Pearson Boats - Common Systems > Standing & Running Rigging and Fitting/Tuning

Another new owner and a question - Lightning ground?

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Carolina Dog:
Thanks everyone! To answer Dragonstar: I had my chainplates made from 304 stainless out of 1/4 by 1.5 inch bar stock. four are 12.5" long and 3 are 15"long. I am drilling the bolt holes myself but I did have the metal guy drill a 1/2 hole 1" down from the polished end and radius the corners like the pictures on this site. I am having the top 3" polished. I will have the forestay reworked when I can pull the fitting and take it to the shop so they can use the original as a pattern.

I am going to do as Dolce Vita and ground to the lag bolts when I replace the step. If I do get hit by lightening I will let ya'll know how that all works out. I agree it all seems like pay your money, take your chances!

Frayed Knot: I live and work in Georgetown. When I bring her down we will get together and compare notes. Did you race?

Frayed Knot:
That is this comming Saterday.  Dont know how the weather is going to be. We will see..    It's Saturday and the weather was to bad, so no race.  I will let you know what happens.

Alma:
Mast grounding is made complicated with our internal lead ballast. All the heavy green wires throughout the boat are bonding wires. They should be clean and tight. The bonding wires need to have electrical continuity with the mast itself and the step plate. This is to prevent corrosion and also to try and protect sailors from lightning strikes and shore power electrocution from open grounds on AC appliances. Some folks isolate their mast but that is difficult if you have masthead instruments and VHF radio antennas which bring their small conductors to ground also. NEVER use the mast as the ground for lights or instruments like automobiles do- corrosion will result. The shrouds and stays chainplates are bonded together with the maststep with the bonding wiring at the factory.

The lag bolts securing the maststep do not reach the lead ballast in most 323s. Even if they did, the lead is inclosed in dielectric fiberglass so the grounding to the sea is compromised. Lag bolts float into the non-conductive fiberglass and at this age have little ability to pull a bonding wire terminal tightly against the steel maststep.

I used stainless allthread and tapped through the fiberglass two inches into the lead for mechanical strength. I believe I have electrical continuity with the bonding wires AND the lead. The four allthread studs wouldn't be strong enough to withstand a direct lightning strike. The idea with bonding to the sea is creating an "ionic umbrella" that protects the boat like an invisible Faraday Cage. The ubiquitous stainless bottle brushes at the tops of masts are part of this school of thought. This ionic umbrella is a very low voltage so all connections must be very clean. If you believe this will work buy your bottle brush from a dairy supply at 10% of the cost of the marine items...

I found electrical continuity in my mast to ground with the bonding wires disconnected from the step. This continuity is from the grounded METZ antenna at the masthead and the rig's bonding. Since the mast is grounded by the stays, shrouds and my VHF antenna's ground I chose to run the green bonding wires in the bilge directly to the mast.  I have a substitute steel bolt holding them until I locate a suitable aluminum bolt to fasten them to the mast. I also made an aluminum washer that goes against the mast to prevent dissimilar metal corrosion from the copper wiring terminals attacking the mast. This is not shown in this photo

Sintered bronze Dynaplate radio grounds are not adequate for lightning protection. A copper sheet a few feet long and a half foot wide at the turn of the bilge directly beside the mast on the hull exterior immersed on all points of sail would be the recommended lightning ground for the 323. It would be quite an engineering and installation feat to do this correctly. Copper at least as thick as a penny formed to the contour of the hull and inlayed so it doesn't peel away... A lot of work! Then there is the connection from the exterior plate through the hull to the mast. It must have a fine radius to prevent side flashes and be of significant size to carry huge current- Difficult at best.

Could lightning strike the mast then enter the inclosed ballast and strip the fiberglass keel from it? That would depend on the unpredictable path of current from the mast to the inclosed lead. The energy just might go through the bonded thruhulls or simply vaporize the voids on the hull and result in hundreds of tiny holes. The boat would sink like a kitchen colander...

The best we can do without splitting the atom is to attach the mast directly to the bonding system and jumper that connection to the maststep lagbolts to reduce galvanic corrosion. My boat came with the green wires attached to the tension rod. Go figure!

Dolce_Vita:

--- Quote from: Alma on August 19, 2013, 12:12:46 PM ---...The lag bolts securing the maststep do not reach the lead ballast in most 323s. ... I used stainless allthread and tapped through the fiberglass two inches into the lead for mechanical strength.

--- End quote ---

Two inches???!!!  When I drilled and tapped new holes for my mast step lagbolts, I went through about 1/4" of fiberglass and then hit lead.  I used 2 1/2" long 3/8" SS lags, same size as what was there originally.

I had to drill 4 new holes, as the mild steel lags that were there originally had corroded and swelled enough to enlarge the holes so much that the new lags wouldn't hold in them at all.

Dulcinea:
I had the same experience as Ed.  Hit the lead pretty quickly. Knew I hit it cuz the drill bit broke right off.

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