Fitting a new instrument panel to a Westerly Centaur by David MacFarlane

I was confronted by every auto electrician’s nightmare in my Cetaur Chiron – An array of wires and appliances which looked as though it had been hurriedly installed or connected in the high season! “That’ll do it!”- we all know this one! Now, seven years on: “I’ll have to get around to wiring that properly…”

Being an electrical engineer (Yes, Phil (Commodore of FCC) and mechanical, and ‘Corgi registered’ (commercial and domestic) …sigh…I sometimes wish I had chosen to be a shopkeeper! However, I am not one to refuse a technical challenge, so here goes! Gosh, it really wisny (Scottish for wasn’t) as exciting as it sounds, going to the source of a wire, stringing through a new one, forever making sure one didn’t extract anything that would leave an orphan circuit. Anyway, emboldened by the work I had seen done by Phil (above mentioned) with his panel, and noting that the wood looked so good afterwards, I set about doing my own.

I purchased two rows of breakers (Figure 1), with various current ratings, then mounted two bus bars, one for the positive rail and the other for the negative. The reason for having the two rails, meant quite simply, I could connect anything. For example, I have recently installed a Yaesu FT2980- a ham radio Rig, which on transmit, can extract a heavy current (yes, I am a radio ham).

The busbars are connected to my trusty two-way switch – the one that everyone hates to wire – How do you keep them separate and charge them from the solar panel simultaneously? I don’t – I use two panels – I also use a starter battery for the engine, and a leisure battery for the electrics – They could both start the engine (Instruments off, in case of spikes), and they both charge from the engine whilst it is running, with the switch at 1 & 2. Effectively, the engine circuitry is separate from the rest except while running. The batteries are connected through the 1 & 2 switch – one being disconnected from the other in position 1 or 2 (Figure 2).

The position for the panel was opposite the battery storage side (starboard), but determined by my wind, speed and depth instruments, already mounted on the port side. We have given the forward bunks to storage, so the wiring just crosses above the port bunk, except for the heater controls and power supply which come up from below.

This seems OK as there is just the two of us, (Wife and self) and we do not know of anyone who might be mad enough to join us on a cruise, we don’t expect to have an overnight. Even if we do, the galley bunks are always available, with a bit of shifting of cruising chute, toolboxes and cockpit cushions!

The circuitry is kept simple as:

  • Each circuit is provided with a circuit breaker nearest its current rating
  • Each appliance having its own switch
  • The 4mm marine cable is suitable for the current, with calculation for diversity
  • The main switch to kill everything is the 1&2 switch off position

The 4mm marine cable is suitable for the current, with calculation for diversity

The main switch to kill everything is the 1&2 switch off position

A Technical note – having been involved in wiring huge panels, my tendency is to tidy, but RF (radio frequency waves) are involved, and can be transferred as interference through inductance (induced current). I apologise for the tech. lingo, but I hope the parenthesis clarifies that a bit. In effect, your radio, depth sounder, speed log, engine, chart plotter (in my case, my HAM radio), can all be adversely affected by annoying spikes from the engine on starting, which could destroy some of these. Hence, I have avoided the temptation to install nice parallel wiring looms, hinged bundles and as much as possible the ‘RF lines’ are segregated from ‘power lines’, (if that doesn’t make sense, please do feel free to contact me by email at fastdave@

You’ll notice two hooks which fasten the panel (Figure 3). I looked at where it opened, and cashed in on the top hook, put an eye on the window side, perfect for holding the panel open!