Bigger fuel tank, more fuel tanks?

[ryanb]

I am thinking about adding more fuel capacity to my boat. The current fuel tank is mounted under the floor. There is 7 inches of empty space between the top of the tank and the supports for the floor. By my calculations I could get another 35-45 gallons in there. Is it feasible to mount another tank on top of the current one, or would it be easier to pull the current tank and replace with a larger? Tank is aluminum, would it be possible to reweld into a larger tank?

 

[Prfisher]

Whichever of the three options you mentioned, the shop labour time will be similar. The difference will be the material cost. If it was me, I wouldn’t dick around with reworking the old tank. Adding a new tank on top complicates the plumbing & won’t save a lot of cash. I think the best option is a new tank. Just my 2 cents.

 

[Aces]

I would put a new tank in with proper baffling and grounding.

DO NOT put spray foam around it....i found out the hard way $$$

 

[Sharphooks]

You didn’t say how big your tank is now....word of warning...carrying piles of fuel is fine if you’re making long runs and burning it off. IF you’re not, you end up with lots of unburned gas in your mega-sized tanks .....fuel, unlike wine, doesn’t get better with age.

My boat came with a 600 L tank.....I’d be happy with a tank that held 50% of that amount....and I do “long-ish” runs!

 

[ryanb]

70 gallons, or about 250 litres. It's enough most of the time, expect when it's not...lol. Long hauls I have to carry jerry cans. Don't usually have to use them but I need them for just in case reserve.

 

[gungadin]

With seven inches above the top of your present tank, (I hope you are actually measuring above the top of the fuel inlet hose}, you would be better off with a new tank if you really need the extra capacity. Although it is possible to extend your present tank, you will be hard pressed to find someone who is willing to do it. Figure on 2-3 thousand dollars for a new certified tank, new sender, new hoses and related hardware, plus installation. Your fabricator will likely need your old tank as a template, so the decision to go ahead is a pretty important one.

 

[ryanb]

Thanks for the comments. Upon further reflection and reading lots of threads onTHT I believe a second inline belly tank might be the best/cheapest option. There is adequate space for this under my pilothouse. Does anyone have any contacts for tank builders on the south Island?

 

[trophywife]

Thanks for the comments. Upon further reflection and reading lots of threads onTHT I believe a second inline belly tank might be the best/cheapest option. There is adequate space for this under my pilothouse. Does anyone have any contacts for tank builders on the south Island?

E&D arrowsmith

 

[gunnerlove]

Bladders. They roll up to nothing when empty.

 

[Oly1]

Bladders. They roll up to nothing when empty.

Whats the life span of a rarely used fuel bladder. How many years do you think it would last? Is it better to use them more often and stretch them out?

Oly

 

[gunnerlove]

Relaxed (flat) would probably be better than stored rolled up or folded. ATL says 10-30 years.

 

[Joelster]

Relaxed (flat) would probably be better than stored rolled up or folded. ATL says 10-30 years.

Any idea where I can buy a bladder that’s approved for use in Canada?