Lightning control?

[Mr. Dave]

I'm the happy newish half owner of a 1968 Signet 20, British built bilge keel sloop, and I just noticed a small (1/8") braided copper wire running from the backstay chain plate to the rudder sleeve.

They made a small pocket in the fiberglass way back in '68 for this wire to ride in, and it's embedded into the glass at the chain plate, appears just twisted around the rudder sleeve but hard to tell about the forward end, but I'm somewhat flummoxed as to what it could be for.

All I can figure is lightning control, but seems dubious that even 52 years ago anybody would have thought that was enough of a conductor for that job.

So Mr. Logic says: "Hey, me, you stupid arsehole! That's not what it's for!" but then Mr. Logic goes and grabs another gin, and as usual is no help whatsoever.

In the photo, ignore the VHF coax and the nasty sodden line hanging down into the bilge...

That is the outboard well, with silly little drain hoses that are always clogged.

Not involved in the stern light, boat never had a radio, it's a hard to reach spot, overly long screws hold the newer flag receiver.

Anybody have any ideas?

 

[PaulK]

Maybe someone thought that being able to advertise that the boat was grounded in case of lightning was worth a sixpence of copper wire. With a boat that size, you're likely to have something bigger nearby that will attract more lightning than you anyway. The day after you remove it, be assured that you will be hit by lightning and the mast will melt. Leave it alone and don't worry about it. It's 50 years old and seems to have worked well so far.

 

[Mr. Dave]

Plenty masts taller in the marina, but few boats as fine...

 

[shemandr]

I'm not an EE but I read somewhere that grounding isn't meant to shunt lightening to the ground (Water). It is to prevent voltage potential from gathering at the mast tip. Supposedly this will make the mast the same as the water around it. So the wire doesn't have to be of a thickness that would carry a strike to the water. This is my understanding or lack thereof, of why rigging is grounded.

 

[Mr. Dave]

So, acting much like lighting rods on a barn. Mr. Logic likes that!

 

[shemandr]

Yes!

 

[MikeHoncho]

Take a listen to this podcast episode. Pretty interesting one on lightening

#290: Jeff Thayer // Lightning Strikes Offshore

#290: Guest host and 59 North Skipper August talks to Jeff Thayer, a lightning expert and avid sailor!

www.59-north.com

 

[Don S/V ILLusion]

Guys - it's "lightning", not "lightening" [sp].
Hope this is taken in the enlightening way it is intended.

 

[MikeHoncho]

It’s Sunday, I’m pretty deep into a large glass of wine........

 

[Mr. Dave]

Lightning up, sir, yew're whey two sirius toenite

 

[MikeHoncho]

Listen to the post cast regardless of how they and I spelled it lol

 

[Mr. Dave]

I will definitely listen, currently enjoying a nice scotch and sodas and watching bad TV...

 

[MikeHoncho]

For the record my liquor cabinet is empty so I’ve had to revert to my wife’s wine. She’s not to happy with me but it’s worth it.

 

[Ken Cross]

I wonder if it was an aid for construction of the boat to hold something temporarily until the fiberglass cured. I have no idea really.

 

[MikeHoncho]

Is the mast keel or deck stepped?

 

[Mr. Dave]

Deck stepped mast. Feeds into the idea of diminishing potential. Seems very intentional

 

[MikeHoncho]

Is there a grounding wire anywhere from the mast to the keel bolts? What you are trying to figure out might be a alternative.

 

[shemandr]

Re my spelling - it is of course spell check’s fault. That’s my story and I’m ....

 

[Mr. Dave]

No grounding wire to the keel bolts. Also, no keel bolts. This boat has two keels, she's a bilge keeler, with an inverted welded tube "U" spanning between them, apparently cast into the lead. The welded U connects the keels and runs under the cabin sole, don't believe it's otherwise connected to the structure of the boat in any way, just ties the keels together.

I'm assuming they laid glass in the keels of the hull mold, then "dropped" the keel assembly in and glassed in all around, though I haven't had her out of the water and handy long enough to do much digging into the details. Appears to be glassed over from inside as well, I have two bilges to keep dry and they're not bare lead. Am pretty curious about the whole build, though, will do more prodding this winter.

 

[Mr. Dave]

Take a listen to this podcast episode. Pretty interesting one on lightening

#290: Jeff Thayer // Lightning Strikes Offshore

#290: Guest host and 59 North Skipper August talks to Jeff Thayer, a lightning expert and avid sailor!

www.59-north.com

That's a really good listen, well reasoned, a rocket engineer/sailor is probably a rare combination... My cute leetle wire is most definitely a grounding wire for reducing electrical potential, thus reducing the chance of a strike. Thanks for the comments, y'all.