groundwire

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DennisG
Posts: 9
Joined: Wed Sep 05, 2012 11:40 am

groundwire

Post by DennisG »

I have a cat ketch 28 and I recently found a ground wire in my bilge that has become disconnected. From the length of the wire, the only place that it could reach is the area of the stuffing box. There is no obvious place where it may have become disconnected from. Also my shaft zinc has been eaten away much too quickly this year. I'm on a mooring all season so I do have a problem. Any input would be helpful.

Thanks,
Dennis

midnightsailor
Posts: 139
Joined: Thu Aug 06, 2009 1:21 pm
Location: Greenport, New York

Re: groundwire

Post by midnightsailor »

Dennis,
If this is a heavy (about 6ga.) heavy stranded, green wire, which I am guessing it is, It is part of the factory installed boding system. Your guess about the stuffing box is correct. What was common practice in the past ,was to clamp this wire with a srtainlees steel hose clamp to the stuffing box. Either the clamp rusted way or it was removed or the wire just pulled out from it and it may still be there. I personally feel that this is not a very good way to doing this as for bonding system to function correctly , one thing(amongst a host of other requirements) is that the connections need to be very sound and just slipping a wire under a hose clamp just doesn't quite do it. Corrosion , dirt, salt,all to easily defeat this connection. You also got three different metals all tied together at one point in what is generally a very damp(if not wet)salty environment, perfect for galvanic corrosion. Another common way connections were done here( the idea is tying the bonding system to the shaft and prop all of which is in contact with the seawater) Is/was to use a couple of brushes (like electric motor brushes)in contact with the prop shaft. with very often the wire connected to the brushes via the hose clamp method. This approach also fails to work properly in my opinion, again, the connections not being what is needed , particularly the brushes contact on the shaft.
If you want to connect to the stuffung box the wire tneeds to be bolted or screwed with a proper ring terminal with a machine screw tapped /threaded into the stuffing bbox. ALl matting surfaces need to be clean ,bright and shiny. This is one area where the wire connection would benefit from being soldered or braised.
Also, keep in mind if you have somthing like a "DriveSaver" coupled between the gear box coupling and the propshaft a jumper wire is needed to make a connection between the engine bond andthe shaft. The wire to the stffing box woulkd not accomplish this as it is isolated/insulated fromthe shaft by the packing.
To put this altogether, and try to clarify what I am trying to say is. You need one green bonding wire properly connected to the stuffing box(in order to include this in the bonding system) and one green bonding wire to the engine with a jumper across the coupling if a drivesaver or such is fitted, in order to tie the bonding system to the engine and propshaft. Shaft brushes may also be installed.
There is much debate on whether bonding all underwater fittings and other large metal objectsie: fuel, water, tanks, engine, thruhulls, etc) is neccesary or even beneficial. After much research, and discussion, I have tended to favor the practice to un bond and just isolate the fittings.
This is a very complex subject. The amount and placement of zincs , which are a crucial part of this system, is almost an art. Placeing one large zinc and tying everything on the boat to it ,which is what this bonding basically does, is maybe ok in theory, not so much in practice IMHO. I prefer to islolate the thruhulls and individually zinc items that need protection. Further, many of these bonding systems, and that installed on my Freedom and others tries to incorporate a lightning protection system into it. The masts are tied via the same green bonding wireto the bonding system and also this is all then connected to a keel bolt. I prefer a dedicated lighting protection system ,including a tall spike or air terminal(lightning rod) on the tallest mast head, connected by heavy gauge (4 ga) downwire on wood or carbon fiber masts(aluminum masts can be used as there own downwire). This wire can then be connected by 6 ga. feeders to a dedicated ground plate( a long thin -1" x 12' better than a square 1'x1' plate) of bronze,copper or monel. Large items like the metal tanks, and engine to be connected by 6ga feeders to this. THe important thing is that the connections be good. The best way I belive is by using heavy tin plated copper split shank bolts. Boats with shrouds and chainplates would also tie these into the ground plate.
On most of the Freedoms ( and many,many others) the bonding wires ore tied togther at various places with a type of terminal block which all to often has wet, dirty,salty,and porly maintained connections. Again, for the system to work properly, ALl the connections need to be clean, shiny, and sound. The system really does need regular maintinence .
As for your prop zinc, If the rate of consumption has jumped I would suspect some stray current corrosion. Check for any hot wires in the bilge , any wires or their connectors in a damp, wet ,salty bilge, or just bundled toghether, can cause stray current to leak and this wil result in zincs dissappearing quickly. Bilge pump ,connections, especially at the submersible float switch are notorious for stray current leakage. There should not be any wire running through or lyingin the bilge. also electric wireing on the engine needs to be clean and well insulated. The prop zinc may just not be large enough, perhaps the prop was changed from a two blade fixed to a larger 3 blade feathering for example. The fact that it is being consumed at least shows that it is working. Worse would be a zinc that lasts forever or more than a season. The zinc should be fairly well eaten up by the end of the season if not, check that it is proper installed ie: making a good connection to the shaft. Perhaps in your case a zinc on the shaft and a zinc on the prop( for instance a prop nut zinc) is needed if you have just one or the other.
For a good discussion of these issues I suggest Nigel Calder's "Boat Owners Mechanical and Electrical Manual" which I believe should be a part of any sailors booklocker. ALSO Charlie Wing's "Boatowners Illustrated Electrical Handbook" presents a lot of good information on this and other electrical Issues, practices, and projects.
Sorry this got so long and winding, I did not mean to go on and on ,but I hope this at least helps to answer your question and if not at least steers you in the right direction.
regards,Rick
1982 Freedom 33 Cat Ketch, Hull # 53, Standard Booms, deep keel ,tall rig
An armed man is a citizen, An unarmed man is a subject. George Washington

DennisG
Posts: 9
Joined: Wed Sep 05, 2012 11:40 am

Re: groundwire

Post by DennisG »

Rick,
I feel like you were looking over my shoulder when I was in the bilge yesterday.Not being exactly sure what to do with the loose ground wire , but also feeling the stuffing box was the only place it could go, I used a hose clamp to attache the wire to the stuffing box.Yes , it is a 6 guage green wire and there is a short ground wire that jumps across the "drive saver'. So, I guess my temporary fix will be good enough to finish the season. I really like your idea of drilling and tapping a small bolt to fasten to, but that will be after we're hauled for the season. Of all the systems on a boat, electronics are my weakest point, so I really appreciate your reply.
Thanks Again,
Dennis

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1980raven
Posts: 101
Joined: Mon Feb 15, 2010 8:50 pm
Location: Warwick Cove, Rhode Island

Re: groundwire

Post by 1980raven »

I am just finishing up a 2.5 year restoration of Raven a 1980 Freedom 28' centerboard cat ketch. The original thru hulls and prop shaft were not grounded. I replaced all the thru hulls with bronze seacocks which have bonding screws. Since the original bronze thruhulls show no signs of corrosion i feel the bonding wire is unnecessary. Thanks for confirming my belief.

Now about the grounding of the masthead fitting; please tell me why that is necessary?

Art
Freedom 28 CK Hull# 14, centerboard, wrap around sails with WB booms
Narragansett Bay, RI

midnightsailor
Posts: 139
Joined: Thu Aug 06, 2009 1:21 pm
Location: Greenport, New York

Re: groundwire

Post by midnightsailor »

I was refering to the lightning protection, which on the Freedoms I have seen, including my own, is incorporated as part of the bonding system. This is inadequate. On my boat, there is a 6 gauge green wire, same as rest of bonding wires,that comes down the mast and is tied to the mast strep and then to the keel bolt . The rest of the bonding system is tied into this also. This is ok as far as bonding goes, if bonding everything is what you decide you want to do. It is not adequate however, as a lightning protection system. For that , a masthead lightning rod or air terminal is required , tied to heavy gauge cable, of a minimum of 6gauge ,run down the mast to a dedicated ground plate affixed to the outside bottom of the hull. A long narrow strip being more effective then a square plate of equal area. I really suggest tryingb tomget a copy of Nigels book to learn more as this is all avery complex subject,which I unfortunately do not have time right now to get into here. His disscussion is one of the best and most comprehensive of any I have read in one place. THat is why I recommend it.

fair winds, Rik
1982 Freedom 33 Cat Ketch, Hull # 53, Standard Booms, deep keel ,tall rig
An armed man is a citizen, An unarmed man is a subject. George Washington

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folotp
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Location: Lake Ontario, Canada
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Re: groundwire

Post by folotp »

Hi,

Regarding lighting protection, I recommend that you also read "NFPA 780: Standard for the Installation of Lightning Protection Systems". Lighting protection recommendations for boats have changed dramatically in the last 10 years.

http://www.nfpa.org/AboutTheCodes/About ... DocNum=780

Another good source of information that helps understand the NFPA 780 standard is the following website:

http://www.marinelightning.com

PA
Pierre-André Folot
s/v “Farfelu” - Freedom 39 PH 1983, hull #14
Sailing the Thousand Islands and Lake Ontario
Canada

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1980raven
Posts: 101
Joined: Mon Feb 15, 2010 8:50 pm
Location: Warwick Cove, Rhode Island

Re: groundwire

Post by 1980raven »

I read NFPA code and ordered Nigel Calder's "Boat Owners Mechanical and Electrical Manual". It should be in next week. Thanks for all the great info.
Freedom 28 CK Hull# 14, centerboard, wrap around sails with WB booms
Narragansett Bay, RI

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1980raven
Posts: 101
Joined: Mon Feb 15, 2010 8:50 pm
Location: Warwick Cove, Rhode Island

Re: groundwire

Post by 1980raven »

So I read NC book and decided that since Raven has survived 30+ years without any lightning protection and after a visual survey of all the sailboats anchored in Bristol, RI harbor (over 100 boats no lightning protection) I am going to take my chances. Regarding bonding the mast. I looked at the existing green wire which ran inside the mast down to what should have been a connection to another green wire at the mast base. The insulation hadn't even been stripped let alone a connection made. So I intend to leave well enough alone. Any thoughts?
Freedom 28 CK Hull# 14, centerboard, wrap around sails with WB booms
Narragansett Bay, RI

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