Can someone explain to me what I am looking at, at the raw water intake under my boat? While diving to clean and inspect the boat bottom I have cleaned around the raw water intake but can't figure out how it works. It appears to be a rectangular box with what looks like two small anodes mounted to it's rear. The engine is picking up water while running but I can't see any points of entry into the box while swimming on the bottom so I am somewhat perplexed as to how it works. I just bought the boat several months ago and have not had it pulled out of the water yet. Can someone familiar with this system on my 1987 S2 9.2c please explain this water pickup and how it works? 