Yes there ARE small cylindrical electric fuel pumps
on boats...sometimes. If you put your hand on the cylinder and then work the switch on and off, you will feel vibration IF that switch coontrols the pump
. Sometimes such pumps
are used to help in bleeding...other times they are used as a lift assist pump
when tanks are lower than the engine. Helps in rough seas.
Caveat...there must be a filter in line
between the tank and such a pump or you risk clogging the fuel line
at the pump in rough weather. Carry a spare if that is indeed what you have. Any standard gas/diesel compatible 12V pump will do and you can get them pretty cheap at any Napa store.