My Boat US insurance mandated an updated Boat survey this year for renewal. The surveyor pointed out the mast grounding cable attached to the keel bolt was long and sagged into the bottom on the bilge, sometimes immersed in water. His report made a “recommendation” to lift this out of the bilge water. Of course the insurance underwriter is not insisting the grounding cable is repaired by a qualified boat yard and receipt provided before they will renew my policy.
Has anyone had this experience? More important, is grounding the mast to the keel bolt a risk? I expect most of our NS boats are grounded this way. Securing the grounding cable above any water in the bilge is an easy fix. Relocating the cable altogether is a task that seems unnecessary for overall safety and protection of the boat.
Can you attach a pic. I’m not grasping the surveyors point. Is he saying the attachment point should not be on the keel bolt or the cable should be immediately routed up to the stringers so it’s not laying on the keel/ bilge/centerline of the boat?
My cable just lies on the centerline. And there’s always some remnant water in the bilge.
Be very careful with boat US. I had them for ten years no claims and then they wanted a survey. In the meant time they had significantly decreased the value of my boat and dramatically changed the prorating of replacements , the year they asked for the survey. Basically if it was older than four years you paid for it. My boat had been in Canada so the surveyor failed the fuel system for not having a US coast guard approved fuel lines. If he had cross referenced the numbers he would have found out they were approved. I had to replace all the fuel lines with type A1 and the filter because it had a glass bowl. After that they did not agree with the surveyors valuation. The surveyor they had me use! I had to appeal it to the underwriters who agreed to use the surveyors value for an extra $800 a year. I have American Modern now better coverage and half the price. I believe boat US only wants to insure newer boats and is trying to get rid of us old boats.
On Wednesday, November 8, 2023 at 12:28:44 PM UTC-5 Brian M. Godfrey wrote:
That foot long splice that the linemen make maximizes the contact area between the two cables. That is much more important for the high current of a lightning strike than it is for the much lower current of a power line.
I think adhering to the 8" radius rule is going to be difficult. You’d need to do it where you connect to the mast and to the keel bolt, too. I think the 90 degree jog from the cable entering the lug to the keel bolt is going to present a much greater problem than a tighter than 8" radius in the cable. Plus, we’ve had anecdotal evidence that it might not be a problem, though I don’t know if those were maximum, 120kA, strikes or “just” 30kA strikes.
I’m curious if anyone knows what happens to the keel bolt during/after a lightning strike. I can imagine the shock separating the bolt from the lead in the keel. I doubt that the lightning current lasts long enough to melt and re-flow the lead, though I suppose it might. It would probably happen too fast for the keel to drop, but might leave the nut a tad loose.
On 11/8/2023 5:39 AM, Rob Cohen “Soave” NS33 Westport, CT wrote:
Thank you all for the great advice… I continue to learn and revise my plans. I do have a couple questions :
As a shop for wire, it looks like “battery cable” is the term commonly used for the wire that is currently there. Any other names or properties I should be searching for ?
Prices vary widely… links to sources others have used would be greatly appreciated.
I plan to be at the boat this weekend and will measure the gauge of the existing wire. I’m probably going to replace the whole run so I could ( if it would make sense) update with any gauge wire. Any suggestions on whether changing the gauge would offer any benefit ?
I’m still confused on physics behind the recommendation of not/never splicing. Having worked for an electric utility as a capacity planner I rubbed elbows with power engineers who would dictate what we could and could not do ( to save a buck ) in our systems. I seem to recall a splice used in lighting protection that would be inline, overlapped, and straight. 1 foot overlap, with multiple clamps, then 3 feet straight on either side of the splice. I realize that in my case a new run is DEFINITELY easier and simpler, and POSSIBLY less expensive if I value my labor cost. ( splices were VERY expensive in our project planning )… Still curious about the physics behind the impact of a “fit-for-purpose” splice. I also understand that the techs doing these splices had skills that I do not have ( yet ? )… which might be the strongest case for a full replacement.
Also, knowing the risks of a splice, it seems like the style of terminal ends would possibly be my weakest link. In fact the hose clamp on the keel bolt sound superior to either a 1/4" tapped attachment or a large lug attached by an extra nut. When I see how the cable is attached to the mast should I consider upgrade ? General lighting protection standards say any change in direction needs to be minimized and that turning on anything less than an 8" radius is not acceptable.
If I have space, I will try and heed the 8" radius rule… likely going to be difficult n the mast end.
Sorry to belabor these points… new owner / in the offseason / with way too much time to obsess about detail … AND my sailing season doesn’t begin till April.
Thanks,
Rob Cohen
s/v SOAVE
NS33 #009
Westport, CT
On Monday, November 6, 2023 at 11:28:46 PM UTC-5 Ward Woodruff wrote:
I’d buy a new length of wire and tinned crimp on connector. If the new wire is marine wire, the strands will be tinned.
Pull the new wire in using the old wire as a pull wire. Crimp a proper tinned connector onto the mast step end. I have a hydraulic crimper and dies if that helps.
Ward Woodruff
N33 #8 Margery
Niantic Bay, CT
On Nov 6, 2023, at 10:29 PM, Bill Wickett EX-22 #38 Makin’ Time bill...@gmail.com wrote:
Hi Robb,
Glad you found the wire. I’m sure at the time the Nonsuch line was built, research on lightning strikes may not have been as advanced. Seems like a lot is still uncertain.
Our 22 was struck in 2017. I was aboard in the cockpit. The energy travelled down the mast and took 2 routes from the bottom of the mast.
First was along that thick cable to the first keel bolt and dissipated out through the lead portion of the keel. This resulted in very fine pock marks in the bottom paint on the forward end of the sides of the lead portion of the keel. Like the bottom paint was blasted off in slightly larger than pin head sizes. None above the keel in the fibreglass
2nd area that the energy travelled to was along a slightly diameter smaller cable from the mast step to a bronze stud under the settee. This stud is one of the 2 fasteners for a Guest Dynaplate that a previous owner had installed on the hull. This is about a foot aft of the mast, forward of the keel. The damage there was scarring in the bottom paint. Looked like branches of a tree radiating out from the plate. There was no substrate damage. We did have the bottom stripped at the end of that season, and ran all new wiring to these 2 grounding points. (as well as all new mast wiring, light fixtures, etc)
Good luck with your refit. Even though copper cable is expensive, I would suggest a full new run and not splicing to the old cable.
Regards,
Bill Wickett
Hamilton , Ontario
On Monday, 6 November 2023 at 14:01:45 UTC-5 Rob Cohen “Soave” NS33 Westport, CT wrote:
Thanks Joe, Thor, & Ward.
Sounds like the answer is : Yes, other Nonsuch boats do have a copper wire attached to their forward Keel Bolts… so yes, I should restore the connection in my boat.
I’ll also add this to my seasonal checklist, I’ll bet more than a few NonSuch have the same corrosion.
On my boat the corrosion starting at the keel bolt shortened the wire enough that it no longer reaches. The remedy will be to buy some wire, cut the old wire till I find sound copper splice in some new wire, tin the end near the keel bolt and reattach with the stainless clamp. Sound right ?
I’m hoping the wire isn’t for lightning protection, because the little I know about lighting protection is that if the conductor makes a right angle bend ( even if the conductor is heavy ) lighting is likely to keep going straight. This I have seen firsthand ( my home has been struck twice).
Rob Cohen
s/v SOAVE
NS33 #009
Westport, CT
On Monday, November 6, 2023 at 1:17:21 PM UTC-5 Ward Woodruff wrote:
The wire runs from the mast step ring to the forward keel bolt. I believe its purpose is lighting protection.
If you have enough wire length, reconnect both ends. You might want to run a new tinned wire. The existing wire does not have tinned strands.
The stainless steel clamp is probably adequate to connect the wire to the keel bolt. A crimped on lug should connect the wire to a bolt on the mast step ring.
Ward Woodruff
N33 #8 Margery
Niantic Bay, CT
On Nov 6, 2023, at 7:11 PM, Rob Cohen “Soave” NS33 Westport, CT rob....@gmail.com wrote:
I was cleaning out the bilge of my NS 33 and discovered a heavy gauge insulated copper wire with a badly corroded end near one of my keel bolts. the wire was led forward through the bulkhead. Removal of the owners cabin floorboard revealed it continued forward ( maybe to the anchor locker ? ) out of sight.
Inspection of the keel bolt revealed a stainless steel clamp and a handful of brittle corroded copper strands. General cruising forums I see conflicting opinions ( not a surprise) about including keel bolts in a boats galvanic bonding circuit.
Do other Nonsuch’s have copper wire attached to a keel bolt ? If so is there a better way to make the connection ?
I don’t understand how you could possibly attach the wire to the keel bolt without it being in the bottom of the bilge? At least where it is attached to the keel bolt. Perhaps you should simply give the surveyor a call and ask him how this is done?
My ground cable runs from the mast step, under the floor boards, and attaches to the most forward keel bolt. I don’t think it wound be terribly difficult to replace the cable if necessary, although getting it attached to the mast step maybe a bit tricky.
My bilge is generally perfectly dry, unless there has been some work on the engine cooling system, or something is leaking that shouldn’t be. At which point I find the leak and fix it. However sometimes in a big rain storm water comes down inside the mast and into the bilge, maybe an inch or so. In that case my grounding cable is sitting in bilge water. Probably I could lift the cable with some nylon electrical ties to the stringers. But at the connection to the keel bolt it could still be in bilge water. Could there be electrolysis between the copper wire and the stainless keel bolts?
