Electrifying guard rails?

[Tim Good]

Ok so this is more of a conceptual question rather than something I'm considering but I read about a guy that electrified his guard rails for a passage down Western Africa.... and apparently need it when 30nm off Weatern Sahara. Anyway it reminds me of a time when I was about 17 and I touched an electric fence for hares and rabbits only about 6 inches off the ground... it literally made me black out for a couple of seconds. The shock was incredible. It was running from a car battery at the other end of the field but I assume they had some special device that made it pulse with incredible effect. It wasn't just me it also made my brother fall over since he didn't believe me.

How would one go about electrifying guard rails do you think? Clearly the one thing I can think of is an on / off switch so it's only activated when absolutely necessary!

 

[Roberto]

Ok so this is more of a conceptual question rather than something I'm considering but I read about a guy that electrified his guard rails for a passage down Western Africa.... and apparently need it when 30nm off Weatern Sahara.

Is he American

 

[Porthandbuoy]

Ok so this is more of a conceptual question rather than something I'm considering but I read about a guy that electrified his guard rails for a passage down Western Africa.... and apparently need it when 30nm off Weatern Sahara. Anyway it reminds me of a time when I was about 17 and I touched an electric fence for hares and rabbits only about 6 inches off the ground... it literally made me black out for a couple of seconds. The shock was incredible. It was running from a car battery at the other end of the field but I assume they had some special device that made it pulse with incredible effect. It wasn't just me it also made my brother fall over since he didn't believe me.

How would one go about electrifying guard rails do you think? Clearly the one thing I can think of is an on / off switch so it's only activated when absolutely necessary!

Do what Slocum did. Scatter some tacks on deck, or try some non-slip boards, ie. planks with nails, sharp end protruding.

 

[Kelpie]

A basic electric fence energiser is fairly cheap (under £100) and simply steps up the voltage from 12v to around 10,000v- at a very low current, of course.
The main problem on a boat would be insulating the guardwires from the hull. 10,000v is capable of going through many materials, such as wood, which are insulating against lower voltages. You'd need a rubber sleeve at each stanchion, plus insulated terminals at the ends; I imagine rope lashings would be no good as saltwater soaked into them would render them conductive.
This still leaves your pushpit non-electrified. Insulating it from the hull would be a bit tricky without compromising the strength of its attachment.
Then you've got the question of turning it off or on whilst not on board. Normally on a fence you just unclip a crocodile clip from the battery- this would be a bit obvious, so you'd want something more discrete, like a switch reachable from your dinghy but hidden from sight, perhaps.

 

[Madeo]

There was a Dutch guy next catway to us in Guadeloupe who had signs on his guardwires to the effect that they were electrified.

'Are they really?'

'Nah, but I tell anyone coming aboard to wait while I switch them off, and it works, they believe me...'

 

[William_H]

I would think the average GRP sail boat would have pushpit pulpit and wires insulated via the GRP hull. Yes there would be a lot of loss via the salt and moisture layer of the deck but it would be interesting to measure resistance to sea. Any shock of course would require current from the wires via the person to the sea. This may or may not happen if the person is standing on say the side of a RIB. Farm type electric fences obviously have a connection through ground.
So we need a fairly high powered pulse to produce a high voltage even with some resistance to sea via damp deck etc. A bit of a tall order which might work but also might prove fatal. ol'will

 

[sailaboutvic]

Also not sure how you would earth it , we used them for horses and we use to have a earth rod that when into the ground .
Yes it would give anyone a hell of a kick , if you could get it to work .

 

[langstonelayabout]

Whilst following this thread with amusement I'd love to see how effective electrified guard rails are against a skiff full of pirates armed with assault rifles and a few rocket propelled grenades.

Seeing the precautions used by cruise ships passing that part of the world I'm pleased to confirm that I wouldn't go sailing there. (although we will be on one of said cruise ships in a couple of months time: I have confidence in the 'additional security' that they employ )

 

[sailaboutvic]

Whilst following this thread with amusement I'd love to see how effective electrified guard rails are against a skiff full of pirates armed with assault rifles and a few rocket propelled grenades.

Seeing the precautions used by cruise ships passing that part of the world I'm pleased to confirm that I wouldn't go sailing there. (although we will be on one of said cruise ships in a couple of months time: I have confidence in the 'additional security' that they employ )

Some how I don't think the OP is talking about a load of Pirates , more of local thieves, trying their luck .

 

[Roberto]

Have a look at what happens to a grp hull going live with electricity: photograph taken in Horta where Keith came in after having suffered the severe storm of June2017 Ostar, it's a big Najad which was "like new" at the start of the race, among the long list of things being damaged there was the satellite antenna, the cable touched the metal structure above the stern, cponnected to the rails and all the rest, everything went live.

 

[moomba]

On a more serious note have you checked the laws of said countries in putting an electric current around a boat which in theory could with lots of water around cause someone a serious or fatal injury ,now ofc we don't want to be robbed but what about the poor fellow reaching up selling you some bananas or a local of the law reaching over to board your vessel and you forget to unclip
lol MADNESS

 

[JumbleDuck]

Also not sure how you would earth it , we used them for horses and we use to have a earth rod that when into the ground .

That's the really big question. For an electric fence it's easy; the animal to which you wish to administer a shock will be standing on the ground. Anyone you want to keep off the guardrails is most unlikely to be dangling legs in the sea; they'll probably be standing on an insulating hull in the fairly insulating water next to your insulating hull. That's a lot of insulation. Maybe use the rig as earth, in the hope that they'll lean over a guardrail, making firm contact, grab a stay and zzzzap.

At which point you've gone from having a malefactor to having a really, really pissed-off malefactor. Not necessarily an improvement.

 

[Billows]

And then of course you would have to remember that it was switched on

 

[lpdsn]

Ok so this is more of a conceptual question rather than something I'm considering but I read about a guy that electrified his guard rails for a passage down Western Africa.... and apparently need it when 30nm off Weatern Sahara. Anyway it reminds me of a time when I was about 17 and I touched an electric fence for hares and rabbits only about 6 inches off the ground... it literally made me black out for a couple of seconds. The shock was incredible. It was running from a car battery at the other end of the field but I assume they had some special device that made it pulse with incredible effect. It wasn't just me it also made my brother fall over since he didn't believe me.

How would one go about electrifying guard rails do you think? Clearly the one thing I can think of is an on / off switch so it's only activated when absolutely necessary!

Not sure how the professional ones work, but you could build your own with an AF coil and a suitable relay that will handle the peak voltages. Basically works by back emf when the DC current is cut off.

Have you considered what will happen when you forget about it, touch it yourself , go over the side and black out?

 

[sailaboutvic]

Most people I know who gone off the beaten track so to speak have fritted bars to all there hatches and made sure they can secure they companion way door , stopping anyone who gets on in getting in or at less making it hard for them to get in Also an alarm , maybe deck sensor and wire up lights to it too .
this becomes a problem , if you need to get out quickly , say in case of a fire .
Our last friends that made the crossing over the pond said in some anchorages one boat stayed up on watch for swimmers boarding boats and would let off a fog horn if they where seen , mostly to steal dinghy to sell back in the morning .
could wait to move on .

 

[Topcat47]

From personal experience, I can assure you that you can get a belt from an electric fence when wearing rubber boots. It's bad enough from a small trembler designed for chicken netting, the big ones fro larger livestock/longer fences really get your attention.

 

[Stemar]

From personal experience, I can assure you that you can get a belt from an electric fence when wearing rubber boots. It's bad enough from a small trembler designed for chicken netting, the big ones fro larger livestock/longer fences really get your attention.

That's my experience as well. I suspect that the capacitance of a potential robber would allow them to get a jolt, even if they were standing on a rubber dinghy tube or GRP, which is probably as good an insulator as you'd get. In any case, whatever they're standing on would have a coating of damp salt, which is all the earthing you'd need.

Here you go... https://cdn.theatlantic.com/assets/...w19_AP18234016200480/main_1500.jpg?1535139027

I reckon you'd probably want to turn it down around salt water, as your victims are likely to be more conductive than someone standing in a field, and even offing a villain is likely to get unwanted attention from the authorities. I'd also want signs to warn anyone approaching the boat, just in case said authorities decide to make an unannounced visit...

 

[GHA]

Our last friends that made the crossing over the pond said in some anchorages one boat stayed up on watch for swimmers boarding boats and would let off a fog horn if they where seen , mostly to steal dinghy to sell back in the morning .
could wait to move on .

As bad as that are few though most folks lift the dinghy at night, selling back in the morning almost certainly rubbish - it's the outboards they are after, local fishermen aren't immune. Fellow cruisers doing the pinching not uncommon as well. Bad places like that are well known and in the cruising guides/web sites.
Usual to lift the dinghy at night - lift it or loose it as they say.

 

[Lon nan Gruagach]

Glad to see that we have covered getting a zap through wellies..,. but that might not be as significant as you might think. Most wellies are designed to be conductive to prevent static build up which has unpleasant consequences. Not even 100V working safety wear is designed to be completely insulating. Having said that a rib tube thats just been splashed around through waves will be a pretty good conductor too.

Livestock electric fence energisers are designed around the amount of energy delivered per zap, not so much concern over exact voltage or even current. While coils appear to be the straightforward solution, they are not the preferred method since they are not as energy efficient as a high voltage capacitor discharge, battery life is a major selling point.

One significant problem not addressed so far is tracking. Where there is a good chance that many zaps will be conducted away by salty water it is likely that it will always occur at the same point. This can (usually) cause creation of a carbonised track on the surface of the insulator (your GRP hull). Such tracks quickly progress into the body of the insulator.

 

[JumbleDuck]

One significant problem not addressed so far is tracking. Where there is a good chance that many zaps will be conducted away by salty water it is likely that it will always occur at the same point. This can (usually) cause creation of a carbonised track on the surface of the insulator (your GRP hull). Such tracks quickly progress into the body of the insulator.

I think that modern electric fences on;y zap when they detect an animal in contact with them, unlike the older ones which zapped regularly, just in case. That might help the tracking problem.