All fuel tanks should be CE marked to the latest ISO standard so you can be rest assured that they have been built and tested to the latest exacting standards. Polyethylene fuel tanks will eliminate any rust problems associated with older mild steel fuel tanks and will not generally corrode


When fitting either a new or replacement fuel tank it is worth checking that the tank is CE marked. The ISO standard that tank manufacturers follow is stringent and will give you peace of mind that what you are fitting to your boat has been thoroughly tested. A leaking fuel tank, especially a petrol one can be fatal. A bilge pump starting up has been known to ignite petrol that was lying in the bilge from a leaking tank.


Fuel tanks materialsAluminium fuel tank manufactured by The Tank Company

Stainless steel, aluminium and polyethylene are all suitable for diesel and petrol. Polyethylene must be of the cross linked variety when used for petrol and this can only be moulded, not fabricated.
Aluminium fuel tanks are best painted (powder coated) to avoid any corrosion. Stainless steel does not need treating.


Whether manufactured in stainless steel, aluminium or polyethylene the tank would normally be baffled. The exception to this is smaller rotamoulded or blow moulded polyethylene fuel tanks which do not have any baffling at all. Baffles can be moulded into these tanks but unfortunately take up so much volume they are invariably omitted.

Fuel tanks construction

Fittings generally are all mounted on the top of the tank with a dip pipe for the outlet and sometimes the return on a diesel tank. Any fittings below the top of the tank should have a tap to isolate the contents in an emergency.


Fuel tanks can be situated in any position in the boat but are normally found near the engine. In a sailing boat they can be found in a cockpit locker and in motor boats often either side of the engine as a pair of “wing” tanks. The relationship to their position and the waterline is irrelevant but careful thought is needed when working out the fill and vent hoses as the fill hose is normally 1 ½” in diameter and can be difficult to route through confined areas.


Fuel tank fittings

The fittings on fuel tanks are nowadays designed to generally accept flexible rubber hose. There are however installations that will still be using copper pipe which require a compression fitting. Both metric and imperial hosetails and compression fittings are readily available. Vents are normally either ½” or ¾” in diameter and fillers are normally 1 ½” or 2″ in diameter.


1. Fuel tanks

2. Water tanks

3. Grey water tanks

4. Waste tanks