For transferring from jerry cans that are already on deck
the siphon hoses work well. But if the full and heavy jerry cans/jugs are in your dinghy
then the electric
pumps are the way to go.
The Walbro is the only UL approved after-market diesel electric fuel pump
that I know of and expensive and is normally used where it is permanently mounted in the engine
compartment. I use the Walbro as a back-up to the engine lift
pump and also as a fuel polishing pump -with a series of valves - to suck fuel from the tanks
through the filter and then back into the tanks
However, the electric drill pumps and other 12vdc diesel rated pumps are available. They can be fitted with vinyl hoses so you can see the fuel being moved. A long two-conductor electrical
cable with a cigarette lighter plug
one end and the other end attached to the pumps gets power to the pump. I use wooden dowels of the size necessary to "plug" the ends of the hoses after transfer is finished. The whole rig goes into a vinyl bag we sewed up to help keep dirt away and smell contained.