FWIW: Proof of "trick" given to us by our diver

Post your technical questions or solutions about your boat's hull, prop or rudder here.

Moderator: KenKrawford

Post Reply
AynB
Posts: 88
Joined: Tue Jul 08, 2008 8:13 pm

FWIW: Proof of "trick" given to us by our diver

Post by AynB »

Six months ago, we had our diver check our zinc just before our big cruising season.
He found no zinc at all, probably had only been a week without one.
His observation had been that with the MaxProp zinc - the weak area is the small, thin zone of zinc that keeps the bolts in place.
Once they erode, the zinc has nothing keeping it on the prop.
His suggestion was to use very little bottom paint and paint just the outer rim and the actual holes the bolts go through.
We did that and the photos below show the value.
Obviously the one on the left is ready to go on, just the 3/8" band around the sides and inside the bolt holes.
( yeah, I remove the tag with solvent before mounting )
Original weight : 260 grams.
DO NOT paint on the back surface - it's there that you get the electrical connection from the prop to the zinc.
The one on the right is the one just removed. Weight is 180 grams.
That's 80 grams of zinc 'lost', about a third of the original weight in about six months. Probably could have gone nine.
Since I have been gunshy about the small zinc size, I also 'trolled' a small extra zinc - it too is about 1/3 gone.
FWIW:



Al & Becca Szymanski , living aboard
"Halona" - Catalina 350 #17
Attachments
ZINCS.JPG
ZINCS.JPG (79.42 KiB) Viewed 9193 times
Post Reply