You’re working on your boat and find that some wiring has chafed through in a couple of places. When you go to repair it, you discover that several connectors have broken off behind the fuse panel. So you get out your trusty soldering iron and splice several wires, solder new connectors on the ends of broken wires, and put the whole thing back together again. Good job done, you think.
But wait! There’s a problem, a really big problem. It’s in the use of a soldering iron. Boat wires are subject to a lot of vibration and should not be soldered. If they are, the soldered part is usually fine where it is held rigid by the solder. But the wires tend to break directly behind the soldered joint where the wire can flex, but it is held rigid by the joint. That’s why most authorities do not recommend soldering wires for boat projects or even keeping a soldering iron on your boat.
The correct way to make a joint on your boat is to use a crimping tool like the one shown here. This one by Ancor Marine is very different from those that you buy in a hardware store. First, it ratchets, so you have constant pressure on the crimp connector. Second, it will not let go until you have crimped the connector at exactly the right pressure. You can’t “overcrimp” simply because the tool won’t go any tighter. You can also change to anvils to allow you to crimp other items such as co-axial cable.
When you using a crimping tool you’ll always need to strip the wires to the correct length. Like most electrical engineers (I spend six years pretending I was an electrical engineering before I got into boats), I have used a knife, clippers, strippers, and other tools to strip wires. But recently I’ve come across a couple of tools that make it so much easier to strip exactly the right length of wire. The stripper pliers ensure you can only strip just enough cable to give the right length to crimp. Again these pliers are made by Ancor who designed them to suit their crimping tool.
First strip your cable then crimp it. When crimping, place the wire into the terminal until it comes right to the end of the portion of the terminal to be crimped. If you shorten the length of wire in the terminal, it may not hold properly. Here we’re talking about making the perfect crimp that will last the life of the boat with a little care.
When the joint or terminal is crimped properly, it will never let go unless the cable corrodes. But the selection of the right terminal is essential. I prefer to use a washer-like terminal because the wire is completely captured, but many production builders prefer to use a U-shaped terminal that can be inserted faster. When using the washer-like terminal, you need to remove the entire screw from the fitting in order to install the wire. Often you’ll drop and lose the screw, so to save time boatbuilders rarely use this type of fitting. If you put a tiny drop of Tanglefoot (It’s a glue-like substance used by gardeners) on your screwdriver, you’ll find that it will hold the screw on the driver until you’ve got it aligned and screwed in properly.
When making a joint, simply insert the wires into a joint terminal and use the crimping tool to ensure that the wires are tightly fastened. I like to give the wires a good tug to make sure they’re tight. If you don’t tug them or the wires are loose, you may have to repeat the job later, and if it is buried behind a panel somewhere, you’ll wish you’d done it properly the first time.
Once you’ve crimped your terminal on the end of the wire, you will probably have a small length of bare wire showing. The best way to protect this wire is to use heat-shrink tubing to cover it. You can shrink the tubing by using Ancor’s butane powered soldering iron or by using several matches or a cigarette lighter.
Of course, if you don’t have any heat-shrink tubing you can wrap the joint with electrical tape. I’ve seen this done many times. But I prefer the neater look of heat-shrink tubing, especially as it can be color-coded on either end of the wire to suit the job.
Making the right connection, then, isn’t hard if you have the right tools and products for the job.
Roger Marshall has written 14 boating related books and his latest book, Fiberglass Repair Illustrated, will be available from International Marine in July 2008.