Electrical Project

The advantage of the distributed power buss systems is that the total amount of wire (by leingth) is greatly reduced, as well as reducing the total amount of copper in the boat by a substantial sum. Instead of running a wire from the panel to each fixture, there is a major trunk line run down the center of the boat (or close to it), with fixtures only needing wiring to the trunk line. What this allows is a significant reduction in the size of the wire that needs to be run to each fixture in order to prevent voltage drop.

For instance in a stern fixture on a 50' boat the normal wireing path would look something like... Battery--->panel--->fixture--->panel--->battery If we assume that the distance from the battery to the panel is 10 feet of wire, and the panel is in the middle of the boat, and there is a 10' penalty for having to fish wires around things, then the total leingth of the instalation is 70' at 10amps that would require a size 12 AWG wire, in order to have a maximum of 10% voltage drop. If this were a stern light where you are only allowed 3% voltage drop the wire size would have to be size 8 AWG wire.

Now compare that to a distributed buss system, there will already be a size 4 AWG wire from the Battery to the back of the boat. Due to its large size it has almost no voltage drop over the 100 foot of its leingth (bow to stern and back), which means you only have to size the 10 amp fixture wire for the run from the trunk line to the fixture itself. Lets be conservative and say that run is 3 foot, well then we only need to use size 16 AWG wire, though we could likely get away with smaller, but the chart I have doesn't go down any smaller than that.

Now how much this will save over the course of the boat is something that is of course a case by case issue, since the specific fixtures, distance from the panel, and price of copper will be controlling. But having spent days trying to fish wire through a boat the savings in time is substantial, how much you pay for that time is up to you to figure. But the price of the panels is about the same, the price of the fuses is about the same, wire is probably a break even, but if you ever want to add a new fixture the ease of doing so is going to be a lot greater.

As I see it:

Advantages:
-Vastly easier installation process than traditional wiring
-Significantly less copper put on the boat
-Easier to trace wiring problems
-Few or no long runs other than the main trunk line, helping to reduce chaff issues, wire routing problems, and simplifying bilge layout
-Much easier to add a new circuit or fixture
-Ability to control groups of points acording to any scheme you can dream up (all lights, all interior lights, all exterior lights, ect) and the ability to quickly change the points in each group
-Wire runs from the trunk to the points can be much smaller since the distance is much less
-Losses due to wiring can be minimized cheaply and overall efficiency gains can be achieved
-Multiple control head can be placed almost anywhere on the boat with minimal wiring (just a data cable run, instead of running load bearing wires)
-Ability to data log each point to determin cycle rates, usage activity, and early warning of failure
-Ability to bypass the computer controllers in the event of a failure (though this would leave multiple circuit breakers scattered throughout the boat instead of one large panel)
-Easier and faster troubleshooting of non-functional points
-Cheaper initial installation
-Cheaper re-wiring job when it becomes necessary
-Remote/internet login and control capability, including the ability of factory technicians to remotly diagnose problems

Disadvantages:
-Must be incorperated from the ground up of a new build or a re-wiring job
-More complexed operation due to advanced features
-Concern over proper shielding
-Lack of qualified technicians who understand the system
-Lack of robust equipment designs to meet varying needs.

Most of this list is from Nigel Calder's article in Professional Boatbuilding june/july 2009. There should be followups to this article which I will be watching closely, but from what I can see now the system seems to be makeing a very good argument that this will become the new way to wire boats in the future. (this list was from a post by me http://www.boatdesign.net/Forums/archive/t-24561.html)

Note that there are other manufacturers of distributed systems, and I am not qualified to compare them. I am only looking at the concept of the system as compared to traditional wiring.


See

http://www.maloyachts.se/Blog/tabid/195/EntryID/14/Default.aspx and other articles written by Nigel Calder

http://www.capi2.com/downLoads/NewCapi2Fine.pdf

 

Oh dear, Such a bold statement, I almost believed you but you've not done your homework! I won't be harsh but isolated/insulated floating DC systems are very common and most so called experts don't know about it. It is also used in AC systems for essential equipment. With starters and alternators you have the option of isolated/insulated negative terminals or a negative case, very common in military systems as well. A little taster:

http://www.brighthub.com/engineering/marine/articles/38231.aspx

http://www.dg2k.co.uk/alternators.htm

Look at the second benefit.

http://www.sheridanhouse.com/excerpts/underboatwiringexcerpt.html

Paragraph seven. Even John Payne knows about it although he's not perfect but please don't quote anyone else as I wouldn't let them change a light bulb!

 

You can see I'm not alone in my views. This is traditional wiring but with unneccessary complicated remote control, a toy!

 

Capt,

I tried to read through your post, but to e honest I don't think you really understand what a distributed power buss system is, let alone know how to critique it.

For instance you comment that under either system there will still be long cable runs. However this is just not true, a DPB eliminates the long runs by allowing anything in the boat to tap directly off of the trunk line. So the longest line in the boat is only from the fixture to the trunk, NO ADDITIONAL wire has to be pulled through to a fuse board. Instead there is a local fuse that is controlled electronically at the point where the fixture wire hits the trunk. Once this fuse is in place it can be controlled from anywhere on the boat. The parralel to the traditional power panel for instance is really just a remote control that could just as easily be wireless as wired in.

You also suggest that tracing a problem is going to be more complexed. Nothing could possible be more false. In a DPB system if the main trunk line is operational then the fault must be either 1) the fuse block, 2) the wiring from the fixture to the fuse block, 3) the fixture itself. Now if it is the trunk, well that will be easy to diagnose since all the power on the boat will be down. So go check the fuse block, if it is fine then there is a relatively short run from the block to the fixture to check. Compare that to crawling through the bilge to chase a 12V wire wrapped in a bundle of other identical wires, through bulkheads, under the engine, passed the generator... You may think it is easier, but for my money being able to start 5' from the fixture is a huge time savings.

You also mention that the extra cost of the trunk wire will not be offset by the savings from reducing the wire leingth of the rest of the wires. Well, 100' of size 4 AWG tinned Marine Ul certified wire will run you $250 or so, So you would need to save about 250' of wire for the price in the wire to match. Considering a recent article mentioned that a 50' fishing boat had around 1 mile of wire in it I doun't think this would be very hard to do. Since it is roughly the savings from 7 fixtures on the ends of the boat.

You also suggest that these systems won't catch on since they don't work that well... I would refer you to a few places to check your facts:

1) papers published by Fred C. Lee from the Depariment of Electrical Engineering, Virginia Power Electronics Center, Virginia Polytechnic Institute & State University, Blacksburg, VA, U.S.A http://www.informaworld.com/smpp/content~content=a777593276&db=all

2) The design for the Boeing 787 electrical system that uses a DPB system

3) An article in Military and Aerospace Electronics by John Keller discussing the continuing deployment of DPB systems in aircraft, particularly commercial and military aircraft.

4) Yacht manufacturers Dutch-Bay, African Cats, Nauticat, ect

5) Article in May/June edition of Ocean Navigator by Ev Collier

6) Deployment of DPB systems in railways, and subways

7) Deployment of DPB systems in modern cars

Yup they certainly aren't going mainstream, and I didn't even mention the large yacht builders that have already switched over to exclusive distributed systems.


Finally you accuse me of being somehow benefited or trying to sell something here. Now I have been posting on this board for years. While I may have made specific recommendations of products I have used and am familure with, I do not, nor have I ever made any money, or have any commercial involvement in any of the products I have suggested (excepting my advice that if people need an attorney in the states I am willing to take the call).

 

What did you expect?
If 1 out of 100 persons is a complete idiot (believe me it is worse) and within that group 1 out of 100 has internet access, there are still over 670.000 people writing nonsense. I call that static.

You are not a complete idiot but took too many things for granted.

 

No no,

you are completely on the wrong trip here!

Bus systems are the internationally agreed standard in cars for more than 20 years now. There is nothing unreliable, complicated or expensive. Can bus was installed in over 55 million applications. (2002 figure)

We save thousands of Euros installing bus systems in each of our yachts from 52ft on.
(our smaller ones, ranging from 28 to 36ft, usually have a simpler wiring, not worth the initial cost of the bus controllers)

Regards
Richard

 

Such as? Who are you to judge? You seem to be inferring that you are and have superior knowledge and experience than others, I've not seen any evidence of that so far. You might well be the static, not a complete idiot but taking things for granted! Personally I don't have a problem with any input or static, you should take notice of static because otherwise you can miss important things and become blinkered etc.

 

Sorry don't agree, you must have very poor electricians if you save money with this, the installer doesn't have to deal with long term problems from a cheaper system. We are not talking about cars and I don't know of any twenty year old cars with this apart from the multifunction unit for wipers, interior lights etc., there is no bus system as such, they are all fully wired, name them? Electrical and ECU problems are far too common on modern cars and usually very difficult to put right, my nephew's new car for example took 6 months to put right with different problems arising each time it was supposed to be fixed!

 

Well, I skimp on a comment about my electricians.............

Can bus is STANDARD in every German car from 1985/87 onwards!!!! And in most of the competitors crap from the mid 90ies too.

Building more then 100 Motoryachts per annum, at a average size of 16 meters (ranges from 8,5 to 46 meters), I claim to have a clue where to save some cost!

Regards
Richard

 

I have three German cars with wiring manuals, there is no bus! Two motor yachts a week that's busy, yet you can still find time on the forum!

Correction we have four German cars forgot my daughters Polo SDI! My Land Rover Disco crap mid nineties doesn't have a bus either.

 

For a guy with -6 reputation you make a lot of noise!
Randy Newman wrote a song about such people.

 

It may surprise you............

I do not build them by my own hands!

And your cars HAVE a CAN bus be sure. At least the German ones.

 

You don't have to listen.

 

That is a bit of a bold statement Richard. He wrote he has 3 German cars with wiring manuals, so they must be, let's say it politely, "classic" because nobody gets or needs wiring manuals anymore.
Siemens offered the first systems in the early 80's, I think BMW used it in their 700-series.

What if he has an Opel Kadett and two beetles.....