Fuel tanks and twin outboard rig

[BoomTish]

Hello,

I'm just trying to figure something out. I'm in the progress of restoring a boat and I've got to the point where I've got a pair of Mercury 150 Optis. At this stage
I'm trying to figure out what would be the best fuel tank setup for my boat. I have two choices with the fuel tanks, single big tank or two tanks.

I'm getting the tank built up by a fabber. Should I run one big 600L tank and have 2 outlet ports to feed the twin outboards or I'm better off running two 300L tanks
and run each tank for each motor. So I'm just posting to ask for advice and any ideas you guys have.

Thank you

[Noelm]

I guess it achieves the same thing, the twin tank setup does provide a bigger margin for safety in the event of some sort of fuel related failure, whether that be water, dirty fuel, fuel line problem and so on, not that it happens much, but the possibility is still there.

[mitc69]

2 motors mean 2 tanks + 1 reserves, always the best back up, even when most go out i'm sure they pack a spare tank

[Chimo]

BoomTish

If it was me I'd get your man to build one tank but instead of a middle baffle put in a wall and then add an inlet to each half and front and rear breathers as well as outlets to each motor from the two tanks. Also based on my experience if the tank is to sit on a bed then to avoid holes in the bottom later on ensure you sit the tank on well spaced teflon spacers so no water stays in contact with the bottom of the tank.

Cheers
Chimo

[Luke G]

The benifit of running two tanks is only really worth it if you fill up at different servos, how many times will you do that?

[BoomTish]

I'm starting to think it'll be alot easier to run a single tank without the hassles of dealing with 2 tanks/extra fuel lines running under the floor. Nowadays there are people running big single tanks for twin outboards. But I do understand about dirty or contaminated fuel especially when going far wide offshore. I'll chat to the fabrication guy and see how much it cost between single and twin tanks. The boat previously had one main 250L with a smaller 100L tank to a single outboard but it won't be enough so I'm going to go bigger.

Thanks Chimo for the advice on placing teflon underneath.

[FisHard]

If it was me, I'd go 2 tanks. My theory is if at sea, your single tank gets a leak or splits, you're stuffed. With 2 tanks, you'd only lose half your fuel.

[ozynorts]

Twin tanks will save you if you have a tank fail but will not save you from bad fuel. If the servo you fill up at has bad fuel it will be in both tanks so both motors will potentially be affected.

[Noelm]

The benifit of running two tanks is only really worth it if you fill up at different servos, how many times will you do that?

aahh, no, lots of times there can be a filter/hose/primer failure, or water getting in the tank from another source other than the garage, filling at different garages will prevent a bad fuel load in both tanks, but not the 100 other "things" that can go wrong, whereas two tanks will.

[Luke G]

aahh, no, lots of times there can be a filter/hose/primer failure, or water getting in the tank from another source other than the garage, filling at different garages will prevent a bad fuel load in both tanks, but not the 100 other "things" that can go wrong, whereas two tanks will.

Most of the issues you mention come down to maintenance, lets be honest it's a very rare issue. Speaking from personal experience, a number of different boats and thousands of hours I've only had issues with dodgy fuel from the servo. I am aware it does happen, but if you change your lines and filters out regularly (Every 5 years or so) it hardly becomes an issues.

You could also say two tanks could cause twice the issues, but theres no point going there.

Good luck with whatever you do!

[Spaniard_King]

Why don't you get 4 tanks and fill up at 4 different servo's ???

1 tank::)