SailNet Community

SailNet Community (
-   Gear & Maintenance (
-   -   old boat wiring (

KasbeKZ 10-16-2008 01:25 AM

old boat wiring
i did a bit of searching, but i wasn't able to really find what i was looking for.

the boats that i'm looking at (catalina 27's) are mostly from the 70s. i'm wondering what kind of a job should be done on a cheaply made boat from the 70s to prepare the wiring for the reliability and safety required for living aboard? will this include a new breaker board? all new wires? re-doing connecions? new outlets? or will it be a purely scenario based job just depending on the particular boat? i figured someone may have had enough experience to generalize what quality and effectiveness of wiring to expect.

perhaps this is not the right question, but forgive me. the only boat i've owned before this was a force 5, and it's wiring was in a different league:p

badsanta 10-16-2008 02:44 AM

I would think it would depend on how many things you install, lights, pumps et all. I would think the hardest and most expensive would be to the charging system and battery if it needs upgrade. Most older boats are severly underpowered. You need to match an alternator with the batteries. You cant just add a monster alternater to a small battery. a good 12 volt boat electric book will help along with the advice from others here. Put some thought in it before you start.

bubb2 10-16-2008 03:02 AM

I would start here (no pun intended)

The 12-Volt Bible for Boats 2nd Edition

floatsome 10-16-2008 05:20 AM

Wiring is humbling. This is just my amateur boater's approach to this problem. There are many others.

My approach with our boat in that vintage was to rip out all the old AC and DC wiring, outlets, connectors and panels - everything. But this is my third boat, and over the years I've learned a bit about boat wiring. I found old solid untinned wire, corroded connections, deteriorating insulation, cobbled wiring that had been added to original circuits by different owners, and parts that did not meet today's standards. The engine was festooned with ground wires. I am starting over with properly coloured multistrand tinned marine wire, proper crimped waterproofed connections, and new outlets, connector boxes, bus bars and modern distribution panels.

I invested in a good set of current boat maintenance books (Calder and Wing, for example) and spent a lot of time cruising the Internet (especially the quality manufacturers' and distributors' websites).

I drew up a list of the devices I want to have on the boat, and their power requirement in amps. That gave me an idea how much battery I need. Personally, I separate house from engine batteries, so I worked out power budgets for each separately (cold cranking amps and running draws for the engine, and amp hours for the house). Then I figured out the maximum alternator the engine can handle (more amps = more strain on the engine). That resulted in cutting back my list of devices. I learned about battery technology, so I could make informed choices.

Next I figured out how I wanted to wire the battery charging system (shore power and engine alternator). I considered auxiliary power sources (solar, wind, generator).

Then I drew up schematics for the AC and DC systems to show wire runs, wire sizes, fuses and components, and checked them many times against various authorities, including ABYC, the Blue Sea online calculator and current standard textbooks, until I was comfortable that I understood the issues. I am still perplexed about grounding, but that's for another thread. Then I started buying parts.

In assembly, I try to follow expert advice about making marine connections, running wire and supporting wire runs on boats. I consult experts on critical steps, like getting an inspection before powering up the AC wiring for the first time.

PBzeer 10-16-2008 06:06 AM

While it is certainly likely that if the boat has it's orginal wiring, upgrading may be, even probably will be, necessary, you won't really know until you have the boat. It may well be you find one that has already been upgraded.

If though, you are faced with the task of re-wiring, and intend to keep the boat for any length of time (say 5 or more years), then I would do a complete re-wire. If not all at once, at least with some plan of doing so in steps. You have to look at it as a system, not just individual components. It will only work as well as the weakest link in the system.

sailingdog 10-16-2008 06:45 AM

Until you have the boat, you won't be able to tell what you will need to do. As PBZ has pointed out, many older boats have been upgraded and will need less work than ones with all original wiring.

If you do decide to re-wire a boat, I would highly recommend ripping all the old wiring out and starting from scratch. This is often faster and easier than trying to make sense of the rat's nest that is usually found on most older boats...

sander06 10-16-2008 06:51 AM

IMHO, rewiring isn't that big of a deal, but it is a royal PITA!!!!

maccauley123 10-16-2008 10:04 AM

It is impossible to know the state of the wiring in your boat. I would think a boat of that era, unless a prior owner rewired it, would be something of a mess.

I bought my 71 Ericson 29 a few years ago knowing at the time the wiring was in bad shape. The panel was a rats nest of confused wires and old, gooey electrical tape. I wanted to install some new gear and had no idea where to hook it in.

I decided this year to rip everything out and start new. All of the old wiring was removed and will be replaced with true multi strand tinned marine wire. New breaker distribution panel, bus bars, etc. The hardest part has been going through all the books and figuring out the wiring diagram. I had originally foolishly thought I could do it without but realized there was no way. The only way to do this is with a clear plan on how to rewire it. This is the only way to know what wire and other parts you will need. Doing this gave me a chance to make sure everything was fused correctly.

I am at the rebuild phase now which I will work on over the winter. Good cold weather job since no epoxy or paint to cure.

Good Luck.

rhaley 10-16-2008 10:32 AM

When I bought my C27 (82), I completely removed ALL the original wiring and started from scratch. And I highly recommend it. The vast majority of the time, you will save neither time nor money trying to "fix" what was there.

As maccauley123 said, it is a good winter project. Let me know if you have any specific questions about the C27.

Good Luck!

badsanta 10-16-2008 12:13 PM

One other thing as you start your project. Label, label and label both ends. You will forget. Don’t use masking tape or any paper label they will come off. I was told, but didn’t listen. Pay back is a hard master. I like John Payne electric books.

All times are GMT -4. The time now is 07:12 AM.

Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging v3.1.0 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
(c) LLC 2000-2012

For the best viewing experience please update your browser to Google Chrome