Why are production boats not 24v

[geem]

NMEA 2000 is CANbus with a proprietary data format.

Of course, but it is only limited to your nav electronics. You are fly by wire on your engines.,you aren't turning on nav lights with it, bilge pumps, etc. It's not running the whole boat as it is on my super yachts

 

[Baggywrinkle]

But that is the problem. My crappy Peugeot car is all canbus. There is a known fault in the bus where it runs alon the rear suspension to the wheel brake sensor. The wire corrodes. The canbus system tells you there is a faulty handbrake. It's obviously not the handbrake. Imagine this is a boat after a few years. It only takes a burst house on the engine to spray a mist of salt water everywhere. You canbus connectors corrode and you are then plagued with faults and the engine goes into limp mode. This is what happens. It happened to a guy I know. Now imagine everything in the boat is canbus. Faults everywhere. This is what happens on the custom 72ft boat my pal is Captain on. The boat is now 12 years old and it's a constant source of pain and irritation. The boat is professionally maintained by a Captain with a degree in mechanical engineering. All maintenance and fault finding is done by flying out the engineers from you build yard in France at great expense, on a regular basis. This is the reality of canbus 'flying' the boat.
On another racer cruiser that I did some deliveries on, the boat is all canbus. Fly by wire engine controls to both helm stations. It uses tiny joysticks for throttle and gear control. It is supposed to be impossible to start the engines with the throttle position in anything but tick over. Canbus controlled.
The Captsin started the engine whilst the boat was at anchor. The throttles were wide open but the inhibitor didn't function and the boat shot forward at high speed! Csn you imagine the damage if it had happened in a marina berth. The Dutch engineers flew out to Antigua to interrogate the system. It couldn't be reproduced and it hasn't yet, happened again.
Who really want these systems on their boat? Certainly not me

I'm surprised Peugeot ran a bus to a sensor that is easily accessible outside of the vehicle. That would break every security rule for the use of CAN. There is secure CAN, but it would cost way to much to embed in a simple sensor, so we never run CAN cables anywhere where they are accessible from the car exterior. Maybe Peugeot do it differently? I don't know - would be a major security flaw if they did.

To me it sounds more like a wire corrosion problem on a standard non-CAN sensor that triggers a fault code within the brake system ECU. This sounds like faulty design of the diagnostic software/check control messaging and has nothing to do with a CAN bus being used or not.

Bus topologies simply allow marine systems to exchange information using a defined message catalogue, and no modern instrument or control system would have half the functionality it does if it were not for bus communication. Of course there are provisions for private messages but both sender and receiver need to be on exactly the same page when using these - same versions of the protocols, pre-tested etc.

Modern systems provide better redundancy precisely because of bus systems, when one MFD goes t!t's up, you get the info on another. Wasn't possible when there were dedicated, hard-wired wind and tri-data displays. Radar used to be connected directly to one plotter, or worse still, a dedicated display. If the plotter or display went t!ts up, radar was lost because it was hard wired. Modern radars communicate on ethernet, through a switch and it can be used on any connected plotter, if a plotter fails there is a backup, and if the ethernet wiring fails, it can be switched to WLAN and used that way. CAN based switching - if a switch fails to turn something on, swap it out, and swap the actuator out - as they are standard you can remove one form somewhere else to see if the fault follows the device .... it is very unlikely to be the BUS that is at fault, because there is no bus failure mode that selectively disables certain messages, it's usually all or nothing if a bus fails. A bus failure is indiscriminant and messes with all functions equally, that's how you know you have a bus wiring problem.

It sounds like your friends had yacht systems that were very poorly designed, it happens. But anecdotal stories of individual cases doesn't negate the fact that every yacht has NMEA systems on board these days - and there are no charter companies ripping them out to replace them with hard-wired alternatives. Charter boats are the bellweather for marine tech, if it can't survive constant use in a rental vehicle then it is not fit for purpose - but it does.

Scaling this up, there are millions of configurations possible when designing a distributed system from multiple independent suppliers, and the devil is always in the detail. The people who specify and build these systems need to know them inside out. Not something your average skipper or mechanic is capable of, and unfortunately, not something your average system designer is necessary capable of either. As I have already stated, the most likely cause of failure in these systems isn't the bus, it's the devices on the bus. A bus in itself is robust, more so than a collection of discreet wires.

Don't shoot the messenger, all it is doing is reliably delivering messages, it's the sender and receiver that cause the problems.

 

[Neeves]

Stop blaming the customer base.

The owners wants to come on board, unlock the hatch, decide where they are going, plot a course, press a couple of buttons, engine on, main hoisted - no issues.

It does not matter to him whether its 12v or 24v. He has never heard of, nor care, about PBO.

Blame the boat builder

Lacks vision, argued against sail drives, does not offer dyneema as standard, supplies as standard a Delta anchor and oversized, but under length chain.

.....what do you expect.

Jonathan

 

[Baggywrinkle]

Stop blaming the customer base.

The owners wants to come on board, unlock the hatch, decide where they are going, plot a course, press a couple of buttons, engine on, main hoisted - no issues.

It does not matter to him whether its 12v or 24v. He has never heard of, nor care, about PBO.

Blame the boat builder

Lacks vision, argued against sail drives, does not offer dyneema as standard, supplies as standard a Delta anchor and oversized, but under length chain.

.....what do you expect.

Jonathan

... or alternatively, don't buy a Trabant expecting Mercedes features.

 

[geem]

I'm surprised Peugeot ran a bus to a sensor that is easily accessible outside of the vehicle. That would break every security rule for the use of CAN. There is secure CAN, but it would cost way to much to embed in a simple sensor, so we never run CAN cables anywhere where they are accessible from the car exterior. Maybe Peugeot do it differently? I don't know - would be a major security flaw if they did.

To me it sounds more like a wire corrosion problem on a standard non-CAN sensor that triggers a fault code within the brake system ECU. This sounds like faulty design of the diagnostic software/check control messaging and has nothing to do with a CAN bus being used or not.

Bus topologies simply allow marine systems to exchange information using a defined message catalogue, and no modern instrument or control system would have half the functionality it does if it were not for bus communication. Of course there are provisions for private messages but both sender and receiver need to be on exactly the same page when using these - same versions of the protocols, pre-tested etc.

Modern systems provide better redundancy precisely because of bus systems, when one MFD goes t!t's up, you get the info on another. Wasn't possible when there were dedicated, hard-wired wind and tri-data displays. Radar used to be connected directly to one plotter, or worse still, a dedicated display. If the plotter or display went t!ts up, radar was lost because it was hard wired. Modern radars communicate on ethernet, through a switch and it can be used on any connected plotter, if a plotter fails there is a backup, and if the ethernet wiring fails, it can be switched to WLAN and used that way. CAN based switching - if a switch fails to turn something on, swap it out, and swap the actuator out - as they are standard you can remove one form somewhere else to see if the fault follows the device .... it is very unlikely to be the BUS that is at fault, because there is no bus failure mode that selectively disables certain messages, it's usually all or nothing if a bus fails. A bus failure is indiscriminant and messes with all functions equally, that's how you know you have a bus wiring problem.

It sounds like your friends had yacht systems that were very poorly designed, it happens. But anecdotal stories of individual cases doesn't negate the fact that every yacht has NMEA systems on board these days - and there are no charter companies ripping them out to replace them with hard-wired alternatives. Charter boats are the bellweather for marine tech, if it can't survive constant use in a rental vehicle then it is not fit for purpose - but it does.

Scaling this up, there are millions of configurations possible when designing a distributed system from multiple independent suppliers, and the devil is always in the detail. The people who specify and build these systems need to know them inside out. Not something your average skipper or mechanic is capable of, and unfortunately, not something your average system designer is necessary capable of either. As I have already stated, the most likely cause of failure in these systems isn't the bus, it's the devices on the bus. A bus in itself is robust, more so than a collection of discreet wires.

Don't shoot the messenger, all it is doing is reliably delivering messages, it's the sender and receiver that cause the problems.

The sender and recievers don't work without canbus. It's the principal of everything on canbus that I am unhappy with. This is how the superyacht industry works. The designers aren't interested in hard wiring certain stuff. Once this principal filters down to the leasure yachts, as it is starting to do, then we are in trouble

 

[RunAgroundHard]

Stop blaming the customer base.



.....what do you expect.

Jonathan

An oxymoron

 

[Baggywrinkle]

The sender and recievers don't work without canbus. It's the principal of everything on canbus that I am unhappy with. This is how the superyacht industry works. The designers aren't interested in hard wiring certain stuff. Once this principal filters down to the leasure yachts, as it is starting to do, then we are in trouble

An NMEA2000 backbone is now the norm. Instruments, plotters, and sensors rely on it, the message catalogue is well defined allowing interoperability between different suppliers ... are you saying you have none of this on your boat?

A CAN bus is just a very reliable way of sending and receiving information. It's the information and the devices that cause the issues. Some are perfectly robust and function well together, some don't... the trick is knowing what is compatible with what, especially if mixing manufacturers.

The bus can be logged and traced, even written to an SD card. The traffic can be decoded into a human readable format - what's not to like?

 

[geem]

An NMEA2000 backbone is now the norm. Instruments, plotters, and sensors rely on it, the message catalogue is well defined allowing interoperability between different suppliers ... are you saying you have none of this on your boat?

A CAN bus is just a very reliable way of sending and receiving information. It's the information and the devices that cause the issues. Some are perfectly robust and function well together, some don't... the trick is knowing what is compatible with what, especially if mixing manufacturers.

The bus can be logged and traced, even written to an SD card. The traffic can be decoded into a human readable format - what's not to like?

Of course I have canbus for my electronics. But like many, we also back up with a tablet and navionics when it fails. Chart plotters crash, my ST to nmea2000 converter failed mid passage recently. Components fail. Fortunately, I knew what it was as I know my system inside out. I had a spare converter and had it replaced in about 15 mins.
Bad connections happen, systems go down, especially if you are using the boat in a tough environment.
A friend joined the owner of a large, nearly new Moody recently for a delivery trip from the UK. The whole B&G network went down. They couldn't fix it and didn't have time to wait ir they would have lost their weather window. They were mob handed with 6 guus inboard so sailed the boat all the way to the Med with just a couple of Ipads.
Extending the canbus systems to the whole boat for switching is, in my opinion, not the way to go. It's been commonplace in the superyacht world for a while, as I have explained. It's not progress. It's convenient for the builder but problematic for the owner or professional crew when it inevitably goes wrong.
Maybe we should start a new thread