Re: water flow GPM per HP of an engine?
On of the easiest places to start looking for blockage is at the mixing elbow water discharge.. but it's entirely possible that engine passages themselves are compromised.
1984 Fast/Nicholson 345 "FastForward"
".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)