Prop, Zinc, etc

[Tim April IV]

A little bit of testing here.

We hauled April IV this week for her bottom paint and I took the opportunity to snap a couple of pictures.

In particular, we on the email list have had a lot of discussion over the last years about zincs. Here is a picture of a "prop cone zinc" installed,
and a little insight as to why many owners have talked about cutting little "donut zincs" to fit on the shaft - don't see how that would work in this picture.


Another item - this is the standard two bladed prop that came on the boat - a 15R10 - 15 inch diameter, 10 inch pitch. Later boats came standard
with a three bladed prop.

[jnnielsen]

Tim,

Thought I'd do a double reply to make sure you got this info.

The short answer is in the FAQ. It reads

"Can I post Images?
Images can indeed be shown in your posts. However, there is no facility at present for uploading images directly to this board. Therefore you must link to an image stored on a publicly accessible web server, e.g. http://www.some-unknown-place.net/my-picture.gif. You cannot link to pictures stored on your own PC (unless it is a publicly accessible server) nor to images stored behind authentication mechanisms such as Hotmail or Yahoo mailboxes, password-protected sites, etc. To display the image use either the BBCode

[SALDI]

Tim,

A great picture of your cutlass bearing, prop, and cone zinc.

After our first couple of cone zincs came off prematurely after only a few months of service due to degradation of the sacrificial zinc material we started coating only the exposed center face area of the zinc where the socket head screw goes through. We used di-electric grease to protect and preserve this thinner area of the zinc where the bolt goes through. Once this was done the entire zinc has degraded evenly and normally around the end of the shaft but the bolt has stayed tight and kept the zinc in place to do it's job.

We also found that our C350 was under zinc'd in our marina using only this shaft mounted cone zinc. To aleviate this problem we ran a 10 gauge wire from the engine block to an eye on the stern. When the boat is in her slip we have an auxilary zinc that is hung off the dock that we connect to the eye and 10 gauge wire. This has also helped our cone zine life and minimized any electrolysis problems on the boat. We are now changing our heat exchanger zincs about every six months and they are roughly 50% gone.

Regarding the cut down "donut" shaft zincs that people have been talking about, I believe they have been reducing the length of the donut zincs and then tightening the remaining zinc around the shaft in the reasonably tight area between the cutlass bearing and the back of the prop.

Best Regards,
Lea & Niki
SALDI #109
Vancouver, B.C.