The good and the bad of fuel
I have 4 x 200 ltr tanks
on my boat, i choose these as the fuel tanks
compartments are designed to fit under the cockpit
seats and to get them custommade in metal or poly was prohibitive, so the builder
suggested to try bladders, i also fitted a bladder designed for black water
So after 6 yrs and 1200 engine
hours i can give a first hand opinion of them.
They are very strong being made of an inner and outer layer of thick welded plastic material ,not unlike Inflatable
Because they colapse as the fuel is used they contain virtually no air ,and so i have never had a problem with condensation
, never had water
in my pre filters .
They where cheaper than moulded poly Tanks ,$1200 v $350.
As long as they are contained in a snug and lined area they do not slop around to any noticable degree even though they have no built in baffles
Goes without saying but you will never have a corrosion
They can leak, the reason they do this is the two layers are constricted together buy the inlet and outlet fittings which are just plastic Thru hull
type fittings which regularly need tightning to compress the layers together at this point, and is part of your warranty , the trouble is if you over tighten which is very easy to do, you will stip the thread and fuel will start to leak in between the two layers causing the outer layer to harden and go brittle and crack, i have lost
2 tanks from this problem, fortunatley they were replaced under warranty and the new ones had heavier duty fitting on them.
They are slow to fill as they do not have breather pipes ,so you will get blow back if you use a standard bowser nozzle. Not a problem i have any more as i fill all my tanks from jerry cans thru a 5 micron filter funnel.
As mentioned above i had i bladder that was specifically for black water, i cannot recommend going this route
as the material is porous to odour, not good if you need to mount it near living or sleeping areas
Hope this helps you to make a more informed decision