Ground plate

My 1976 E27 is an outboard model, so grounding is all made to small ground plate located under the froward floor board. I just tried to attach an additional ground wire, when I noticed that the 1/2" stud gave somewhat and started a small trickle of seawater. I could patch the leakage with underwater epoxy, as a temporary fix until boat is hauled out. Question is what have other Ericson owners done to replace or repair the ground plate? In case of the latter, what is a good source for this particular size?

Joe

What sort of ground plate is attached to your hull? That bronze bolt on my E27 doesn't really attach to anything - only the head of the bolt is exposed on the hull side. Mine has Atomic-4 power, but engine ground did not go this bolt - only the solid copper wires that connect to shrouds and stays. Can't imagine my setup would be of much help in conducting any amount of current. If the original equipment had a plate of decent size, maybe I'm missing something.

What kind of plate is it?

http://www.westmarine.com/webapp/wc...001&langId=-1&catalogId=10001&productId=13911

Here is a link to a common grounding plate (several sizes) sold by large retailer West Marine. You may have to use cut-and-paste to put this into the address URL box of your browser.

If yours has only one bolt, perhaps it is another brand, but smaller.

Have you seen this thing when the boat was last hauled?

I would hazzard a guess that in Florida you need this due to lightning. Is there a large guage wire from this stud to the mast step as well?

Best,

Loren in Portland, OR

Loren,
Unfortunately, I see that hull for six months out of every 12 and there doesn't appear to have been anything ever attached to that throughbolt. I've been digging around for information on what E27 owners have done for lightning protection, but there isn't much info to be had. Some of the literature warns against those Dynaplates for lightning ground and the area recommended for fresh water ground plates gets quite large. Seems for anything effective, it would have to be a custom plate somehow fitted around the keel edge for quite a bit of its length. Not sure I'm ready for that.

The bolt (ground) that your refering to is the same set-up I had on my 1975 E27 w/atomic four. This must be what the factory was doing at the time for lightning grounding. Mine had heavy cables from the shrouds & stays connected to it. This boat was a fresh water boat from new (Great Lakes). Lightning grounding theories vary greatly with no one able to guarentee that there's is the best in every instance. There was not a plate attached to the bolt, though. Bud E34 "Escapade"

Attached to the ground bolt in my E27 is the ground wire for most electronics in the boat. I must confess that I have not looked under the hull lately to see what, if any, type of ground plate is attached. I might have looked in the area at some time during haulout, but can't remember. In any case, whatever this ground bolt and/or plate is, I will need to replace soon. I do not want to overlook this as it poses great potential threat of sinking the boat. Any thoughts on this will be greatly appreciated.

Thanks.

Joe,
I would guess your boat is similar to mine and the E27 described by Bud and there probably wouldn't be anything attached to that bolt on the outside of the hull. Do you think it has rotated so that the bedding sealant is compromised? Can you hold the threaded portion and tighten the first nut to snug it up more? Mine has a nut and washer that tightens on the hull and then two more nuts and washers that tighten on the ground wires.

As Bud mentioned, there are several theories about getting better lightning protection. There are even some contradictions among the 'experts', so the more I read, the more I get mental paralysis about doing anything. It may be that some things not done quite well enough would just blow larger holes in the boat during a strike. I've had that nasty sizzling static sound in the rigging during certain weather conditions, but so far I have not been smack in the center of a severe electrical storm, so have been lucky to date.

It sure seems the main strike's current path would like to come down the mast and there is no place to go after that mast step plate. Supposedly you should provide a large conductor from the mast to the submerged ground plate. Our encapsulated keels don't offer much in the way of a ground plate, so it would have to be external. The whole system has details which I am not sure about with our particular boat. Sorry - a lot of thoughts, but not much in the way of help.

Walter,

You are probably correct in assuming that the beeding sealant on the ground bolt has been compromised. I could try tighten the nut in an effort to improve the sealing, but it could that the bolt itselt has been compromised, and further tighten may cause a very undesireable situation while the boat is in the water. I think that I will do my experimenting at the next haulout in a month or so. In any case, a grounding system would be needed mainly for electronics on board a boat without an inboard engine.

As far as the lightining protection theories, I am also totally confused. However, I would think that any strike will carry the current down the shrouds rather than straight down the mast. That being the case, it may well serve to have extra sets of battery jumping cables aboard, and modified to be able to clip individual cable to each shroud and drop other end in the water.
What do you think?

Regards

This company sells a system to be temporarily bolted on to the mast (the site also contains information about what not to do e.g. ground the shrouds). However, I can't comment on the merits of the system/information.

http://www.strikeshield.com/product.html

Thanks for that link. I wonder if there have been any independent evaluations. And you also wonder how lab testing correlates to the real thing, seeing as how lightning has that unpredictable aspect. But even if the product isn't quite as effective as they claim, it doesn't appear that it would make things worse. Maybe the placebo effect will work with mother nature.

Whether this type of temporary grounding system is used or not, would anyone suggest that it would be good to disconnect those copper wires going from the shrouds to the through-hull bolt?

One of the FAQ's on the Strikeshield site says it should be disconnected and if the plate is a Dynaplate, it can explode if used as a lightning ground.

The Strikeshield system looks like it would be easy enough to make with battery cable and a heavy copper plate. I can't see how it would make things worse. Seems to me that the object is to try to keep the lightning from entering the cabin.

I spoke to the engineer at strikeshield about their testing, and it was soundly done, although the limit of the power they were able to test with was such that there was a lot of extrapolation to determine it could handle a strike.
Although lightening is unpredictable, based on the testing I would trust a strikeshield to take the vast majority of strikes and leave the boat occupants fairly safe. That said, I would also prefer a grounding plate, which would not be smacking into the hull whilst sailing in the conditions that typically surround thunderstorms.

The one thunderstorm I have been in (much more frightening than an Atlantic gale IMHO) we definitely were not doing any sailing (60 knot + winds)! The storm came on so fast, we had just time to get the sails down and to motor away from land. Makes me wonder if there would be time to deploy the Strikeshield.

I have been through a number of thunderstorms, as it is impossible to avoid them in Pensacola bay. Since they are visible a long distance away, there has always been time to get prepared - dropping/reefing sails, getting crew into life jackets and below if possible, and if the strikeshield is attached to the mast already, throwing the grounds overboard takes not much time at all.
Gareth

Bonding and Lightning Protection

Has there been any new developements on this thread? A buddy of mine has an Island Packet 32 and was struck about 3 weeks ago while anchored on the chesapeake (Fairley Creek). His GPS, Knot meter, stereo, and Autopilot suffered damage. His bilge pump which has an internal float switch came on immediately which frightened him quite a bit. The float switch fried in the on position. His tach not longer works either. No other significatn damage although insurance is covering new wiring for the mast and a number of other things. I have a big ground cable from my mast step to a keel bolt but in terms of bonding thats the only thing I have. No bronze t-hulls and nothing attached to the chainplates. I have seen those wire brush looking things on peoples masts and have heard that one company that sells them will pay your insurance deductable if you get struck. They also charge 2-3 hundo more for theirs than a competitor...So what is everyone doing about it these days? We get a lot of t-storms around here in the summer.

I saw a recent article on data from either Seatow or Boat US to the effect that your chances of getting hit are nationally about 1 in 1,000 and that in the Florida it was about four times as high and twice the rate on the Chesapeake, the second most active place in the US. Multihills are twice as likely to be hit as monohulls (go figure) and the boats with the wire brush thingy on the mast didn't do any better than boats without.

Pretty much what I thought. I am just wondering if there is anything other than my cable from the mast to the keel bolts that I should do?