Cummins Marine Diesel Repower Specialists Forums Cummins Marine Engines QSB Man Overboard Killswitch Wiring

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    Topic
  • #56493

    Robert Vetrano
    Participant
    Vessel Name: Knot Flying
    Engines: qsb 5.9
    Location: Merritt Island FL
    Country: USA

    Hi, I bought a Fell Marine MOB+ wireless man overboard system for my Meridian w twin QSBs. The goal is to kill the motors if I go in the drink, and have an alarm go off if the Admiral or the dogs go in. The system seems to be built for outboard boats primarily……but I gotta think it can be wired in to my existing start stop switches. I’ve been in touch w Fell tech support but am not getting all the answers I need. I’ve seen the kill switch photos on sbmar regarding the purple wire. Unable to get under my helm till tmrw…..is this wire coming off the start/stop switch? And would I just wire this unit in?

    While there are a few diagrams in the install manual; this picture seems to pertain to what needs to be done on a QSB. Looking for some guidance.

    This is an email from them w some more detail on the system……

    “If your system does not take harm in that you continue to hold down the buttons for stop then the MOB+ could be installed on the circuit.
    The thing is that when the FOB is not connected to the HUB, the relays will stay in the closed position. Then when a FOB connects the relay opens and if you fall overboard it will close to stop the engines.

    Also the current of the stop circuit should be measured as the MOB+ should not be exposed to more than 5A of continous current.”

    2 users thanked author for this post.
Viewing 17 replies - 1 through 17 (of 17 total)
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  • #157350

    SardDiesel
    Participant

    Still working and your opinion?

    I found this tread regarding the same question I have so I pull it up again.

    I bought the Fell Marine MOB+ for my actual 30ft single engine RIB for the same reason OP Robert wrote, but in my case as I boat often alone and I guess its a uncomfortable situation falling over word and see the boat leaving.

    Any else who managed to install the Fell Marine MOB+ (or any other similar wireless kill switch as the ACR Olas Guardian)?<br />If so, how does it work, reliability, problems, etc?

    Thanks for your time and personal first-hand review!<br /><br />Greez from Sardinia

    Chris

    #59093

    Philip
    Participant
    Vessel Name: 2007 35’ Cabo ‘FUGA’
    Engines: Cummins QSC8.3-540’s
    Location: Long Beach, CA

    Good job!

    1 user thanked author for this post.
    #59090

    Robert Vetrano
    Participant
    Vessel Name: Knot Flying
    Engines: qsb 5.9
    Location: Merritt Island FL
    Country: USA

    Thanks for the help everyone. I got the MOB+ system wired up and installed today. I found the right relay on amazon for $10. The system seems to work great! It has 4 fobs. The 1st fob that connects is the STOP fob which I will wear; and the subsequent 3 connections are ALARM fobs for the wife and dogs.
    The relay stops both engines when my fob is dunked in the water, and allows each engine to be shut off indiviually under normal circumstances.

    Thanks again.

    #57209

    Robert Vetrano
    Participant
    Vessel Name: Knot Flying
    Engines: qsb 5.9
    Location: Merritt Island FL
    Country: USA

    Why would you have to re-engineer the system…surely you are not the first twin engine user. Did you buy a single engine version and the twin engine version comes with a different control unit? I am not at all familiar with the product but just speaking as to what makes sense..

    Any way to furnish a simple wiring schematic of the MOB system? It really should be very straight forward to wire this thing up… SIMPLE is better.

    Yes, I included one in my original post. They have some others for Merc and Yamaha OBs……but the one I screen shotted seems to be the most applicable.

    #57171

    Corey Schmidt
    Forum Moderator
    Vessel Name: Rebel Belle
    Engines: Cummins
    Location: Oxnard, CA
    Country: USA

    Why would you have to re-engineer the system…surely you are not the first twin engine user. Did you buy a single engine version and the twin engine version comes with a different control unit? I am not at all familiar with the product but just speaking as to what makes sense..

    Any way to furnish a simple wiring schematic of the MOB system? It really should be very straight forward to wire this thing up… SIMPLE is better.

    #57158

    Robert Vetrano
    Participant
    Vessel Name: Knot Flying
    Engines: qsb 5.9
    Location: Merritt Island FL
    Country: USA

    Rob, good question for sure. They do sell a multi engine harness that I assume does what I need it to do. But in my emails to them they say that’s only for outboard motors and for my scenario I need to rig it up the way I mentioned. All of their website and literature is geared to the center console outboard crowd.

    #57146

    Rob Schepis
    Forum Moderator
    Vessel Name: Tenacious
    Engines: 6BTA 5.9 330's - "Seaboard Style"
    Location: Long Island, NY
    Country: USA

    Why would you have to re-engineer the system…surely you are not the first twin engine user. Did you buy a single engine version and the twin engine version comes with a different control unit? I am not at all familiar with the product but just speaking as to what makes sense..

    1 user thanked author for this post.
    #57133

    Robert Vetrano
    Participant
    Vessel Name: Knot Flying
    Engines: qsb 5.9
    Location: Merritt Island FL
    Country: USA

    So I asked my neighbor for some advice…..he was a submarine commander and electrical engineer in the Navy……so he hooked me up. Seems the way to do this is with a DPST-NC relay. NC being “normal closed.” It’ll allow the MOB to shut off both motors, but still let each start/stop switch operate independently of each other. I’ll update with progress when i get this going. Thanks so far though!

    #57131

    Corey Schmidt
    Forum Moderator
    Vessel Name: Rebel Belle
    Engines: Cummins
    Location: Oxnard, CA
    Country: USA

    Probably best to hook up the MOB system to the wires you “think” are correct and test at the dock under safe conditions? IMO, best way to flush out any potential bugs…

    #57100

    Robert Vetrano
    Participant
    Vessel Name: Knot Flying
    Engines: qsb 5.9
    Location: Merritt Island FL
    Country: USA

    So I pulled the purple wire off my start/stop switch and indeed the motor shut off. Actually there is a 16ga purple that shut it off, as well as a separate 12-14ga wire that shut it off when pulled.

    So my confusion now lies in that if I wire the MOB up to both switches in parallel, to kill both engines if I fall over, how do I keep the port start/stop switch from turning off the stbd motor during a normal shutdown scenario? I can get about this far w my electrical knowledge and then it’s downhill, lol.

    #56721

    Rob Schepis
    Forum Moderator
    Vessel Name: Tenacious
    Engines: 6BTA 5.9 330's - "Seaboard Style"
    Location: Long Island, NY
    Country: USA

    Not all guys I know would want the system to shut the engines down if the wife goes over…… but for sure if the dog does!

    2 users thanked author for this post.
    #56626

    Philip
    Participant
    Vessel Name: 2007 35’ Cabo ‘FUGA’
    Engines: Cummins QSC8.3-540’s
    Location: Long Beach, CA

    Identify the wire at the switch as mentioned. Then run that wire up to the helm location where the MOB unit is installed and run the wire back to the switch.

    Phil

    #56617

    Robert Vetrano
    Participant
    Vessel Name: Knot Flying
    Engines: qsb 5.9
    Location: Merritt Island FL
    Country: USA

    Do it in the salon off the key switch if that key kills the engine.

    For engine restart purposes…….if the wife or dogs go over……it will be necessary to have the MOB base station up at the helm next to the start/stop switches, as all you have to is press a button on the base and it will allow the engines to restart.

    #56593

    Rob Schepis
    Forum Moderator
    Vessel Name: Tenacious
    Engines: 6BTA 5.9 330's - "Seaboard Style"
    Location: Long Island, NY
    Country: USA

    Do it in the salon off the key switch if that key kills the engine.

    #56588

    Corey Schmidt
    Forum Moderator
    Vessel Name: Rebel Belle
    Engines: Cummins
    Location: Oxnard, CA
    Country: USA

    Basically yes, as long as you interrupt the IGN circuit that is SWITCHED back to the engine… it will work.

    Easy way to test… start the engine, disconnect the wire you’re going to use… if the engine stops, success!

    #56551

    Robert Vetrano
    Participant
    Vessel Name: Knot Flying
    Engines: qsb 5.9
    Location: Merritt Island FL
    Country: USA

    Thanks for the response. So since my key on is in my salon, and my start/stop switches are at the flybridge helm……I should be able to wire in the MOB+ on the incoming wire to the start/stop switch? Or the outgoing one from the switch to the engine?

    #56498

    Corey Schmidt
    Forum Moderator
    Vessel Name: Rebel Belle
    Engines: Cummins
    Location: Oxnard, CA
    Country: USA

    Purple Wire

    You will need to interrupt the IGN power back to the engine in order to properly shut it down. The power from the KEY (switched) side will accomplish this. All you need to do is route the IGN wire through your system in the OPEN TO STOP circuit.

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