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Contessa 26 Refit ep.28 - Grounding and Bonding For Lightning Protection
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- เผยแพร่เมื่อ 16 ส.ค. 2024
- *Understanding that this may be a contentious topic for some... please watch the entire video if you intend to leave comments. Non-relevant comments get deleted without ever getting published.*
Documenting the refit of a 1975 Contessa 26 - J.J. Taylor build. NOT AN INSTRUCTIONAL VIDEO; recording for my own reference.
In this episode I ground the mast/rig and bond internal and external components for lightning protection.
Links mentioned in video:
Overview of strike attenuation for boats:
www.kastenmarin...
Realtime lightning map:
www.lightningm...
Another option is Ewan Thompson's new Siedarc electrodes:
www.marinelight...
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This man has done what 99.9% of sailors who worry about lightning, have THOUGHT of doing😂😂
Ha ha truth. And then there are the ones who say that they are more likely to win the lottery than get struck, which is BS. Current insurance company statistics state that 1 in 1000 boats get struck and 3.8 in 1000 Monohull sailboats get struck every year.
That's an improvement. Those poured keels are a lightning disaster.
Another excellent discussion. Cheers.
The clip at the beginning of the video, looks like a strike near Boston to a friend of my son-in-laws boat which my daughter sent to me that same day 6-8 years back. I'd been nearby in the same storm system. It was that event which brought the risk close enough to home that I'm very interested in mitigation and so really appreciate your detailed video.
Thanks. I believe that video was from CNN.
Working on doing this with my boat: Morgan 462 Ketch. Loved this video and was great to see someone doing this more recently. Don Casey’s book spurred my motivation to do this project. The only other similar project I’ve seen was on an Ericson 25, but it was done back in 2015! Thanks for also making note of the dyna-plate style ground plates. Super misleading with their marketing…. Cheers and happy sailing!
Awesome! Thank you!
I'm having a great time vicariously re-living my own sailboat refit years ago watching your episodes on YT. However I didn't exercise as much discipline on my repairs, etc, as you did, which I contend is due to your being a Marine (saw the hat). An example is my version of grounding for lightning is bolting a huge snap hook to the mast, attaching a length of triple OOO copper wire with a basketball size loop at the end and dropping it over the side. I basically was making it up as I went along. Just luck I never got a lightning strike, at least not while aboard, but the 34 ft Cal at the next mooring sizzled, a lot of smoke and steam came out of the hatch. While the boat had a ground plate, but non ABYC compliant, the hull did not suffer any damage, but all electronics on board was fried. After seeing that I ended up using one of those large tin cans that ship biscuits came in and used it as my faraday cage for everything that would fit. The Contessa 26 is really a jewel of a boat. My first introduction to it was reading all the magazine reports of Tanya, the 17 yr old who circumnavigated on her 26 Contessa back in '83 I recall. There's a British YT Repair and Refit channel who does nothing but refit Contessa 32s, and is as meticulous as you are on details, which means a lot of good info. Anyway, great channel, hope you do some awesome cruising.
Thanks Joaquin. Another way to bond your mast is to attach jumper cables to the shrouds and toss them overboard. However, this is for bonding and not grounding. The difference being that the grounding wire needs to be a pretty direct and straight line to the water.
Also, I make it a rule to disconnect all of the electronics that I can from the wires going up the mast before leaving boat. I did an episode on installing some quick release plugs at the base of the mast a year or two ago.
Well done! Beautiful boat! Look forward to seeing more!
Fine job! Not having this scares me 😬🤣
My shrouds are bonded to plates on the hull, but the mast isn’t. It will be interesting to look at the lightning statics. I’ll have to decide if I want to up grade. Thanks for video.
Thanks Matt. Check out some of the references I cited in this video to make an informed decision. There’s some links in the description.
I know which video you’re talking about when you mentioned the diffuser. That’s a good channel and he seems to know his stuff. But after watching that video I was like, well sh1t, sounds like there’s nothing you can really do.
I like your approach here better.
Thanks. Yeah there’s a lot of snake oil out there when it comes to lightning protection.
I may have seen the same adventure also... so, a diffuser won't diffuse but could it potentially (pun intended) serve a purpose as the very first bit of the conduction path so that if something is struck, it picks the diffuser rather than any antenna or lights?
I've also wondered whether it could work for a grounding plate if you had a long strip of copper glued to the underside of the keel and it ran up above the waterline (either at the bow or aft; I don't know what might be best) before penetrating the hull. Bonus: no need to repaint the bottom of the keel... although replacing the copper if it does erode or wear out would be a job and a half. Maybe a sacrificial anode for it could postpone some of it.
By diffuser I think you mean the static dissipater? I would not use it in a lightning protection system in any case, since research has strongly suggested that they can attract a lightning strike.
Stainless steel bolts vs brass? Nice video, great detail, and explanation.
Thanks. All bolts are actually silicon bronze.
Enjoyed your video and information. I was a little concerned when you drilled your keel but I'm guessing the water proofing worked. Has it kept the "Elephants" away?
I was concerned too, so I went back and epoxied the bolts in. I didn’t launch this year, so can’t test the elephant hypothesis. :)
My only concern would be some electrolysis, from experience that copper will get eaten away quickly given the right circumstances. Something to keep an eye on.
Yes, eventually the plate would need replacement.
Fascinated to see the approach and how you managed it all. Great job. My question is though, are those relatively thin cables going to be enough to carry a whole lightning strike out to the water? Or would they just melt?
Thanks. The three thinner cables that attach the shrouds to the grounding plate are for secondary grounding and are 6 gauge. The primary grounding wire from the mast to the grounding plate is zero gauge. Both are much heavier than ABYC standards recommend. Whether it would work every time or not would be impossible to say. Though at least it makes me FEEL BETTER having this system than none at all, lol.
The main reason for having a system like this is not only to direct a lightning strike to the grounding plate, but also to prevent a lightning strike in the first place by equalizing the charge potential of the boat with the surrounding water.
Very useful video, thanks! What do you mean by 'not wanting current to flow away via the shaft, but you're still bonding the engine'?
You do want the electrical potential to equilibrate through the shaft and into the water, but as I said in the video, engine parts are coated in oil and this can make it resistive. If a lightning strike did go through the engine it would destroy the bearings, therefore I bonded the engine to the grounding plate also.
@@EpoxyAndButylTape Thanks for the [swift] reply. I've listened to that section again: th-cam.com/video/8sAhJ_nTxck/w-d-xo.htmlsi=tR456PQ6rwoW44IK&t=431 First I thought you meant that you don't want lightning current to flow away via the engine/shaft/prop (as others argue would be dangerous), but you were referring to bearing metal eaten by corrosion. After seeing this, wish my Rustler 31 was on the hard so I could get things done in the same nice. Going to be September-ish I think.
Corrosion is a concern with this set up and my most recent video (ep. 54) confirms that with the prop zinc degradation, but that’s not what I meant in this particular video. You do not want lightning to go through the engine because it would weld the bearings to the crank and destroy the engine.
@@EpoxyAndButylTape Finished ep. 54 now. Ins't it worrying that the zinc is eating away that fast?
It was expected because of all the dissimilar metals being tied together by the bonding wires. I just need to make sure to change it more often. That one was three years old, so not that new.
Thanks for putting this video together! We purchased a new catamaran, don't take possession until 2024. I'm curious, you never mentioned using a DDCE or CMCE lightning prevention system. Both Dinnteco and Sertec make these systems and claim there's never been a strike with one of these domes installed. Granted, they are expensive but if they work there could be an argument made that they are worth it. What are your thoughts??
Hey Todd, glad to see people are still watching this video. I didn't mention those systems because there is no legitimate peer reviewed literature that verifies their effectiveness. In fact Ewen Thomson, the person whose work I cite during the video even states “Their science is non-existent”. He also states that “ What they rely on are glowing reports: ‘Oh, we put this thing on a tower, and in three years it didn’t get struck by lightning. All of their accounts are just that.”
Be careful of the marketing hype and do your research before wasting your money on the snake oil out there. There is no current prevention system that can be 100% effective, and no legitimate way to prove that a system can be 100% effective.
a man. I'm also rebuilding a contest 26. was wondering if you wanted to sell that other pin and gudgeon. I think I'll do the same set up as you did
Hey Jeff. Contact me through FB messenger... we were messaging about your CDT thru hike after we met on the CO26 FB group.
Working on doing this with my boat: Morgan 462 Ketch. Loved this video and was great to see someone doing this more recently. Don Casey’s book spurred my motivation to do this project. The only other similar project I’ve seen was on an Ericson 25, but it was done back in 2015! Thanks for also making note of the dyna-plate style ground plates. Super misleading with their marketing…. Cheers and happy sailing!
Thanks. There is a lot of misinformation out there, not the least of which is how likely/unlikely you are to get struck. Insurance companies have some pretty interesting statistics.
Curious, what did you do when it came to grounding the VHF / AIS antenna? We currently have two antennas on both masts. Wouldn’t the antennas act as a higher point and thus more likely for the strike to hit that, then be carried down through the coax cable rather than the mast? Not too sure… I haven’t seen much mention of this, maybe I’m totally wrong, again, no clue!
The base of my antenna is screwed into the mast, therefore it’s tied in to the plate. Either way, I make it my policy to disconnect everything I can at the through-the-deck plugs either before a storm or when I’m away from the boat for any period of time.
It’s still possible, if not likely that your electronics will be wiped out in a lightning strike. The idea of this system is to reduce the chance of having a hole blown through the hull.
@@EpoxyAndButylTape thank you for the advice and knowledge!
@@EpoxyAndButylTape we just got our copper rods from Online Metals. Going to be installing in the next few days. 2x 72” rectangular bars, not rounded. One for our Main and the other for the mizzen, will be attaching both via heavy gauge wire or flattened copper tubing. Fingers crossed we can pull it off!