Fuel tank woes

[john_morris_uk]

I’ve been following Concerto’s water tank thread with interest as I’ve only today removed our fuel tank. I’m very pleased it did…

You can only remove the fuel tank when the engine is out and so we thought a new stainless tank might be a good idea while we had the chance. When I got the old tank out and sheets of rust fell off it I realised what a REALLY GOOD IDEA a new tank was going to be.

All feeds and returns will be from the top of the tank. With a generator feed and return and diesel heater, breather and Tank Tender probe, plus main engine feed and excess fuel return and filler, that’s a lot of fixings/holes in the top of the tank!
New one will have baffle plus a mini sump for water drain off.

It would hurt slightly less if I hadn’t taken the tank out 12 years ago and wire brushed it and painted it with Hammerite.
The moral is to beware of mild steel tanks.
I’ve then discovered that one of the Jerry cans of diesel that I keep in the bottom of the cockpit locker has actually rusted through and is peeing diesel everywhere.

 

[Concerto]

Wow, that looks bad. I know my fuel tank was removed 10 years ago and fully checked at the same time the new engine was fitted.

 

[Blueboatman]

Yeah… wow
Can only add
Fitting a drain lever valve rathe than a screw ‘ drop’ plug would be good
And a girt big -accessible -inspection hatch in the new one for easy cleaning…

 

[harvey38]

We were in the process of buying a Corvette 32 a few years ago and it came to light that one of the tanks was stainless, the other was the original mild steel so one tank had already let go and been replaced with stainless. When we requested to have the original mild steel pressure tested as suggested by the surveyor, the owner declined.

We didn't pursue the purchase!

 

[john_morris_uk]

Yeah… wow
Can only add
Fitting a drain lever valve rathe than a screw ‘ drop’ plug would be good
And a girt big -accessible -inspection hatch in the new one for easy cleaning…

I regret that no size of inspection hatch would facilitate ‘easy cleaning or inspection’ where the tank sits in the boat. It’s in the engine compartment behind the engine hard up against the bulkhead of the aft cabin. Solid bulkheads on either side and a few inches gap up to the cockpit sole above. The cockpit drain pipes are just in front of it along with the cables from the wheel above. I don’t fancy specifying an inspection hatch on the vertical front face behind all those pipes etc which is the only semi-accessible/visible part of the tank when it’s fitted.

 

[vas]

is stainless steel the right material for a diesel tank though?

 

[Blueboatman]

I regret that no size of inspection hatch would facilitate ‘easy cleaning or inspection’ where the tank sits in the boat. It’s in the engine compartment behind the engine hard up against the bulkhead of the aft cabin. Solid bulkheads on either side and a few inches gap up to the cockpit sole above. The cockpit drain pipes are just in front of it along with the cables from the wheel above. I don’t fancy specifying an inspection hatch on the vertical front face behind all those pipes etc which is the only semi-accessible/visible part of the tank when it’s fitted.

Indeed.

I don’t have a pic but the front inspection hatch route was what I had - sitting on a 1/4 inch neoprene gasket, once unbolted all round there was a vertical oblong hole 5inches x 4 . Enough, lying on top of the engine , to get a hand in and a mop or wet vac and torch.. I cleaned it once but it was worth it ..
(By the by J, this mod and a few others had been done in Trinidad by previous owner. My impression was that a very competent standard of reasonably priced workmanship , coupled with a lot of skill and experience about sorting out cruising boats, was the norm..) fyi
Had a sight gauge too on front of tank .

 

[Stemar]

is stainless steel the right material for a diesel tank though?

Mine are a translucent plastic, which has the additional advantage - when they're reasonably new, at least, that you can easily see the fuel level. Unfortunately, mine are no longer so new or translucent, so it's a bit more difficult.

Yes, I know about fire and plastic tanks, but they're well away from sources of ignition and if they get hot enough to melt, that'll be the least of my worries.

 

[Tranona]

Have you looked at having a plastic tank made by Tek Tanks? Better long term solution than any metal tank.

 

[Dunx]

+1 for Tectank solution. Might also reduce condensation potential , with modern diesel fuels said to have a shelf life of 6months the former wisdom of topping your tanks for winter may no longer be the preferred option. With a new tank potential to put in a draw off point for a polishing circuit?

 

[davidmh]

Good Idea to fit a lever valve in the sump bottom makes it easy to drain out any muck in the tank without any mess. I have fitted short pipe below the valve, and as an extra safety measure I have a compression fitting with a blanking cap on the end of that pipe so that any drips from the valve are trapped so they do not go in the bilge
David MH

 

[john_morris_uk]

Good Idea to fit a lever valve in the sump bottom makes it easy to drain out any muck in the tank without any mess. I have fitted short pipe below the valve, and as an extra safety measure I have a compression fitting with a blanking cap on the end of that pipe so that any drips from the valve are trapped so they do not go in the bilge
David MH

That sounds like a plan that I will take up. Thank you.

 

[Graham376]

Have you looked at having a plastic tank made by Tek Tanks? Better long term solution than any metal tank.

How long do you intend to live? Many of us here are of an age where longevity of tank isn't worth the extra cost

 

[vyv_cox]

is stainless steel the right material for a diesel tank though?

It certainly is if made correctly. Mine is now coming up to 40 years old. Inspected just a few years ago it was pristine, could have been made yesterday. Its only problem was that a brass drain plug at the base had corroded galvanically due to the small amount of condensed water lying there.

 

[fredrussell]

For my money, the only place for mild steel on a boat is in the engine compartment.

 

[Tranona]

How long do you intend to live? Many of us here are of an age where longevity of tank isn't worth the extra cost

I am not sure that it will be any more expensive than a stainless one. Certainly was not when I had 2 Tek Tanks made a few years ago.