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Finnaly tipped over the edge...

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farmer boy says:

I have just re-read the comments on my recent photo uploads and realised that I may need help... psychological help! However unless we have an Achilles owning trickcyclist amongst us I shall stick to things nautical.

I arose this morning content in the knowledge that the Spinlock things are now secure in their new home and the windows are working fine - I tested them by descended the stairs, strolling to the starboard seaberth and and looked out of one of the windows - I could see outside quite well so I am pleased with the outcome.

I then mused that a bit of tidying up of the interior would be a welcome change. Where to begin? At the pointy end I think.... The journey to the forward state room did not take long and I was soon bent double inspecting the ghastly vinyl that adorns the cabin. I gasped a little as my back went into spasm causing a sizeable portion of vinyl to fall off the wall... mmm... didn't like it anyway...
The intense back pain was demanding a hasty retreat to the more spacious main saloon when my head popped up through the hatch and I was suddenly more comfortable but unable to see what I was doing. What was that film with the mini submarines laying mines....? I think they all got bloody medals! ... anyway back to my need for help..

Electrical wiring!!!

I know from bitter experience that putting cables in is best done before putting the finishing touches to the decor so I guess I need to put a "ring main" in the boat? The existing wiring is less than elegant and seems to be pretty much ad hoc... has anyone re-wired and have any advice?
6:16AM, 25 March 2011 PDT (permalink)

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blueachilles says:

We rewired Blue, it was one of the first jobs; everything on the boat worked, but not necessarily all at the same time. So we ripped it all out, and started again.

Not a ring main as such, but the following works for us:

We have a battery in each of the cockpit lockers, with a "Main" 1,2, both, off, switch in the port cockpit locker. From there, the +ve cable goes to a switch panel (from Force4) on the port side of the cabin, in the middle cubby hole. If we did it again, the switch panel would go above/behind the sink. We chose the port side because the cables would not interfere with the compass - not sure if this is a valid concern, or not, but I had read somewhere that current flowing could affect the compass - does this include 12v?

Anyway, the switch panel includes switches for:- Interior lights, Navigation lights, Steaming light, Log/depth, Bilge pump, FM Radio, and a Spare.

From the panel, a pos goes to the light or whatever, and then a neg comes back to a bus bar, and then one neg cable goes back to the Main switch and thence back to each battery.

The light for the compass is wired via the nav lights, so it can only come on when the nav lights are on.

The VHF radio is wired straight from the Main switch so that in emergency you don't have to fiddle about with anything extra. There is a fuse in the +ve cable.

Oh, and the switch panel has a fuse for each switch.

Hope this helps.

103 months ago (permalink)

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farmer boy says:

Thanks Rod - that sounds a lot simpler than I imagined... I assume "normal" cable is ok... just thinking about corrosion? I guess the bare ends of all wires (at the connections) need to be tinned?
I was thinking ahead to allow for any additional bits of electrical gear such as autopilots, extra reading lights, cigar lighter charging sockets etc... hence the idea of putting a biggish cable around the entire boat so I could "tap" into it as required but this buggers up any chance of fusing things individually... I may just put conduit in so I can feed extra cables if required.
103 months ago (permalink)

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G4NLA1 says:

I reworked Little Plums 12V wiring as follows...

Unlike a vessel with a requirement for a reliable engine start battery, and a deep discharge battery for domestic electicary, most of the Achilles 24s I have come across use a hand start/pull outboard.

LP has two batteries that can be switched from -

a) Battery A
b) Battery B
c) Battery A & B in parallel.

The other benefit of this approach is that I can choose which battery(ies) I want to charge from the battery charger, but my outboard charges both in parallel.

The VHF is directly connected, albeit via an inline fuse to BOTH batteries via steering diodes. It works on the principle that 'best battery wins'. There is a small loss across the diode junctions, but nothing really to worry about.

After the main selector switch +12V is supplied to a switch and fuse box ( a bit like a consumer unit ) and each of those fused circuits are fed separately with both 'live' (12V) and 'deck' (0V). The 0V cables are indeed fed back to a bus bar ... and from that bus bar back to 0V on both batteries by 4 separate conductors. Don't be tempted to use a common 0V cable across the ship ( sorry yacht )

Why ?

If that 0V cable fails ... then every lump of electrical wizardry fails beyond the fault. The extra 0V cable only costs a few quid, and if you lose one circuit due to a 0V fail, you only lose that one circuit.

There is some cabling on LP that needs replacing, but on the whole I still use RED for +12V and black for 0V.

In my experience the 'weird wiring' league is a follows -

a) Farms
b) Pubs
c) Anything that looks as though it floats.


103 months ago (permalink)

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farmer boy says:

mmmmm.... as usual there is more to this than meets the eye! I went out and bought Nigel Calders Mechanical and Electrical Manual - a bit over the top but it has thrown my simplistic plan in the bin! I never realised how complicated a DC circuit could be! I am studying it now and will no doubt get very confused before the fog begins to clear!
103 months ago (permalink)

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G4NLA1 says:


Without trying to be too technical, what you need to avoid in a yacht ( or aircraft for that matter ) is what is known as a 'single point of failure'.

Simples.. For every circuit on board .. run a +12V ( from the fuse panel ) to the 'unit' and then its companion 0V back to the 0V bus bar ( normally inside the fuse panel ) ... and then make sure that you are running at least two 0V cables back from the 0V bus back to the negative terminals on your batteries.. The -ve terminals on the two batteries being strapped together.

And that, is pretty much that...


103 months ago (permalink)

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G4NLA1 says:

Oh nearly forgot..

It is great knowing that photons can get in through your windows, but it might just be worth checking that water is denied the same opportunity.

LP is a bit scruffy at the moment.. to find out I used a hose and blasted the windows. They did leak a bit.. well quite a lot. Liberal application of gooey stuff.. and a retest. They don't any more. Not elegant, but no leaks either...
103 months ago (permalink)

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rothwell_neil says:

Agree with Gee, keep it simple, run a cable round the boat for lights on one switch, keep the nav instruments, VHF and Nav lights on separate switches. Use a fused switch panel that has a common negative busbar or make one out of choc block, and screw this next to switch panel. Emily came with the seadog 6 way switch panel and once re-wired this is excellent. Busbar and fused plus lights. Tin the ends, it takes minutes and is worth it in the long run.

Also wire up the tiller pilot from a feed direct from the battery so can use with the electrics off and so there is minimal voltage drop as they need umpff. Put a fuse in line to protect. I also fuse the battery feed to the main panel with an inline fuse and put these in the rear locker where I keep the battery.

Originally posted 103 months ago. (permalink)
rothwell_neil edited this topic 103 months ago.

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Skykomish E29 says:

Yes don't even look at the "Boat Electrical Manual" unless you want to have many sleepless nights!!!! I made the mistake of buying it and spent months worrying needlessly it is far too technical.
As the others said keep it simple. It is tempting to buy a bulk supply of wire from the shop and use it all to do the wiring (this is something that has caused me nightmares on Skykomish as ALL of the wires are red!!!!) it is better to buy a few different colours and colour code the various circuits, which will make wiring the switch panel easier.
On an Achilles there is really very little to worry about, especially if you use LEDs for the lighting. The thing that did worry me was that for a 12 volt supply you need heavier duty wire than for domestic supply as the amps rating is more critical. So DO ensure that you don't cut corners using cheap domestic wire for any serious watttage light bulbs on the boat.

This was the switch panel that we ended up with on Aeolus www.flickr.com/photos/8644331@N08/915692282/

If you follow the photo thread you will see what we started with.
These are very cheap on E bay and can transform your boat
103 months ago (permalink)

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