Steel in Keel Fuel Tank Overhaul or Plastic Tanks

[Rustic Charm]

I've struggled with dirty fuel and this week the fuel has literally killed my Volvo Penta 2003T. So I need to repower as well. But before I purchase a new engine, I need to decide what to do with my fuel.

My 200+ fuel tank is in the keel. It's a steel boat. In November I thought I had cleaned the tank out pretty well when I was repainting the boat. But, I simply can't get at the sides from the top.

What I can do, is to cut one side out of the keel so I can get at the entire inside narrow tank. Clean it, get rid of the rust, treat any I can't get rid off, then paint the inside with aircraft tank sealer. Then weld a new side on to the keel, prime, and copper coat the repair. And finish up by sealing the inside of the new cover with a long paint brush. Cost would be minimal, maybe $500 for sealer and paints but a few days work.

The other option is I have two custom built plast fuel tanks made up to my specs to fit in storage cavities in the settee area. Not a lot of labour, but perhaps $600 each tank ($1200) plus two new deck fillers, pipes and fuel hoses to engine. Perhaps $2000? Then if I do this, I'd need to decommission the old tank. How do I do this? Do I fill it with sump oil? Concentrated anti corrosion liquid?

Note: the keel tank is not serviceable by the access covers. It's simply too narrow and too deep.

[Snowpetrel]

How about a big day tank. If you can polish and filter the keel tank a few times eventually it will probably clean up enough to be useful as a bulk storage tank that is always filtered into the day tank before use. Just another option for you!

Shame that cutting up the keel tank will damage your nice new coppercoat.

Maybe just run from a few jerry cans for now until you have the engine issues sorted.

I once did a delivery from Townsville to Hobart using 10 jerrycans the whole way on a 42 foot steel ketch. Lots of refuelling stops, but the tanks were too contaminated to trust.

Where did you fuel up? Maybe the fuel you got was nasty? After all that tank got you across to melbourne without issues..

[Rustic Charm]

Originally Posted by Snowpetrel

How about a big day tank. If you can polish and filter the keel tank a few times eventually it will probably clean up enough to be useful as a bulk storage tank that is always filtered into the day tank before use. Just another option for you!

Shame that cutting up the keel tank will damage your nice new coppercoat.

Maybe just run from a few jerry cans for now until you have the engine issues sorted.

I once did a delivery from Townsville to Hobart using 10 jerrycans the whole way on a 42 foot steel ketch. Lots of refuelling stops, but the tanks were too contaminated to trust.

Where did you fuel up? Maybe the fuel you got was nasty? After all that tank got you across to melbourne without issues..

The injector pump is stuffed. Jerry cans won't get me anywhere for that reason.

The tank got me across, yes, but it was calm until Friday when I hit the roughness after leaving the rip. Then when I left Sunday morning I motored in calm weather for what 20 hours. The fuel tank reduced and then I was into the worst of it. Setting off for Melbourne how ever I had 200 ltrs.

[Snowpetrel]

Well, my vote is for fixing the keel tank. The old one on Snow Petrel 1 has never given a jot of problems. What micron filter were you running out of curiosity?

Sent from my SM-G930F using Cruisers Sailing Forum mobile app

[zeehag]

rc, you will NOT like plastic.
it totally SUCCCCKKKKSSSS. plastic tank was my fail issue with mine.
i am going to have intrinsic fg tanks made to fit my boat.
you have steel boat, make the tank you have become serviceable.
remove top. clean treat, make top so you can reach into it for cleaning in future and weld all back together brand new. ta daa. easy peasy. no frikkin pl asssss tik. crud seems to grow nicely in pl ass tick

[Rustic Charm]

Originally Posted by Snowpetrel

Well, my vote is for fixing the keel tank. The old one on Snow Petrel 1 has never given a jot of problems. What micron filter were you running out of curiosity?

Sent from my SM-G930F using Cruisers Sailing Forum mobile app

They were 30's in the racor's. I think the engine one is a 10.

I'm am thinking carefully about cutting an access into the keel tank from the outside. Something the size of a 1m by 1m would do it nicely I think.

[Rustic Charm]

Originally Posted by zeehag

rc, you will NOT like plastic.
it totally SUCCCCKKKKSSSS. plastic tank was my fail issue with mine.
i am going to have intrinsic fg tanks made to fit my boat.
you have steel boat, make the tank you have become serviceable.
remove top. clean treat, make top so you can reach into it for cleaning in future and weld all back together brand new. ta daa. easy peasy. no frikkin pl asssss tik. crud seems to grow nicely in pl ass tick

What are 'intrinsic fg' thanks?

I can't 'make an access' in the top any bigger than it already is. My only option would be to come from the side.

[El Pinguino]

I'd come in from the side...clean thoroughly , coat as required.

Then I would install two pickups... one drawing from a few inches up from the bottom and supplying the engine... another as close to the bottom (5mm?) as you can put it to draw off the crud every now and again.

Then filter all fuel before it goes in and run through a pair of day tanks on its way back out to the engine....

[Rustic Charm]

Originally Posted by El Pinguino

I'd come in from the side...clean thoroughly , coat as required.

Then I would install two pickups... one drawing from a few inches up from the bottom and supplying the engine... another as close to the bottom (5mm?) as you can put it to draw off the crud every now and again.

Then filter all fuel before it goes in and run through a pair of day tanks on its way back out to the engine....

A 'pair' of day tanks?

[El Pinguino]

yep and a pair of Alfa Laval purifiers

Once bitten twice shy etc..

OK one day tank .....

[Rustic Charm]

Originally Posted by El Pinguino

yep and a pair of Alfa Laval purifiers

Once bitten twice shy etc..

OK one day tank .....

Are you leading me on? I've found a Alfa Laval conditioner which is worth thousands?

[El Pinguino]

Sorry.... was wandering off into the wilderness.....

Alfa Laval is dairy farm and big ship stuff.... standard kit on big ships... which these days use heavy fuel oil in their 'diesels' which is somewhere south of bitumen and has to be seriously heated just to get it to flow.....


But yes... single big day tank with gravity feed to engine is good.... until your lift pump diaphragm calls it a day but that doesn't happen every day.. only once every 10 years or so.... don't ask me how I know this...

[Snowpetrel]

Originally Posted by El Pinguino

yep and a pair of Alfa Laval purifiers

Once bitten twice shy etc..

OK one day tank .....

Then you would have to put up with engineers wingeing day and night about having to clean the things..

[On The Water]

Going from the assumption the tank is in sound condition.
Cutting out the keel to .....

Just have it cleaned, plenty of operations in Melbourne, get a outfit that does said job, a vacuum truck with a 250+ bar industrial pressure washer with steam capability, in and out 500 AUD max, not a drop of rust or dirt left behind.
Fill with clean diesel to prevent rusting.
Fix the hoses, start the engine and be on with it.

[Rustic Charm]

Originally Posted by On The Water

Going from the assumption the tank is in sound condition.
Cutting out the keel to .....

Just have it cleaned, plenty of operations in Melbourne, get a outfit that does said job, a vacuum truck with a 250+ bar industrial pressure washer with steam capability, in and out 500 AUD max, not a drop of rust or dirt left behind.
Fill with clean diesel to prevent rusting.
Fix the hoses, start the engine and be on with it.

I appreciate your suggestion, but just a couple of problems with it,

A. I'm not in Melbourne
B. The inspection hatch in the forward compartment is 50mm at its widest and 20mm at the narrow end and;
C. Baffles in the tank mean I can't see the entire tank, yet alone blast it with a steam pressure system.

I actually have a friend with a high pressure steam cleaner. It would cost me nothing to use it. But, I can't get it in where it needs to go. In addition, there is some form of plastic sealer that's been dropped or dripped into the bottom of the tank. I suspect that is hiding some rust or gunk below it. If I cut the tank out then I'd dig that out and see what the steel is like below it.