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Author Topic:   Gas tank cavity on 18' Outrage
commodore posted 09-06-2001 08:22 AM ET (US)   Profile for commodore   Send Email to commodore  
I own an'85 18' Outrage. A friend also bought one in Florida, and discovered that the floor above the gas tank cavity was soft, so he removed the floor and replaced the plywood underneath with new, bonded by West System. Anyway, have any of you guys ever pulled the floor up? There are several molded in "scuttle" areas, on the port side for the gas fill/vent lines, on the stbd. side for the wiring harness and fore and aft for the steering cables. In short, numerous opportunities for water to enter the cavity, and no means to escape! In his case, there was standing water in the aft of the cavity, and also a dime-sized hole in the tank forward and on top. Don't know whether salt water or just rain/condensation caused it. I wonder what MY gas tank cavity looks like! Anyway, he is doing it right, with a new tank from Florida Marine Tanks, then epoxy-coated etc, and foamed in with slow-set closed-cell foam. In a clever move he is also foaming in a 1/4" o.d. PVV pipe vertically back by the tank pickup inspection plate, to which he will attach a rubber hose and a primer bulb to "suck out" any water that might get in going forward. Anyone else have any experience with this area of the 18"Outrage ?
Bubba posted 09-06-2001 09:00 AM ET (US)     Profile for Bubba  Send Email to Bubba     
I recently purchased a 84 Outrage 18. (not a lurker any longer........Yahoo>>>)
I would like to pull my flooring up but aprehensive of disconnecting all the cables and wiring to remove the console. My Fuel Guage cover is broken and I'm sure rain water is in this cavity. Heck if not for the Console I would pull the flooring up just out of curiosity. The hose and bulb sound like a good idea. I've thought about reducing down from a shop-vac hose.
DCPeters posted 09-06-2001 11:06 AM ET (US)     Profile for DCPeters  Send Email to DCPeters     
I'd love to see photos of this project; does your friend have some?
eric_from_MD posted 09-06-2001 05:18 PM ET (US)     Profile for eric_from_MD  Send Email to eric_from_MD     
Guys- I have mine apart as well. A new baby has really slowed my progress but am now ready to put it back together. Anyway you are absolutly correct, there is NO WAY for all of the water to escape the fuel tank tub/cavity once it gets in there. I have a few pics of the hull with the floor and tank out if interested shoot me an email and I will forward them.
Bubba posted 09-06-2001 06:49 PM ET (US)     Profile for Bubba  Send Email to Bubba     
Thanks for the Email and pics. I had no idea what these cavities looked like. I know now that I wont be satisfied untill I pull up my deck and check mine out.
I know these boats are designed well, so I have to wonder why BW was not concerned with draining these cavities. If they are sealed properly they will stay dry is my guess. Mine may be dry, but I'll have a look to make sure. (sharpening pencil and putting this on my list)
waagdiver posted 10-24-2001 09:25 AM ET (US)     Profile for waagdiver  Send Email to waagdiver     
I am restoring a 1978 19' Outrage Lo-Profile. I believe that you can unbolt/unscrew the console and tilt it to the starboard side and remove the fuel tank deck plate without undoing the console wiring (note that this is NOT what I did, since I am restoring the entire boat). The fuel tank did have holes in it, and was filled with dried salt, as well as a goey mix of salt water and old fuel. I too, think this is a poor design. I am thinking of running a drainage line from the lowest part of the aft end of the tank compartment to the sump in front of the outboard. I can pump water into the compartment from the round deck access and flush water out through this compartment. This will require using cut foam pieces that are glued in, rather than foamed in.
dfmcintyre posted 10-24-2001 09:32 AM ET (US)     Profile for dfmcintyre  Send Email to dfmcintyre     
That's what I ended up doing (and another member here on the forum is also doing) with my 21 Outrage. I drilled a hole from the tank cavity to the rear bilge, and used 5200 to seal a brass tube into the hole. If I was going to do it again, I'd go with a polyurthane piece of tubing (won't corrode) instead.

Then took and cut two new commercial mud flaps into strips about 4' wide, and glued them to the floor of the tank cavity, at a slight angle. The tank rests on the strips, and the metal cross pieces hold the tank tightly to the rubber strips. That way, when (not if) water is introduced into the cavity, it can drain around, past the tank and through the drain hole into the bilge cavity.


LarrySherman posted 10-24-2001 02:02 PM ET (US)     Profile for LarrySherman  Send Email to LarrySherman     
I'll be making the same repair this winter.

I like the idea of a plastic thru hull to connect the compartments, perhaps with a valve on the sump side.

Does Florida Marine Tanks make tanks for whalers, or do you have to provide measurments? Are there ant other good sources for tanks?


Chap posted 10-24-2001 03:20 PM ET (US)     Profile for Chap  Send Email to Chap     

Tried and true tanks. Folks go there from all over. They'll make anything you want.
Atlantic Coastal Welding
16 Butler Blvd
Bayville, NJ
(732) 269-1088


bigz posted 10-24-2001 03:51 PM ET (US)     Profile for bigz    
FMT should have your tank for the 25 Larry.

One thought fellows is use a plastic one way valve which you can find at West by several manufactures under the holding waste tank plumbing area these are usually 1-1/8" and epoxy it into the aft partition.

The other item when reattaching the cockpit deck section use a good grade sealant.

This tank cavity configuration today isn't allowed by the USCG just for your information and for the very reasons you all mention is why it isn't.


Jim Bennett posted 10-24-2001 09:15 PM ET (US)     Profile for Jim Bennett  Send Email to Jim Bennett     
A note on my recent efforts. As mentioned above by D McIntyre, I went ahead on advice by him and Chris Price and epoxied in a 3/4" ID PVC drain tube at rear of my tank cavity about 1/2" above v-bottom in my 73 OR 21. Need to allow this 1/2" as v-bottom of cavity is slightly lower than bilge bottom behind. Allowed drain tube to protrude about 1" into bilge area so can put simple $.20 cap on tube if needed. Plan to leave unplugged so any water that collects in cavity readily drains into bilge.
Am going to fill all screw holes in tank(deck) lid, put gasket on lid and just let weight hold it in place; whatever water gets in, will just flow out. If needed for hold-downs, may put couple rotating clamps of some kind under RPS and also back near live wells; these should be out of way.
Ordered new tank from FMT. They sent me actual drawing of tank to compare with mine which I then returned with order. They start making custom tank when they receive order including payment. Delivery approx 4 weeks. Am having twin-sight sender which is visual gauge plus provides electrical signal for instrument panel fuel gauge as well. Will pass wires from sender thru clear vinyl tubing back over tank to second PVC tube we epoxied in high on cavity wall thru to wiring trough aft.
waagdiver posted 10-26-2001 02:06 PM ET (US)     Profile for waagdiver  Send Email to waagdiver     
Just as a side note, on my 19' loprofile, water can get out of the fuel tank area via a tube that connects from the fuel tank area to the small bilge sump area at the end of the tunnel in the stern; note however that the tube is near the top of the fuel tank compartment and will not come even close to draining the compartment dry; its within 1 or 2 inches of the top of the compartment.

Bubba, there is little or no change that your fuel tank area is dry (IMHO). There are too many ways for moisture to get in, and no way to get it out! That is, unless you live in the Arizona desert!

RE: drilling a tube from fuel compartment to aft bilge area: I just went out and looked at my 19' and indeed, the fuel compartment is slightly lower than bilge compartment. However, my question is, wouldn't it make more sense to put the tube in the BOTTOM of the fuel tank compartment, and ANGLE IT UP SLIGHTLY to reach the bilge compartment; that way, when it is up on a trailer, you can lift the bow higher and drain ALL the water out??? Any flaw in my thinking?

Re: the tube itself, some have mentioned using tubing made of brass, polyurthane, or 3/4 ID PVC. Which is recommended? Is 3/4" ID PVC just PVC tubing like that used for your sprinkler system in your yard? (what does the ID mean?). Since I'm also looking at replacing the drain tubes in several other parts of the boat, can I get away with using PVC for all of them? or ?

dfmcintyre, what are the commercial mud flaps that you are referring to? off of a truck? my tank is 6' 10" long! what length are the flaps? when you say you glued them at a slight angle, what do you mean? also, did you fill your cavity with anything else? or just the strips under the V part of the tank, plus the straps holding the tank down? how wide are the strips? is the tank ONLY resting on the strips?

Love the idea of the drain tube protruding an inch or so into the bilge compartment. For instance, in the case of a fuel tank rupture, I wouldn't want this compartment to drain!

I'm intrigued by the concept of a gasket rather than screwing down the deck lid, as the weight of the lid, plus the stuff sitting on top of it will hold it down. Obviously, less holes in the boat! If not using a gasket, than what type of material is recommended? My boat fuel tank deck lid was sealed with plain old silicone. Is there something that would work better?

Thanks in advance for all your responses to my questions. Gotta lot of work to do on this boat and would like to get it right the first time!

grandmufti posted 11-08-2001 10:29 AM ET (US)     Profile for grandmufti  Send Email to grandmufti     
Wish I had read this thread 8 years ago when I replaced gas tank on a 1973 outrage. I would have installed the tube.
Ever since I did the job I have had a nagging thought on the bilge pump I installed in the cavity.Are bilge pumps sealed in such a way that they would not ignite a future leak or buildup of fumes in the cavity?I would feel a lot better if I knew as every time I flip the switch to check for water I wonder if it is safe after reading some of these posts.

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