Originally Posted by sailorchic34
Are you sure the windless is grounded / bonded. The issue is the zinc used for galvanizing the chain and anchor (assuming its not SS). With a bonded anchor chain, that zinc coating protecting the chain will get used up as it's a anode to steel. It does this anyway for the steel chain, but tie it to the boats bond and it would increase the de-zincing of the galvanized chain. It depends on lots of variables but to me it seems counter productive to use an expensive chain as a zinc anode.
Yes, the windlass
is grounded. A wire runs from the windlass gear
case to the boat ground system (engine, copper plate in the water
, all the underwater bronze
, stays...). I also suspect, but do not know for sure, that the negative 12V motor
power wire is connected to the windlass motor
case providing another ground path (and to force a circuit breaker trip should a short occur from the internal wiring
to the motor case).
I am not sure of the safety
of having the anchor chain in the water and not connected to the boat ground system in the case of a lightning
strike. I would think a low resistance path would be desirable to prevent arcing at the bow.
Would would not a couple of hundred pounds of iron chain in the chain locker rate as a large metal object needing to be connected to the boat ground for lightning
flash over protection?
As I said the bow fitting (anchor roller and forestay chainplate) is grounded and thus grounds the chain whenever they touch. With the chain tension taken up with the rope snubber, that is the usual case. The slack chain drops down on the stainless steel
I realize the potential problem with the anchor chain zinc. I started this thread which got no replies.
In talking to others about the use of expensive and thin chain galvanizing for anodic protection rather than cheap
and big hunks of zinc anode, it was pointed out to me that the distance from the zinc galvanizing on the anchor and chain to the underwater bronze
was much much greater than the distance from the anodes to the underwater bronze. That would make the anchor chain galvanizing much less effective at protecting the bronze (read it would not dissolve as fast).
I don't know the "right" answer to all this... But, I do know that we have had the boat at anchor for 150+ days per year for each of the last 8 years. We re-galvanize the chains at the first sign of rust stains on the deck
. That is once every three years for the primary anchor chain and once in 8 years for the secondary. The anchors themselves (a 44 lb Bruce which is used 98% of the time and a 35 lb Delta
which is used 3% of the time) have each been re-galvanized once in the 11 years we have owned the boat. We will have the primary chain re-galvanized when we get home this summer. It needs it again; its three years are up. The zinc has been lost
in the areas where each link bears on its neighbors, so I suspect this is mostly wear.
Irish Eyes to the Bahamas