How to Fill a LARGE Hull Void ?

[atoll]

try boiling water and engine degreaser,use wet n dry vacume to remove detrius,repeat untill clean

[skipmac]

Originally Posted by atoll

try boiling water and engine degreaser,use wet n dry vacume to remove detrius,repeat untill clean

Yea, that's kind of what I'm doing now, but it's a long, painful process (more so since I can't get access to rub and scrub) and disposal of the oily water is a pain in the posterior.

[tager]

I would say: put in degreaser, go sailing, pump bilge (into bucket). Repeat.

The good news is you get to go sailing.

[SabreKai]

Dumb question, but why is the cabin sole over the tank not removable? Is the cabin sole part of the tank?

How about measuring the distance forward and backward from the open access you have to the point where the sump drops of into the nether regions, and then measure the same distance on the cabin sole and using a hole saw, cut a 2 inch hole directly over the edge of the sump. Looking at your sketch there appears to be some distance between the edge of the sump and the face of the tank. That's where you want to drill the hole. Do it at both ends, and then you can use a shop vac with an extension tube. You can also put a pressure washer wand down the hole and spray in hot water and degreaser. Then suck it out with the shop vac. Lather, rinse, repeat. Once the area is clean, I'd fill it with clean sand, and then pour cement over it. Then you can recess the two holes a bit, and put in a nice shiny stainless cover about 3 inchs in diameter using countersunk screws.

Sabre

[skipmac]

Originally Posted by SabreKai

Dumb question, but why is the cabin sole over the tank not removable? Is the cabin sole part of the tank?

How about measuring the distance forward and backward from the open access you have to the point where the sump drops of into the nether regions, and then measure the same distance on the cabin sole and using a hole saw, cut a 2 inch hole directly over the edge of the sump. Looking at your sketch there appears to be some distance between the edge of the sump and the face of the tank. That's where you want to drill the hole. Do it at both ends, and then you can use a shop vac with an extension tube. You can also put a pressure washer wand down the hole and spray in hot water and degreaser. Then suck it out with the shop vac. Lather, rinse, repeat. Once the area is clean, I'd fill it with clean sand, and then pour cement over it. Then you can recess the two holes a bit, and put in a nice shiny stainless cover about 3 inchs in diameter using countersunk screws.

Sabre

The cabin sole over the tank does have an access hatch but then I get to see the top of the water tank.

From the aft side which is open into the engine compartment I can look down and see a small piece of the bottom of the sump. But it is about 10" lower than the bilge next to it and not wide enough to get a pressure washing wand into it. Even if I cut open the sole foward of the water tank to see down that side the gap between the water tank and the edge of the sump is not large enough to reach with a pressure washer.

Believe me I have spent a lot of time looking and there is no access with a pressure washer, with a rag on a stick, a long handled brush. Maybe a dwarf octopus could reach it but no way to clean, scrub, touch or even to see into this hole. That is one reason I want to fill it in. The hole is inaccessible without major destruction of the interior. I am looking for an easier solution.

[osirissail]

Originally Posted by skipmac

Making access would require destroying the cabin. The water tank is glassed in over the top of the sump and under the settees and the galley. Without tearing up the cabin the only way to gain access would be to cut open the top and bottom of the water tank to get to the space under it.
Nothing passes through the area so that's not a concern. Even though I cannnot see into the sump I can see the front and back.

You misunderstand or I didn't explain very well. The idea is to seal the forward end of the area probably using the forward side of the water tank as one attachment for the new fiberglass "tabbing/wall." And then somewhat the same thing at the aft end of the area. Then fill or not fill the void between the water tank and the hull with foam. But then you have to seal the top of the tank to the hull so water does not breach the new forward and aft tabbing/bulkheads made of fiberglass.
- - If you cannot get to the top of the tank and along the top edges of the tank then you are S.O.L. on sealing off the area as any water washing over the top of the tank would get down in between the tank sidewalls and the hull. In that case you accept the bilge and use a diaphragm bilge pump and hoses/pipes to lift any water out of the area.
- - You are correct in that expanding foam does not expand uniformly but expands in a spherical fashion with crevices between the spheres. Liquid can migrate down into the crevices in the foam so any foam area should be sealed completely with fiberglass to preclude liquid from washing over it.
- - Cleaning the area could probably only be done by "washing" it with auto engine degreasing solution pumped/hosed over the tank area so it leaks down into the area around and under the tank. Then pump it out and follow with a bilge cleaner solution and finally normal water. When the plain water comes out without any indication of residual oil the area is clean. We're talking flooding the area with sufficient cleaning liquids to get to all the surfaces that are not manually accessible for cleaning. The cleaning liquids will do the oil removal. So you need a large pump out system and preferably a way of sealing temporarily the area forward and aft of the tank area so that you don't have to submerge the whole bilge area of the vessel. But if you are in a boatyard on jackstands then flooding the whole bilge of the boat is not a serious problem so long as you have sufficient pump out capability.

[ozskipper]

Its an interesting problem, because unless you make it totally watertight, you are going to end up with stagnent water and oils totally stuck in there. Are you able to drill inspection ports into the Floor supports as you call them? That may allow an easier reach to clean out underneath and to aid in the filling process.

You may find it smarter to simply block the area at the for and aft ends to catch most fluids and bilge jewelery and leave the void itself open. This way you can access it again in the future if needed. If you sika some ply into place fore and aft it can be easilly removed and can be somewhat sacrificial too.

Cheers
Oz

[skipmac]

Originally Posted by ozskipper

Its an interesting problem, because unless you make it totally watertight, you are going to end up with stagnent water and oils totally stuck in there.

This is probably my biggest concern. I can find plenty of things to pour into the hole to fill the space, and due to the size and shape, as long as any filler stayed in one piece it would be held firmly in place. BUT, unless the filler forms a perfect, water-tight bond to the hull, I have just created an even more inaccessible spot for smelly grunge to accumulate.

Originally Posted by ozskipper

Are you able to drill inspection ports into the Floor supports as you call them? That may allow an easier reach to clean out underneath and to aid in the filling process.

I can cut out a big part of the floor supports (what would be the correct nautical terminology for these things, maybe a bulkhead?) but still would not give access to clean under the tank but might give access to build a dam across the lip to keep the typical bilge water and seapage in the accessible areas where it is easier to deal with as you suggest.

Originally Posted by ozskipper

You may find it smarter to simply block the area at the for and aft ends to catch most fluids and bilge jewelery and leave the void itself open. This way you can access it again in the future if needed. If you sika some ply into place fore and aft it can be easilly removed and can be somewhat sacrificial too.

Cheers
Oz

Thanks
Skip

[Pblais]

I really don't think you can just dump stuff down it and get it clean nor fill it solid.

In your case I don't see an easy solution. You could slosh a lot of bilge cleaner in there and flush it out repeatedly a few dozen times and maybe get the worst of the worst out of it. It will work on the oil and emulsify it but you'll need fresh water to flush it out. An electric pump with a small hose might help.

Next you need to build the dam on each end such that you can clean that out even if it isn't easy.

I wouldn't try filling it with anything since you'll never get it perfectly filled and it will come back to bite you if you own the boat long enough. Most very bad ideas start out this way.

The better way (much harder) is build a hatch over the tank and remove the tank totally and fabricate a water tank to fill the hole and then block with dams. You'll get more water storage as a small bonus. It's a very huge job I would agree.

[skipmac]

Originally Posted by Pblais

I really don't think you can just dump stuff down it and get it clean nor fill it solid.

In your case I don't see an easy solution. You could slosh a lot of bilge cleaner in there and flush it out repeatedly a few dozen times and maybe get the worst of the worst out of it. It will work on the oil and emulsify it but you'll need fresh water to flush it out. An electric pump with a small hose might help.

Next you need to build the dam on each end such that you can clean that out even if it isn't easy.

I wouldn't try filling it with anything since you'll never get it perfectly filled and it will come back to bite you if you own the boat long enough. Most very bad ideas start out this way.

The better way (much harder) is build a hatch over the tank and remove the tank totally and fabricate a water tank to fill the hole and then block with dams. You'll get more water storage as a small bonus. It's a very huge job I would agree.

Thanks Paul. As much as I hate to admit it, I'm afraid you're pretty much correct all around. All the same conclusions I have come to but had to give it one last shot on the forum in case I had missed something in my analysis of the situation.

Filling the hole, unless done perfectly, I am sure will come back with big, sharp teeth and bite me in a sensitive area. Since the only way I or anyone else can see to do this is to pull out the water tank to get good access, then this project is going in the round file for the present.

Current plan, clean the hole as best I can by filling with appropriate stuff. Once clean, build small dams front and back to try and keep the bilge water in the more accessible areas.

Long term, maybe tear out the tank, clean, glass over, and seal the whole thing as a larger tank. This would result in two separated bilge areas but I'm ok with that.

Skip

[skipmac]

Originally Posted by osirissail

You misunderstand or I didn't explain very well.

Even though English is supposedly my first language I do get confused at times.

Originally Posted by osirissail

The idea is to seal the forward end of the area probably using the forward side of the water tank as one attachment for the new fiberglass "tabbing/wall." And then somewhat the same thing at the aft end of the area. Then fill or not fill the void between the water tank and the hull with foam. But then you have to seal the top of the tank to the hull so water does not breach the new forward and aft tabbing/bulkheads made of fiberglass.
- - If you cannot get to the top of the tank and along the top edges of the tank then you are S.O.L. on sealing off the area as any water washing over the top of the tank would get down in between the tank sidewalls and the hull. In that case you accept the bilge and use a diaphragm bilge pump and hoses/pipes to lift any water out of the area.

This is what my current thinking is leading to. Since I have not found a solution that makes me feel 100% about filling and sealing I think isolation is the plan with a pump pickup in the hole for just in case.

Thanks for the ideas.

Skip

[Pblais]

One question? Might there be keel bolts at the bottom of the hole or is the keel full encapsulated. My last boat had a deep hole but there was a hatch over it and if someone held your ankles you could clean the bottom (fun job). That was a fully encapsulated keel. Concrete over lead.

Current boat the water tanks are in the middle and the forward is storage but the aft has a tiny hatch with a dark hole. The water tank has twin hatches above and it can be removed easily and hauled out of the boat. Fuel tanks too. They are under berths. I think I could get all three out in a day with some help once they were empty enough to lift. All have large inspection ports.

[Bash]

Originally Posted by skipmac

I am trying to figure out how to fill a large sump area in the bilge of my boat.

A contrary opinion:

If you fill the void, you may find yourself missing the service this sump provides to the rest of the bilge. The nice thing about a sump that's lower than the rest of the bilge is that it contains all the groady stuff in one spot.

My advice would be to install a small bilge pump in the sump, and then use that as a way of keeping the rest of the bilge dry and clean. I have no doubt that this is how the sump was supposed to work in the original design.

[smurphny]

Ain't it amazing how Pearson created these kinds of spots? My A35 has a couple of them although I can, using some long bent contraptions, eventually get stuff out that falls in. You're absolutely right about anything dropped ANYWHERE making its way to spots like these. Foam would probably deteriorate, even a good polyisocyanurate will eventually break down in sludgy bilge water. It's also buoyant. Think I'd opt for max slow set West epoxy with a lot of cheap filler added. Polyester might also work but I'd worry about the heat produced by anything reacting quickly. Quite a few old wood boats used concrete in the bilge. No problem with that either. Wonder why they didn't fill it to begin with if completely inaccessible?

[Jim Cate]

Skip,

One possible means of cleaning your black hole: rent a steam cleaner from the local hire place and use appropriate flexible extension hoses to direct the steam around all the things in the way. Don't know if this is physically possible for you, but steam plus some detergent will clean really dirty, greasy engines, and would likely do a good job on bilge grunge.

Good luck to you, and some sort of nasty afterlife to the folks who design these things into boats!

Cheers,

Jim