Fuel Tank Access Ports

[tikvah59]

Hello folks,

Academic pursuits have kept me away from this forum for a while, but I'm gearing up to get the boat in this year. I've removed the Monel fuel tank that was installed in my Triton in 1977. Judging from the crud in the bottom of it this may be the first time it's been cleaned!

While the tank is clean and out of the boat I put in a hole for a fuel gauge sender. I read recently (Good Old Boat?) that a fuel tank should have access holes in each section of the tank which is separated by baffles. My question: is there a commercially-made access port that I can install, or should I just make a cover for the hole out of stainless and bolt it down with some sealant? The access ports I've seen seem to be appropriate for water tanks, but don't indicate that they are resistant to gasoline.

Any suggestions appreciated.

Thanks!

Mark Whipple

[Tim]

I was going to suggest you look at the Sea Built access ports, but it would appear that they are not recommending their product for gasoline tanks.

They specifically mention diesel, water, and waste. Compatibility with gasoline is conspiculously absent.

Link: Sea Built Access Plate

[catamount]

For my diesel tank, I built something along the lines of the SeaBuilt Access plates that Tim mentioned, because I thought they were too expensive. In the end, if you count my time machining the thing, etc.., it might have been a wash. Regarding the compatability with gasoline, I suspect that there may be two issues, one having to do with the material used for gaskets, the second possibly having to do with USCG or other regulations regarding the construction of gasoline tanks -- such an access port might be prohibited from a safety perspective, just as drain ports on the bottom of diesel tanks are frowned upon. (Don't know, just speculating)

[tikvah59]

I was going to suggest you look at the Sea Built access ports, but it would appear that they are not recommending their product for gasoline tanks.

They specifically mention diesel, water, and waste. Compatibility with gasoline is conspiculously absent.

Link: Sea Built Access Plate

Thanks for the link, Tim. In the FAQ they state:

Why do I need an Access Plate System on my tank?

The majority of tanks are manufactured and installed with no access; therefore no ability to be cleaned and maintenanced. Note: The Access Plate System is for use on water and diesel fuel tanks - never install it on a gasoline tank or other tanks containing highly flammable liquids or gasses.


Too bad - they look like they would be perfect!

Mark

[The Good Goose]

I think you could make them from stainless. You might want to consider two pieces . The monel is thin so it would be difficult to tap a bolt into so it would probaly need through bolting. I would make a ring of 1/8" stainless or for that matter a 5" square with a 4" inch hole in it Bolt that to the tank with countersunk flat head bolts with a gasoline rated gasket. Tap this piece to recieve the bolts for your cover put a gasket between the two and bolt it down. Maybe make the ring out of 3/16" or 1/4" to get more purchase for a bolt. Make sure to smooth the monel after cutting it with a hole saw. I didn't on my tank and it is rough on my arm when I clean it.

Brock

[catamount]

What Brock describes more or less is what the SeaBuilt Access Port is, and is basically what I made myself for my diesel tank. But the question is whether or not any such access port is acceptable/permissable on a gasoline tank, with the unconfirmed suggestion being that it is not.

[Tim]

ABYC H-24 makes no specific reference to--and therefore no specific prohibition of--access ports in gasoline tanks; the standard dictates only that all openings (of non-specified nature) be at or above the topmost surface of the tank, and that all gasoline fuel tanks meet certain construction and safety standards.

33 CFR 183.510 dictates, in so many words, that all fuel tanks must be tested under the applicable conditions dictated by further and specific sections of the code, and also that the tank must be labeled as such.

Therefore, whether any access port, maunfactured or home-made, can, after installation, withstand the various testing procedures dictated by 33 CFR 183.510, as well as the testing standards of ABYC H-24.18.4 and H-24.18.5 , is the real question here, and this is the fine point upon which some future surveyor could raise issue.

Certainly you or I are not going to perform these tests, so install any access port at your own risk, and with full knowledge of the fact that it may be deemed unacceptable during some future inspection.

Or it may not, either. Obviously the key, either way, is that the access plate--and any other such additions--are extremely safe and free from vapor or fluid leaks. Remember that these safety standards exist for a reason. Gasoline boats with sound fuel systems don't just blow up; the ones that blow up probably had deficiencies somewhere in the system that led to the eventual problem.

Stay safe and smart.

[tikvah59]

I called Seabuilt to ask about the use of their ports for gasoline tanks. The reason they strongly advise against the use of their product in gasoline tanks: liability insurance. Their insurance providers will not allow the product to be sold for use with gasoline (or any other highly flammable fuel) because somebody might install one of their ports then blow up their boat and sue Seabuilt.

I asked if there was a problem with the gasket or some other design feature, and the person I spoke to (I believe it was the owner) said there was no problem at all, just the liability issue. Then he went on to tell me where I could order the product, if a some point I intended to use it for a tank that did not contain a highly flammable substance. (wink, wink, nudge, nudge)

Hmm, wonder what I should do? Perhaps I'll purchase one of these in case I decide to install a diesel . . .

You gotta love our legal system.

Mark

[Tim]

You gotta love our legal system.

Don't get me started.

Good luck. I'm sure that access plate will look nice in your living room while you wait to put it in your future diesel tank. :<)