Zincs and propeller

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J

John Ehricht

We were surprised when our 36 was hauled out for a bottom job in April of 2007 and noted that there were no zincs and the prop was loose. We know that there were zincs before it was spashed in at the end of 2005. Anyway, we noted the new zincs in May of 2007 before it was spashed in again. In the last two weeks, a diver inspected and cleaned the bottom and noted there were no zincs and the prop was loose. We have not noted any vibration. Has anyone else had this happen? Your comments will be welcome. At this point, we intend to monitor this closely with inspections about every 3-4 months.
 
Dec 24, 2003
233
- - Va. Beach, Va
John,

Welcome to the world of stray current in marinas. (You didn't say that your boat is in a marina, but I'm betting it is). If so, complain to your marina manager... they may be able to isolate a boat near yours that is "bleeding" current into the water and causing your boat to loose its zincs... its a difficult problem. You might want to hang a zinc "fish" off the side of your boat (connect it to a spreader) to help assure you prevent damage to your prop, shaft, and other exposed metal.
 

GuyT

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May 8, 2007
406
Hunter 34 South Amboy, NJ
Did you replace Cutlass bearing at haul out?

Sounds like your zincs are falling off because your cutlass bearing is causing vibration on your shaft. Many people install 2 zincs just in the event one falls off. No zincs can be a problem if you are connected to shore power alot. If this the case, your prop and shaft may have been the sacrificial anodes... not good!
 
Aug 9, 2005
772
Hunter 28.5 Palm Coast, FL
Put on two fresh zincs and tighten your prop.

and see if the problem repeats itself. Also check the cutlass bearing and measure for stray current in the water near your boat. The boat yard may have simply forgot to tighten everything on the shaft.
 
H

harry

serious situation

wouldn't think vibration is the problem if you never feel vibration. If you eat up zincs every 3 months you have a very serious situation which can eat your prop and prop shaft and thru hulls. Suggest you call in a professional, quickly.
 
Aug 19, 2004
239
Hunter 35 Vancouver, BC
Measure for stray current in the water

near your boat. So Landsend, please tell us how to do this! Neil
 
Aug 9, 2005
772
Hunter 28.5 Palm Coast, FL
Use a multimeter...

Measure between boat ground and stick the other end in the water around the boat. Check on both the ac and dc scale.
 
Dec 4, 2006
279
Hunter 34 Havre de Grace
Also measure the voltage in the water

In addtion to measuring from boat ground to water.... I remember reading a surveyor reccommended making up a stick about a foot long with a handle long enough for you to reach over the side. Attach the voltmeter probes on either end. Stick the probes into the water. This will give you an idea how much general stray current is flowing in the water between all the boats in the area. I haven't tried it yet, but seems logical. Might be interesting to measure voltage and current (hopefully small) with this setup.
 
Oct 14, 2005
2,191
1983 Hunter H34 North East, MD
Hey Bob...

If you can figure out what sort of apparatus the surveyor was thinking of, let us know or post a drawing. I for one would be interested as the leads on my digital meter aren't all that long. Also, I thought one lead should be on the boat's ground system (and/or on the shore power cable's ground wire) and the other dipped in the water. I've also heard of the neutral to water being tested, but I hesitate to mention this for fear that someone clueless would choose the hot side instead!
 
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