Association Forum - Lightning

Assn Members Area · Join

Home.

Association Forum

Ships Store

Cruising

Racing

Technical Tips

Photo Gallery - New

Boat Search - Updated

Manuals & Brochures

Swap Meet

Links

Officer Flag Line & Staff

Bylaws & Constitution

Members Area

Join the Association

Notice:
The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.

Association Forum

Username:	Password:
Save Password
Forgot your Password?

All Forums

Catalina/Capri 25/250 Sailor's Forums

Catalina 25 Specific Forum

Lightning

New Topic

Topic Locked

Printer Friendly

Author

Topic

Bruce Baker
Captain

Member Avatar

USA
402 Posts

Initially Posted - 03/21/2005 : 08:37:18

I was out working on the boat yesterday, and a thunderstorm blew through. Lightning is really common in DC in the summertime, and I'm always concerned about it. I know that there is a longstanding debate about "to ground or not to ground". I'm of the opinion that, on balance, you're safer if you're grounded.

My question: does a Catalina 25 SK come from the factory grounded? If not, what needs to be done to ground it?

Thanks,

Bruce Baker
Falls Church, VA
"Yee Ha" 3573
'83SR/SK

Edited by - on

thaind
Navigator

Members Avatar

Canada
145 Posts

Response Posted - 03/21/2005 : 10:16:34

There has been a lot of discussion on this topic, with both the pro's and cons of grounding. The cons mostly centre on the increased likelihood of being struck now that you are grounded, and that Catalina and most boat building companies seem to chose not to ground their masts.

I am in the same situation, and would like to hear from any C25 owner that has been struck, and whether or not they were grounded.

Derek Thain

Edited by - on

Dave Bristle
Master Marine Consultant

Members Avatar

Djibouti
10005 Posts

Response Posted - 03/21/2005 : 14:18:24

No manufacturers I know of ground their rigs--I presume because of liability if the system proves inadequate, which it is likely to be. From what I've heard and read, if you choose to ground, you should be sure it's done "right"--with a copper plate on the exterior of the hull and a heavy coductor running in a fairly straight line from the mast to the plate. I've been told that things dangling from the shrouds are useless, primarily because stainless is a poor conductor--the lightning will choose the aluminum mast anyway. I've also been given the opinion that my cabintop-stepped mast is sufficiently insulated from the water (two layers of fiberglass and about six feet of dry air) that lightning is as likely to go to the water near the boat as hit the mast. Whether grounding increases the likelihood of being struck has been debated endlessly with references to statistics that look shaky to me. People I know who have had lightning damage apparently got it from a strike to the water near their boat, causing a magnetic pulse that fried their eletronics. I know it can be worse... But I don't plan to be on the boat to observe either outcome. If storms are predicted, I'll stay within reach of a hiding place, and if a storm is approaching, I'll run and hide. If the boat is hit and nobody is on it, it's like the tree falling in the forest... (except for the insurance).

Edited by - Dave Bristle on 03/21/2005 14:20:17

ChrisDara
1st Mate

Members Avatar

USA
88 Posts

Response Posted - 03/21/2005 : 20:07:19

I've read in a couple of electrical boating books on the topic. The books said that if struck, and not grounded, it can be as bad as blowing a hole in the bottom of the boat...a sizable whole.

The books suggest attaching a HEAVY guage wire to the mast and affixing to the keel. (The anti-fouling paint would not have enough resistance to stop the ground of that much voltage)

I'm not sure though if the precaution is worth the risk of increasing the potential to get struck in the first place.

Edited by - on

seastream
Navigator

Members Avatar

USA
242 Posts

Response Posted - 03/21/2005 : 20:59:37

Given the massive quantities of voltage and current that can exist in a lightning strike, a mast would probably be vaporized in a direct hit

let alone the gossamer thread of wire that might be used to ground it.

Bob

Edited by - on

Leon Sisson
Master Marine Consultant

Members Avatar

USA
1893 Posts

Response Posted - 03/21/2005 : 21:20:27

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">No manufacturers I know of ground their rigs...<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">I'm pretty sure that at least some late 70's Hunters and Ventures were grounded from the factory. The Hunter 27 had a wide flat copper conductor built in between the hull, deck, and liners running from deck stepped mast to external keel bolts in the bilge. The V-22 had what looked like a hunk of cheap jumper cable from a mast step bolt to a one square foot copper plate under the hull.

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">..would like to hear from any C25 owner that has been struck, and whether or not they were grounded.<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">Yes, at least twice that I know of, once grounded, once not.

I used to have a beautiful classic 19' wooden day sailor. The mast was not grounded. To make a long and colorful story short, the boat was struck by lightning during a violent summer thunder storm.

In one blinding flash, the ungrounded wooden mast was instantly turned into a spray of splinters while my girlfriend and I huddled under some bushes and a small sail a few yards away on an uninhabited island. There were what looked like bullet holes through the topsides where each of the chainplate mounting screws had been. Over all, the boat did not look confidence inspiring just then. The young lady elected to seek alternative transportation back to civilization.

On my C-25, I built a grounding system similar to the V-22 setup described above. I connected a very heavy marine grade battery cable with crimped and soldered terminals to the thru-bolts for my bronze swing keel pivot reinforcements. I routed the cable nearly straight down, along side the compression post, and a gentle curve inside the dinette locker to the port fwd keel bolt.

I noticed one day, after yet another of our violent summer thunder storms, that the windvane seemed to be missing altogether, and the anchor light had stopped working. The next time I had the rig down, I took a closer look. All the remaining masthead accessories looked like they had been splattered with black spray paint from exactly the direction of the former windvane when it vaporized. The anchor light bulb filiment was gone, as were the wires inside the bulb that supported it.

I just noticed recently the new anchor light bulb has stopped working again...

-- Leon Sisson

Edited by - on

atgep
Master Marine Consultant

Members Avatar

1009 Posts

Response Posted - 03/22/2005 : 07:51:37

If you recieve a direct hit, there will be a weak point in the system. Where that is, there will be burn through. On my friends gulfstar 39, it was the bolts that held on the copper plate to the bottom. This left 2 holes open to the sea that the bilge pumps were happy to take care of.

My neibour with an Island packet 31 "sojourner" was hit 2 years ago. This year when the boat was hauled, there was a silver dollar sized exit wound about 1 foot below the waterline. The yard manager was able to open it up with a screwdiver!

All scary stuff. I have left my boat ungrounded.

Tom.

Edited by - on

Steve Milby
Past Commodore

Members Avatar

USA
5909 Posts

Response Posted - 03/22/2005 : 08:29:04

An ungrounded C25 was struck at our lake while in its slip, and the damage consisted mainly of numerous pinholes in the fiberglass, all above the waterline. The boat was repaired with no apparent long-term problems.

An ungrounded Seafarer 24 was hit at our lake, while on its mooring. The damage from the strike was mainly that it blew the depth sounder transducer out of the bottom, leaving about a 2 inch hole in the bottom. The boat sank in 30 ft. of water, was raised about 3 days later with the help of a local scuba club, and was cleaned up and beautifully restored after cleaning mud out of all the cushions and every nook and cranny.

Those are the only two strikes I can recall in 25 years. Strikes on boats at our lake are such a rare occurrence that very few people at our lake ground their boats, myself included. (Although lightning strikes all around the lake are commonplace. Perhaps it hits the hills and trees, and bleeds off its stored energy before it hits our boats.) If I buy a boat in the future to sail offshore, I'll probably ground it. If a transducer blows out on a small inland lake, you can swim to shore, if you don't panic and if you stop to rest. If it happens offshore, you can't do that.

Edited by - on

aeckhart
Master Marine Consultant

Members Avatar

USA
1709 Posts

Response Posted - 03/22/2005 : 08:40:31

I was struck by lightning four years ago. We were sitting down for dinner when this huge bang occurred. I commented to my wife that "it sounds like something was struck by lightning". Two days later I went out to the boat (on a mooring in front of the house)to prep for a weekend regatta. All of my electronics were fried - radio, speedo, depth, two batterys, and the electrical panel. The masthead wind indicator was missing also. Surprise, surprise, the unlucky person was me. I also noticed, when the insurance adjuster came out, two small holes on the boot stripe near the bow - about 6" above the water. This turned out to be the exit point of the electrical charge. While doing the repair I also found numerous tiny pin holes in the bottom - perhaps 20 or 30. None of these allowed water into the boat. The largest on the boot stripe was about the size of a quarter. The other was dime-size. The hole was actually blackened pulverized fiberglass which actually narrowed and then spidered up through the hull toward the chain plates. I cleaned out the pulverized stuff with a roto-tool - a very handy tool for boat repair by the way. Fortunately my insurance covered everything, including the cost of repairng the topsides which was struct by a motor boat several weeks later. 2001 was bad year for me and my boat.

As far as prevention is concerned, I have read that interconnecting the shrouds with chain and then dangling the chain in the water, will act as a passable grounding system. It is my understaning that there is no real lighting protection for boats. I've had to friends who have also been struck. One, a Santo Cruz 27 actually sank after having "several thousand" tiny holes punched through the bottom. He had no lighting protection either. The other friend had just bought one of those masthead static electricity dispersing gadgets, to the tune of $300. It didn't help either. He had the same relative damage that I had.

I used to teach the weather portion of the Coast Guard Auxiliary Boating Course. This subject generated the most interest among the students and is worth a little study in your spare time. Understanding the physics of lightning is an important step toward preventing a strike. It's amazing what can generate enough static electricity on your boat to attract lightning. Just a coil of rope rubbing on a stanchion can do it. I now take great pains to ensure that as many possible sources of static eletricity are eliminated before I leave the boat.

Al
GALLIVANT #5801.

Edited by - aeckhart on 03/22/2005 08:48:52

Ben
Master Marine Consultant

Members Avatar

USA
1234 Posts

Response Posted - 03/22/2005 : 13:20:27

One day after work last year my wife and I went out to the lake and were on the docks with some dock neighbors waiting for some wind. We were invited into their Clipper Marine 26 having refreshments when one of those mild, but sudden, summer storms came through with a little bit of wind and a little bit of lightning. I know my wife and I were a little nervous, but our two hosts didn't seem to think anything of sitting around a vessel with a big metal spike on top of it during a lightning storm. Needless to say the storm passed within 20 minutes, without hitting any of the boats. Maybe they were a couple of dummies, but I'm thinking my wife and I were even bigger dummies for sticking around.

Edited by - on

Frank Hopper
Past Commodore

Members Avatar

Pitcairn Island
6776 Posts

Response Posted - 03/22/2005 : 14:56:08

In the 15 odd years I have sailed on our lake, I have never noticed people leaving their boats at the slips from fear of lightning. We usually get off the water, but not leave the boats. I know I assume the tallest mast or other object will take the hit.

Edited by - on

Mark Loyacano
Navigator

Members Avatar

USA
247 Posts

Response Posted - 03/22/2005 : 15:35:04

The only problem about the "rules" men have written for lightning, tornados, thunderstorms or hurricanes is that none of those facinating, dynamic forces have read or obey them.
Cheers :))

Edited by - on

ronrryan
Admiral

Members Avatar

USA
561 Posts

Response Posted - 03/22/2005 : 20:29:01

Two lightning stories I used to tell the USPS seamanship students: (1) An offshore cruiser, hit, lightning went down forestay into chain locker, welded all the chain together. They had to cut the structural bulkhead to get the chain out.(2) An offshore racer, they stored cases of beer forward, hit by lightning, down the forestay again, blew up all the beercans and welded THEM together. This was worse because they were then OUT OF BEER. Seriously, in every case I know of personally, all masthead stuff was simply vaporized, and all electronics zapped, and often there was pinhole damage as described. The debate as to ground or not to ground has been going on for thirty years or so with no resolution, you takes yer chances either way, ron srsk orion sw fl

Edited by - on

dlucier
Master Marine Consultant

Members Avatar

Virgin Islands (United Kingdom)
7583 Posts

Response Posted - 03/23/2005 : 09:49:28

One time when I was night sailing with my brother-in-law, lightning started flashing all around us. It was a bit unnerving and I remember sitting far forward in the cockpit as far away from the backstay as I could get!

Edited by - on

Topic

New Topic

Topic Locked

Printer Friendly

Jump To:

Association Forum

Notice: The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.