In areas with high barnacle or muscle growth these creatures know no bounds and often take up residence in the no-mans-land hiding behind the intake screen. After spending nearly three hours one day, in really, really cold water, even with a wet suit, trying to get eel grass out of one, I vowed to never, ever have one again. Any time you dive in your risk goes up. A diver spent two hours trying to get the barnacles out of this one and it still netted insufficient water flow.
This particular strainer is one piece meaning the thru-hull fitting and strainer are one integral piece. The grate could not be removed for a proper cleaning so the boat had to be hauled aat a fairly large expense. because the woenr could not see up into the area, or get bottom paint into the thru-hull he had no idea the barnacles had nearly blocked off his entire intake.