GroupThink

John Green of Kemah, Texas, asks:"Many sailboats in my marina have “grouper” or “guppy” anodes that dangle in the water on a wire clamped to a shroud or backstay. I’ve asked a number of owners why they are doing this, and their answers range from grounding the standing rigging, to preventing galvanic corrosion of the rigging, to helping lightning find a route to the water
Author:
Publish date:
Updated on
GroupThinkPhoto1

John Green of Kemah, Texas, asks:

"Many sailboats in my marina have “grouper” or “guppy” anodes that dangle in the water on a wire clamped to a shroud or backstay. I’ve asked a number of owners why they are doing this, and their answers range from grounding the standing rigging, to preventing galvanic corrosion of the rigging, to helping lightning find a route to the water in the event of a strike. Have you seen grouper anodes being used in this way?"

Don Casey replies:

Considering the gauge of the wires I’ve seen attached to the ever-popular grouper anode, I am doubtful that the arrangement will be able to provide much of a path to ground for a lightning strike. And I don’t think that galvanic corrosion of the rigging is a legitimate concern either. Sacrificial anodes are always installed on a boat to protect underwater metal from corrosion. Because it is less noble the anode metal will corrode first and that action protects any adjacent, nobler, metal. An anode that becomes reduced in size does provide an early warning that there is corrosion somewhere.

However an anode has to be connected to the metal it is protecting and the better the electrical connection the more effective that protection will be. That’s why an anode bolted to an underwater metal component is a better choice than one that’s connected by a wire and hung over the side.

Grouper anodes are often deployed in marinas because they do give a boat owner a warning that there is stray current corrosion that needs to be explored further. However, it’s my view that unless an anode is actually connected to the boat’s underwater metal it won’t be very successful at this.

And just clipping a wire lead from the grouper to the standing rigging will not provide much protection against a strike unless the rigging is also bonded or otherwise connected to the boat’s underwater metal components.

Related

Pestilence

Sailor-Punk and the State of Cruising

Back when I was a young man, sailing back and forth across the North Atlantic in an old fiberglass sailboat, it seemed fairly obvious to me how all that was wrong in the world might be set right. Everyone should be issued a boat at birth! Or so I declared to any who would listen ...read more

promoOnTheHorizon600x

Cats On The Horizon

Dragonfly 32 Evolution Denmark’s Quorning Boats has been systematically upgrading its line of folding, performance-cruiser trimarans in recent years as part of a long-term effort to incorporate the latest developments in yacht design, with the latest to receive this treatment ...read more

TOTW_PromoSite

SAIL's Tip of the Week

Presented by Vetus-Maxwell. Got a tip? Send it to sailmail@sailmagazine.com The double range  Every skipper knows about ranging two objects in line to keep the boat on track in a cross-current. What’s less obvious is monitoring both sides of a gap such as a harbor entrance. ...read more

FamilyCruise

Bareboating on Puget Sound

Depending on where you are, Puget Sound can look no bigger than a mountainous version of the Intracoastal Waterway. That’s what I thought when I first laid eyes on it from the lighthouse at Mukilteo Park on a sunny day last July. Then I went to the top of the iconic Space Needle ...read more

Bali4point1

Boat Review: Bali 4.1

Coming fast on the heels of its predecessor, the Bali 4.0, the Bali 4.1 adds a number of improvements, many of them inspired by feedback from owners and charterers. She’s an evolution of a concept that has already proven popular and very many benefits from its builder’s ...read more

Headsail

Ask Sail: Silencing A Rattling Headsail

Q: Our Pearson 26 has a 110-percent jib that tends to rattle very noisily at the top hank. We only bought the old boat recently, but it must have been happening for a long time, since there’s a deep groove worn inside that bronze hank. The jib has an unusually large and wide ...read more

Alerion2048x

Alerion Yachts 33, the 90 Minute Get Away

Easy to sail, luxurious, and swift; the Alerion 33 is the solution to your busy life. The intuitive, simple rig design, easy set-up, and put-away mean there’s no need to wait for crew to enjoy a weekend, a day, or an hour out sailing. Her beauty and comfort are evident in the ...read more