zincs on 31 TE

[sharffj]

Brought a 2004 31' twin Yanmar TE up to Oregon this spring. In going through the boat it had some issues with electrolysis. The boat was well bonded, but did not have a galvanic isolator and had zincs on the rudders and shafts, but did not have a zinc plate on the hull. Sanding the struts showed some pitting and the start of leeching of zinc from the bronze. Will install the isolator and will put a plate on the hull which will link to the bonding system. Feel on top of it now, but wondered what others experiences are. Am I missing something or do Albins not have a zinc plate on the hull?
Jeff S

[Pitou]

My experience on my 28 was similar ... at time of purchase/delivery (2004) all anodes were fresh and new. Got the hull to home port plugged her in and watched the anodes decay rapidly ... prop nut anode, R4 on the rudder, bow thruster anode and trim tab anodes. Engine anodes were all fine. Hauled after 2 1/2 months as the prop nut anode ("F") was completely gone, rudder and trim tab zincs 80% gone and checked the bow thruster zinc which was more than half gone. I replaced all anodes to have it all happen again by the time I was hauled for the season in October.

The following spring commissioning I added a galvanic isolator and with all other conditions being the same I now make my 6 month season on one set of anodes, now reducing by only 50% at time of fall haul out. What a difference! Why an isolator is not standard at build out is beyond me. I have thought of adding a hull zinc plate and attaching to the bonding system, but have neglected to do so as the isolator seems to be adequate with no pitting of the strut, prop, skeg, rudder shoe, rudder spud, rudder or any bronze thru hulls. "A Galvanic Isolator is a Must."

[zinbaad]

I also wondered why my 31 with twins lacked a zinc plate like I have seen on most 28's. I requested one to be installed & bonded last year but instead they installed 2- 4 lbers on the shafts and additional heavy rudder zincs on the trim tabs & rudders. At first view they seemed to wear away fast, after complaining to marina to check grounding an having two "abandoned" floating boats removed the erossion seemed to subside lasting the whole season. I also considered an isolater.
Docking at a new marina this year with a lot less boats & less possibility of stray elec current. Guess I'll wait & see

[Halcyon]

Regarding abandoned boats and stray currents, can anyone tell me how to detect current in the water? How close does a source need to be to cause trouble, in brackish water? What type of Galvanic isolator is best? thx

[sharffj]

Mine is a CE marine. They are rated for 35amps, 50 amps or 100 amps depending on how much shore power you draw. The higher amp models will cover lower amps as well. If you have moorage in salt and a hot boat nearby I'm told it is a must.
Jeff S

[Carl]

My experiance was exactly the same as Pitou's. Once I installed the isolator my problems were gone, even though the boats around me continued to complain about having to replace their zincs mid season. Below is a link that might help explain. If you decide to install one, look for one that says it is "fail safe". They are more money, but worth the peice of mind. Just remember, once you plug into shore power, your boat is electricaly connected to every boat in the marina through the ground wire.

http://www.yandina.com/electrolysis.htm