Article by Pat Schrawder
PROPER BOAT BONDING
No, I’m not talking about making new friends on your dock. What I’m referring to is the electrical bonding system on your boat and its proper ground. If you’ve ever been offshore in an electrical storm, you know how precarious and downright frightening that can be. If you are one of the unlucky ones whose boat happens to take a direct hit from a lightning bolt or even a close one, you know the potential damage that it can cause. That’s where your vessel’s bonding system really becomes important. Aside from the protection factor, there are plenty of other good reasons to have a well grounded boat that has to do with the efficient operation of your electronics. So, you might ask, just what constitutes a good ground or bonding system?
During a storm event, a good bonding system can save you from very expensive damage to your electronics. Lightning is looking for a connection to ground. It will instinctively seek the shortest path with the least resistance. If your vessel’s ground system is to be effective, you need to provide just that; a short, easy path to ground for the lightning bolt to follow that doesn’t compromise your electronic equipment. If you do not, lightning will “wander” around your boat, looking for a way out to ground. This can cause complete melt-downs of equipment and mini “explosions” of electrical components in your equipment that can rarely be fixed. In fact, even if an item has been successfully repaired for the moment, past experience has shown us that the repair seldom holds for the long run. Sooner or later (and it’s usually sooner), the equipment will develop additional problems. Often, these problems are intermittent and hard to track down. Even if you’re lucky enough to not be the target of a direct hit, you’re still not out of the woods. I have even seen instances where a lightning strike on one boat in a marina has jumped over to other boats, continuing its search for ground until it finally finds it, wreaking havoc along the way.
Aside from the lightning situation, on a day to day basis proper grounding of your equipment will usually result in improved performance of your equipment. It reduces noise and interference in some items and is absolutely essential for successful performance of your single sideband radio. Most manufacturers recommend running a separate ground wire to their unit. Many of them provide a ground bolt or wing nut on the back of the unit for just that purpose. It usually isn’t a difficult thing to do and I would highly recommend you take the time and effort to do it. The way equipment ground connections are designed, they make it somewhat more cumbersome to remove your equipment from the boat and for that reason, people often ignore them. For example, it is more often than not a bolt with a wing nut onto which you put a wire with a ring tongue terminal. A good solution is to make that wire connection to the equipment a short one of six inches or so and on the other end, place a “quick disconnect” terminal end that connects to another long wire which is permanently linked to your ship’s ground system.
A good ground for your boat consists of a complete system– not just one or two critically run wires. Ideally, it starts with a ground plate. Ground plates are made of thousands of tiny copper beads, fused together into a rectangular block that is about one half inch thick and comes in several sizes. Because the beads are round, they provide a great deal of copper surface in a small space. The larger the block, the greater the resulting ground equivalent. In any case, a ground plate provides ground that is electrically equal to a huge copper plate. They have a hole drilled in each end so that the ground plate can be secured with copper bolts which run through the hull to the outside in order to make contact with the water. The ground plate is then attached to the bolt at one end with a copper strap, braid and/or wire, which is then run to a central place on the boat that is accessible. A single large bolt run through the bulkhead to which the ground wire is attached makes a good, easy source for ground hookup. The important thing is that your ground is completely bonded to a single point. In other words, you do not want several separate grounds, each doing its own thing. You need all of your grounding run to one central location and then connected to a single wire that runs straight to the ground (water).
If you do not have a ground plate, you can use an existing thru hull fitting. Do not use a transducer thru hull fitting, however, as that can only lead to another problem like electrolysis. If you are having problems with thru hull fittings corroding off or taking on a strange color, you already have evidence of electrolysis and need to address it soon before it causes damage. Whether your primary purpose for installing a good ground system network is lightning damage reduction or improved performance of your electronics, the fact is that you will get both results. Don’t forget to inquire with your insurance carrier if you qualify for a better insurance rate because of this bonding. Some companies will give you a better rate. All companies should do so because a good ground will prevent future damage to your equipment in a storm. In any event, proper bonding on your boat is a worthwhile endeavor and ground plates are relatively cheap, running less than $100 and up, depending on the size. It is an expense that is well worth it.
Pat Schrawder and her husband Larry are owners of L&L Marine Electronics on Golf Course Road in West Ocean City.