MorningBird said..
Do you really need it? After 10.5 years of sailing around Pittwater and elsewhere I have never had anything caught in the inlet. MB has a water strainer as an inline filter and it works a treat. It hasn't happened yet but a fish or any debris that can fit in the inlet will go to the filter and get stuck there. The filter is long enough that it is unlikely to stop water flow.
A strainer over the inlet will just block up with growth and it will be the time you forgot to clean it that you really need to engine.
I'm with Sam & MB on this one, I have no external strainer & rely on my filter.
I have 2 inlets with large filters inside. If the engine intake gets blocked, at an inconvenient time, I can flick a tap over to feed the motor with the other (heads, deck-wash etc) intake.
So far no blockages but if I had to I can ram a broom handle down through the open ball valve to clear anything in either intake.