Why mild steel fuel tanks?

stuartwineberg

stuartwineberg

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I am looking at Nauticats and they tend to have large painted mild steel tanks. Any reason why they do this as opposed to stainless? I appreciate they are probably cheaper but Nauticat tend not to do things to save cost
 
Westerly had them.Mine is still in place but I'm preparing myself for the worst.It can be taken out more or less easily but it's a task I'm not looking forward to.
 
30boat said:
Westerly had them.Mine is still in place but I'm preparing myself for the worst.It can be taken out more or less easily but it's a task I'm not looking forward to.
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I was very relieved to discover that the original owner of my boat paid an extra forty quid for a stainless tank (50l) back in 1986. Of course there can still be issues with welds, but it seems to be holding up OK.
 
fergie_mac66 said:
seem to remember there were reasons for tanks . steel, galvanised ,stainless depending on fuel.
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Zinc reacts with diesel so no galvanizing.Stainless is more expensive and can fail at the welds.Mild steel is easier to make.These days we have plastic tanks.If I ever need to replace mine I'll make a plywood epoxy one.
 
Westery& Moody boats were fitted with painted steel fuel tanks and most are still serviceable even after 30 years if looked after. If i had to replace mine I would still go with painted steel as it would certainly outlive my ownership so cannot see any reason to spend considerable more on S/S or plastic.
 
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theoldsalt said:
Westery& Moody boats were fitted with painted steel fuel tanks and most are still serviceable even after 30 years if looked after. If i had to replace mine I would still go with painted steel as it would certainly outlive my ownership so cannot see any reason to spend considerable more on S/S or plastic.
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You have a point.I would quite probably make a mild steel tank.
 
I have a 1984 NC43 and am in the process of replacing the mild steel water and fuel tanks. The water tanks had rusted away and the fuel tanks were probably a year away from failing. Putting in Tek tank plastic ones, but have to be multiple tanks as access through the main saloon roof is limited. Not sure why mild steel, but I suspect that S/S welding in the olden days was unreliable and it was thought better a reliable weld in mild steel than a failing weld in stainless. To be fair they have lasted 31 years... Just had the lead keel keel off to reseal. A huge expensive project but very excited about getting it all back together with a new engine genny watermaker etc and going sailing!!

Puggy
 
wully1 said:
Mild steel anything on a boat is stupid!
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Good job nobody builds hulls out of it then :p

I sort of know where you're coming from though. If I had a mild steel fuel tank I'd worry that water at the bottom of the tank would be rusting the insides. Obviously there are thousands of them out there without trouble, but I'd still wonder.

Pete
 
prv said:
Good job nobody builds hulls out of it then :p

I sort of know where you're coming from though. If I had a mild steel fuel tank I'd worry that water at the bottom of the tank would be rusting the insides. Obviously there are thousands of them out there without trouble, but I'd still wonder.

Pete
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When we cut out my steel one (both fuel and water) the rust inside the tanks was incredible. If I could ever work out how to include a photo, I have some to really scare you....
 
stuartwineberg said:
I am looking at Nauticats and they tend to have large painted mild steel tanks. Any reason why they do this as opposed to stainless? I appreciate they are probably cheaper but Nauticat tend not to do things to save cost
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If you would like to chat Nauticats feel free to PM me .. I love mine..
 
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I seem to remember the BT Challenge boats had hulls made of mild steel. I understand that mild steel suffers less fatigue stress, which is why it was favoured and I suspect that is the reason why tanks are mild steel. The reality is that they really shouldn't be exposed to water to much.
 
30boat said:
Zinc reacts with diesel so no galvanizing.Stainless is more expensive and can fail at the welds.Mild steel is easier to make.These days we have plastic tanks.If I ever need to replace mine I'll make a plywood epoxy one.
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That's interesting. When we bought Avocet 20-odd years ago, the surveyor made a comment about the galvanised diesel tank and muttered something about a reaction. What is supposed to happen? The tank is now 43 years old and nothing bad has happened yet!
 
rb_stretch said:
The reality is that they really shouldn't be exposed to water to much.
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Surely you mean the theory is that they shouldn't be exposed to water much? The reality is that they probably are, whether from condensation, leaking side-deck filler caps, or delivered along with the fuel from the supplier's own tank.

Pete
 
Avocet said:
That's interesting. When we bought Avocet 20-odd years ago, the surveyor made a comment about the galvanised diesel tank and muttered something about a reaction. What is supposed to happen? The tank is now 43 years old and nothing bad has happened yet!
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I think it's the sulphur that reacts with the zinc.Probably with the help of water sloshing under the diesel.
 
theoldsalt said:
Westery& Moody boats were fitted with painted steel fuel tanks and most are still serviceable even after 30 years if looked after. If i had to replace mine I would still go with painted steel as it would certainly outlive my ownership so cannot see any reason to spend considerable more on S/S or plastic.
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I'd go the other way - once you consider the costs of removing the old tank, fabricating a new one and then fitting it, the additional material cost for stainless is trivial. For precisely the same reason, any skin fittings or seacocks I ever fir will be bronze.
 
rb_stretch said:
I seem to remember the BT Challenge boats had hulls made of mild steel. I understand that mild steel suffers less fatigue stress, which is why it was favoured and I suspect that is the reason why tanks are mild steel. The reality is that they really shouldn't be exposed to water to much.
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The only way to do that is to keep the tank full at all times to prevent condensation above the fuel level - somewhat impractical during use but essential when laying up for winter.

I once had to change a mild steel tank in a Trapper 500 and had a SS one fabricated by a local specialist, it was an easy fit in a cockpit locker. The original had a rust sludge that tended to block the outlet in rough seas.

I'm surprised that Nauticat still use mild steel, if I'd known that I would have discussed it with the nice lady marketing person who showed me over the 331 at the Düsseldorf Boot this year, I'm really interested in why, nothing else on board is done on the cheap and the difference in build cost of a €300'000 boat would be trivial.
 
I believe Nauticats have a sludge pump on each tank, I guess pumping out any water from the fuel tanks has to become part of the routine maintenance. Wonder how many people actually do that.
 
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