Oily bilge problems and what to do with a tank I found

[suntreader]

In spending the day cleaning the bilge and generally trying to figure out how things are set up beneath the sole I have generated some questions.

First off, the bilge is the oilyist, grimyist, nastiest thing I've ever come across. Here is an access hatch I cut today. The current state is after several hosing outs, scrubbings, SimpleGreenings, etc.



The bilge access was pretty limited. The area under the engine was open and a hatch in the middle of the saloon sole. I have cut two additional hatches forward to get to more of the bilge. There are limited limber holes which were all clogged.

I have done plenty of hosing, pressure washing, and scrubbing with Simple Green, Krud Kutter, and TSP. Even with that it still seems pretty oily down there. I was planning on painting the bilge and lockers with Shermin Williams Tile Clad II primer and finish. I had read about it and seems like a good product. Bilge Kote is the other option. How clean do I need to get it down there? I'm doing what I can but it still seems nasty.

Also the plywood sole, which appears unfinished but is holding up well, is pretty well soaked with oily water. The plan is to clean it up, paint it and then overlay a nice sole. I need to get this surface clean enough that it will take paint well, take a new sole overtop, and not smell bad down the line.

Now the odd part. There is a tank in the bilge seperating the engine bilge and the main bilge. I had though it was a later addition but now I'm thinking it may be factory original. I cut the top off with the intention of pulling the tank and opening the bilge back up. The tank was tapped into the hull so I used the sawzall to cut the tabbing. Of course once the tank was open I can see it goes all the way back under the engine compartment and deep enough that I can't reach the bottom from a kneeling position.



So, what do I do with this tank now? I see several options. First one would be to cut/grint the top of the tank off until I have one big open bilge. That would be fine with me, a nice deep sump, lots of room for dust bunnies. If I can't lift out the tank then all the cutting and grinding will be a lot of work and I'm worried the tank isn't bonded enough to ever really be a solid part of the bilge.

Second option would be to cut and grind it down, and put a new top on. I could use it as it was intended as a water tank and still have that clean run throughout the bilge I was looking for.

Third option would be to cut and grind it down enough to bring it level with the top of the proposed smooth-run-bilge then fill the rest with concrete. It would add some ballast and prevent any oily bilge water from getting down between the tank and the keep.

If this were your bilge, what would you do? Any technique or tool reccomendation for cutting the tank up? Something like a grinter with a cutter wheel and just trying not to go thorugh the tank and into the side of the keel. I don't really know how to go about it.

David

[Tim]

Wow, that's an oily bilge and sole. That's fishing boat dirty.

I think you need to get it a lot cleaner before you can think of treating it or doing any sort of new work down there. Filling it with very soapy water and allowing it to soak for a period will help; you may need to repeat this once or more.

Try something like Comet or other powdered cleaner once you've done this. It will help emulsify more of the oil and the grit will also help get it out of the weave of the fiberglass cloth in the bilge. Dishwashing liquid has pretty good oil-cutting properties too.

Frankly, cleaning that bilge is all about repetition and continued efforts, and plenty of elbow grease. It will eventually clean up, but something that nasty will take quite a few substantial cleaning efforts to fully succeed. For all future steps in your rebuild, it's totally worth just taking the time and effort now to clean this area up, and all other areas. Get it out of the way, and you'll thank yourself later.

Then allow it to dry thoroughly. Grind it with coarse sandpaper. You don't need to get the bilge perfectly clean, or perfectly smooth, but it needs to be basically clean to avoid paint adhesion problems.

I don't know anything about Tile Clad II, but I think you'd be hard pressed to find a better bilge and locker paint than Bilgekote. It will stick well even to a bilge that remains at least partially contaminated with oil in the fiberglass or wood, is easy to apply, and is incredibly tough. And you don't need any primers. Plus I know from experience that it sticks perfectly to imperfect surfaces. One coat often does the trick.

How oil-soaked is that plywood sole? If it's really saturated, like it looks, then you may have trouble ever getting any residual smell out. You may be able to clean it up and dry it out, but if you have any doubts you'll be better off replacing it, rather than building on top of it and regretting it later.

The good news is that with all that oil in the plywood, it'll never rot!

I think removing the tank will be a similar exercise in perserverence and hard, miserable work. It sounds like it's a separate structure from the boat, so it should be removable. That doesn't mean it will be easy, but it doesn't look like anything that you necessarily want to have around. If you find that you simply cannot get it out, then you can proceed with some other plan that leaves it in place.

Does the tank extend all the way to the bottom of the bilge, or is there space beneath? I would think there should be space beneath for free passage of water, but just because it should be so doesn't mean that's actually what you'll find. If it goes right to the bottom of the bilge, there's a chance that it's set into some sort of goop there too, which may complicate removal.

Do you have any cause to think the boat requires additional ballast? I wouldn't go pouring concrete indiscriminately into parts of the boat. Even if the boat needs weight for some reason, one would need to be careful that the weight was properly placed to avoid affecting the balance of the boat. If you need some filler to allow you to glass a flat top on the tank, you'd be better off with foam.

If it were me, I'd make all efforts to remove the tank, unless it just resists all reasonable attempts. But without truly seeing or understanding how it is installed, I can't say exactly how possible removal truly is. Cutting it carefully into sections with an angle grinder and cutoff wheel might be a good way to go about it, along with judicious prying from the sides.

I don't know how extensive your renovation plans for this boat are, but I have found that working around old, undesired features only complicates the new work, and that one often lives to regret trying to save things that really aren't that good to begin with. So be wary of spending too much effort on things such as that cabin sole if there's a part of you that wonders if it's worth it, or if it will ever be truly salvageable.

[bhartley]

If nothing else works, try Driveway Cleaner. Can't remember the brand I used last time, but it came from Lowe's or Home Depot. It is VERY aggressive with oil.

[suntreader]

Thanks Tim,

You about summed up what I knew I needed to do, I just wanted some validation! The bilge forward of the tank is maybe 16" deep (which is a lot compared to my old Hunter.) The tank must be three or four feet deep and six feet long, though only 4-8 inches wide. The bilge water from the under-the-engine bilge cannot drain to the forward bilges unless it is high enough to go over the tank.

The plan for the boat is a complete rebuilt, every surface, every system. I'm planning on two years for the project. It is important to me to get the bilge right, I've delt with a oily wet bilge before and I never will again! The plywood is in surprisingly good shape, probably because of all the oil! The parts I've cut out have been in good shape and there isn't any evidence of the fibers fraying or of delamination. If I can get the oil and grim out of the surface and grind it down some I think it will still work for the under-sole. We will see though as the cleaning progresses.

I will pick up the heaviest degreaser I can find at the Lowe's today. Fill the bilge up and let it rip. As far as tank removal goes, the sides I can pry loose so they at least aren't completely bedded, but I am worried that the whole thing was bedded in some serious goop. I guess I'll just get in there with a grinder and a cutting wheel and see how it goes.

David

[Ceasar Choppy]

I've had good luck with MarineClean... it is sold by the POR-15 folks. It is what you are supposed to use to prep metal before you apply the POR-15 to it. Worked a treat on a bilge I had that was very similar to yours.

[suntreader]

Two more days of grinding, pulling, and getting nasty. At this point I have the majority of the tank sides out, the top out, and the forward wall out. The bottom, back, and lower sides are still left. The tank is bedded in the nastiest stuff I've ever encountered, I mean really, really nasty.

I don't think the rest of the tank is coming out. The areas is too narrow to get the grinder in any deeper. We tried pulling the whole deal out with a bolt through both sides of the tank and a pully set up to a 4x4 through the cabinport openings. Even with enough force to bow the 4x4 down about 1/2" the tank wasn't budging. I think it is simply bedded too well. Under the forward portion of the tank the ballast casting is exposed.

What I'm thinking now is I don't really need a 4' deep bilge directly under the engine. I don't really see a way to get the rest of the tank out without doing some major cutting into the keel sides, which I don't want to do. I would like to shape a new bilge bottom out of foam sheet or ply that would cover the remaining tank parts and the bedding which isn't coming out. I could fit the new bilge in place, use some void filling 2-part urethane foam to fill the voids then glass over the new bilge bottom. This would encapsulate the parts I can't get to, and shape the bilge into a good shape with deep sump. Another option would be to do several pours of epoxy to fill the void, it would take a lot though and I'm not sure it is needed as the foam seems to be the usual way of doing this.

Has anyone done something like this? I am pretty wary of effectively sealing off an area never to be opened again.

Here's a sketch of the area from the side.

[Tim]

It seems like your hands are pretty tied, since you can't get to the final remains of the old tank without serious destructive surgery. Since such serious surgery doesn't make sense for many reasons, I think your plan sounds like the most effective way to deal with the bilge.

You may be permanently sealing over whatever is left in there, but I don't see a problem with that, since that stuff has been down there all this time and I don't see any harm in leaving it, nor in covering it. It was essentially covered and inaccessible from the getgo. While enclosed, inaccessible spaces aren't necessarily things to strive for, sometimes there is little or no choice, and you have to look at the bigger picture to determine the best way to proceed. As long as you do a good job with the encapsulation and construction of the "new bilge", you'll be all set.