Anybody have any ideas of how to dry out a foam core in a Dory

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paulcadd

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I have recently purchased a second hand Eurosport dory, only to find that the internal hull space is allowing water to enter, and thus soaking the foam core used between the outer hull and the internal moulding.
The boat has a drain plug at the stern, between the two skins, which I have left open to allow water to drain out. I have identified some areas where the water may be getting in from, and these need repairing, but apparently before any repairs can be undertaken the foam needs to be fully dried out.
Has anyone any experience of the best way to dry the foam core? I have been told that the only truly successful way is to cut an inspection opening and remove the wet foam and replace with new dry foam.
I do like the boat, but as it is only small, and is probably already 15 years old I am trying to refrain from going overboard on the repair costs.

Has anyone any experience of repairing boats like these, or the best and most economical method that would allow the boat to dry out.

The boat is stored out of the water, and in the open air. It does have a cover that protects the inside of the boat, but as it is in the open I have been hoping that if it is not used over the winter period then the water may drain of its own accord over the next few months.

Any help or advice would be gratefully received.

Many thanks,
Paul.
 
It'll never dry out over a UK winter without some sort of active help.

Condensation alone along with rain, humidity and foam will work hard against you!

The person who told you about cutting the affected part away is right.

The only other way would be to get the boat into a warm garage/shed/warehouse for the winter along with a couple of dehumidifiers but the electricity bill alone could be crippling!
 
Wet foam out. You might dry it out with a heater etc but you might not.

Where is the damage? If its suitable for a hatch a fiver sorts the hatch then dig out the foam. A closed cell expanding foam £15¿ job done?
 
This is quite a common problem for angling boats. Most people take out the foam and replace with playpit balls and plastic sealed bottles. I think they just use spray adhesive. This method puts an end to it happening again. Try a search on WSF boat owning and equipment. Lots of threads and advice to be found there on the foam issue.
 
Have to agree with the others. Polyurethane foam blown into buoyancy chambers is never 100% closed cell unless done professionally using a different base than is available to most of us (MDI v TDI). Some of the cells will fill with water that can never be dried out. In some cases the buoyancy becomes negative and will sink. RNLI boats used to have PU buoyancy in blocks that were replaced on a regular basis, we used to see the old stuff in skips at Dickies in Bangor.

As suggested, cut out the old stuff and refill with something else. Polystyrene foam is closed cell and much lighter than PU.
 
I've had this problem with a very old Dell Quay Dory.

I wasn't worth spend any significant money on it, but I did want to use it for a while.

I decided that it was, in the long term, beyond repair. So I drilled some 6mm holes in the transom and stood the dory on its stern, leaning against a wall in a dry but unheated boat shed over the winter. This allowed most of the "free water" to drain out, but you'll never get all the water out tis way, it's trapped in the foam. However, I did make the dory a lot lighter.

In the spring I patched up the hull and drain holes with polyester resin and glass mat, the keels of the two outer hulls where well worn from running it up the beach. Applied some paint and used it for a season.

This is not a long term solution, but could be repeated the following winter, it's a minimum cost, minimum effort way of getting by.
 
why not turn it into a feature in your dining room chuck the table away use it upside down for the winter I'm sure your misses will confir
 
I'm wondering whether the foam serves a structural purpose in that particular boat. Others will know.
Also I wonder where and how you use the boat, and hence how important it is to have a reserve of foam buoyancy.

I once had a small launch on the river, old and a bit tatty but she got me out and about and to the pub and back, and more. She was double skinned with foam between, but it was clear that the foam wasn't really structural. I found that there was loads of water trapped between the skins, and clearly much of the foam was sodden. I drilled some holes in the inner moulding and sucked free water out with a hand syphon pump ("home brew style").

I filled the holes again, leaving one which every now and then I used to pump some more water out through. About ten years later I sold the boat having done nothing more, and ten years on from that she's still in commission and the present owners have likewise done nothing more in this regard.

Oh - and by the way she had big osmosis blisters when I bought her, and no-one's ever done anything about them either.

I would have thought twice before taking her to sea, though.
 
Alan ashore said:
I'm wondering whether the foam serves a structural purpose in that particular boat. Others will know.
......
Click to expand...
I think they can be quite floppy without the foam.
The deck may be prone to crazing?
I'd say either drill holes and allow to drain, or cut the deck out and remove the old foam.
It's tempting to dream up some heat and vacuum approach, but I can't see it working, how do you apply vacuum to the foam without crushing the boat?
 
nimbusgb said:
It'll never dry out over a UK winter without some sort of active help.

Condensation alone along with rain, humidity and foam will work hard against you!

The person who told you about cutting the affected part away is right.

The only other way would be to get the boat into a warm garage/shed/warehouse for the winter along with a couple of dehumidifiers but the electricity bill alone could be crippling!
Click to expand...
My eurosport had the same problem. I've attached pics of the resolve
 
Despite what the manufacturers say there is no closed cell foam ever used in any boat that is 100% waterproof, any boat builder that has ever had to chop out sodden wet foam will tell you this. Rudders, Hulls, under floors, in stringers, sooner or later it all soaks up sea water.
You cant dry it out. In something lke a small dory you might get away with cutting a strip of deck out down the centreline to get access to hack the soggy foam out & fix the leaks then as said fill with plastic bottles.
 
This is a common problem with foam cored hulls like the Dell Quay Dory. I had one that suffered this way and cut the entire internal bottom out. The outer hull was fine but the foam core was a stinking mess of crap! Totally delaminated and impossible to dry out. I removed it all and cleaned the outer hull internally and set new foam down on crestomer paste. Then replaced the inner skin, also on crestomer paste and glassed over the edges where it was cut with woven roving tape. The resulting job was excellent and the boat is still in use 10 years later with no further water ingress. A lot of work though. Crestomer paste is expensive so I guess you could use a thixotropic resin with maybe a glass bead filler ??? I would not economise however. Worth it if you want to restore the boat to a good serviceable state but frankly nothing short of a full rebuild will work as the foam is probably totally unrecoverable. The reason it has got wet in the first place is because it delaminated. even if you dried it all out (which you probably cant) it would get water in it again as soon as you put it in the water.
 
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