Buehler simplified boat wiring scheme

[cluttonfred]

In Buehler's Backyard Boatbuilding, George Buehler described a simplified wiring system for a boat that I thought was pretty slick. I believe this was for a engineless cruising sailboat, or at least one with a hand-cranked or pull-started engine, so all the power draws were pretty small.

Basically, he put put a main fuse and cutoff switch at the battery, then a live wire and ground wire in one continuous loop ending near the battery with a push-to-test lamp. Then he spiced into the main loop (live and ground) as close as possible to whatever he needed to power, adding an inline fuse (and a switch if necessary) right next to the item. Presumably he fudged that a little (putting navigation light switches near the helm, for example) but that was the general idea. Got a problem? Check the fuse on the item. If that's OK, check the push-to-test lamp to see if the main circuit is hot. If it is, then the problem has to be between the spice and the item or in the item.

I am traveling and don't have access to my books, so I am paraphrasing from memory, but you get the idea. That does seem to me like a good approach in that application, though I'd probably add a voltmeter and ammeter at the battery.

What do folks think? Pros or cons compared with the usual central switch panel approach?

Cheers,

Matthew

 

[C. Dog]

Inline ammeter not advised as they are hooked in series. Induction type may not be as accurate but are less dangerous and problematic. Kinda wondering why bother? In this age of small devices with rechargeable lithium batteries. I would not have permanent wiring in a small engineless boat that will rarely be out at night and easily bailed with a chunk of sponge foam.

 

[cluttonfred]

Inline ammeter not advised as they are hooked in series. Induction type may not be as accurate but are less dangerous and problematic. Kinda wondering why bother? In this age of small devices with rechargeable lithium batteries. I would not have permanent wiring in a small engineless boat that will rarely be out at night and easily bailed with a chunk of sponge foam.

When Buehler was talking about an engineless boat, it was a heavily-built, ballasted 26-28’ wooden sailing cruiser, I believe Hagar or the design that led to that one. Even when he started putting in engines, he was a big believer in the reliability of manual crank start as primary or backup on old-school small marine diesels since electrical system failures are frequent when cruising.

You’re right that there are simpler options today. I was thinking of using a modest, self-contained, portable power station (GoalZero, Jackery, etc.) charged at home and kept topped up with a solar panel. It would be strapped in place as the 12v power source, protected from the weather in the cabin or a ventilated compartment. That approach saves needing to charge multiple separate portable navigation lights and provides backup power for portable devices as well.

 

[C. Dog]

I have investigated using 18v power tool batteries to run a boat with low electricity supply needs. 12-24V range bilge pumps, navigation lights, sounder, USB charging outlet for phones and handheld VHF, what else? Adapters for many batteries are available, and a lot of gear runs on 12-24v so 18v should be fine without transforming the voltage to 12v. It appears feasible if all gear will handle 18V. Single centralised power supply, or multiple local batteries depending on installation.

 

[Rumars]

A distributed arhitecture makes sense only until you start working out the details. The looped main line needs to carry the entire amperage for double the boat length without voltage loss, it's the equivalent of a busbar. Every one of those "splices" needs to be secure against vibration and potected against humidity. Done right it costs a lot of money, you don't just strip the insulation from the main wire, loop the branch around it and wrap with tape.
If you want simple use an automotive style fuseblock in a waterproof box. Add a main battery breaker and connect your power station with anderson connectors to it.

 

[cluttonfred]

C. Dog, on the 18V batteries, I love the idea except that good quality tool batteries are often quite expensive. Still, if you are to find some good ones on sale, it could be a very handy system, easy to switch a low battery for a fresh one and to take low batteries home to charge. A step-down voltage converter that will do 18v-->12v is not hard to find or expensive if you did want to do that.

Rumars, I hear you and I suspect that the quick and dirty splice method is exactly what Buehler used. I don't think the amperage question is a big deal for the application I described with no single large electrical loads (LED lighting, 12v outlet, radio, etc.). On a 16' boat you could probably get away with a 32' loop, so for a modest 10 amps at 14v max then 8 gauge AWG (3.3 mm) would be just fine per the wire size calculators I have seen (1.5% voltage drop, 24 amps max current). Take the same principle but make it a straight line not a loop (say the battery at the stern) then you could go even smaller. On the splice question, there are certainly a lot of T-tap connectors out there, some better than others, and combined with heat-shrink tape you ought to be able to make reasonably good connections.

 

[Rumars]

Why bother at all for lights, there are plenty of waterproof camping lights that run on 18650 batteries, some are solar rechargeable from the factory, if not solar and 12V USB chargers for 18650 are also plenty. The same applies to navigation lights, all that's left is the radio and a phone charger, and both have battery powered options if needed, if not you connect them to the power station. Since the power station already includes USB ports, all you need is one connection to the radio.