E38 Lightning Groun Plate

[juneausailin]

E38 Lightning Ground Plate

Greetings all.. so I'm replacining the original DC and AC distro panels in my E38 and have a few questions.. Does the E38 have a lightning ground plate? Looking at the base of the mast I don't see any sort of heavy guage wires running to keel bolts or the likes..

Also, as far as grounding/bonding the DC panel what is a good point on the boat to attach that to? I have negative of the house bank connected to negative of the start bank... but is that the same thing as having a ground? Ground and the Negative terminal of the battery are two different things correct?

Have been looking through this article: http://www.sailmail.com/grounds.htm

Thanks for any insights..,
David

 

[exoduse35]

As far as I know none of the Ericsons came with a ground plate as part of the original lay up. You should tie the Negative of the batteries to the engine block and the A/C ground can go there as well. If you are planning to put in a battery monitor, you will need to install a shunt between the battery negative and All other grounds so now would be the time to incorporate it into the plan. ( for that reason I ran the ground to the D/C panel to the engine block as well so there would be only a single cable to the batteries) This is about as simple as you can get in the " ground" subject and from here there will be a great number of variations depending on how complex your system gets and who you ask! There is differing opinions on how to create a "GROUND" for lightning, and if it helps, is necessary, or hurts. Then there is the whole issue of a GROUND PLANE for use with SSB Radio. And then there is RF grounding for the instruments and various displays & computers you may want and not have interfering with each other and your radios. And then there is the question of how much separation or integration between them is acceptable or desirable. My life would be SO MUCH easier If someones could make a simple and easy gospel on this subject! So I think you may have opened a major thread when all the electron experts chime in, hold on and enjoy, Edd

 

[juneausailin]

Re: E38 Ground Plate

So, check and check on the negative of both battery banks being connected to the engine block and AC ground. And since have clarified a bit to myself that a good general rule of thumb is that all DC electrical items should have a dedicated return to the negative terminal of the house bank instead of using various metal runs/items throughout the boat as a ground return to the negative terminal.. for example.. .masthead lights should have a dedicated return to house bank negative as opposed to using the mast itself as a conduit... so far so good... And I generally like the idea of keeping all through hulls isolated and or not grounded... I think the E38 through hulls are plastic flush mount anyhow?


But, I do now see the need to set up some cable runs to handle lighting... suggestions being to run say 2ot guage from the mast and upper shrouds to a keel bolt.. this begs another question though... the E38 keel/balast is not exposed to water so this may not be a good path to ground for a lightning strike?

Thanks for you .02
-David

 

[Guy Stevens]

Lightening

The best conductor for lightening is foil, not wire. Lightening operates more like Radio Frequency than either ac or dc currents. As such it travels on the skin of the conductor.

The internal encapsulated keel is not going to offer much in the way of a SAFE ground path for lightening.

A plate mounted to the outside of the boat, with a thru bolt system and foil running to the cap shrouds, (v1/d2's for those using the newer terminology), would potentially help in a strike.

However personal experience says that lightening is a flukey bugger, and it will do what it wants when it wants with what it wants no matter what you want it to do.

I generally wouldn't waste my time on trying to prevent and or ground the boat.

Guy

 

[rwthomas1]

The best conductor for lightening is foil, not wire. Lightening operates more like Radio Frequency than either ac or dc currents. As such it travels on the skin of the conductor.

The internal encapsulated keel is not going to offer much in the way of a SAFE ground path for lightening.

A plate mounted to the outside of the boat, with a thru bolt system and foil running to the cap shrouds, (v1/d2's for those using the newer terminology), would potentially help in a strike.

However personal experience says that lightening is a flukey bugger, and it will do what it wants when it wants with what it wants no matter what you want it to do.

I generally wouldn't waste my time on trying to prevent and or ground the boat.

Guy

I'm with Guy on this one. Amen. Too many differing opinions from the experts and not enough real data to prove anyone right or wrong. RT

 

[Tom Metzger]

However personal experience says that lightening is a flukey bugger, and it will do what it wants when it wants with what it wants no matter what you want it to do.

I generally wouldn't waste my time on trying to prevent and or ground the boat. - Guy

I'm with Guy on this one. Amen. Too many differing opinions from the experts and not enough real data to prove anyone right or wrong. RT

The engineering community and I respectfully disagree with the quotes above.

I have no idea what the lightning conditions are in Alaska, but on the east coast there are lots of boats hit by lightning. My understanding is that on the west coast it is not a real problem. My previous boat was built in Virginia and came from the factory with the mast step, all chain plates, bow and stern rails, and the engine tied to the keel.

The primary difference between trusting to luck and doing some grounding is the chances are much greater of the stroke going to the water through the fiberglass and the crew if you have not grounded to the keel. When it does go through the fiberglass it blows a hole in it. A hole in the hull can ruin your whole day. I wouldn't worry about barrier coats or fairing on the keel.

if nothing else, run a ground from the base of your mast to a keel bolt. Stranded wire is fine to use; #4 copper is adequate. Avoid sharp bends and as many other bends as you can.

With an encapsulated keel lightning grounding becomes much more difficult.

There is a lot of information on sailboat grounding on the net. One well known example is:

http://edis.ifas.ufl.edu/pdffiles/SG/SG07100.pdf

 

[exoduse35]

I would think it is at least as effective to throw a couple wraps of one end of a chain around the base of the mast and toss the other end overboard when lightning is about. The object is to get the strike to the water and providing it a path that is not through the boat has got to be the safest bet.

 

[juneausailin]

Grounding plate

Thanks all for the ideas and feedback...

 

[Tom Metzger]

I would think it is at least as effective to throw a couple wraps of one end of a chain around the base of the mast and toss the other end overboard when lightning is about. The object is to get the strike to the water and providing it a path that is not through the boat has got to be the safest bet.

This may be good for a boat with a deck stepped mast, an encapsulated keel, AND someone on board and awake . Take a turn around the shrouds, and use LOTS of chain in fresh water. Keep in mind that you are not really keeping the lightning out of the boat because of the mast wiring which is tied to the water through the engine. Oh yes, don't forget the chafe gear.

With a keel stepped mast I doubt this would be very effective, but, perhaps, better than nothing with an encapsulated keel. With a bolted on keel the cost and bother is ridiculous compared to 2 feet of # 4 wire and a couple of terminals.

Even on the newer Ericsons a complete lightning protection system would be very difficult to install because of the grid, but some is much, much better than nothing.

FWIW, I have seen several boats on moorings with a jumper cables dangling in the water clipped onto a shroud. Again, perhaps, better than nothing.

 

[rwthomas1]

I'm on the East Coast and I can say I've never met a sailor here that has a lightning grounded boat. There isn't one in my marina. I've been on all the sailboats and poked about. I also know 3 boats that have been hit. One of them twice. All the electronics fried. Thats it, no sinkings, holes, nada. I have more things to worry about. I'm not saying you may not think its important, if you do by all means do something that makes you feel better. Theres a lot of stuff higher on my list. RT

 

[Tom Metzger]

I'm on the East Coast and I can say I've never met a sailor here that has a lightning grounded boat.

Rob - I respect your right to express your opinions, but I challenge you to find one competent authority that recommends against having a lightning protection system on a boat. Try the ABYC E-4.

You are in Rhode Island. I believe they made a few Pearson Sailboats in Rhode Island over the years, and I would bet that you have known a few owners. The P-30 lists bonding in the brochure.

This pic from one of Pearson's Owner's Manuals, the first one I came up with in a quick search. They used #8 wire which is no longer considered adequate. #4 AWG copper is now preferred.

 

[u079721]

In the "something is better than nothing" category........if there was lightning about, whether anchored or underway, I would fasten an 8 foot length of welding cable to the backstay with a hose clamp and toss the other end into the water. Thank goodness I never had the opportunity to test it!

 

[Emerald]

sigh - I've been watching this one mulling over a post

First, I'm not an expert at anything. I know enough about electricity to handle what I've needed to on the boat, car, house etc. I've read a lot about lightning and boats. It seems just as I'm convinced I should install a sintered plate, I find someone who sank because the plate blew out of the boat in a strike, but then someone else survives because of the plate, or whatever the grounding method was. I read that lightning wants to go strait and really doesn't care about the path you pick, if it decides there is a more direct route. There seems to be many accounts of lightning jumping to make the shortest path. I do feel that I consistently hear that chain/cable wrapped around shrouds etc. dangling in the water is somewhat effective - better than nothing certainly, and not likely to cause damage.

Now, for my real life experience. Many years ago, we were at anchor on my Dad's Tartan 34. It was one of those typical Maryland summer afternoons with the ever present thunderstorm chance, but not enough of a chance to keep you off the water (or you would never sail in the summer time in Maryland). There is maybe some very distant thunder, but nothing particularly close. As we sit there, a buzzing starts in the rigging. It comes on suddenly and is growing in intensity. This boat did have a sintered grounding plate. I don't remember exactly why (this was in the mid '70's now, so it's been awhile) but the VHF radio, the VHF antenna and this plate were configured so that the antenna could either go to the radio, or to the plate, but not both, and the connection had to be manually switched. So, as this buzzing in the rigging is growing, my Dad goes below and disconnects the radio and makes the connection to the sintered plate. As he does this, he gets zapped like nobody's business and is knocked back, and the buzzing instantly stops. By total coincidence, he was doing business with a lightning expert at the time. A follow up conversation with the expert confirmed that we were probably building a charge in the rigging and were on the verge of taking a hit. When my father switched the connection for the antenna from the radio to the plate, he allowed the charge to dissipate.

So, what to do? Based on this, I have really thought about adding a sintered plate to Emerald, but then I go back to the other issues, and I haven't made up my mind. I think the only solution is to try to balance comfort levels with something reasonable to implement. I don't feel there is a "right answer" that is definitive, but there are things that are probably not wrong either.....

 

[Tom Metzger]

David - A sintered plate is for grounding your radios, not lightning. Lightning will cause the water trapped in the sintered plate to boil rapidly enough that it will blow the plate apart. You want to use a solid plate for lightning grounding.

Charge dissipation is what one wants to avoid taking a stroke.

I'm also not an expert, but have lots of experience in a previous life engineering lightning protection for electric substations. Just because the protection doesn't always work is not much of an excuse if someone gets hurt.

I personally ignore lots of safety advice, but never recommend someone else follow my example in those cases.

 

[Emerald]

Hi Tom,

thank you for the information on a sintered plate being a boiling bomb. It would seem though, that on our Tartan, it did dissipate the charge and keep us from getting struck, but it was part of the radio setup.

I agree that doing nothing isn't a very good strategy. My inclination for the moment is to go with hanging cables off of stays.

 

[Tom Metzger]

David - You're right. the sintered plate is great for dissapating a charge, just not adequate for the thousands of amps of a stroke.

An important point that I did not mention before, the real purpose of a lightning protection system is to prevent a stroke from occurring at your boat, along with damage limitation if it does. Obviously, no stroke, no damage.

I became a believer in a T-storm off of St Georges, Bermuda while watching strokes hit the water close around us while we were the only thing above the water for a few miles.

 

[davisr]

proper grounding for ac and dc, and related issue of lightning

Greetings all.. so I'm replacining the original DC and AC distro panels in my E38 and have a few questions.. Does the E38 have a lightning ground plate? Looking at the base of the mast I don't see any sort of heavy guage wires running to keel bolts or the likes..

Also, as far as grounding/bonding the DC panel what is a good point on the boat to attach that to? I have negative of the house bank connected to negative of the start bank... but is that the same thing as having a ground? Ground and the Negative terminal of the battery are two different things correct?

Have been looking through this article: http://www.sailmail.com/grounds.htm

Thanks for any insights..,
David

David,

In response to your original question, I thought it would be helpful to post this link to a thread I initiated on the Cruisers Forum some months ago. There is some helpful information regarding ABYC regulations for AC and DC grounding. There is also a lively discussion (and some good videos) on the related subject of lightning strikes.

http://www.cruisersforum.com/forums/f14/proper-grounding-for-ac-and-dc-72432.html

My plan is to adhere to ABYC regulations and thus ground the AC and DC to a single point during my upcoming rewiring project. Currently, this single point consists of a bolt in the bilge near the mast compression post. On the exterior of the boat, the tip of this bolt is just barely visible, flush with the hull. Thus, there is no plate, only a bolt. ABYC does not require a lightning ground plate, but given that I live in an area where thunderstorms are the norm in the afternoons in the spring and summer, I figure it won't hurt to add some sort of plate beneath the single bolt. Don Casey, Complete Illustrated Sailboat Maintenance Manual, suggests that a 1 inch x 2 ft copper plate is not a bad idea for boats in salt water. These can be had for about $25 at online metals. Not bad, and it might make a difference.

http://www.onlinemetals.com/merchant.cfm?pid=4284&step=4&showunits=inches&id=253&top_cat=87


Regards,
Roscoe

 

[dwigle]

encapsulated keel ???

In some of the earlier posts, encapsulated keel was mentioned. My 38 and others I've seen in yards just have a big lead fin hanging down, no fiberglass covering.

Don Wigle
Wiggle Room
Pt. Richmond, CA

 

[PDX]

In some of the earlier posts, encapsulated keel was mentioned. My 38 and others I've seen in yards just have a big lead fin hanging down, no fiberglass covering.

Don Wigle
Wiggle Room
Pt. Richmond, CA

You are correct. The 1980s King designs (38, 35, 32, 30+ I believe) had external ballast. Prior to that most Ericsons, including the extremely popular 1970s 27, 29, 32, and 35, were built with encapsulated keels.