H33.5 Fuel Tank Removal

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tcbro

tcbro

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Jun 3, 2004
375
Hunter 33.5 Middle River, MD
This is a copy of my post on the Mid-sized Boats forum.

Drove the hour and a half to check on my boat last night. My 1992 H33.5 has a bilge full of diesel and my 21 gal tank shows a little over half full. It was full when it was hauled out last fall. The fuel is coming from the compartment where the fuel tank is. At this point I'm not sure if the aluminium tank is leaking or if the fuel line is leaking close to the tank as I cannot access it easily. It is under the floor of the battery locker, port side next to the helm seat. I have removed the batteries (at least the bilge pump can't pump it out) and the little access panel above the tank to try to get a clearer view of the situation. The battery locker floor appears to be screwed to cleats along the forward and aft bulkheads but it extends under the walk thru transom deck further than I can see and under the electric panel which appears to be glassed in place. Rough measurements of the tank top are 18"x18". The locker lid is 15" at it's widest point and gets down to 13" towards the boats centerline. I was not prepared to go any further last night. This was unexpected.

Does anybody have any idea how this tank comes out? Should it come out through the locker or can it come out through the aft berth. I don't think my aft berth has a removable bulkhead. I figured I'd get a slightly smaller tank from Ronco if I need to replace it. Are Ronco HDPE tanks rated for diesel?

The good news......I was looking for an excuse to buy a sawzall.

The bad news.... to top off a bad night, I wrecked my Boxster on the way home!

Does anybody have any experience with this?

Thanks,
Tom
 
Alan

Alan

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Jun 2, 2004
4,174
Hunter 35.5 LI, NY
Tom,
You will have to cut the aft bulkhead to remove the tank in much the same way as the holding tank in the 35.5 which also came through from Hunter made of aluminum. FYI Ronco does not make fuel tanks. Their tanks are for water storage only.
My suggestion would be to verify that the tank is leaking. If the fuel line were to develop a leak below the level of the filled tank a siphon could develop and empty your tank though very slowly. A good test would be to close the shutoff valve at the top of the tank after emptying the bilge. If fuel continues to fill the bilge the tank is leaking.
 
tcbro

tcbro

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Jun 3, 2004
375
Hunter 33.5 Middle River, MD
Tank removal update

Thanks for your responses. I saw Moeller tanks in the West catalog but I hadn't heard about the inca products, thanks for the tip. I plan to search their websites this morning.

I went back down to the boat over the weekend. I ended up cutting the floor out of the locker as I really don't want to violate the integrity of the bulkhead separating the aft cabin from the fuel tank and the batteries. After experimenting with several methods (those drill powered pumps are useless) I was able to use a friend's hand pump to pump it dry through the fuel pick-up. This probably leaves 1/2" in the bottom but I can get to that when I'm able to pry the fuel guage out. It must be sealed with 5200, I'm gonna need a bigger prybar. The tank is slightly wedge shaped when looking down on the top. One side is 18.25" and the opposite side is 19.75". The across dimension is 18" and it is 14" high, plus 2" for fittings. There is no way it's coming out through that locker in 1 piece. I am 99.5% sure that it is the tank, not the hoses.

I used the hand pump to pump the bilge sump dry. I've wiped up everything that I can gain access to and I've left oil absorbant pads everywhere. I'm really surprised that the smell is very light. A friend suggested a home heating/airconditioning distributer for products that remove the smell. He said the guys that work on home oil burners have to deal with customers who are angry about the fuel oil smell and that there are some good products available in that industry.

A bit of a mystery; while it has only been trickling through the bilge since Thursday it appears as though there may have been a surge of fuel at some point, probably at the start. There was fuel pooled in areas that appear to be an inch or more higher than the floor under the tank.

My plan is to pry the fuel guage out, pump the last of the fuel out and use my sabre saw to cut a large hole in the top panel. Then from the inside I can cut all around the sides about half way up to remove the top half. I may have to cut down one side to crush the top half. Still not sure exactly what tool to use to make this cut. The tank is too tight against the forward and aft bulkheads for a sawzall and my angle grinder would send sparks everywhere. The dremel tool seems a little wimpy for the job but that's the only thing I can think of right now. Any ideas?? Once the top half is off I should be able to reach all of the 8 screws that secure it to the floor. I'll probably need someone to help me back out of the locker because I'll be in head first and fairly deep at that point.

I need to find a slightly smaller (15-16 gal) replacement tank that will fit through the locker lid. The Moeller and Inca Products websites should be helpful with this. This is also a good time to replace all fuel lines and install that remote display fuel guage that I've been wanting. Then I'll just have to rebuild the locker floor strong enough to support my 3 batteries.

Again, thanks for your input. I'll keep you posted as I progress.

Tom
 
Dan Johnson

Dan Johnson

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Oct 14, 2005
2,191
1983 Hunter H34 North East, MD
Tom...

one of the deodorizing thingies you could use is an ozone generator. They are used for odor control, but you need to be very careful with it. They generate O2, which will combine with any free carbon atoms to create CO2. It also will attack things like closed and open cell foam, and may create some strange odors of its own as a result of the oxidation process interacting with other substances it contacts. In closed quarters you will need to let it air out after use--you don't want to be in there when it's running either! In the HVAC business I've used them to deodorize motel rooms for cigarette smoke and related issues.

The other things that oil burner/HVAC people use are basically chemical masking sprays and cleaning agents. For them to be effective you need to remove all traces of diesel fuel first.

Suspect you will find a leak point fairly high up on the tank near where the level is now if you went looking for it. It sounds like the fuel drained at a greater rate than now, probably down to the point of the leak itself, then trickled afterward as a result of less column pressure.

Good Luck!
 
tcbro

tcbro

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Jun 3, 2004
375
Hunter 33.5 Middle River, MD
Tank Removal update for those interested

When I left last weekend there was ~1/2 inch of fuel left in the bottom of the tank and the bilge and the "spillways" were fairly clean with absorbant pads everywhere. When I got there this weekend the pads were soaked. I still have a leak. I pulled feed and return lines into the aft cabin and examined them carefully. I could find no damage and since the fuel is coming from the tank compartment I'm now 100% sure it's the tank. I pryed the fuel guage off, pumped out what remaining fuel I could get with the hand pump and started cutting. I cut the top panel out with my sabre saw, slow but it worked. My plan to make horizontal cuts around all 4 sides to remove the top half wasn't working. It was awkward, slow, painful and I kept breaking blades.

I went to Home Depot and bought that sawzall I've always wanted (10amp Dewalt w/ 4 way head. I highly reccomend it) and switched to "PLAN B". Starting at the top of the outboard side I made 2 cuts down in an inverted "V" (I love my new sawzall). I did the same on the inboard side and after a bit of wrestling I was able to bend the fore and aft sides in on top of the tank bottom (did I mention how much I love my new sawzall?). I was now able to reach all of the mounting screws and finally, the formerly large tank came out through the small locker lid. It was kind of like orthroscopic surgery while hanging upside down by your ankles.

I examined the tank and found a small corroded spot on the bottom panel where the tank sat on 1 of 2 rubber strips. I guess the rubber strips were to isolate the tank from some of the vibration.

The cardboard mock-up of an 18 gal aluminum tank from RDS manufacturing fits in with a push and a twist so I guess that's what I'll get to replace it. I plan on mounting a remote fuel guage next to the engine instrument panel, replacing ALL rubber hose in the system and adding a second Racor for a dual, switchable filter system.

Also under consideration is an electric fuel pump close to the tank that can be switched on to bleed the system or as an emergency back-up for the yanmar fuel pump. I would like to hear comments about this option. Will an electric fuel pump allow fuel to flow through it freely when it is turned off? Is it worth the extra expense and trouble?

Boxster update: body shop says $6665, Insurance Co. says $5450 and that's where we are right now.

Thanks,
Tom
 
Dan Johnson

Dan Johnson

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Oct 14, 2005
2,191
1983 Hunter H34 North East, MD
Tom...

from your write-up you're quite the cut-up (couldn't resist!). Keep us posted on your project progress. Metal tanks do tend to develop leaks where they come in contact with prolonged moisture such as the rubber strip was able to provide.

Hope the Boxster is back rolling in time for top-down weather!
 
tcbro

tcbro

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Jun 3, 2004
375
Hunter 33.5 Middle River, MD
Drivin' topless

Dan,

I don't understand the phrase "top down weather"(?). I'm confused. The tops on convertibles are there to keep you dry in the rain, period. Even when it's raining, if you go fast enough and don't get any red lights, you might not need the top. I drive topless here in PA year round. I drive my convertible to work just about every day (36mi RT) unless there's snow in my driveway or snow in the day's forcast (or if I take a Harley). The only time the top goes up is if it's raining.

I see other drivers driving with their tops up even when it's not raining. I figure their tops must be broken.

As for corroded aluminum tanks, I'm going to paint the new tank with aircraft primer to try to fend corrosion off.

Tom
 
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Alice A.

Alice A.

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Feb 13, 2004
92
Hunter 37.5 Plattsburgh, NY
Re: Tank Removal update for those interested

Hi, Tom. We had to replace the aluminum fuel tank on our 92 37.5 three years ago. It had corroded on the bottom where the tank was in contact with rubber strips used to cushion it, I guess. We replaced it with a plastic tank and replaced all fuel lines at the same time. Alice
 
tcbro

tcbro

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Jun 3, 2004
375
Hunter 33.5 Middle River, MD
That's what happened here, Alice.

Our tank corroded where it sat on the rubber strip. I'll be replacing with aluminum only because it's the largest stock tank that will fit. I'd prefer to replace it with polyetheylene but I'd have to drop down to 15-16 gallons. Original was 21 gal, aluminum replacement is 18. I'll paint the outside with aircraft primer in an effort to delay corrosion.

Mike,
I may try that bilge cleaner you recommended. Thanks for the tip.

Tom





Alice A. said:
Hi, Tom. We had to replace the aluminum fuel tank on our 92 37.5 three years ago. It had corroded on the bottom where the tank was in contact with rubber strips used to cushion it, I guess. We replaced it with a plastic tank and replaced all fuel lines at the same time. Alice
Click to expand
 
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Dan Johnson

Dan Johnson

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Oct 14, 2005
2,191
1983 Hunter H34 North East, MD
Tom, having had Triumphs and MG's...

I know all about top-down driving: tonneau cover on, the windows down, heater turned up all the way, commuting from west suburbs to the greater northeast in Philly many years ago. The hardtop went on only when the temp didn't go above 40 any more. (In the service I wouldn't ride the cycle if the temp was below 45!).

After years of coupes and sedans I rented a convert while out in LA last year--forgot how loud turnpike speeds were in them even with the top up! Those new steel hard-top convertibles are starting to get my attention as I think about replacing my highway car.

Try setting your new tank down on blocks of Starboard, which shouldn't hold moisture against the metal.
 
tcbro

tcbro

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Jun 3, 2004
375
Hunter 33.5 Middle River, MD
New Aluminum Tank

OK, so I called and talked to Sam at RDS Aluminim and placed my order for their stock 18 gal. below deck tank on Monday. They were kind enough to move the fill pipe, make it a 90* elbow, move the pick-up tube and the vent tube all for no extra charge. They re-tested the tank and sent it out the next day. I received it on Friday and took it to the boat Saturday evening.

A PERFECT FIT!!!!!

Just like the cardboard mock-up, with a little jiggle and a twist the new tank slid into place. I need to make a platform to mount it as it is shorter that the tank it replaces and a bit longer. The extra length puts it into the curve of the hull slightly. I'll build a platform that raises the new tank 2" to clear the hull curve and coat it with epoxy. I'll screw it to the old base and mount the new tank to it.

I see the light at the end of the tunnel (or is that the headlight of a train?)

Tom
 
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