Lightning Protection for Cape Dory 25

[Andy Bazar]

I have noted in the "Cape Dory Yachts Owners Manual" that the Cape Dory 27/28/and 30 chainplate attachment systems have lighning ground wire connections below deck. The manual does not show where these ground wires terminate. The Cape Dory 25 chainplate attachment system does not show this ground wire arrangement and shows no lightning protection as far as I can determine.

I own a 1977 Cape Dory 25 and see no evidence of any sort of mast/rigging grounding system. If anyone else has ever taken measures to provide lightning protection for this boat I would be interested in hearing about their approach.

The lightning protection method published by the United States Power Squadron in their boating course manual dated USPS 1992 is as follows:

"All shrouds, stays, and masts should be grounded to a metal plated on the keel below the waterline. In the absence of this, clamp one end of a heavy (8 gauge or larger) automobile battery jumper cable to the base of a metal mast or to a shroud and the other end to a metal plate (1 square foot minimum) immersed in the water."

I have made up a facsimile of the above device and can attach it to the bottom of my aluminum mast with a large hose clamp to which I have bolted a grounding cable and metal electrode to toss over the side in the event of lightning concern. I have never had the occasion to use it and would only put it in place if things looked serious. I suspect the arrangement would be vaporized on a lightning strike but it would be easy to make up another one if I got back alive!

Any other suggestions would be interesting to hear about.
Andy Bazar
Rochester, NY, Lake Ontario sailor.



awbazar@yahoo.com

[Ed Campbell]

I have noted in the "Cape Dory Yachts Owners Manual" that the Cape Dory 27/28/and 30 chainplate attachment systems have lighning ground wire connections below deck. The manual does not show where these ground wires terminate. The Cape Dory 25 chainplate attachment system does not show this ground wire arrangement and shows no lightning protection as far as I can determine.

I own a 1977 Cape Dory 25 and see no evidence of any sort of mast/rigging grounding system. If anyone else has ever taken measures to provide lightning protection for this boat I would be interested in hearing about their approach.

The lightning protection method published by the United States Power Squadron in their boating course manual dated USPS 1992 is as follows:

"All shrouds, stays, and masts should be grounded to a metal plated on the keel below the waterline. In the absence of this, clamp one end of a heavy (8 gauge or larger) automobile battery jumper cable to the base of a metal mast or to a shroud and the other end to a metal plate (1 square foot minimum) immersed in the water."

I have made up a facsimile of the above device and can attach it to the bottom of my aluminum mast with a large hose clamp to which I have bolted a grounding cable and metal electrode to toss over the side in the event of lightning concern. I have never had the occasion to use it and would only put it in place if things looked serious. I suspect the arrangement would be vaporized on a lightning strike but it would be easy to make up another one if I got back alive!

Any other suggestions would be interesting to hear about.
Andy Bazar
Rochester, NY, Lake Ontario sailor.

Andy:
The best authority I've heard in a long time just appeared at our yacht club as speaker. Since taking an expensive hit a number of years ago, he installed one of those gizmo's that looks like a feather duster at his masthead, and although he's all bonded and grounded to hull mounted plates, he still tosses over the likeness of battery jumper cables off each shroud. It seems the trick is to dissipate the charge before the strike or at least give it an easy way to get off the rigging without going through the boat.
Regards,
Ed



campbell@waltereden.com

[Norm Penick]

I have noted in the "Cape Dory Yachts Owners Manual" that the Cape Dory 27/28/and 30 chainplate attachment systems have lighning ground wire connections below deck. The manual does not show where these ground wires terminate. The Cape Dory 25 chainplate attachment system does not show this ground wire arrangement and shows no lightning protection as far as I can determine.

I own a 1977 Cape Dory 25 and see no evidence of any sort of mast/rigging grounding system. If anyone else has ever taken measures to provide lightning protection for this boat I would be interested in hearing about their approach.

The lightning protection method published by the United States Power Squadron in their boating course manual dated USPS 1992 is as follows:

"All shrouds, stays, and masts should be grounded to a metal plated on the keel below the waterline. In the absence of this, clamp one end of a heavy (8 gauge or larger) automobile battery jumper cable to the base of a metal mast or to a shroud and the other end to a metal plate (1 square foot minimum) immersed in the water."

I have made up a facsimile of the above device and can attach it to the bottom of my aluminum mast with a large hose clamp to which I have bolted a grounding cable and metal electrode to toss over the side in the event of lightning concern. I have never had the occasion to use it and would only put it in place if things looked serious. I suspect the arrangement would be vaporized on a lightning strike but it would be easy to make up another one if I got back alive!

Any other suggestions would be interesting to hear about.
Andy Bazar
Rochester, NY, Lake Ontario sailor.

Andy:
The best authority I've heard in a long time just appeared at our yacht club as speaker. Since taking an expensive hit a number of years ago, he installed one of those gizmo's that looks like a feather duster at his masthead, and although he's all bonded and grounded to hull mounted plates, he still tosses over the likeness of battery jumper cables off each shroud. It seems the trick is to dissipate the charge before the strike or at least give it an easy way to get off the rigging without going through the boat.
Regards,
Ed

Ed,
I think you've got it exactly right: provide a path for the lightening charge to follow and you won't suffer damage. We have lots of lightning storms on Galveston Bay and I've been in more than my share. I've always attached one end of a battery booster cable to the back stay and thrown the other one overboard. During a storm the charge would build until the entire rigging buzzed like a transformer (unnerving) until lightening finally struck, the charge was dissipated, and the buzzing stopped. I've never suffered any damage other than to my nerves.
Norm Penick
norman@hal-pc.org



norman@hal-pc.org