We have used a small very
cheap in line
electric pump (Not a pressurizing pump) operated by a foot switch. It cannot drain the tank as the pump only operates when the foot switch is depressed (one of those momentary type switches). There is no need for a faucet (tap), just a swivel outlet into the sink. It has been there for 40 years without failure so we are happy with it.
It uses bugger all
power and it's quiet. The only downside is that you can't control the water flow rate, but that has never been an issue.
We also have a pressurized system with a control flow faucet at the sink. It can really pump a lot of water quickly but it's noisy and we are aware that should the
plumbing leak, then it will empty the tank, so we always religiously switch it off at the
power board. The
shower also uses a pressurized system as control of the water flow is important plus the small in line pump would probably be inadequate.
I originally had 2 Whale foot operated pumps at the galley but they invariably leaked and to operate them you needed to grab hold of the sink edge for balance, which defeated the purpose of having the foot pumps (ostensibly to free up your hands).