Thru-hull and impeller question

The scoop A/C raw water pick ups are a great idea for the A/C water inlets.
With all that water, air and froth, the A/C raw water pump needs all the help it can get while operating your ship at some speed.
Also helps keep your pump primed when your anchored or tied up ready to get primed, ah , er, relax and want some cool air blowing.

On your engine water pump; Not shure of any tricks on a Volvo D4 but try this;
Close sea cock, remove impeller cover, while the engine if bumped over, spray WD40 in and on the impeller.
If the engine tried to start, ensure a good dowse of WD40 and shut down the engine.

The WD40 keeps the rubber from dragging on the pump housing.

With a proper impeller puller (Jabsco) yank that puppy out.

An impeller puller is ideal, have you tried that ? Some impellers have a female thread in the hub so you thread a bolt and use a socket to crank it out.

as to the AC pick up, it helps on boats where the pick up is too far forward. You d think boat builder would think about that... the best type of scoop are what’s called South Bay strainer, it s a wedge with a SS mesh. It s great in areas with sea weed clogging the strainer too quickly. Kills two birds with one stone

Great with plastic bags too. With conventional slotted scoops plastic bags get stuck in the slots and don’t fall off when suction is shut down. With the mesh, they fall off