money only to have it destroyed by more water later.

As soon as you pull her out drill a small hole at the top and apply just a little air or water pressure to force the water out of the hole/s. Grind out and repair, drill holes thru hollow sounding areas and at the base to drain all water, A heat lamp on each side of the keel will speed up the drying.

Starting from the bottom, inject closed cell balloons to fill the voids till it comes out of the hole above it (About 50 mm apart) and put a temporary screw in the hole to block it. Next day, remove screws, grind back the holes to a feathered edge and apply fibreglass to all holes, (use epoxy resin) and apply at least 3 coats of epoxy resin after fairing: a light sand, a coat of Polyurethane and antifoul.

I hope this helps.

Avagoodweekend. Old Salt Oz /forums/images/icons/cool.gif



Is the keel lead shot filled, moulded lead or perhaps lead ballast on rods. In any event

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[steffen]

Got your point, thanks for the elaboration, didnt know that.

Happy sailing, Steffen

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[steffen]

Hi Oldsaltoz,
Thanks for the info, Veeeeryyyy usefull.
As for your PS, the keel is moulded lead.

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