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  • Adam Morris

You are (Probably) Crimping Marine Electrical Connectors Wrong, and I Was Too

Updated: Dec 15, 2023

Note: I/we are not sponsored by any companies mentioned in this article. We cruise full time on our test bed, SV Confianza, and we enjoy sharing our tests and opinions to give back to the community.

If you own a cruising boat, you will have to learn to be an electrician (in addition to a painter, a detailer, a mechanic, a rigger, and a plumber...).

I've had one marine electrician that I've worked with that I would trust with almost anything on Confianza, but he is quite expensive. I've had another that I respect his knowledge. but I had to constantly chase to actually show up. And I mean constantly.

It was very frustrating, since he was helping me install the lithium battery bank and charging system. What should have taken a week took six.

As usual, I find myself preferring to do the work myself, and with the amount of modifications and upgrades that are electrical, I have spent probably more time on electrical than anything else on the boat.

My Early Work was Awful

I have to admit, my early work on Confianza still makes me cringey. Planning was poor, cable organization a mess, and too much "good enough is good enough" attitude. That approach, at the least, just leads to thrice the work in the future or even a fire.

I inherited quite the plethora of tools when we bought Confianza from the previous owners. They had spent many years sailing all around the globe, so I had an inherent trust of the tools that got them there.

But, I was finding that my electrical work over the years was not lasting the test of time (and elements). Years ago, I replaced all of the interior lights with LEDs (twenty-five or so) to give us much more usability out of the legacy lead acid battery setup. Five years later, one started flickering, then another, then another, four flickering now, and the co-captain was not pleased with my work after all.

The Right Tools for the Job

Having the right tools makes jobs take way less time in a household environment, but on a boat, that includes your total maintenance time of its lifecycle. On a boat it can also be about safety. And making bad crimps can trigger both problems. Bad crimps means corrosion.

Corrosion means voltage drops that cause intermittent issues and damages more sensitive electronics. Corrosion means higher resistance, and higher resistance means heat.

And it's not that I was consciously lazy when crimping, I was just using the wrong tool.

The Wrong Tool for the Job

Super Champ Crimper Above, Sea-dog Heat Shrink Crimper Below
Super Champ Crimper Above, Sea-dog Heat Shrink Crimper Below

Can you guess which one?

The top one is a $30 Super Champ crimper that came with the boat. It's also the one I generally see in everyone's toolbox that I lend a hand to.

The results from this tool are very subpar. The crimps it makes are thin enough to cut through the shrink wrap if you're not careful, inviting a short life to the crimp. You'll also need to double crimp each side, so that means four chances of damaging the heat shrink. It's also very challenging to apply the right amount of force for a proper crimp.

The bottom one is a Sea-Dog Heat Shrink Terminal Crimper, which also can be regularly found at around $30.

"Wait, you're not going to recommend a crimper that costs real boat dollars?"

In my experience, this crimper, which I believe is a copycat of the FTZ Industries / FTZ Electrical Control Cycle Ratcheting Crimp tool, does a very fine job. Fun fact, FTZ was actually the inventor of the heat shrink terminal itself, according to Rod at Compass Marine.

The ratchet action forces you to actually put enough pressure on the crimp before it will release, giving you a great crimp every time. It will not release until you have crimped down all the way.

The ABYC specifications for a crimp on a 14 gauge wire to resist 30 pounds of pull force. With the old crimpers, I was definitely not crimping hard enough (for fear of cutting the heat shrink). The new crimpers even took some getting used to with how much you will squish those suckers.

After spending too much time researching crimpers, I found negative reviews on nearly all $100 crimpers. Why bother? When you get above the $175 mark, you can start into the professional grade, but it seems quite overkill for the average cruiser and tinkerer. I've not yet had any problems with a crimp made from this tool.

When you cut off a cross section of the crimp, you can see the wire strands have been squished into almost a solid wire, making a connection that will last a long time.

Wire Stripping

My old Super Champ had a wire stripper built right in. Wasn't that more convinent? Well no, actually. I'm not sure how many times I had to re-do a wire stripping because I realized I had taken some of the wire itself off with it. They make for sloppy strippers (*ehem*).

"Ok, this is where we break out the big bucks then?"

Nope. My favorite is the Irwin Vise-Grip Wire Stripper ($25).

Irwin Vise Grip Wire Stripper
Irwin Vise Grip Wire Stripper

This stripper automatically adjusts to the gauge, clamps on, and strips the wire with a quick squeeze. The yellow plastic guide piece is how you set how long of an exposed end you are looking for.

"An automatic? Oh come on, those automatic strippers are garbage! Get a real crimper! Like the IDEAL 45-092 Stripmaster!"

Ok, yes, most of the automatic strippers are total garbage. I have bought multiple different brands throughout the years, and most have broken. I even listed to a pitch from a guy at the Annapolis boat show claiming his company had fixed all the problems, and it will work forever! I bought two, and both broke within 6 months.

The convenience factor is just worth it. I'm sure it's not rugged enough for a daily driver, but I've been using this one for over 2 years, and it has held up nicely. Clean strips and no broken wire strands.

If you are worried about longevity and perfection over convenience, just go with the IDEAL 45-092 Stripmaster ($45). I have one of those as well as a backup.

Hope this was helpful for cruisers that don't want to break the bank but want to have their electrical connections last a long time. Happy Crimping!




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