Zinc, Counter Torque, Installation - Maxum Boat Owners Club

n1mie · 06-19-2010, 11:24 AM

On my Alpha One outdrive, there is a zinc just above the propeller. The zinc was completely gone when I acquired the boat. The zinc is supposed to have a secondary function of providing counter torque for the propellor. Anyone have any guidance on how to decide on the angle to which to set this fin-shaped zinc? I'd like to guess an angle and not fiddle with it.

seapuppy · 06-19-2010, 03:26 PM

welcome to the zoo...what size/model boat do you have..?????..actually on my old A1G2 it didn't come with one of those anti torque zinc's ..what I'd do is set it at zero angle.......take it out for a spin and if you excperience pull to port...put the zinc at -1 deg stbd....etc.....

sorry I can't help better but I have no direct experience with these zinc's....

SP

n1mie · 06-19-2010, 07:15 PM

I have a 25'5" from 1990. I believe it's a 2500 SCR. Only the second owner, and I work with the previous owner so I have access to data.

It would seem to me that although it would be slightly different for each drive that there ought to be a fairly standard starting point. But I've been unable to find any information by searching online. I am very surprised at that lack of info.

PS - I served on the Lipscomb (SSN685) and the Whale (SSN638).

seapuppy · 06-19-2010, 08:14 PM

you were on the leanard P lipscomb and the whale??..cooooooool!!!...I worked on the Drum...richard b. russell....snook...and 2 of the 585 boats as well as the 575 boat and the 21 class boats..WELCOME FELLOW BUBBLE HEAD!!!!...
as you can see from my tag line...I was involved on the 683 final configuration in the ocean engineering group at mare island!!....we got the stuff on the boat for the missions in blind man's bluff.....so..yes I know all about those missions....

SP

n1mie · 06-20-2010, 11:09 AM

I was on the Lipscomb from 1987 thru decommissioning in 1990. I was on the Whale from 1990 thru 1992.

seapuppy · 06-20-2010, 02:30 PM

awesome chip.....welcome to the zoo....

SP

Horizon · 06-24-2010, 01:57 PM

Hi n1mie,
I used to have a bravo one and before that an omc. If memory serves me correctly, the rear of the tab on the zinc should be slightly to port. Some drives have notches underneath. Its trial and error depending on your prop size and pitch but if you go about 1/8" to port with each try you might compensate for prop counter torque. Someone correct me please if I'm wrong, it's been a while since I've had a single screw. You will know if you've started wrong because the torque will be more not less.