I use a hand operated semi rotary pump for any diesel transfer operations, simple and effective it is mounted on a piece of plywood .The idea was that iI could secure the plywood with a bit of rope to the back end rail on a working boat with suction and discharge hoses long enough to reach into my grand union style tanks[town class] Last 2 uses as follows, 1 emptying tanks into drums for tank cleaning, repair of 2 pinholes in a welded seam and sorting out small but annoying leaks in the pipework. 2 Removing a quantity of fuel from a friends boat into drums to allow for tank cleaning and maintainance.This last use saw 2 clamps being used to clamp the set up to a back door. I do not not keep this handy item on my boat, just bring it from home if needed,no accusations of going equipped to commit an offense and no easy pickings for thieves.Must admit that if the "bizzies" stopped me in my van with that pump and a quantity of drums in the back it could get interesting