Hit something Saturday

[Lil Grizz]

No it wasnt while going fast either. Whatever it was I couldnt see it and dont know what it was. Dad and I have some guesses ranging from a log, rope, chain, and sea creature.
Although I have no idea what it was I do for sure know what it damaged. broke off the front upper cavitation plate or whatever you call it. Didnt contact the hull or even touch the lower unit. No scratches on anything. Somehow whatever it was got between the transom and upper drive and missed everything else. About 4 inches are broken off on each side but there are no cracks or leaks and the boat seems to drive normal.

I have three questions; what does the upper cav plate do?
How important is it?
Can it be fixed/who can do it/how much will it cost?
I circled the area that is now missing in the attatched photo, forgot to snap a shot of the actual damage. http://www.donzi.net/photos/Drivecloseup.JPG

[MOP]

Honest not much in my eyes, a little more initial lift for take off. I'd clean it up a little and paint it and forget it.

[jwright]

I beleive the purpose is to reduce the possibility of ventilating the prop. They should realy be called ventilation plates because they run rigth on the surface of the water and prevent the prop from "sucking" air. If the boat runs ok at speed it seems like you could leave it alone.
I have never been an engineer at Mercruiser so take my advice (opinion) with a grain of salt!
Good Luck

[MOP]

My two cents again, if you stand back and look at the plate it is a fair bit above the cavitation plate. Non of its predecessors had it nor do many others, I am sure it was added to help lift heavier or marginaly powered boats during initial take off. It at speed is completely clear of the water except for spray. I bet even your Cav plate is above the bottom of the hull like mine. I have a hunch since Mercury has boat some ties to cheap blow out boat lines, the plate helps them preform batter on the bottom end with the weak motors they put in those package boats. I know you seen boat motor and trailer just touching 10k.

[Fish boy]

Man, sorry to hear about the lower unit. Hope it works ok without having to do too much to it.

[Lil Grizz]

Well after talking it over here and with the local go fast shop I have decided its no big deal. From what everyone has said about it I gather its not vital on my boat. I plan on filing down the rough edges and leaving it alone.
On my boat that plate barely touches water at idle so as far as hydrodynamics are concerned it has no effect. The guy who I buy my parts from says that the only reason to fix it would be if it cracked the case and was leaking or if I just couldnt stand it being broken. I can deal with the broken. I can always fab up a stainless piece in the same shape of what was there and rivit it on the remaining portion if I get some free time to experiment.