Boat electrics

[extravert]

It's the same in the nuclear industry. No soldered joints, just crimped. They are less likely to fail because of vibration induced fatigue than soldered joints is the nuclear industry's reason. This must be particularly important on boat engine electrics.

Paying the £30 for the proper crimp tool is money well spent rather than the nasty £5 ones.

 

[ccscott49]

Now will you believe me?

 

[tome]

I work in the offshore (seismic survey) industry and we avoid soldered joints like the plague. The only exceptions are military connectors (gold plated) with solder buckets which are then hermetically back-sealed with glue and heatshrink sleeving.

We fit navigation equipment to boats, air-boats, hovercraft, RIBS, marsh buggies etc etc and some of the equipment is directly exposed to salt spray. Failure can cost us many times the replacement value of the equipment.

Best advice is to use tinned copper wire and a decent ratchet crimp tool (the ones we issue cost 80 quid, but you can get them from about £30) - avoid the cheap ones which don't give a decent crimp. If you really want long term reliability, you can get the crimp terminals with glue filled heatshrink sleeves which are heated after crimping to flow the glue and seal the joint.

If you use bare copper wire it's ok until you want to make a repair, and you'll find that the copper has black oxidised right along its length - no matter how far you strip the insulation.

Calculate the voltage drop (function of length and cross-section of cable) and make sure that you use adequately beefy cable. Any boat electrics book will give you this info.

Finally, do yourself a great favour as advised by others and draw a circuit diagram and label both ends of every cable.

 

[Guest]

I would just like to say that as a complete electrics novice who has just spent the last 3 days trying to sort out the aging electrics on his 28 foot yacht this is one of the most informative discussions I have yet read on this forum.Thankyou to all who contributed.

Keltman

 

[jollyjacktar]

I stand corrected

Next time I rewire my full submersable, permanently awash, nuclear powered, hovercraft, seismic, drilling rig, I will only use gold plated bus bars, fully crimped with those expensive crimping pliers, and run all the wiring externally so that I can prove that all the best stuff works proper like.

Now let me see if I can hook up a bicycle dynamo.

All jesting aside, keep things simple, after all it is only a yacht, not many electrical things are needed or advisable, unless you have another auxiliary power source. You only need your navigation lights and a few carefully located interior lights plus the electrical circuit for your engine.

Consider the use of high intensity LED diodes as lighting, they will last for ever and use practically no electricity and repay themselves in no time. Bright lights are not really needed and a good waterproof torch or two are well worth having aboard. However if you intend to have a deep freeze/refrigerator, microwave, TV, stereo CDs, computers, dehumidifiers, electric blankets, radar, fish finders, sonar, fans, power capstains, power washes and showers, laundry and drier, dish washing machine, presurizes hot water system, power this, power that etc, you may need some expert help. Then a better alternative is to buy a nice little seaside cottage or stay in a hotel and keep ashore.

Have fun.

 

[jollyjacktar]

P.S.

I must remember to gold crimp the next electronic circuit that I build, it will be guarenteed not to fail.

 

[Guest]

This may be old hat by now, but some of you in this string of posts have been struggling to find multi-strand tinned marine wire in the UK. I've come across a couple of suppliers:

Index Marine (www.indexmarine.co.uk) offer a range of two-, three- and four-core wire, but it's not cheap -- £1.92 per metre for 13amp stuff.

PCS Boatbits (www.pcsboatbits.co.uk) do single-core Ancor wire from the US in various amperages & colours. A 35ft roll of 17 amp is £5.57. Although you can get the same stuff from the States for around $6, it hardly seems worth the hassle unless you're buying lots.

Hope this helps. Have a good winter.

 

[SteveA]

I find it interesting that the only form of connection recommended is crimping - in critical areas spiral connection is often used, not common in the leisure industry but very effective.

 

[webcraft]

What a lot of fuss . . .

What's wrong with twisting the wires together and using a bit of insulating tape? I've seen it on lots of boats . . . . this way you can use up all those randomly coloured short lengths of wire as well.

Electrics are fun and endlessly challenging. This year alone (on other peoples' boats) I've enjoyed complete electric failure entering a narrow fjord entrance at night after a difficult 22 hour passage; a constant low-grade panic about finding a shorepower socket or battery charger during a two week passage from Suffolk to Cumbria; starting the engine with a pair of pliers on a trip across the North Sea; shortening the battery earth cable ina seaway to replace a shrivelled alternator cable; hours up the mast with a roll of insulating tape . . . and more no doubt that I have had chemically removed from my memory in the pub post voyage

When I get my new (old) boat rewiring will be a top priority, and if I don't do it all myself then I will be there and I WILL understand it all and have a real wiring diagram. I will use the best materials I can afford, because I go sailing to get away from aggravation. I will not have lots of fancy electric gadgets, but all the lights will come on when I need them, the engine will start and there will always be power for the radio and the GPS. Then you can concentrate on the sailing.

Sound to me like crimped connections are the best - I always believe the boys on the rigs, having been a N.S. Tigger myself - but I have only used a £5.00 (including 1,000 connectors) crimping tool in the past, which is definitely not worth the money.



- Nick

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