water logged foam

[simonfraser]

mobo, there is sweet water in the foam, i have drilled a 50mm hole in the forward floor down into the foam to the hull.
and can pull about 50ml of water out every time i am on the boat, weekly or daily makes no difference, never ending.
i have fixed numerous leaks over the last 18 months, she is now not leaking any more.

but how to get all the water out of the foam which is in the sides around the engine bilge and forward of the bilge.
the bilge under the engine is solid, no double skin / foam there.

at first i noticed water seeping into the forward end of the engine bilge, where there are some drainage holes from the sides, when launched down the hard. same b4 she got onto the plane.
that is now not occurring any more, so guess there is at least less water in the foam now.

but there is still some water in as the foam is still wet, i could crane her up by the bow or drill a hole in the keel

thinking of rigging up a small pump with a time switch for the forward hole, any other (sensible) suggestions ?

 

[Mr Googler]

Heating and a big dehumidifier?

 

[oldgit]

Had this problem with an old Regal sports boat, it was around the fuel tank and transom, due to leaking of seal round outdrive casting. Removed floor panel and dug out all the foam we could could get at. Left the rest to hopefully dry out over time.Fortunately this boat was built at time when hatches to enable access to hidden areas was far more common.
Do not think it will damage anything, other than any unsealed ply or wood.Only concern was perhaps the weight of the water absorbed in the foam.

 

[A_8]

Not native English so sorry but are you referring to water in the core of the cored hull?

 

[simonfraser]

Water in the foam in the space between the hull and the lining.
Yeh the weight of the water is my main concern, it used to list to one side, now its drier not any more, but who knows how much is in the ‘keel’ space ....

 

[BruceK]

I presume the foam buoyancy in the stern and bow. Wet foam will never dry out and is likely to cause stringer rot with any it is in contact with. The only sensible course of action is the one you least want to hear. Mechanical removal and replacement.
This is a common issue with small fast fisher boats with low freeboard to have foam as buoyancy many do not replace the foam or choose play pit balls, plastic bottles etc to replace the foam and still provide buoyancy. The latter can "implode" during cold weather so the argument for the ideal alternative to foam rages on.

 

[rbcoomer]

Agree with BruceK - you'll likely need to remove it as it never dries properly - although if enough is exposed you might be able to remove most? Even left in warm weather it will partially evaporate and then condensate again when it cools. When I did the Arrowbolt there was perhaps 30-40 litres of water in there - that's a lot of weight! I removed and replaced floors, stringers and transom. The closed cells on the old foams break down over time and it becomes a big sponge if water gets in. You could try forcing warm air through, but I doubt this would do more than dry a small channel or route through the foam. If it absorbs water then the structure of the foam has probably degraded with age.

 

[simonfraser]

Hm, kinda what i thought you might say.

Without taking the lid off the boat = cabin, there is no way to get access to all the areas.
Shall rig up some 12v fans to leave running with the dehumidifier ....

 

[BruceK]

It might, but it is a huge guess on my part, be worth researching if there is any solvent safe to use that will dissolve the foam allowing for replacement. Maybe a bit of correspondence with the manufacturer to see if they have a solution. But I'd be very hesitant on leaving wet foam in. Rot it does cause.

 

[simonfraser]

It’s all GRP down there, it’s the weight i want rid of.