Distributed Power Systems Suitable for Yachts?

[TradewindSailor]

In the Cruising Technology section of January's YM Nigel Calder suggested the use of Distributed Power Systems for use on yachts. I understand this to mean that instead of having one or more positive cables running to each system from the main switch panel, there are just a few small signal wires sending messages to distributed control boxes that then control the boats systems in their location.

I came across a system like this on a modern Catana. The circuit board at one of the distributed control boxes had caught fire, but luckily had just burnt out the control box. It wasn't my boat, and I don't now any more about this case.

My experience with electrical systems include:

1 that small gauge cables can cause fires if shorted with larger cables. This is particularly relevant for example when a fitter has spliced in a low power pump, say 5 amp, into a larger cable system that is fused at 15 amp. If the pump then seizes the wires will glow red hot and melt other cables in their proxmity and can and have caused fires. This would have been avoided if the pump had been appropriately fused at the point of the splice ...... but it has been my experience that this is hardly ever the case.

2 that micro plugs and sockets used in equipment like this are vulnerable to water damage and need to be sealed properly. I had a Adler Barber? refridgeration system with a telephone type plug to connect the control panel to the main unit - a drop of seawater found it's way across the positive and negative pins resulting in 4 hrs of fault finding and repairs.

3 that all systems on the yacht must be repairable by the owner. In the case of the Catana problem above, the systems operate by the control box were out of operation until a replacement board was obtained from Catana. How is one to deal with this in the middle of nowhere?

4 that printed circuit boards need to be marinised .... covered in silicon rubber, or encapsulated in epoxy, etc. If this is done it becomes difficult to track a fault without having replacement parts at hand.

I would like to hear from other people who have had experience of these types of systems ..... and indeed from Nigel Calder ....

 

[Ubergeekian]

In the Cruising Technology section of January's YM Nigel Calder suggested the use of Distributed Power Systems for use on yachts.

It is, in my humble opinion, a crazy idea. Replacing simple technology of switches and wires with a hugely more complicated system of electronics is just asking for trouble. Car makers are beginning to go for these things because the wiring density in a modern luxury car is incredible, but they are still notoriously unreliable and difficult to repair.

 

[lw395]

In the Cruising Technology section of January's YM Nigel Calder suggested the use of Distributed Power Systems for use on yachts. ...

I suppose there's only so many sensbile things that can be said about 12V, and NC has previously said most of them.

This is the kind of technology that lands you with a £500 bill to make your Range Rover brake light turn off, to quote one real example!

 

[nimbusgb]

I suppose there's only so many sensbile things that can be said about 12V,

Agreed

and NC has previously said most of them.

If NC thinks microprocessor controlled electrics aboard the average production AWB is a good idea then I think he may have been inhaling the toner of the laser printer printing his manuscripts for too long.

I'm with TradewindSailor all the way here.


Once devices come integrated with their own controller ( ie an LED tail lamp has an integrated chip with either a flash programmable address or a fixed device address ) we may be getting close to the time when this may be a good idea but until then its just plain nuts. Even then the average single bulb installation ( ie a side navigation light) must have at least 3 wires to it rather than the current 2! ( Negative, positive and control signal. ) those same 3 wires now need to run to the other single light installations around the vessel.

Other devices still need all the rest of their wiring. Radios, Chartplotter, instruments etc still need some isolated power feed. Nothing is gained on devices such as these by using an 'intelligent' distributed power system.

Don't get me wrong, if this comes about no doubt I could make a nice 'live aboard' living installing, repairing and tweaking people installations. I have all the experience, tools and knowledge to do so. I could in fact knock up and program a couple of 'distributed' signal controllers 'on a galley worktop'.

I suspect however that I could make an even better living converting peoples shiny new AWB distributed power systems back to traditional two wire regular 12v systems, at least for long enough to see me through any liveaboard time I might have

Its almosts as nuts as fitting electric drives to a cruising yacht. The technology is just way too expensive, too hard to fix 'on the galley worktop' and too 'bespoke' to each installation to be at all practical. Storing energy in the form of diesel ( or even LPG or similar gas ) is just far far too convenient for use on a boat. The fuel in my diesel tank goes from season to season without 'maintainence'. Going electric is going to result in having to book your boat into a workshop for services every year.

 

[halcyon]

I would like to hear from other people who have had experience of these types of systems ..... and indeed from Nigel Calder ....

I've been looking into designing fly-by-wire systems since 1995, mainly power cruiser side, but still do not like it. Basically it's trying to fit a new ( in ) technology to a boat, not use the best system for a boat.

One power cruiser builder has fitted it to some boats, if the micro goes down, every system on the boat is dead. The engineer then has to go out with laptop to program the system, not good if you are mid Atlantic.

Can it be done, yes, it's complicated, but on big yachts it could work, but not as most are trying.

Is it the future, I do not think so, found a new type circuit breaker, and I think I can do the same type of system, but without the micro. So it does not have connection problems, will operate under water, and fit even small yachts.

The world moves on, the micro system may even now be obsolete in small craft.

Brian

 

[Ubergeekian]

Other devices still need all the rest of their wiring. Radios, Chartplotter, instruments etc still need some isolated power feed. Nothing is gained on devices such as these by using an 'intelligent' distributed power system.

That's an excellent point. Distributed power systems are only a sensible idea when you have a large number of devices which need to be controlled from a distance. On yachts that's the masthead and navigation lights and, erm, that's it. Everything else has a switch on, beside or near it.

 

[exfinnsailor]

Fly by wire sounds good ..

With a bit of FUZZY Logic ..

You move the wheel to PORT and the brain on board thinks .. He's turned the wheel to PORT .. Did he really want to do that .. Lets wait and see what he does next .. Hmmm .. He's turned the wheel more to PORT .. Still not sure .. Does he REALLY want to turn to PORT .. Hmmm .. He's moving it back ..

See I was right he wanted to turn to STARBOARD .. Quick kick the rudder right over he may change his mind again ..

Keep it Simple ..

You turn the wheel the rudder moves ..

On the other hand .. If you feel you want to experiment with a fly by wire system I would be more than happy to program one of my little PIC Micro Chips to do the steering for you ..

 

[Ex-SolentBoy]

Sorry guys, got to chip in here as I have one of these distributed power systems that from reading above it seems that no-one likes. I thought I would write as there is another side to the story.

I think it is important to distinguish between simply distributing the 12v power supplies, which is the base technology, and adding other complex electrical items, such as energy storing devices for propulsion. One of the posters above seems to have these confused.

The base distributed system on our boat works really well. I like it for several reasons, but the most important one is flexibility. If I want to add a new electrical device, such as a light, a chartplotter, AIS, 12v socket for my phone or anything, all that I need to do is run 2 small wires to a node, which is never more than a few feet away. In the case of a light I do not even need to add a switch - I can simply plug in my laptop and tell one of the existing switches to operate the light. I have a switch next to my bunk that can turn off all the lights on the boat when I go to bed, or turn them and the deck lights on if I hear a strange noise in the night. I added that function after the whole boat was wired without any additional wiring - try doing that with a conventional system.

Oh, and we also have a remote control so we can turn the deck lights on when we row back to the boat, and an access panel so we can operate key systems such as fridge remotely from a mobile phone (turn it on so it is cold when you get to the boat with all the fridge stuff).

The list goes on. Some of it is frivolous I know, but it is not expensive to install and is no harder, in my opinion to maintain than a traditional system if the boat is big enough. I accept that for smaller boats maybe it is not worth the cost effort.

So, not everyone likes electric and electronic stuff on boats, but some people do, and that number is increasing.

Try it, you might like it. It wasn't that long ago that many sailors raised their noses at the thought of any sort of electronic navigation aid. Times change - there is now a school of opinion that considers sailing offshore without such aids to be irresponsible. Who would have thought?

 

[TradewindSailor]

......The base distributed system on our boat works really well. I like it for several reasons, but the most important one is flexibility. If I want to add a new electrical device, such as a light, a chartplotter, AIS, 12v socket for my phone or anything, all that I need to do is run 2 small wires to a node, which is never more than a few feet away. In the case of a light I do not even need to add a switch - I can simply plug in my laptop and tell one of the existing switches to operate the light. I have a switch next to my bunk that can turn off all the lights on the boat when I go to bed, or turn them and the deck lights on if I hear a strange noise in the night. I added that function after the whole boat was wired without any additional wiring - try doing that with a conventional system ......

Not quite ..... where do you get the power from? If the added item needs 5 amps or more you still need to supply it with appropriate sized cables and from a source that can provide it .... no difference here surely? Sure if you're adding an LED you won't need to ..... but then all I'd have to do on a conventional 12V circuit it to tap into the lighting or services circuit that runs all over the boat anyway.

 

[Ex-SolentBoy]

Not quite ..... where do you get the power from? If the added item needs 5 amps or more you still need to supply it with appropriate sized cables and from a source that can provide it .... no difference here surely? Sure if you're adding an LED you won't need to ..... but then all I'd have to do on a conventional 12V circuit it to tap into the lighting or services circuit that runs all over the boat anyway.

For full technical details on how this works, you could refer to www.empirbus.com

 

[Coaster]

Not quite ..... where do you get the power from? If the added item needs 5 amps or more you still need to supply it with appropriate sized cables and from a source that can provide it .... no difference here surely? Sure if you're adding an LED you won't need to ..... but then all I'd have to do on a conventional 12V circuit it to tap into the lighting or services circuit that runs all over the boat anyway.

I thought that ample provision of current was the principal advantage of such systems? As I understand it there are large section cables routed through the boat, short spurs to each appliance, relay switches and a complicated electronic control system to operate the switches. Presumably there is very small section wiring in the control system, much like the cabling used to network computers?

 

[Ubergeekian]

The base distributed system on our boat works really well. I like it for several reasons, but the most important one is flexibility. If I want to add a new electrical device, such as a light, a chartplotter, AIS, 12v socket for my phone or anything, all that I need to do is run 2 small wires to a node, which is never more than a few feet away.

All I have to do is run two wires to a suitable supply, which is never far away (mainly I grant you, because the boat is only 26 feet long). I have the great advantage of having different circuit breakers for different purposes, so if my masthead light were to short circuit I wouldn't lose the GPS as well.

Try it, you might like it. It wasn't that long ago that many sailors raised their noses at the thought of any sort of electronic navigation aid. Times change - there is now a school of opinion that considers sailing offshore without such aids to be irresponsible. Who would have thought?

I just can't see what benefits I would get for complexity. I can rearrange my electrical system with a small screwdriver: you need a laptop ...

 

[Ex-SolentBoy]

All I have to do is run two wires to a suitable supply, which is never far away (mainly I grant you, because the boat is only 26 feet long). I have the great advantage of having different circuit breakers for different purposes, so if my masthead light were to short circuit I wouldn't lose the GPS as well.



I just can't see what benefits I would get for complexity. I can rearrange my electrical system with a small screwdriver: you need a laptop ...

I understand, but it is 100ft from my masthead to my batteries!

 

[TradewindSailor]

Okay, now I understand a little more about the system.

Is there some type of intelligent fuse/circuit-breaker in the distribution unit?

I can see that in an ideal world that these units offer lots of benefits ...... but I believe that in the real marine world, for any sailing yacht that cannot carry a complete replacement system, it is a non-starter on reliability grounds. I also don't like the reliance on a particular manufacturer for the parts. Even if I did have a complete replacement system, I would be very wary of placing critical systems into such a unit. I don't even pass my bilge pumps through the switchboard because I believe in keeping the pumps on a direct line, through fuses, to the batteries.

Traditional boat electrical wiring is low tech and can be replaced or repaired anywhere in the world. Circuitboards are bespoke and extremely vulnerable to moisture damage, whether being used or in storage. Also the parts are likely to be become out-dated within a few years. Just look at chart plotters and other nav-gear. Yachts are not like cars, they not scrapped after ten years.

Traditional boat electrical wiring can also be distributed ..... by placing breakers and switches in zones where the instruments are located, leaving the main switch board to control the zones.

What about reliability? As I stated in my first post, I know of one incidence here in Mexico of an electrical fire in a distribution unit. What experiences have people had with these systems ...... good or bad?

 

[Ubergeekian]

I understand, but it is 100ft from my masthead to my batteries!

Helluva long way up to sort out a dodgy connection or replace a chip.

 

[Bobobolinsky]

A friend is building these systems and I have to say I was very impressed. When he fitted the first sytem to his own yacht, he removed bucket loads of redundant wiring. The controls are run from a touch screen LCD and very simple to work. It is almost impossible to have any failures in the main loom and faults are easy to locate and bulb failure systems are simple to add