Batteries - Current & Lightning - Oh My

[ebb]

Take a suitable length of #6 stranded marine wire, winde one end once around a bolt of the aftlower shroud plate and tighten the nut? Proceed similarly to the uppershroud plate on the compression bulkhead with the same wire, one turn round, tighten nut, and then to the forward shroud plate? Take the same wire to a bolt of the forward pulpit socket fitting, Connect. Take the same wire to the other forward pulpit fitting?

Do the same with the other side up to the other fpf. Then take both wires over to the grounding nut(s.) Most Ariels still have 4 metal thruhulls (mine are history.) You connect these singley or in series and take tese wires to the grounding plate stud?

Is the mast also wired to the grounding plate with a wire from the mast, thru the deck, down the bulkhead, etc?

Defender has 4 Guest Dynaplate grounding plates listed (pg210, 2002.) In inches: 6 X 2 (50.49) - 8 X 2 1/2(82.49) - 12 X 3(131.79) - 18 X 6(274.79). Cryptically they "protect" 12 - 20 - 40 - 100 sq.ft. In the miniature illustration they have 2 holes and are vaguely hydrodynamic. These any good? Where did you place the plate on the hull? Paste it on with 5200? Guest and Whale products have a largely lukewarm reaction on the web. Hope I get a passing grade!

[ebb]

What is the difference between lightening strike protection to a grounding plate and bonding all your bronze spincters and chainplates together? And going to an external grounding plate? I'm confused. And I think I remember a controversy around bonding - whether it's necessary or if it doesn't promote galvonic action.
When the big one hits, or when your mast rises up for that good shot, you want a direct route to the water, no? Do we want it following #6s around inside? Let's weld dynoplates to the aligator clips of a battery cable and fasten the other ends to the upper shrouds.
How do you keep the electric system ground separate from the lightening protection system? This stuff hurts my head

[Theis]

The dynaplates are what most people use for grounding. Guest, however, disclaims their use for lightning protection and the organization that figures these things out does not endorse the Dynaplate. That does not mean they don't work. Rather it means that they don't have the benefit of the equivalent of Coast Guard Approval. Frankly, I don't understand why they are not approved, unless they figure that the porous bronze. Guest may just be trying to avoid the insurance liability.

I would assume that with the Dynaplate you get a good set of instructions that will explain these things a lot better than I can. After all who am I but a dumb Swede that doesn't know better than to not go out in a lightning storm.

I do notice that the grounding plate I bought from West is not listed any more (I bought mine last year), so you might want to contact them and ask the question where you can get them and why they are discontinued.

The plate is mounted with 5200 and should be placed as low in the water as possible. Mine is mounted on the bottom directly under the starboard hanging locker.

As for the connections to the stays, you are correct to a point. You only need to connect one shroud to the ground point. Don't worry about the aft or bow stay. Connect the wire to one of the bolts that goes through the chain plates, but in my case, I wired the three chainplates on each side together. Make sure there is no paint on the chainplate of the bolt where the wire is connected. The contact must be good metal to metal. For peace of mind, you can wire both the port and starboard chainplate to the bonding point. I did that through the bow pulpit as I explained.

Although the wire could be twisted aroung the bolt as you suggest, I would use an Anchor crimp ring connectors. You want to be right on that connection - there is no room for error - or you will have the Kittiwake type problem. I am not pushing West, but they have been helpful to me. I had them mount the crimp connectors on to the 6 ga wire (so that I wouldn't have to buy the tool).

As for the current going inside the boat, in my opinion, that doesn't make any difference - as long as there is a near zero resistance path. If not, the lightning strike will go whereever it wants.

Make sure the bow pulpit is grounded also. That extends outside the stays and, if not grounded could give someone a jolt.

As for the single point grounding, if the grounding plate is good, and your electronics are connected to the grounding plate, the lightning will not pass through the electronics. The battery ground and water ground will always be the same, lightning strike or no.

Now, what I don't know about is the antenna. There is a lightning suppressor on the Shakespeare antenna that causes the lightning to jump to the masthead fitting and not pass through the antenna to the VHF radio. That should solve the problem there, but if that doesn't work, there goes your onboard VHF - which is the reason you should also carry a portable VHF - after all it is only money.

Hope this helps.

[ebb]

Thanks Theis, may Thor keep his thunderbolts to histhelf next time yer out in yer little thip!

Couple things: You used the smallest grounding plate. right?

The heel of the mast is also grounded?

The crimp rings certainly are the best way to connect to the shroud plate bolts but how did you get them to crimp in exactly the right place? Have them come to your boat?

My guess is also that the wire runs should be as strate as possible without loops and ins and outs?

Be awhile befor I do this, but I will. Don't know if weather is better reported but it seems like it is getting crazier & crazier. Grounding for lightening protection is the way to go

[Theis]

Heel of Mast: The answer is that there is little reason to ground the heel, and I haven't seen that done when the shrouds are grounded. However, I have considered doing it to be as cautious as possible because the aluminum mast is so much better a conductor than the stainless. If the stays were not tied together electrically creatting effectively multiple parallel circuits (the total resistance would be the resistance of one stay divided by the number of stays tied together), I probably would ground the mast base. However, as your Kittiwake story points out, the issue then becomes how do you bond the foot of the mast to the wire? The foot is often wet fostering corrosion, and even if you use an aluminum bolt, aluminum corrodes as well. I don't know the answer, but I have not bothered grounding the foot and don't think it is really necessary. I would classify it as overkill.

Keep in mind that with electricity, generally, the physical path is not relevant. The relevant issue is the low resistance path. In other words, for example, if the port side shrouds are not grounded, it doesn't make any difference because the low resistance path would be the grounded starboard side shrouds. The same with the back stay. However, if the starboard side is not adequately grounded , then there is a totally different story.

What I am considering doing next year as a result of this dialog is to run a short length of 6 ga. wire from the masthead lightning rod to the masthead plate that holds the stays. Right now, that rod is connected to the cast aluminum masthead fitting, which then is connected to the aluminum mast, which is then connected to the stainless plate. There is plenty of surface area with those connections, so it is reasonable to assume there is no problem with resistance, but then on the other hand, how can you be sure. I don't know at this time. Perhaps in the fall when I take the mast down, I will do a resistance check.

By the way, in the way of filling you in on a detail or two, the problem with the least bit of resistance is this. Let us assume that the resistance in a connection is only 0.01 ohms. - which may even be hard to measure with a cheap meter. If you have a million amps going through that weak spot, the voltage across that connection is 10,000 volts. The heat produced (which is proportional to the square of the current) will cause the resistance to increase until there is arcing - slash a flash. If the voltage becomes high enough for the current to jump from the stay directly to the water, that is what it will do rather than going through the weak spot. With the bonding kit, there was included a copper based high conductivity paste that was put all over the bolts and nuts to be sure there was conductivity. You might also look into buying some of this stuff. I would suggest West or Radio Shack. If you can't find it, I will see if my bottle lists the manufacturer

Keep in mind that the purpose of a lightning rod (i.e. the mast) is to prevent a lightning hit, not to discharge it after it has hit. To get rid of the positive charge accumulation so that lightning is not attracted, the current flow is less than with lightning, but over a longer duration. I point this out because we can never achieve perfection in this life, and we are aming to maintain this life with this exercise, but the closer you can come to the ideal connection, the more comfortable you should be.

I got the biggest grounding plate that was commercially available and that I could afford. Almost anything is better than the through hull that was on the original Ariel. But then even with that as company issue, I have never heard of an Ariel being hit by lightning and that is over a period of forty years. Maybe someone has a tale to tell.

How to get the wires the right length. I started cutting them to the right length and then taking them to West. That go old so I finally broke down and bought the $30 fixture - which, unfortunately fell into the big pond last fall.

Straight runs. Yes. all runs should be as straight as possible, and where there is a bend, the radius should be as large as possible. There is one bend, for example, in my Ariel in the line from the chainplate to the bonding point in the hull, and that probably has a 6" to 1 ft radius. The bend is inside the starboard side locker.

As for through hulls, I only have two metal through hulls in the forward cabin for the toilet. The cockpit through hulls are fiberglass, which doesn't count because they don't conduct.