Raw Water Strainer Mesh Size

[TBOT422]

I and several fellow boaters (C350 and C355) have noticed that the raw water pumps (Sherwood, Oberdorfer, Johnson (on the 355)), all seem to start leaking at the shaft seals every couple years or 400-500 engine hours. Depco says the sand and dirt in the water around the west coast of Florida, just eats up the shaft seals in the raw water pumps. Of course, they enjoy rebuilding them every couple of years. This got me to thinking about whether there would be any benefit to using a finer mesh in the raw water strainer. I see that Sherwood has both a 20 mesh and 50 mesh. I'm not sure what is standard, or whether a finer mesh would reduce water flow. Obviously, it may need to be cleaned more often, but that is a lot cheaper than rebuilding the raw water pump every other year. Any thoughts or suggestions?