1986 Outrage 18 Tar-like Goop Seeping from Gel Coat Crack

[Don SSDD]

On my 1986 OUTRAGE 18 I see a black, tar-like goop seeping out of cracks in the engine splash well where the batteries were once located. There is no odor of gasoline associated with the goop.

I think that I read [on the continuousWave website somewhere] that [the appearance of a black, tar-like goop seeping from cracks in the gel coat in the engine splash well] is a sign of gasoline getting into the foam [interior of the Unibond hull].

Q1: what is a likely source of the black, tar-like goop?

FUEL TANK

On this 1986 OUTRAGE 18 the fuel tank is the original tank. I have a suspicion that [a leak of gasoline from the fuel tank is] likely source of the goop

Q2: what is a source for a replacement fuel tank for a 1986 OUTRAGE 18?

I plan to drain the fuel tank and perform a pressure test. The fuel hoses--the vent and fill hoses--are only a few years old. The electrical conductors bonding the fuel system are also only a few years old.

[jimh]

Q1: what is a likely source of the black, tar-like goop?

My guess for the source of the black tar-like goop you are seeing seeping out of cracks in the gel coat in the area where the boat batteries were once located is from uncured resin from the original molding of the hull, possibly mixed with some seawater that got into the interior foam from poor sealing of holes, such as the holes for the footman's loops that were anchors for the battery hold down straps.

I have seen the same sort of goop coming out of a fastener hole on a similar era OUTRAGE hull--in fact I think it was also a 1986 model year boat. The black goop has a notable odor, which I would describe as acidic or maybe vinegar-like.

On this 1986 OUTRAGE 18 the fuel tank is the original tank. I have a suspicion that [a leak of gasoline from the fuel tank is] the likely source of the goop.

I don't see a basis for that. If there were a gasoline leak involved in the creation of the material, I am sure there would be an odor of gasoline.

Q2: what is a source for a replacement fuel tank for a 1986 OUTRAGE 18?

The welded aluminum fuel tank found in most all classic era Boston Whaler boats with internal fuel tanks was made by Florida Marina Tanks, which actually now are no longer in Florida. You can find their information from their website: https://floridamarinetanks.com/. Getting a fuel tank made in North Carolina and shipped to Nova Scotia could be a complicated and expensive process.

The electrical conductors bonding the fuel system are also only a few years old.

I don't think the electrical bonding conductors would be playing any role in the generation of the black tar-like goop.

If there were a leak in the fuel tank, I would expect you would be smelling an odor of gasoline from the black goop.

When a Boston Whaler Unibond hull is created, the chemical reaction that creates the foam from two liquids probably produces some water as a product. Most of the water is driven out of the closed shell of the hull and liner via the sprue and vent holes, but there inevitably must be some water that remains in the hull. It may take 30-years or more for this water to slowly react with any uncured resin and produce the black good you are seeing.

I plan to drain the fuel tank and perform a pressure test.

Be certain when pressure testing the aluminum welded fuel tank that you limit the pressure to the stated maximum pressure permitted as shown on the Florida Marine Tank label.

[Don SSDD]

JIMH--Thanks for the informaiton. Maybe my 37-year-old fuel tank is still fine.

On the fuel tank there is a sticker from a marina in New Jersey. The boat has been in Nova Scotia at least since 1998: so the boat has been in saltwater all its life.

I have removed all the fuel from the fuel tank. The fuel tank seemed perfect, There was no water in the fuel tank.

I use ethanol-free 91-Octane gasoline.

In the fuel-water separating filter I found some fine sand grit. I replace the fuel-water separating filter. I did not find any fine sand grit when emptying the fuel tank by siphoning.

Next I will perform a pressure test on the fuel tank, guided by the Florida Marine Tank sticker--which is still there. I had not previously looked at in for details.

[Phil T]

[The black tar-like goop is] uncured resin.

Test [the fuel tank to a maximum pressure of] 2-PSI.

ASIDE: I hope you got by okay with that storm. I talked to Chris Leblanc (TBS,The Boat Shop) south of Halifax and it was rippen' there.

[Don SSDD]

[The label on the fuel tank says the maximum test pressure is] 4-PSI. I tested the fuel tank to a shade over 2-PSI. After 15-minutes the fuel tank pressure decreased to 1-PSI.

I tightened the screw-in fuel filler very tight, and I put a plug in the vent hose that exits on the port side by the filler. The pressure loss could be occurring there--or in some of my tester connections. If my 1986 OUTRAGE 18 fueltank had any holes or weak spots in the aluminum, it wouldn’t even build pressure, let alone hold it for 15 minutes.

I’ll leave the fuel tank alone.

ASIDE: Phil, by car I'm about 45 minutes from The Boat Shop. Hurricane Lee was a wind and storm surge event around my area. I lost a few trees, a few boats broke their moorings, I took my boat out. We had no power from Saturday morning until late Monday afternoon. Our power company has been weak on tree maintenance for many years, so that wasn’t a surprise unfortunately.


Thanks for the advice to you both.

[KARLOW]

You are dealing with a very large volume and looking for small leaks indicated by pressure change.

Remove the inspection hatches, and apply a soapy solution to all of the connections.

Re-apply the pressure. I have done this with a shop vacuum.

Any small leak will foam up.

Large leaks will sing to you (but you can't hear them with the pump or vacuum going).

Happy hunting!