tassie48,
The use of small water pumps, usually auto windscreen washer pumps, to act as discrete "bow thrusters" is something I have used since 1978. It wont spin the model around but gives a gentle sideways push that is usually good enough for gentle maneuvers. The small inlet/outlet holes in the hull sides are not too obvious, which can matter for scale models that didn't feature such things.
This idea was fully described in the January 2019 issue of the "Model Boats" magazine.
Glynn Guest