Dangerous Dave

I'm replacing the old merc through transom water pick ups on my boat with new stainless steel ones that need to be cut to the right depth. My question is, what is the right depth? How far below the bottom of the boat should they hang? should I cut them at an angle? It's an '85 Cigarette 28 w/ small blocks and TRS drives.
Thanks

monstaaa

they should be cut at a slight angle. as far as how much , maybe start a 3/4 of an inch run the boat, check water psi at w.o.t , then cut or trim accordingly

mmwalters

I think with the front edge even with the bottom the back edge should be at least 3/8'' lower to start.See what the water pressure is and trim as needed. Remember it is much eaiser to trim some off then to weld metal back on.

Cord

iTrader: (2)

The best ones are the designs with a adjustable cutting edge. I have an adjustable one and I'm seeing 10psi at 3/16".

zahndok

Since the water curls up off the bottom of the boat you don't need it as long as you would think.

Dangerous Dave

What is a good target for water psi? Would the fact that I have crossovers change anything? Thanks for the replies.
Dave

Cord

iTrader: (2)

The crossovers typically cause the engine to run cold. Keeping the pressure under 20psi is a good rule of thumb.