Problem with Water in Fuel Tank Cavity

[gubernaculum]

One of the major design flaws of the Boston Whaler boats is the fuel tank sits in a indentation in the deck, covered with a wood and glass cover, console on top, with no way to drain water. Water gets in, gas tank decays, expensive repairs ensue. There are several ways water can get in.

My previously dry fuel tank cavity [on a 1987 OUTRAGE 22] is now soaked and has standing freshwater you can feel with your hand when you reach over the rear edge of the tank when you remove the rear-most large inspection access plate.

Removing the water presents a problem. The tank is foamed-in with open cell foam. A hose cannot be snaked to the bottom.

The edge cannot be reached over more than an inch or two, so the foam cannot be dug out

The inspection access plates cannot be left open as it rains all the time, and even with the boat cover on, water would probably drip in faster than it would evaporate.

Quite frustrating.

Give ideas [about how to work around or remedy all the problems mentioned above].

[gubernaculum]

Q1: Does there existsome kind of flexible drill and auger that could hog out the foam around that blind corner, so that it could be vacuumed out and then the water could be vacuumed or siphoned out?

Q2: Would you drill a hole from the compartment behind the fuel tank (e.g., live well in my boat) and somehow rig up a drain?

Q3: Would you drill a new inspection hole at the aft-most extreme of the fuel cavity deck cover, then remove foam and suck water as a straight shot, then replace with a small cover of some kind?

[jimh]

Read the two part article in REFERENCE on this topic.

It begins at

http://continuouswave.com/whaler/refere ... store.html

Read part two for details on adding a sump pump to evacuate water from the fuel tank cavity.

[jimh]

What is the basis for your assertion that the foam used by by Boston Whaler is “open cell”?

If the “foam” were really open-cell then it would be called a “sponge.”

Closed cell foam that has been damaged and had the closed cells crushed or burst (by water expanding into ice) can then hold water. But the foam used by Boston Whaler did not start out as open cell foam.

[gubernaculum]

Not sure what [the foam surrounding the fuel tank in the deck cavity] was 32 years ago, but it is squishy wet sponge now, on this dry-stored south Florida boat. Think of the green stuff used in floral arrangements but coarser, yellow, and a bit stronger. I hope [Boston Whaler] used a different foam inside the hull [than they used] in the fuel tank cavity.

The link provided above illustrates the problem and the design leading to it very well, but I’m not willing to remove the console and deck to solve this problem. I’d actually read the article previously.

I’m sure there are a ton of—nearly all—OUTRAGE boats out there with a similar problem as mine, whether or not the owner is aware.

I’m mainly looking for ideas to remove enough foam from behind the tank (see fig 46 in the link) to suck out the water, but without removing the console and fuel tank deck.

[jimh]

...looking for ideas to remove enough foam from behind the tank...to suck out the water, but without removing the console and fuel tank deck.

—Cut a circular hole in the deck at the location you need.

—Perform the work through this new hole

—Install a new circular deck access plate in the hole.

Alternate: change “circular” to “rectangular” (two places) above.

[jimh]

I hope [Boston Whaler] used a different foam inside the hull...

As far as I know, Boston Whaler used the same foam in both applications. The density of the foam may be different. The foamed-in cavity is open to the atmosphere when the foam is expanding so that material is likely lower density than the material in the hull spaces which was constrained in expansion by the closed molding method.

[jimh]

I’m sure there are a ton of—nearly all—OUTRAGE boats out there with a similar problem as mine...

I am equally sure there are just as many OUTRAGE-type hulls and probably way more hulls without a fuel tank cavity with water-saturated foam.

[Malcolm Goodfellow]

Read:

Outrage 18 Rigging Tunnel Dam
http://continuouswave.com/forum/viewtopic.php?f=6&t=3171

You will find a good discussion and some solutions to this concern.

[ASIDE: Malcom--learn how to use the [url] and the [/url] tags to make hypertext. See

https://www.phpbb.com/community/help/bbcode]

[NLA01]

The deck will need to be pulled and the foam dug out. It has become common practice to not foam in aluminum tanks now. Boat shops and manufactures who are up with modern boat building trends will not foam in the tank and allow air to flow around the tank to keep it dry.

If the tank is foamed in the boat the top of the foam needs to be glassed over to prevent water intrusion. This is also a new practice with builders and restorers.

You could pull the deck and dig out foam and refoam and glass over. Then make sure that area is seamed up tight and the deck on top is sealed.

Or dig foam and put a pump back out there. If it were me I would dig all foam and put a pump in there

I owned a 1984 22 Outrage that I restored a while back and never had water in that area, but I sealed all drains and holes that went into that area and 4200 that deck down good. This key is too keep water out.

1000s of boats are designed with the tank it a cavity like that and it worked well as long as it is sealed from water. Luckily the deck comes right off with screws on yours. Many boat designed the deck must be cut out. (There are actually some Whalers where the deck has to be cut out)

Closed cell foam has to be damaged to soak up water. Just look at closed cell foam in floating boat docks.

Archie

[biggiefl]

I REALLY do not think it is a good idea to put an electric bilge pump next to a fuel tank in a confined area w/o a blower.

[steelhead55]

Removing the water in the fuel tank cavity is a big deal for us that have the belowdeck, polyethylene fuel tanks, as the water pressure on the bottom of the tank will cause the tank to deform, reducing the tank capacity dramatically (mine was reduced from 70 to 53 gallons). To fix this, I installed a 1 inch fiberglass drain tube between the tank cavity and the rear fish well. This allows me to drain the tank cavity of water at the end of ocean trips wear water is splashing on the deck (way too often) I have included some pics of my setup for your information.

This pic shows the location of the fiberglass drain tube connecting the tank cavity to the fish well cavity.

https://garys22revenge.shutterfly.com/pictures/132

This pic shows the foamed in, refurbished polyethylene tank. Beneath the foam on each side are a pvc tube that facilitates the movement of water from the bow side of the cavity to the stern.

https://garys22revenge.shutterfly.com/pictures/128

Feel free to access any of the pics on my shutterfly account, as I have many showing the laborious process of refurbishing that tank and fuel cavity.

[rcapriola]

There is a lot said about this topic in earlier posts and they reflect a real mix of approaches...from installing a separate sump pump for the fuel tank compartment after removing the foam, to putting in a drain tube connecting the fuel compartment to the aft compartment via drain tube. I am considering the latter approach for my 1980 Revenge V22 sterndrive unit. If anyone has done this, what did they construct the tube with and how did they seal it on each of the surfaces penetrated?

[rcapriola]

There is a lot said about this topic in earlier posts and they reflect a real mix of approaches, from installing a separate sump pump for the fuel tank compartment after removing the foam, to putting in a drain tube connecting the fuel compartment to the aft compartment via drain tube. I am considering the latter approach for my 1980 Revenge V22 sterndrive boat. If anyone has done this, what did they construct the tube with and how did they seal it on each of the surfaces penetrated?

[gubernaculum]

Malcom,
Interesting you mention the rigging tunnel dam idea. I actually came up with the idea and implemented my own version independently once I saw the poor design ( last year). Mine wasnt as good as the one shown though.

Also, one of the major routes of water entry is the port side hole/tunnel under the console. On my boat it was simply open to the fuel tank cavity, no lip or dam. Sbd side at least had a plastic raised lip but wasn’t sealed or fastened well. So for the port side I ended up using life seal to fasten a modified upside down pvc toilet flange as a lip to prevent wash over the deck from draining directly into the fuel tank cavity.

[gubernaculum]

If I am able to remove the foam with or without removing the cover, my plan would be to fasten a tube that I could hook up to a manual pump or shop vac as needed. Installing wiring and an electric pump and switch in the area seems more trouble than it is worth for many reasons.

[Malcolm Goodfellow]

Gubernaculum,
The following relates to the classic Outrage 18:
There are two sets of collars for the console/rigging tunnel area. One collar attaches to the console storage floor to keep items from dropping into the rigging tunnel. This collar is simply fastened with screws, no sealant necessary. The second, and vital, collar is attached to the fuel tank cover/ floor of the boat. This collar was just screwed in using no sealant from the factory. I believe it came as a one piece collar but most have been cut to allow removal after the boat was rigged. Most boats I have seen are missing this critical piece. There are a number of posts about it. Look in the parts manual and you will see it called out. I think still available in white or black, not desert tan, but get your hands on one.

This second collar should be completely sealed to the floor, and, if cut, sealed at the cut. Water can still splash up over it and get the floor coring plywood wet, but the 2- to 3-inch high collar will probably keep things dry. I saturated the floor's plywood core edge at this location with epoxy to further protect the core from water damage. Good luck.

[steelhead55]

There is a lot said about this topic in earlier posts and they reflect a real mix of approaches...from installing a separate sump pump for the fuel tank compartment after removing the foam, to putting in a drain tube connecting the fuel compartment to the aft compartment via drain tube. I am considering the latter approach for my 1980 Revenge V22 sterndrive unit. If anyone has done this, what did they construct the tube with and how did they seal it on each of the surfaces penetrated?

I bought 1" fiberglass tubes online, and sealed them with Epoxy resin on each side.

[Phil T]

I recall 1/2 a dozen V-22 owners who have installed a drain from the fuel tank cavity into the rear bait/fish well.

Several solutions were completed including: installing brass drain tube (most popular), sealed the tunnel with epoxy or installed pvc tube (thin wall, not schedule 40)