User

What is the proper orientation for the clamshell thru hull? Should the slots face aft or forward?The vessel in question is a 1990 Carver 534 with MerCruiser 7.4l inboards with V-drives. The intakes are mounted, slots forward. I believe this is incorrect even though it appears to be a factory installation.

Doug

Doug:

If equipped, scoop-type or clamshell hull strainers should be installed on propulsion engines, air-conditioners and water cooled refrigeration systems with the slots or holes facing forward.  In this configuration the scoop, “rams” water into the pump, assisting it and maintaining prime.  However, because water may be forced into them while the vessel is underway generator intakes should never be equipped with scoop strainers.  Additionally, if you operate a twin screw vessel on a single engine, the dormant engine’s scoop-equipped intake seacock should be closed.  Finally, choose strainers that are easily serviceable without requiring the use of tools.  Some models utilize a trap door and pin for easy in or out of water access and cleaning.

Steve D'Antonio, Technical Editor