Dory Wet Foam Issue

[markymarkP]

hi guys,
i have a 17ft Dory, with foam under the deck, about 15inches thick in the middle
it has got wet where it was moored for months without covering, previous owner!
apart from this its a lovely boat so is it worth removing the foam? i know it does often ends up waterlogged, thus making the boat heavier

just wondered if any have done this, and if they replaced it with new foam, or just left it with bilge pumps and so on.

does it affect the stability of the boat to remove it?

any advice/thoughts would be appreciated


thanks

[m chappelow]

yes i have seen it dozens of times when scrapping boats,and yes it can have a large weight increase with waterlogged foam ,,on one of my hard boats the seat/bouyancy tanks were soaking wet ,,so i removed the old foam and replaced with some closed cell2 pack stuff,,when removing the old foam i could hardly pick it up it was that full of water ,,suppose there is various ways water can find its way in over the years ,,but whatever you do i would replace the foam with something similar as with some boats its not just a bouyancy issue as giving stiffness ridgidity to the boat and sound dampning .

[Rib T]

If you have long term access to dry storage it is possible to drill the fibre glass hull in a number of places above the waterline turn it upside down and let it drain. Once its stopped draining, no weeps and a reduced wieght, simply prepare, fill and gell coat the drilled holes to make good repair. also while it is out the water check it over to see where the water is gaining entry.

Draining takes months rather than days.

The foam makes the hull rigid because the inner and outer skins are held in opposite tensions.

[markymarkP]

so sorry to appear thick, but the foam i am talking about is between the deck, and the hull, is there foam beween what i can see as the hull, from inside the boat, and the outer hull?

i cut a hatch in the deck, and cut a circular hole down through the foam until i got to the hull.
i am presuming that is the inner hull, and there is an outer one too.

if this is the case, when i take out the drain bolts in the back of the boat, very little water comes out.

i am wanting to sort out the foam just under the deck. would it be best to just let it dry for some months, then rubberize the deck to waterproof it?

[Poly]

I believe the entire void between the deck and the outer hull is filled with foam. When you take the bung out and there is just a trickle this is because there is a giant sponge under the deck holding all the water, my experience is once it gets wet its virtually impossible to get dry.

[Mollers]

A water logged dory is pretty much a skip shaped log.

[Poly]

Originally Posted by Mollers

A water logged dory is pretty much a skip shaped log.

nah - at least you can burn a log

[markymarkP]

i have been using it for about 9 months, and it is slowly drying out, at first, when i cut the hole in the deck, it was always full of water, now it has about 2" in the bottom when i look.

so it is slowly improving.

also, i have a good cover for her, so she does not get wet when left in the pound.

i take the bilge screws out every time i have used her, and leave them out until next time.
when i remove them, about a pint of water comes out, so not much.

perhaps i need to be patient and wait, and with my cover and removing the screws, she may be ok.

i keep meaning to take her to the weighbridge, to see what she weighs, then in a few months, i could see how she is doing on her diet!

[Poly]

Originally Posted by markymarkP

i take the bilge screws out every time i have used her, and leave them out until next time.
when i remove them, about a pint of water comes out, so not much.

when I take mine out nothing comes out. theres no foam in my void to soak it up either.

[markymarkP]

so have you removed the foam?
i hear if you do, you must replace it?

i just presumed the water that comes out is what splashes into the boat as you go along, the boat has no cuddy, and it does get wet as we use it for diving.
there must be small holes from the deck that it goes through??

[Poly]

Originally Posted by markymarkP

so have you removed the foam?
i hear if you do, you must replace it?

i just presumed the water that comes out is what splashes into the boat as you go along, the boat has no cuddy, and it does get wet as we use it for diving.
there must be small holes from the deck that it goes through??

No sorry I don't have a dory (although I have had the pleasure of their acquaintance in the past!). The point I was trying to make was the void under the hull should (and can actually be) properly sealed, if it is full of foam and you get a pint out the drain you've probably soaked up 3 or 4 times that too.

There SHOULDN'T be holes that go through the deck and let water through - and holes through the deck should be properly sealed with Sikaflex. My experience is that water gets into the hull void in two ways (1) damage to the hull e.g. from someone driving it up a rocky beach or hitting a jetty (2) through the seal between the deck and the hull - once this starts to let water in you are looking at a major repair.

You might be able to trace the leak by connecting an air pump to the bung hole and going carefullly over every possibility with soapy water until you find where it is bubbling.

[markymarkP]

Thanks I will try that this autumn when I am done diving for the year

[Andy B]

i've got no foam in my bilge and never had any strength issues!
the best thing you can do is cut your floor out to remove all the water logged foam
if it's been water logged for a long time then chances are it's gona need a new floor anyway!
mine was the same before i got it, and now it's had a new floor glassed in.
my bilges are clear and i've got a nice pump down there cos they do like to take on water in the chop! (cue comment from jizm )

[markymarkP]

one thing i forgot to mention, but is probably the cause of this wet foam, is that one of the two bilge screws wont tighten, it goes so far, then just turns around, someone stripped the thread at some point

would it be better to glue that one in place? it is probably where the pint of water gets in when i am out in her.

also, behind the transom, the main wires and cables to the engine used to come through the deck, under it, then back up to the steering etc
this i blanked off, and rerouted much higher, as i thought it was an obvious area to leak water under the decks. now the cables go out higher than the transom, so should never leach water in

[Jizm]

Originally Posted by Andy B

my bilges are clear and i've got a nice pump down there cos they do like to take on water in the chop! (cue comment from jizm )

There doesn't need to be any chop....

[Jizm]

Originally Posted by Andy B

the best thing you can do is cut your floor out

.....and use it as a skip?

[9D280]

The foam in those boats is what is preventing the SE of England from dissappearing under rising seal levels!

I got an 11' one. We spent 6 months at a silly angle in a shed with multiple holes along the transom, and I've no idea how much water got out, but suffice to say we could lift it as opposed to the 4 people it needed to drag it up the beach on it's trolley before.

Every screw etc was taken out & re- sealed, all fibreglass imperfections removed. One half hour trip later & we were back to square one.

Having done that twice, we're now looking for an Avon W350 / 400 or equivalent to replace it.

PS anyone want an 11' dory, 2 careful owners?

[biffer]

take the black fendering off from around the boat, thats where the top is fixed to the bottom, take the top deck off, dig out the foam glass a layer of ply on the underside of the deck and put the deck back on the hull.
it's not easy but thats the way

[Andy B]

Originally Posted by Jizm

.....and use it as a skip?

so were getting fish guts and rag worm all over your new ride then?

[Jizm]

Originally Posted by Andy B

so were getting fish guts and rag worm all over your new ride then?

In order to have fish guts first we need to actually catch fish...