Note from Trish: Mike and his wife Barb are part of the THS Canada contingent. Their home port is Halifax, Nova Scotia. Skip and I had the pleasure of visiting them on our vacation last year. Mike has lots of experience, lots of knowledge, and lots of opinions —- after all, he is a sailor!

Monkey’s Breakfast – a thorough mess, a mix up, an unplanned and unattractive mish-mash that has probably been stepped in.

Sooner or later, and that would be sooner, if you have purchased a used boat, you will find yourself in the inevitable position of having to rewire some, if not all, of the electrical system.   Our boat, Nelleke, a Moody 42, Pilot House ketch, was no exception.  She was built in the UK in Southampton, launched in 1980, and we are her third owners.  Each of the previous owners have added equipment, strung new wires, added circuits and generally contributed to what might be politely termed confusion, but which I can only refer to as the “Monkey’s Breakfast”.

Older European boats in general and British boats in particular need close scrutiny, if for no other reason than that the folks over there simply do things differently. 

First of all, their shore power systems are usually wired for 240VAC (in some places DC) and the AC appliances that come with the boat will be designed for that voltage. In our case there were only a few major items that we needed to be concerned about: the shore power battery charger, the refrigerator and the hot water heater element. 

The battery charger had to be replaced.  We opted for a combination charger and power inverter that have paid multiple dividends since we installed it.  For those of you unfamiliar with these, its basic functions are twofold:  when plugged into shore power it rectifies the AC voltage and produces DC voltage to charge the battery banks, and when it doesn’t detect shore power, on demand it will invert the battery power and provide 110VAC to the wall plugs throughout the boat.   A remote computerized monitor usually controls high-end charger/inverters.  A good one is not cheap, approximately $1000Cdn for the charger/inverter and another $500 for the controller, but the peace of mind, versatility, and flexibility make them an investment well worth considering.

The AC component of the electrical circuit for the water heater that came with the boat would work but would draw twice the intended current for the wiring since the heating element draws current based on its power requirement – half the voltage means it will suck twice the current for the same amount of heat.  Fortunately replacing the heater element was easy and relatively cheap so we chose to convert to a 120VAC element. 

The fridge, however, is a different situation.  Although the compressor will run on 120VAC, it can’t deliver enough power to cool down the contents bay shore power alone and falls back on the batteries.  Due to the cost of buying a new fridge, we have postponed this fix and we rely on the DC system to cool it.

The other issue with European appliances pertains to the AC power cycle.  Appliances manufactured for the North American market are designed for 60 Hz AC cycle whereas those build for use in Europe run on 50 Hz.  For devices like a heater this won’t make any difference, but for anything that has rectifying circuits in it, it will function with less efficiency and over time can cause damage to the rest of the unit.  For example, if your boat has a European radio that runs off AC power, it will in all likelihood have rectifying circuit in it that is designed for 50 Hz.  The radio will work but at reduced efficiency and will eventually be damaged.  Read the manual.  If it says something like “this appliance will run on 100-260VAC 45-65 Hz”, then you’ll be OK.  Otherwise, stand by for cloudy weather in the future!

Another thing, on older British devices they switch the ground side of their circuits.  The appliance still turns on and off at the flick of a switch but there is a small problem.  Even if the device is turned off and you happen to be grounded when you touch the appliance, you complete the circuit to ground and you become the on switch.  Isn’t that something special!  How can you be grounded?  Oh, there are many ways: hold on to the tap in the galley when you reach out to turn on the radio, or be barefoot in a damp environment (you are on a boat, remember!) just to name a couple.  I think this is a hold over from the days that people used to think that electricity flowed from the negative to the positive instead of the other way around.  Neat, eh?  You definitely want to check that out.

What we couldn’t put off any longer was the rewiring of the 24VDC circuit panel.  The original one that came with the boat looked like a “Monkey’s Breakfast”. First of all it was not a marine grade panel.  The breakers were plenty big and sturdy enough, in fact they were too big, weighed a lot, and occupied a great deal of space, rusting bus connectors – the works; and the wiring, after two previous owners and who knows how many well meaning friends and contractors fooling with it, was all over the place, none tied together, no colour standardization, joints soldered or crimped or twisted together….. In brief – a mess!

We were able to detect a good deal of stray or trickle voltage which is usually caused by old wires and dirt or oil breaking down the insulation and causing a low current short from one circuit to another or to ground.  Finally, after a weekend cruise plagued with intermittent electrical problems, we finally decided enough was enough!  We couldn’t put it off any longer!   A new panel and rewiring was in order.

My initial advice is that if you are going to do this, do it completely and do it right.  Otherwise you become just another contributor to the “Monkey’s Breakfast”.

Firstly, and most important, only use marine grade equipment.  This homily should be obvious for the new panel, but you should also include the wires and their connections.  Marine grade wiring is more expensive because it has “tinned” strands that protects them from corrosion and will greatly extend the life of the wire.  Yes, common household wiring is a lot cheaper to use, but chances are in 5-10 years you will be having many of the same problems again. 

Because it is “tinned”, marine grade wire should not be heat soldered since that will burn off the “tinning” and defeat the advantage.  All connections should be made with crimp fittings whether they are butt connectors to join two wires, or spade, ring, or fork connectors to fasten to the appliance.  Don’t use the cheap scissor-type crimping tool.  It doesn’t generate enough pressure, you’ll hurt your hand, and if it is a big job, chances are you’ll break the damn thing half way through.  The right crimping tool is double-action and can generate a tremendous amount of pressure evenly, cleanly and on the right spot.  If done correctly, the pressure generated by the crimping tool causes the metal in the connector to flow around the wire – in effect cold soldering the connection.  (See Diagram 1)

Diagram 1

Diagram 2

Secondly – shrink-wrap all wiring connections.  The plastic sleeves that you can cut and slide over the join and then shrink with a heat gun will totally waterproof the join and greatly extend the life of the job.  The only factor to consider is to get the right size and to heat the wrap enough to fully shrink it around the fitting but not so much that you burn or bubble the plastic.  A good clue, if you have purchased a reasonable quality shrink fitting plastic, is that if you look closely at the edge as you are applying the heat, you will see a thin edge of clear material begin to protrude.  If you have uniformly heated the fitting, when you see that clear material, you are done.

Table 1

Thirdly – when buying wire, not only buy the marine grade, but also make sure that you buy wire that is heavy enough to carry the current.  The factors that govern the necessary size of the wire are the voltage and current requirements (ie power) and the distance run.  Remember that distance run is not only the distance from the power source to the appliance but also the distance back.  So, if your appliance is 30’ from the power source the distance run factor is 60’!  The higher the gauge number the thinner the wire, the greater the resistance per foot.  No 1 wire is ½” thick whereas No 16 only has a couple of strands in it.  It’s like a pipe that you try to pump water through.  The thinner the pipe the harder it is to push a given volume of water through it.  With an electrical circuit, this translates to voltage drop in the line and heat dissipation.  For some appliances, such as lights, you may not care or notice if the loss of voltage results in a slightly dimmer illumination, but I can assure you that you will very much care if the heat loss over time melts through the insulation in the cable and you have a short which will cause a fire.  Not only that, but some appliances simply will not work if the voltage loss is too great.  It is safer to use the right gauge wire in the first place.  If you’re the type that likes formulas and tables, check out Table 1.

Table 2

We haven’t even begun the re-wiring yet and here I am still talking...