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:
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

arc18-3981

Stories from the Cruisers of the ARC

Each December, the docks at Rodney Bay Marina in St. Lucia are abuzz as the fleet of the ARC—the Atlantic Rally for Cruisers—arrives to much fanfare. No matter what time of day or night, the staff of the World Cruising Club, organizers of the 33-year-old rally, are there to ...read more

TOTW_PromoSite

SAIL's Tip of the Week

Presented by Vetus-Maxwell. Got a tip? Send it to sailmail@sailmagazine.com A sign from outside the box  Rev counters on modern engines are driven electronically from a terminal on the alternator. If all is well, as soon as the engine fires up the revs will read true. If, ...read more

emSelf-tacking-jib

Ask Sail: Are Self-trackers Worth It?

Q: I’m seeing more and more self-tacking jibs out on the water (and in the pages of SAIL) these days. I can’t help thinking these boats are all hopelessly underpowered, especially off the wind, when compared to boats with even slightly overlapping headsails. But I could be ...read more

01-LEAD-hose-leak-CREDIT-BoatUS

Know how: Is Your Bilge Pump up to the Job?

Without much reflection, I recently replaced my broken bilge pump with a slightly larger model. After all, I thought, surely an 800 gallon-per-hour (gph) pump will outperform the previous 500gph unit? Well, yes, but that’s no reason to feel much safer, as I soon discovered. The ...read more

190314-viddy

St. Maarten Heineken Regatta: A Source of Hope

The tagline for the St. Maarten Heineken Regatta is "serious sailing, serious fun." However, for the inhabitants of St. Maarten, the event is more than just a festival of great music and some of the best sailing around. Local blogger Angie Soeffker explains the impact the race ...read more

SPOTX-1500x1500_front

Gear: SPOT-X Satellite

Hits the SPOT The SPOT-X two-way satellite messenger is an economical way of staying connected to the outside world via text or e-mail when you’re at sea. As well as the messaging service, it has a distress function that not only alerts authorities if you’re in trouble, but lets ...read more

_8105684

A Kid’s Take on the Northwest Passage

Going North—and West Crack! Crunch! I woke with a start to the sound of ice scraping the hull of our 60ft sailboat, Dogbark. In a drowsy daze, I hobbled out of the small cabin I was sharing with my little sister. As I emerged into the cockpit, I swiveled my head, searching for ...read more