Hi Dave,

First, to be clear, this is the bonding (think safety and corrosion protection) ground here, not an RF ground for an offshore SSB radio, which is a significantly different subject. I'm pretty confident that the original J/30 construction did not use a bus bar, but I can't say for sure, and I am not saying that you shouldn't use one. My suggestion would be to try to get as close to the ABYC standards and original J/30 construction standard as possible.

Connection to the keel bolts should be of high concern. The stainless steel plate method that Bill describes seems good to me. 300 series stainless is available from McMaster.com and OnlineMetals.com. OnlineMetals has the advantage that they will cut to your LxW dimensions and is very reasonable in terms of price.

-Chris

The common ground system serves multiple masters. In the case of my boat I think the night crew was at work smoking some local weed and installed a terminal bar rather than a bus bar or tieing all the leads together some other way. All of these various elements need to be tied together however you manage to do it (see Bill's J/109 diagram). These leads could have been tied together multiple different ways, but together they should have been tied. A terminal bar is terminal if, it doesn't go anywhere, there were no jumpers from one lead to the other. They all simply dead ended. Hard to imagine that would suit the ABYC. It is also hard to see how or why an owner over the years would mess with this stuff, so I have to believe it left the plant the way I saw it, but who knows.

I will over time try to improve this system, but it is just not a high priority as compared to getting the boat back in the water to go sailing. My manual pump works for sure so if lightning hits I'm good for about 5 to 10 minutes of vigorous pumping before the bubble blowing act starts. :-)

I'm recovering from some hand surgery this week and starting to plan out some more inside projects and this bonding issue is part of my winters electrical work. While I will admit to having a large tool collection, big tools that will break the keel nuts loose are not part of that collection. I have the socket, breaker bar and an extension, but this looks like it would need a multiplier to break loose and then retighten. It then occurred to me that another approach might be to drill and tap the bolt in place using a 1/4-20 into a 7/32" hole. I don't need a lot of hole depth, or even much thread engagement as long as I can get a solid connection I think I would be golden.

I know drilling and tapping SS is challenging, but a modestly oversized hole and not much thread depth seems like it might solve that problem. Please let me know if this is a waste of my time, before I beat my knuckles up trying. Renting the multiplier and making a SS plate up is possible too.

If you get one keel bolt off the best solution is to place a small stainless plate with a terminal screw on the side of the plate under the keel bolt nut. This is what they did on my J/109 keel ground and allows you to easily access the terminal without removing the keel bolt in the future. It will be difficult to drill into the center of the keel bolt and tapping it in place.

Ok, plate it will be then. Since I will likely get to buy foot of the stuff I think what I might do is use a little more of the plate and have it bent upward a few inches to get the actual electrical connector out of the bottom of the bilge. Chris had suggested 1/4" plate, but it seems that 1/8" would be adequate. My bolts and the nuts are flush on top now and I don't want to give up much thread engagement by putting a thick plate into the mix.

My plan will be to risk my standard socket on this large nut with my impact tool and see if I can break it loose. If that doesn't break it loose then I will sort out either a bigger impact tool or the multiplier. The reinstall will be to get the nut tight, but not overly so. I don't know the torque values and I have to suspect that it would not be that hard to start crushing the glass structure by getting carried away tightening this back up.

This afternoon I was up in the boat and was looking at the keel bolts/nuts again and it occurred to me that there was another option beside breaking the nut loose and making a plate to go under the nut like in Bill's image. The washer under these nuts is a pretty large diameter and I thought that drilling and tapping it would be an easier and equally good solution. So I got out the 7/32" cobalt drill bit, a long bit extension, the large 1/2 variable speed drill and using a pretty slow drill speed easily drilled a hole through this washer. So then it was on to the tapping part of the exercise and that went OK too. Then I went to install a standard 1/4"-20 by 1/2" hex bolt and found the error of that plan (the hex interfered). So I decided I would try to drill another hole a little further out from the nut and again that went fine, but just as I was finishing the tap, it broke off in the hole.

So I sat there a while saying a few choice terms and it then occurred to me that the answer is a socket head cap screw because it has a much smaller head diameter. Sure enough another quick trip to the local hardware store and yahoo it worked just fine. So now I need to make up a lead that will run back to the common bus bar and we will be golden. The only thing that concerns me is that this is a dissimilar metal situation that is going to be wet a lot of the time. The tinned connector, tinned #8 copper wire and the SS washer and screw does not seem ideal at all. I have Duralac and can coat this connection, but is that a good long term solution, or is there another way?

The J/109 connection is not in the area of the bilge normally covered by water. I see two possible options.

1. Remove one keel bolt hex nut and put on stainless L-bracket drilled so it fits under the hex nut. At the top drill a hole and tap to attach ground terminal at the top section out of the area that is normally wet, but under the floor board.

2. Attach the terminal to one of the holes that you drilled, then completely seal the terminal and connection with a compound that will prevent water infiltration. You'll need to investigate what a good durable waterproof material would be.

Edit:
3rd option - Instead of #1, create an L bracket of stainless steel that is screwed to one of the holes you drilled, then attach the bonding wire to the top part of the L-bracket out of the area normally wet but under the floor board.

I think the L bracket makes sense. It gets the terminal and the wire out of the frequently wet area. Will use the Duralac to coat the terminal connection to deal with the dissimilar metals. This whole connection is directly under the grate in the sole I made, so it is easy to access and inspect.

Now it is on to a ton of other electrical and mechanical projects.

Bill,
I was studying the J/109 diagram and it is interesting to see that this common wire is now twice the size of the #8 in my boat. I just got in another reel of #8 wire so my plan is to double up a couple of these connections, which would match the #4 in the 109's. I had earlier cleaned up and repainted the mast base and will have to decide if I want to run a double lead from the new keel strap direct to the base, or drill and tap a lead directly to the mast and then coat that connection with the Duralac. My inclination is to go with the tapped arrangement to the mast because with the superduper paint job I did on the base the mast might not be well electrically connected, not to mention the corrosion coating on the inside of the mast itself. For sure the inexpensive hydraulic crimping tool is perfect for these big connectors.

The common ground system on MaJic Carpet has now been completely rebuilt and upgraded. Using a new bus bar it made collecting up all of the strands of the system pretty easy. Even with the bus bar this eats up a bunch of wire. The J/109 sketch that Bill provided shows all of the connections on this new system. I used 8 gage tinned wire and in the case of the connection directly between the mast to the keel bolt I doubled those leads up. My plan is to drill and tap the mast for 2 ea. 1/4-20 bolts. When I get ahold of some more 14 or 16 gage green wire i will add some leads to the through hulls that have a terminal screws to prevent any possibility of galvanic corrosion (of which there is none of now).

The hydraulic crimping tool is perfect for these heavy gage connectors, you just need three hands to operate it. I really like the heat shrink connectors, but I kept stocking West Marine out of the sizes I needed, so did use standard connectors. I am trying some liquid tape I found at West. It seems to do a pretty good job of sealing the connectors up, so I plan to use it on these standard connectors. The less moisture that gets into the wire and the connector the better for the long term. I also deviated from the SS L bracket and used a piece of aluminum that I already had in the shop. The ends and connections are all coated with Duralac (it has lots of zinc in it) so I am not concerned with galvanic corrosion and I used it also on the connector to the strut knowing the SS would work on that connector and you would never see it disintegrate. I moved the bus bar to directly under the grate in the sole so that it is easy to inspect and will get looked at far more often than in the first location where the original terminal strip was.

Work is now well underway in the battery box and the new DC panel and I will share that when it is a little further along. I will probably need the chiropractor by the time this electrical work is completed, being cramped into small spaces all folded up and on your knees is not the kind of exercise the Dr. ordered. I am also not well known for following written instructions, but I followed Bill's outline very carefully with only a couple of small deviations for my requirements. I can't thank him enough for documenting his work so well.