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Working in the Engine Room

As rewarding as aesthetic work is in reconditioning a vessel, the rubber really hits the road in the engine room. Wired has a great one. Not the dark stinky place that lurks under the cockpit of so many boats, but a real one with standing headroom; a clean, inviting, well-lit, ventilated home for the machinery that propels the vessel and powers the systems. It is obvious that a great deal of attention has been afforded this important space.

The problem is that there is still no escaping the fact that Wired is a 30 year-old boat, and harbors some old equipment and outdated thinking which extends to the onboard electrical system. Complex and cumbersome might be fitting adjectives. Wired's DC system is primarily 32 volts. Some people will already be gasping. Add to that a 24 volt system powered by two converters, two separate 12 volt systems for starting generators and operating electronic equipment, and both 120 and 240 volt AC systems, and you will begin to see the full picture.

It became obvious after I spent only a few days onboard that something was amiss in the system. Despite conservative use of DC powered lighting, the house batteries required frequent charging and in one instance after only a couple days' rest, one of the main engines refused to turn over.

After exploring the bilges and reading the manuals I found that the factory installation did not include a dedicated "house" bank as is now commonplace. Instead one bank of 32vdc starts the port engine and supplies the "32v Ships Service." The second 32v bank starts the second engine and originally powered some long-replaced navigational equipment. Making matters worse, on the original analogue voltage meter the difference between full charge and 50% is less than 1/8" of travel on the needle.

Although 32v systems are no longer commonly installed, there are advantages to high voltage/low amperage systems. Since changing to 12 or 24 volts would include replacing equipment and in some cases having to increase cable size, I decided a better solution would be to add an additional 32v bank for house loads and to install new digital voltage metering in the engine room.

Installing the meters is a simple task so I decided to begin there. I chose digital meters because the data is accurate and requires no interpretation. I chose Blue Seas Model 8235 which can monitor up to three banks. My final arrangement will have five banks so I chose to install two meters.

Installation was simple and straightforward. Step one was to find a good mounting location for the display panel. In our instance it made sense to install the meters in the engine room next to the selector switches and the breaker panels. In most instances the nav or helm positions might be appropriate. Make sure you chose a dry, accessible location with easy access for running wires and out of direct sunlight so the LED is easy to read.

I began by running a red 16 AWG "sensing" lead from each battery box to the meter. (One of these doubles as my power source). Each sensing wire should be continuous length with no splices. A crimp-on butt connects the sense wire a short lead on the meter. On the battery end, instead of connecting the lead to the positive post, I followed the instructions (and ABYC and C.G. rules) and inserted an inline fuse holder. Do not insert the fuse just yet.

Next I ran the negative conductor. This lead runs from the ground terminal on the meter to the negative buss. In my case I connected the grounds of both meters together and ran a single conductor to the common ground at the panel. (I had a spool of black # 16 AWG, but if you want to do a first rate job, start using yellow for your DC grounds.)

At this point I stopped to check the integrity of my crimps and connections and verified that my leads were straight and not pinched or chafed. I applied a number of plastic wire ties along the length of the conductors to ensure they are well supported and will not be subject to wear from vibration or stress. After one last check, I inserted a 1 amp fuse into each of the watertight inline fuse holders and pushed them together.

The system powered up instantly. Accurate, easy to read and easy to install, this was a DIY project with big dividends.

Peter Patterson is a Canadian Coast Guard certificated Master and an ABYC certified marine technician. He is a former Canadian Yachting Association Instructor/Evaluator and powerboat instructor. Currently he is on trickle charge while he re-invents himself.

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