Marine Wiring Harness
- Dave LeGear
- Aug 7
- 8 min read
Updated: Aug 12
I have looked over quite a few harnesses over the years, and seen both good and (let's just say questionable) Marine Wiring Harness and rigging by some builders even if they had a NMMA sticker on those boats.
An example of a high quality marine harness as found on Hell's Bay Estero. Wiring / Rigging done correct, is a work of art for sure!
Personally, my take on this subject comes down to two simple concepts...
System failures are inevitable, particularly in the marine environment, where losing power in rough seas can be deadly. Even losing power to something as basic as a bilge pump is never advisable.
The hull's main gig is to keep the wiring harness dry and snug, and I'm totally sticking to my guns on this one. Because, let's be real, if the electrics go "Dead Jim", you'll be drifting off into the ocean like a lost rubber ducky—and we all know that never happens on those picture-perfect, postcard-worthy days!
So, when shopping for any new or used Skiff / Boat for that matter. Pay very close attention to the condition of the wiring harness AND how hard it is going to be to both service it, and or replace it? Even some of the finest Boats, get a total re-wire after X amount time. What is the condition of yours? And for members of our group that live up North. Winter is a great time to get yours repaired (and secure) or replaced and back up to being "Seaworthy" when she is not getting used for months on end.
What makes a quality harness install, versus those that you see all coiled up like a snake from a ton of extra wiring that is not needed and looking like a Bird Nest at the same time!
Unless it is (not) wise to cut and shorten a component harnesses to fend off moisture intrusion... It is much better to have the harness made to the correct length and properly secured but, not super tight as guitar string at the same time. How many times do you launch your car or truck off of a wave and the entire vehicle is totally airborne? Compare that to your Skiff or Bay Boat as you are flying though the chop and your back is feeling every single hard landing!
Here are some tips to tips for inspecting and maintaining your boat’s wiring harness:
1. Inspect Regularly (Every Season at Least)
• Look for corrosion, fraying, heat damage, loose connections.
• Pay extra attention around bends, battery terminals, and anywhere wiring passes through bulkheads.
• Don’t just look—wiggle. Sometimes what looks tight isn't.
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2. Use Marine-Grade Everything.
• No car parts on the water! Use marine-grade wire (tinned copper) and connectors.
• Regular stuff corrodes faster than your patience with a dead bilge pump.
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3. Keep it Clean and Dry!
• Moisture is the enemy. Use dielectric grease on connections and spray corrosion inhibitor on terminals.
• Move and secure up higher, harnesses or wires (laying) in the bottom of the bilge.
• Wipe away salt or mildew during routine cleanups—your boat isn’t seasoning itself.
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4. Support and Secure the Harness.
• Wires should be bundled, supported, and secured every 18 inches or less.
• Don’t forget to check and re-secure all the grounds back at the outboard engine block.
• No drooping lines or tension pulls. Zip ties are good—but use the UV-resistant kind.
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5. If not already, label everything (Future You, Will Thank You!)
• Use heat-shrink labels or waterproof tags.
• Label both ends of every wire. In 3 years, you won’t remember what (that) red one does—and neither will your mechanic.
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6. Battery Terminal TLC
• Clean and tighten battery terminals often. Corrosion here can cause phantom issues throughout the system. Once the voltage drops below 10.5 volts, most engine ECU's (Electronic Control Units) drops into a limp home mode blowing smoke and hardy runs above idle, or the engines just stalls out altogether.
• Use terminal protectors or grease. Keep them tight (snug may be a better term), but don’t strip the posts. Lock washers can come in handy for these types of connections, so they do not loosen up as quickly as compared to those that do not have them. And don’t forget those (behind) the battery A-B switch.
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7. Fuse It or Lose It
• Every circuit should have a fuse or breaker—close to the power source. Fuses pulled and cleaned, a spot of dielectric grease added, make sure all connections are snug.
• Replace any sketchy “repairs” involving tinfoil, coins, etc.
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8. Avoid Splicing If You Can.
• If you must splice, use heat-shrink butt connectors with adhesive lining.
• No twist-and-tape. This isn’t 1976, and you’re not wiring a CB radio.
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9. Keep a Wiring Diagram and consider keeping a spare copy onboard.
• Update it with any modifications. Laminate it or keep it in a dry pouch.
• If you don’t have one? Make one—future electrical gremlins will cower before your preparedness.
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10. Watch for Voltage Drops.
• Dim lights or slow pumps can mean bad grounds or corroded wires.
• Use a multi-meter to test voltage under load. It’s not voodoo—it’s volts.
Click below to download a print out our version of the wiring harness checklist, to take with you next time you are performing that task on your Skiff!
What about when it looks like a total Rat's Nest and creating all kinds of problems including no start or system bugs in an older boat? Well, this might be the time to invest in a rewire of the entire boat by professionals who are experienced in making such repairs/upgrades. By going this route can have several advantages...
Improved reliability and safety along the peace of mind that comes with such! How much value do you put on your time? The last thing you want to do is be at the ramp and the she won't start, or the trolling motor is as dead as a door nail (been there done that) for those few hours most only have on the weekend to hit the water.
Discovery of other marginal or needed repairs while the techs are inside the hull pulling the old harness or parts of it out.
Better conduit materials can be employed during the repair and upgrade process (like simple PVC pipe) to help prevent chaffing and the rubbing of the new harness.
Much improved vessel resale and overall value! Let's face it, some production boats when it comes to the harness work by the OEM, can be very sloppy at best. And only seems to go downhill from that point quickly, even within the first few years of ownership.
Not everybody has the budget for a new skiff. Some skiff models do not change much over the years when it comes to the basic hull design and running surfaces. They do though, improve as time progresses, with age and the technology advances that employed on the later models. Click below for one of our Sound Bites with Hells' Bay Owner and Guru Chris Peterson on their use (and why) of Carbon Innegra for their hulls now.
Then, develop a project plan (more on those files later) and shop carefully for one that is used in the condition you can afford, and are willing to invest in... Unless you are a technician yourself, leave the electrical repairs and related upgrades to the experts like the team over at "The Skiff Shop" while you handle the clean up and detailing chores afterwards. This and save many thousands of dollars in the initial acquisition process! Click play below to see a slide show of some well executed repairs and more like works of Art!
Now, If you're diving into your own wiring repairs or even rewiring your boat, we've have some great tools and guides below that will be incredibly helpful both before and during your project!
The (Pager Group) posted some great resources and guides to help you no matter your level of education or experience... Here are a few with those direct page links that focus on the more basic repairs:
Glossary of Electrical Terms Every industry has it's own acronyms and terminology, this may help with those "what is that" type of questions.
Voltage Drop Calculator Long runs for D/C current can create voltage drops which is why your house runs on A/C current. This guide should help you choose what you need wire gauge wise for X need.
ABYC COLOR CODES The American Boat and Yacht Council has established standards to streamline the wiring process, making repairs and wire replacements simpler and more efficient. This does not mean the "last person" followed those same guidelines! But it may come in handy to trace out what is left of the original harness, this or help you get your repairs back to them.
Full Technical Database This is great page with all of the shortcuts above as well as others that you may find comes in handy! And do let the Team at Pager Group know you found them on Flats Nation.
We hope this little guide and the resources help your boat always start, and get you back home with everything working every time you launch her!
Do like and share this article and the rest of Flats Nation with family and friends! We will have more on a related subject (project plans) both for buying, as well as restoration and upgrades for your vessel soon to help.
And speaking of Skiff and Boat upgrades, make sure you check out our Industry Colleagues over at Ruckus Marine for some unique products for your Skiff and Boat, while using our exclusive saving code at the same time.
In the meantime,
We invite you to take in a few Flats Nation Podcast Episodes to help "Scratch that Fishing Itch" when working or traveling and you cannot hitch up the Skiff and go by clicking Here: and do share with your family and friends!
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Many Blessings!
Dave and the Team
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