Head Scratcher

[Bob S]

Went to winterize the genny today and found a odd situation. Genny is mounted above waterline, thru-hull and strainer are below water line. Thru hull has an aft facing slotted scoop and is mounted directly to valve and strainer ie: no hose. Hose runs to raw water pump on genny. I closed the valve and removed the cover of the strainer to add antifreeze and the strainer was bone dry, not a drop of water in it. I often run the boat without the genny and only thing I can figure is somehow the water was pulled out of the system while underway. Never seen anything like it before. Any ideas? once i filled the strainer with antifreeze and ran genny it pumped fine.

[Navatech]

Went to winterize the genny today and found a odd situation. Genny is mounted above waterline, thru-hull and strainer are below water line. Thru hull has an aft facing slotted scoop and is mounted directly to valve and strainer ie: no hose. Hose runs to raw water pump on genny. I closed the valve and removed the cover of the strainer to add antifreeze and the strainer was bone dry, not a drop of water in it. I often run the boat without the genny and only thing I can figure is somehow the water was pulled out of the system while underway. Never seen anything like it before. Any ideas? once i filled the strainer with antifreeze and ran genny it pumped fine.

Aft facing scoop will result = suction when moving forward... AFAIK most if not all generator manufacturers specify a standard (i.e. non scooped) through hull... The reasons being that an aft facing scoop will cause suction and a forward facing scoop will cause over flow of cooling water...