EIM Can Bus Advantages/Disadvantages

[argus1]

I asked this question before, but now I am really curious. What is the advantages of Can Bus system (EIM) over discrete switches? From my reading, I understand Can Bus saves money on installation because various electrical and electronic systems use the same wiring backbone, share information and can communicate with each other. For example, the NMEA 2000 system is a type of Can Bus system that the marine industry standardized. However, on the Sea Ray the actual wiring to the devices from the EIM Box is discrete (each device has a separate wire) from the 40 pin connector out to the boat, so that is not an advantage. And, there is no communication between the devices controlled by the EIM. The only advantage of the EIM Can Bus, that I can determine, is the ability to have a fancy custom switch keypad on the dash of the boat.

As for the disadvantages of the EIM Can Bus is that it is sensitive to electrical overload, current surges, under current, electrical spikes, stray current and near lightning strikes; malfunctions are difficult to diagnose and the system cannot be repaired. On a boat, the fact that you cannot repair critical safety equipment like navigation lights, that seems extremely stupid. It is not like a car, where you can pull over to side of the road if your driving lights fail. In a boat, at night, in a busy harbor or out on the high seas, if you have a failure with your lights and can not repair them, that could lead to a real disaster.

 

[Carpediem44DB]

I asked this question before, but now I am really curious. What is the advantages of Can Bus system (EIM) over discrete switches? From my reading, I understand Can Bus saves money on installation because various electrical and electronic systems use the same wiring backbone, share information and can communicate with each other. For example, the NMEA 2000 system is a type of Can Bus system that the marine industry standardized. However, on the Sea Ray the actual wiring to the devices from the EIM Box is discrete (each device has a separate wire) from the 40 pin connector out to the boat, so that is not an advantage. And, there is no communication between the devices controlled by the EIM. The only advantage of the EIM Can Bus, that I can determine, is the ability to have a fancy custom switch keypad on the dash of the boat.

As for the disadvantages of the EIM Can Bus is that it is sensitive to electrical overload, current surges, under current, electrical spikes, stray current and near lightning strikes; malfunctions are difficult to diagnose and the system cannot be repaired. On a boat, the fact that you cannot repair critical safety equipment like navigation lights, that seems extremely stupid. It is not like a car, where you can pull over to side of the road if your driving lights fail. In a boat, at night, in a busy harbor or out on the high seas, if you have a failure with your lights and can not repair them, that could lead to a real disaster.

I have just started retrofitting my boat's systems using a Raymarine STNG backbone. I don't see ever replacing every single circuit but I can see one advantage is the way the hardware is constructed is quite robust and water proof. It is also quite compact so one simply runs a single cable instead of multiple conductors. I do see the disadvantage of the whole boat having what amounts to a single point failure exposure with every thing operated on a CAN Bus system. At the end of the day it comes down to preference. I for one, never wanted to convert my plane to a glass cockpit, I prefer steam gauges and redundant avionics myself as opposed to relying on a 10 amp fuse keeping my vital information displayed. Over all the modern technologies are so reliable it really is just a matter of 'what ever floats your boat'!
Carpe Diem

 

[argus1]

I have just started retrofitting my boat's systems using a Raymarine STNG backbone. I don't see ever replacing every single circuit but I can see one advantage is the way the hardware is constructed is quite robust and water proof. It is also quite compact so one simply runs a single cable instead of multiple conductors. I do see the disadvantage of the whole boat having what amounts to a single point failure exposure with every thing operated on a CAN Bus system. At the end of the day it comes down to preference. I for one, never wanted to convert my plane to a glass cockpit, I prefer steam gauges and redundant avionics myself as opposed to relying on a 10 amp fuse keeping my vital information displayed. Over all the modern technologies are so reliable it really is just a matter of 'what ever floats your boat'!
Carpe Diem

I do understand a little about airplanes and avionics system where redundancy is a requirement for critical systems. Even end the seamanship courses that I have taken, it has been shared that safe skippers will have backups in case of failures, like carrying a spare handheld radio, know how to navigate using a paper chart and compass, extra fuses, extra batteries for devices, etc. However, if the EIM fails there is no way get lights back working, opening the engine hatch, dropping the anchor and more. The EIM controls many of the safety devices on the boat and there is no way to repair a malfunctioning EIM. As far as reliable; so many us on this forum has had EIM failures the general consensus that is also shared by MarineMax service departments, that the original Sea Ray EIM was a bad design from the start. Now the that original EIM is no longer in production and the replacement systems are north of $4000; the question is are there any advantages in going with a replacement EIM (Can Bus) System for $6000 or discrete switch system for $4,000?

 

[hughespat57]

On your other thread I tried to stay technical. I avoid academic discussion for the most part. And this is academic in that we are unlikely to sway the manufacturers (in this case Sea Ray) one way or the other. Even if the "system" were a standards based bus like NMEA 2000, SNTG or industry standard automotive. I would never have it control my primary operational systems. Entertainment systems no problem, elaborate cabin lighting ok, insert your favorite toy here...
"Glass cockpit" fish sonar, navigation, engine monitoring, boat monitoring; all cool stuff and fine.
My VHF has a dedicated simple GPS and I have a good magnetic compass, I can get by in a pinch.

Nav lights, bilge pumps, blowers, engine controls, shift control, steering, winches; no way in hell.

The original "fly by wire" aircraft the F-16 Falcon had numerous A model catastrophic failures of the control systems.
I've already read of several newer "fly by wire" boats that are in lawsuits over out of control accidents.
Yes mechanical cables can break, shift levers fall off, steering gears jam but usually after many many years of poor or no maintenance.
And every year the Sea Ray EIM problems grows.

When Ford, GM, Chrysler manufacture a model they produce 50 to 100 THOUSAND units per year. And today when they break you can sit on the side of the road and play on your cell phone until you get towed to the shop. If an auto manufacturer can save $5 per unit they damn well will cut corners.
Sea Ray only produces several thousand boats of all model per year. There is just no comparison. What works in a car does not mean it will work well in a boat. The average car lasts 10 years, the average boat 20 years and larger ones 40 years.
Auto parts availability most often is affected by the Magnuson-Moss Warranty Act
https://en.wikipedia.org/wiki/Magnuson–Moss_Warranty_Act
which states parts must be available for a product during its warranty period. For autos this has been generally accepted as 10 years, not that most warranties are that long but due to the average life expectancy. Patents expire after 17 years. So if an auto manufacturer stops making a part after 10 years or after 17 years any manufacturer is allowed to copy, manufacture and sell any part they like. Thus the aftermarket replacement parts industry was born. But again there is just not the volume of parts sales in boats to interest a manufacturer to build replacement Sea Ray compatible EIMs.

Finally Sea Ray could have used a simpler tried and true auto innovation, relays. Most heavy loads in cars today are controlled by CAN switches, an ECM going thru a nice heavy Bosch style relay ($7). They could have used standard marine breakers, low current mini switches, light gauge control wiring and Bosch relay panels. And it would have saved them much more money per unit.

The only thing I could ever come up with for why they chose EIM is either the engineers came from the auto industry and thought it was a fine idea. And Sea Ray engineers are mostly Industrial engineers not Naval engineers.
Or the marketing people thought little button and LEDs and touch panels have a cool factor for sales.

 

[argus1]

Again I appreciate your response. I fairly new to boating so I am learning a lot. When I really doved into what the EIM really was doing; I was amazed that this is want ended up on a boat. Coupled with the fact the Sea Ray is sourcing the part from outside vendors who at anyway time may decide to get out of the boat parts supplier business, it becomes a little scary. The original EIM, when it was in production, replacement units costed at its max $400. Now the new Sea Ray EIMs are $6,000 the system (Front and AFT EIMS and both dash switch pads). What got me questioning the utility of the EIM system, is that Flounder Pounder has been able to replace both EIMs with fuse boxes that plugs into the Sea Ray 40 pin connector that is in between the EIMs and the boat's electrical devices. This is simplicity of the Flounder Pounder's fuse box that replaced the AFT EIM. I count 5 fuses. If this fails, I with no real mechanical training, can fix it.

 

[pyro]

My opinion:

Advantages of EIM:
- 4 small communication wires to run between remote power unit and the switches
- Reduces length of current carrying wiring
- Bidirectional control meaning, it can turn LED status indicators on
- Customizable to multiple configurations
- Assuming MOSFETs are used instead of relays:
- Flash proof. No spark from relays.
- MOSFETs provide higher reliability than mechanical relays

- Actually cheaper to manufacture. Everything can be mounted on one PCB and easily mass-produced
- Smaller volume. MOSFETs are tiny compared to relays

Disadvantages of EIM:
- Higher development cost due to microcontroller firmware
- More complex design
- Higher risk of end of life components if manufacturing for long periods of time. What do you do when the main microcontroller goes end of life?
- Low volume results in higher cost, especially for service

I don't believe the EIM itself leads to worse reliability. As mentioned your car relies on it everyday. They can be designed to withstand environmental conditions, surges, etc. I think the increased complexity leads to a higher risk they are they are not designed properly and can result in higher likelihood of failures. It sounds like the company SeaRay used unfortunately did not design a robust product.​

 

[Bt Doctur]

hard wired systems never failed like EIM`s

 

[hughespat57]

Argus1 knows from previous thread but just for background, I'm 62, former USCG MK1 (machinery tech), ASE Master Heavy Truck technician, ASE Auto technician and currently Senior Computer Systems Engineer & Infrastructure Architect for company with a three letter acronym. I design for high availability every day, based primarily on redundancy because we know all equipment will fail at some point. And all people make mistakes at some point.

Of course even analog systems fail, people tend to be overly optimistic (including manufacturers), everything fails eventually if its in service long enough.

Analog systems are just usually easier to diagnose and repair with common tools and basic electrical knowledge. A 12 volt test light as opposed to a CAN bus analyzer, oscilloscope and a logic probe. And of course even if we track the digital system down to a module or component failure is it still available and can we fix it (at a reasonable cost).

As I said mostly academic as we just have deal with what the manufacturer left us with. And the fact that Sea Ray introduced a $6000 digital replacement system, they obviously have not re-thought the practicality of this solution in the marine world.

And Pyro's points are all valid, there is no right or wrong for an EIM concept. The question is "is it practical" in the marine world given the low volume. I doubt it will ever be. And even that is relative, I can't afford a new 2020 Sea Ray Sundancer, if one can than $6k to fix the EIM in 10 years may be fine with that owner.

Again cars have high volume and lower risk. No huge deal to break down on a road right? But even in cars as computers get into primary control vs engine emissions look at unintended acceleration, unintended breaking, auto lane change avoidance, etc. these problems are already leading to major recalls in some models. The argument that the computer can save lives and prevent accidents better than a (careless) driver. But now you are depending on the reliability of the manufacturers and the diligence of the programmers. I drive a 2001 Dodge Ram 2500 with 289,000 miles and one engine computer which has failed, and one injection pump controller which has failed. Not bad given the mileage and age but that was towed twice. How long will a 2020 car be able to be kept running? Will it be unrepairable or to costly after 10 years?
Another real world example of the EIM concept taken to extremes and going badly wrong.
Boeing 727 Max, when the computer (programmers) "always" knows better than the pilots. Should have had a big red button on the console that says "My aircraft".

It's all academic as we have little control over this except what we choose to buy...

 

[argus1]

Again, I think that the Sea Ray EIM was not the best solution for what is does on the boat. The implementation on the Sea Ray did not take full advantage of what a CAN Bus offers. Although there are only 4 wires from each switch pad on the dash to the EIM, the Sea Ray EIM still connected the down stream devices by discrete wires to each device. But there was never any communication that I am aware of between the EIM and devices. The biggest advantage is that Sea Ray boats are very low volume enterprise. Sea Ray produces about 2,000 boats per year compared to General Motors for example who produces 10 million vehicles per year. GM has the R&D budget and is legally mandated to verify automobile parts will not have a safety failure once in operation. Boat manufacturers do have the same level of legal compliance rules to follow. Sea Ray is getting its parts from small boutique suppliers who may be adapting components from other types of vehicles to be placed on boats. Follow that path of the EIM supplier to see what I mean. There is no guarantee that new Sea Ray suppler of the $6,000 EIM will in operation long enough to be able to honor the 5-year warranty. In in short, in my humble opinion, the EIM is way too complicated for what it does.

 

[Henry Boyd]

As Patrick pointed out, Sea Ray engineers tend to be focused on an industrial engineering point of view. From that perspective there is a lot to like about the EIM. Basic dashboard rigging is reduced to a very short time. Assembly and wiring of a dozen relays and circuits is potentially automated. The real shortcoming is not an inherent design flaw, it is a business failure.

Sea Ray and its EIM supplier no longer support the product. Don't forget this technology has been in place for twenty years or more. We gladly accept navigation hardware that wears out, or becomes, obsolete after ten years, or a cell phone that is dead after three. Why? Because a replacement is readily available.

Before I retired I was a marine engineer. Modular electronic devices like PLCs (programmable logic controllers) have literally revolutionized the control systems of marine crane and cargo handling machines making the automated container port a reality. The EIM is a tremendous concept. Sure you can have easy to fix relays, that oh by the way are circuit points of failure waiting to happen. That's the reason why the land rover and its Japanese clone, the land cruiser, are the darlings of the third world.

In a perverse way Sea Ray's quest to build the most reliable and best boat has kind of back fired. They made the boats too good. The boats have lasted longer than they care to support. So now we have boats that have ridiculous costs to fix because parts are simply not available. I mean $6000 to $ 10,000 to rewire a helm because of a failure of an unavailable item that was originally a $400-$500 part? And then they wonder why no one wants to drop $500K -$700K on a new boat?

 

[hughespat57]

a recent update, multi million dollar super yacht fly by wire computer failure, had no control except the bow thruster.

 

[Ed H]

I need a starboard side touch pad to my 2006 340DA part number 1810626. Any ideas?

 

[Christopher Carter]

I need the same thing... can’t find anywhere. Everything I’m finding online points to changing out entire system. FP marine has the setup for $3,700 I’m ordering on Monday. Good Luck with yours as well.