Hi guys: That same old chestnut. I seem to recall raising this subject arround a year ago. My vessel, RHAPSODY, is a 2009/2010 21EC. In calm seas, or on rivers, there is no problem, however when in choppy conditions, slight swells, or rough seas, whenever the vessel rolls, the fuel in the tank surges and sloshes from side to side. Result: fuel escapes from the fuel tank filler cap vent, runs down the transom gunwales and down each side and into the sea.
There is no tank vent on the port side, contrary to the owner's manual, however there is a vent in the filler tube, leading to a hose which runs transversely across the top of the tank to the port side where it is then led into the tank via a metal L-shaped connection. I guess this is designed to act as a relief/escape medium for excess fuel when filling under pressure and/or, maybe in side-to-side surge conditions. The problem is, it cannot cope with the volume of fuel displaced upwards through the filler tube - being the only escape for fuel displaced by the violent surging action in a tank with no baffles (fore and aft dwarf bulkheads).
As you all may be aware, the fuel filler cap has two holes in a circular plate atached to the underside of the cap. These two holes vent to the underside of the cap and then to the outside elements, as they are supposed to do.
Not sure what anyone else thinks, but from many years experience in the Navy as a Marine Technician (Boiler Tech) and many years handling marine fuels and managing ballasting and trim in warships, I feel there is a simple solution: baffles or dwarf bulkheads in the fuel tanks. Limber holes in the base and centre of these baffles would allow free movement of fuel, while limiting the surge effect and the resultant upwards passage of fuel under pressure.
Be interested to hear what others in the Tugnut fraternity think.
Having said all this, I am extremely happy with my Tug. I just would like to see this problem fixed. It can't be that hard to design a modified fuel tank.
Regards to all. Stevan
