bilge and spongy floor

[DanM]

Hello
I'm new to the site and new to owning a boat. Hoping some of you more experienced users can help. Apologies for not knowing the terminology.

I've recently bought a share in a dolphin 21 cabin cruiser. Part of the cabin floor is spongy. Its around the area above the bilge pump. The carpet in the same place keeps getting damp.
I've taken the pump inspection hatch out. The floor is fibre glass on top with about an inch of wood support underneath. The wood is sodden and rotting. That explains the spongyness. I've left the inspection hatches off in a desperate hope it will allow the wood to dry out.

The bilge pump pumps water out fine. But the set up seems strange to me - as someone who knows very little boats boats. I'd appreciate the opinion of others. The pump sits about 3 inches above the bottom of the bilge. The float switch is at the same level. It seems to be designed like that rather than a later bodge. As far as I can tell it means it only pumps water out once it reaches a height of a few inches. So the remaining water just sits in the bilge. I've been using a handpump to remove it recently. But my guess is that over the years water stayed in there rising up, rotting the wood slowly. My guess is the damp carpet is caused by water rising up through the damp wood and the inspection hatch screw holes/around the lip of the hatch (my physics may be bad?).

Does the design seem unusual? It seems ineffective to me but maybe there is a reason for it. I assumed a pump would be set up reach the very bottom of the bilge.

Any thoughts very much appreciated. And yes I realise I should have had a survey done before buying...

 

[Rappey]

Welcome to the site. No question is stupid and this is a great place to learn
The bilge pump ideally should be at the lowest point and "on the floor"
It is very unlikely it will ever dry out by leaving hatches open.
I would suggest leaving your pump where it is and adding another in a better position as you can never have enough bilge pumps.

 

[BruceK]

As above but also note very few standard bilge pumps will ever completely drain the bilge. To this end a low volume diaphragm scavenger pump connected to a manual switch is best.

 

[simonfraser]

why is it wet ?
sweet or salt water ?
find the leaks

 

[DanM]

Thanks everyone. Very helpful.

I was thinking of adding another pump. I also know nothing about electrics. Any idea if using the same circuit (splitting the wiring) for the existing pump would be ok? I don't want to have to install a separate switch, fuse etc.

Simon - plenty of leaks. It had leaky windows. Now repaired. I keep discovering uncovered small holes in the frame from removed attachments. I'm dealing with them. Doubt I'll ever sort it fully. Its on non tidal thames - i don't know how far the salt travels but im assuming it wont be salty.

 

[jrudge]

The wood really needs cutting out and replacing. You might be able to try it out and then use some liquid wood restorer and then epoxy over it but it would not be a real repair.

 

[DanM]

jrudge - i realise the wood will need replacing. i cant really do that now. it will have to wait.

my plan is as you suggest. hope it for it to dry and add wood hardener. but what do you mean by epoxy?

 

[DanM]

jrudge - i realise the wood will need replacing. i cant really do that now. it will have to wait.

my plan is as you suggest. hope it for it to dry and add wood hardener. but what do you mean by epoxy?

Ps thanks for your response.

 

[ChromeDome]

Even if you succeed in drying it out, the rotted, soggy wood need to come out as it will not provide the structural strength needed.

Not a small task as once you start you most likely will realize it is more/worse than you expected.

Plenty of pics and videos on the web, some even helpful. Try Google for replace rotted boat floor

 

[jrudge]

Epoxy is the plastic bit of fibreglass.

very simplistically epoxy keeps stuff dry and the fibreglass mat gives it strength.

take photos and post on the Pbo forum ( practical boat owner) someone will give you the best bodge / full repair plan.

as per the post above the issue is probably widespread. All wood on a boat in wet areas is usually encapsulated for this very reason. It rots

 

[PCUK]

Get the West System handbook. That will give you a great start in learning about fibreglass repair. You have a big but easy job ahead of you. You may find that you enjoy this type of work. I certainly do!

 

[DanM]

Thanks everyone. Very useful.
sounds like a big job. Just hope it hasn’t spread to any wood under the cabinets and sink.

 

[ChromeDome]

While preparing you're bound to get a lot of insight in materials, methods, what can be used in conjunction with what, best practises (may not be same as used initially on a boat with some age), flotation, structural strength and tools.

Exciting, but really worth studying when making the plan and securing the budget.