Strainer is NICE TO HAVE with a raw water cooled engine. There are some tight
cooling water passages in the engine. IMO, it's essential with FWC to keep
stuff out of the heat exchanger(s). Even with positive displacement gear pump
some debris ground up by the pump will get past but much less than with a
flexible impeller type pump.

For me it would depend upon only one thing. Do you have space in the bilge to
install and SERVICE a strainer? You'll want to be certain you have sufficient
room to operate the seacock if you opt for a strainer.

Butch