Replacing original fuel tank

There was a persistent smell of diesel in the boat. The odor was so strong we would get headaches and after cleaning out the bilge, in dry dock, we would see more diesel fuel along the port stringer. I read stories about pinhole leaks in the aluminum tanks. I started to probe the fuel tank supporting plywood and it would pull apart in diesel infused chunks. So it was with great reluctance to rip up the deck.
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First pump out the fuel.
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Then cut the stringers.

Finally reaching the diesel soaked and rotted board.

Finally removed from the boat.

And here's the corroded culprit.

Now to find a replacement fuel tank.

I'd suggest that you begin here with the people who made the original...
Bruce

Custom Marine Fuel Tanks

Bruce B said:

I'd suggest that you begin here with the people who made the original...
Bruce

Custom Marine Fuel Tanks

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Thanks for the suggestion. We sent off the original tank information. Now we're waiting for a quote.

I had to replace my starboard aft fuel tank on my Prairie 36 last year. Thankfully it came out in one piece. I had a local fabricator build a new one to the same size using the old tank as a template.

Speaking for myself, not wishing to cross oceans, or even go large distances locally, I would always replace corroded metal tanks with fuel grade plastic ones, and solve the baffle and stale fuel/fuel polishing issue in one stroke by having several smaller tanks, all interconnected, and all draining from the bottom, with taps between. So, unless wanting to do long distances, one would use a smaller tank volume for normal use, which is then turned over more frequently, obviating corrosion, galvanic or otherwise, stale fuel, organic growth, and sludge build-up issues, all in one hit.

Peter B said:

...I would always replace corroded metal tanks with fuel grade plastic ones...and all draining from the bottom...

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Have you seen a manufacturer who does this? All the plastic diesel tanks I've found so far have pick up tubes from the top.

MurrayM said:

Have you seen a manufacturer who does this? All the plastic diesel tanks I've found so far have pick up tubes from the top.

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Most offer made to order, so I'd just insist on that approach. It prevents muck from accumulating, as my tanks are done like that, and I only ever get about 1 teaspoonful of water out of the separator on the primary filter, and the filters last for years. I've never really understood where this idea of fuel pick-ups up from the bottom came from, unless it's paranoia about a leak at the outlet..?

If Norhavn draw from the bottom of the tank, (and they do), it appears it's not a must have thing. Continuous fuel polishing as you go makes more sense to me than the risk of sludge stirred up in a seaway, right when you least need it happening, causing a filter outage from blockage with old tank sludge.

The tanks that pull from the top will usually have a screen or punched plate inside across the tank bottom.

The fuel draw is from above the plate which is hopefully seperateing the fuel from the gunk.

A drain valve (with plug to be more secure) is used below the screen to remove gunk as required.''

This is usually done on boats that do not have room for a proper sump.

Fine for inshore , less so for Blue Water boats.

I just heard about a place that's not to far from where I live called Triple M Plastics. When I mentioned it to some other local boaters, they also had good things to say about this company. I'd never even heard of them, much less used them, but I did make sure to bookmark their site for future reference: Triple 'M' Plastics

Considering the first tank lasted 40 years, I'd likely go back with the same thing. If a sump to draw from could be added, so much the better.

Ted

Proud Mary said:

Thanks for the suggestion. We sent off the original tank information. Now we're waiting for a quote.

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We had 2 tanks made by RDS last fall. We toured the facility and met all the key people. A first class operation. I'd use them again. Good luck with the project.

My boat's previous owner had sight glasses installed, and rigged a portable filtration/pump system between tanks from each lower fitting. Fuel polishing worked like a charm.

RDS has manufactured thousands of tanks for the marine industry. But their attitude of doing one off tanks has declined in the last few years. This past year I had a custom one off tank done by Best Fab in Florida.

Best Fab Inc. - Fuel, Water, Oil & Holding Tanks

They were very responsive, readily available by email and pretty competitive. They will also coat their tanks with two choices, Coal Tar or Awlgrip before shipping them. The crating was more than adequate too. Of course you will need to have access to a local common carrier if you are not close to their route of their truck.

O C Diver said:

Considering the first tank lasted 40 years, I'd likely go back with the same thing.

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This was my thought when I replaced my 35 year old tank. However, the fabricator did use slightly thicker aluminum and I coated the exterior with 2 thick coats of Coal Tar Epoxy. I'm confident the tank will out live me.

Hello from Willow B... Proud Mary is the exact layout as Willow B. She is the perfect (for us) layout for the Great Loop. We brought Willow B home from Boston to the Ohio River MM363 via Erie Canal & Great Lakes. Our only issue we encountered was a leaking Injection Fuel Pump. I found stripped threads while rebuilding the pump. I made temporary repairs with the limited tools & supplies I had on hand. The repair got Willow B home. What a great adventure it was! Today we begin addressing the deferred maintenance issues!!!

Willow B is loaded with accessories & electronics, but NO bow thruster. You will appreciate that BIG TIME.

Once you get the issues addressed, Proud Mary will serve you and your crew well. I look forward to following your refit. Good luck and enjoy the experience.

I had a similar experience with an aluminium tank in a prior boat. (A gas boat, so far more dangerous, but that is another story!), What I was told at the time was the problem was the tank sitting hard on the flat support - water/moisture would remain between them and pinholes/pitting formed from the outside to the inside of the tank.
The solution I went with was epoxy coating on the outside of the aluminium replacement as per Fog, plus some 1/4" plastic sleepers bonded to the tank to provide a bit of circulation if moisture ever got in.
As per others, I expect it to well outlast the balance of the boat!

Remember plastic tanks are installed differently from metal tanks , because they expand on the first filling.

You might want to look at this thread http://www.trawlerforum.com/forums/s32/leaking-fuel-tank-25830.html . This was my leaking fuel tank adventure from last year. Got a ton of good info from TFers.

"I'm confident the tank will out live me"

Most tanks will last "forever" if kept out of the rain.

Stopping deck leaks should be part of thank repair/replacement.