Alum props for heavy boats
 

Have a 34' cruiser, 12' beam, 12k lbs with 454's B1's. Boat has 3 blade 19" SS Mirage props and lives in water full time, thus drives have taken a beating (corrosion). Freshawater use. I have a new set of 20" alum 4 bladed Alpha4 props I'm considering using to cut down on the SS/alum galvanic issues. Performance is not a concern. Will the alum props hold up behind a boat of this size, weight and power, or will they just straighten out? Rather not ruin them experimenting if possible.
Thanks

Have you tried a isolator kit from Mercury to help aid in controlling stray voltage corrosion?
The aluminum props will work fine for your performance desire. However, cups will become "washed out" at a quicker rate.
Also, Aluminum will also corrode with stray voltage.

Brett

boat is equiped with an galvanic isolator. Dont know if the drives got ate up from stray voltage or galvanic corrosion. I just bought the boat a month ago. Pretty sure its age has had some bering on the wear

I know every boat and prop is different but my friend went from a 15x15 3 blade stainless omc to a 16 pitch 4 blade aluminum michigan wheel i think and it was no good. 26 cruiser with a 350 in it. Went back to the stainless.

Going to go back to boating again Jerry?

Yep. Its what we do. Keeping the bike though

solas makes some nice flowtorq(rubix) aluminum Suzuki props that will replace the mirage well in 15.5 " diameter....

Buy a cheap multimeter. Ground to the battery and put the positive lead on to the drive .
Now check for voltage at the marina and away from the marina.

My guess is you have a ground problem on the boat causing the corrosion.

I use these on an old heavy ass Bayliner. Best prop I ever had on the boat and they are disposable. Says they are rated for 300 HP but I bet you would be fine with the 330 hp big block since it is twins. The Big ears really help it get on plane quickly and hold plane at low rpm. Not sure what pitch you need or what pitch they come in.

https://www.generalpropeller.com/qa2...yABEgJZ8PD_BwE

Chris

Thanks for the replies. I currently have the boat home for a winter makeover. Checking all the wiring, mecathode and the condition of the isolator is in works now. The ground wires were broken off both drives between gimble housing and drive. I’m sure that had a major role.