Cavitation from wrong skeg zinc ???

[crazy charlie]

Hey guys.I have had a cavitation problem when raising the outdrive angle while underway to raise bow.I have tried a host of things from changing props to increasing the up range of my trim tabs.Very little improvement.I have been using a bravo skeg zinc because it is beefier and lasts me an entire season because of its beefyness.Is it probable that this may be causing the cav/ventilation???The fin of the zinc IS set back further than an alpha zinc which is the drive that I have.My set up is dual 230 xl mercruisers with alpha drives.Anyone with experience on this?? Charlie

 

[Reel Poor]

Re: Cavitation from wrong skeg zinc ???

How high can you trim the drive before it starts cavitating? Which drive, port or starboard? Are they counter rotating drives? What is the part # of the anode your using?

You may want to check the amount of toe-in the drives have. Should be 1/4 to 3/8 of an inch. Measure the difference in distance between the leading edge of the drive cases and the tail end of the anti cavitation plates.

Also check for obstructions on the bottom of the hull, ie; thru hulls ect.

 

[crazy charlie]

Re: Cavitation from wrong skeg zinc ???

Thanks for the reply.They are not counter rot. The drives dont cav. immediately ,but they cavitate way earlier than they should.I would like to be able to raise the drives while under way to raise the bow during a choppy day out.No obstructions.8500 lb boat at 28ft. It was worse with 14 1/2x17 3 blade props which were std. on the boat.I switched to 4 blade 15x16 and it improved somewhat.Charlie

 

[crazy charlie]

Re: Cavitation from wrong skeg zinc ???

Well,I am going to try the alpha skeg zinc anyway.I just thought some one here may have some expertise in this area.