FELL Marine MOB+ Install

ESGWheel

Chief Petty Officer
Joined
Aug 29, 2015
Messages
469
With the advent of the new law in 2021 regarding boaters to use an engine cut-off switch on all personal watercraft and powerboats less than 26 feet in length, I bought the FELL Marine Mob+ Wireless Man-Overboard Cutoff Switch.

My 2005 Larson 228 LXi with VP 5.0 GXi-E engine already came with a lanyard style kill switch. But I never wore it because it tethers you to the helm and I was frankly too lazy to hook / unhook every time.

With the new law coming into effect, I figured there may be more focus on this by law enforcement. That coupled with we were now bringing our dog out on the boat prompted me to buy this back in early 2021.

However, life happens and I never got around to installing it until today. So now I am all set for this coming season here in New England.

Below are some hopefully help tips from my installation experience that others can use:

The device can be Closed to Stop or Open to Stop depending on your situation > this is easy to test with your existing kill switch by using a multimeter with leads that are made to pierce wiring insulation. See pic. Well worth getting a set.

Leave your existing kill switch in place and wire in parallel if “Closed to Kill” or in series if “Open to Kill”

My location for the device would result in the antenna being uncomfortably bent so I used a 90-degree RF connector. See pic.

You must have access to get behind the MOB unit to install it. Fortunately, I had significant access due to the recessed cup holder that I removed during the installation.

I found and then tested power from the key switch. The need is that the power cannot be interrupted between “run” and “start”. The MOB device needs constant power to disable the kill aspect. The instructions suggest tapping into a constant power line and then installing a separate switch to turn it off when not in use to preclude a power drain. I thought this inelegant. One of the terminals on the key switch had +12VDC power with the switch in the Run and Start and not the ACC positions. Suspecting that there may be a ‘break before make’ as the key it turned from Run to Start that I could not see on my multimeter (i.e., a momentary power interruption) I temporarily wired it all up and tested it. And sure enough, this particular terminal worked just fine, so I used it.

Caution: if the Stop FOB falls overboard, it kills the engine but after a 6 second delay someone still on board can restart the engine. This is an excellent feature as the passengers can restart and rescue the captain in the water. But it just occurred to me that if someone turns off the key, depowering the MOB device, this feature may not work. If the key is turned only from Run to Start, I am sure it would start but cannot depend on that happing in an emergency. I will have to test this and talk to the FELL Marine folks about this aspect. Note that per the instructions I could not simulate the Stop FOB falling into the water > they state that even a 5-gal bucket of water will not do it. Thus, perhaps their power thru a switch suggestion has merit. More to follow on this.

I used a marine grade in line fuse holder with a 3A fuse on the power line. See pic,

And I used the crimp, shrink with glue connecters along with 18GA tinned copper wire See pic for installed device.

I will wear the Stop FOB on a wrist band and our dog will have the Alarm FOB on their collar.
 

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dingbat

Supreme Mariner
Joined
Nov 20, 2001
Messages
16,074
I have a kill switch built into the ignition switch but it’s useless if I’m up and about.

Left the ignition intact and simply wired the MOB to the fuse panel at the helm. Wired in series with the kill switch in the ignition.

Unit only draws 2.5W so the current drain is insignificant.
 

ESGWheel

Chief Petty Officer
Joined
Aug 29, 2015
Messages
469
Dingbat,
How long have you had it? Any issues, regrets or tips?
 

dingbat

Supreme Mariner
Joined
Nov 20, 2001
Messages
16,074
Dingbat,
How long have you had it? Any issues, regrets or tips?
This will be season 4.
Had an auto-tether before this. Worked ok but not ideal.

No regrets. Works as advertised. I’m free to roam about the cockpit
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
12,655
The way I read the law this was for new boats but you don’t have to retro fit it to older boats unless you want to.
 

ESGWheel

Chief Petty Officer
Joined
Aug 29, 2015
Messages
469
The way I read the law this was for new boats but you don’t have to retro fit it to older boats unless you want to.
Agree. And I already had the lanyard style. I just figured there would be more focus on using it. And actually using a kill switch it is a good idea. Now I have no excuse :cool:
 

ESGWheel

Chief Petty Officer
Joined
Aug 29, 2015
Messages
469
This is a follow up and close out to 1 plus a partial season of using the Fell Marine MOB device.

First off a correction in my wiring. As noted above the device would power off anytime the key was off. This was not good as needed to resync with the fob every time starting up during the day. Also, it could be an issue during an overboard situation. I did talk to Fell and they – as expected – suggested using constant power and providing an interrupt switch if desired. I tested the current draw and was a low 0.1 amps so I was not worried about it drawing down my battery (I only do day trips), so I wired it up such what once the Battery Disconnect is ON it has power. Close the Batt Switch, sync the fobs and done for the day worrying about it.

And no issues using the 90-degree antenna connection.

And I also added to my on board stash a few of the button batteries the fobs use.

Note: there are clear ‘override’ instructions on the device if the fobs are not working or present (such as when in the shop). Plus, there is a jumper on the backside of the device if it somehow fails. However, need to gain access to the back of it to install the attached jumper. But this is the worst case > a complete failure of the unit.

The Fell wrist band: I have found it difficult to thread / fasten but with a little help from DW, no issue. I wear it looser than a watch and have never found it uncomfortable or interfering.

The fob holder on the dog’s collar is non-interfering and I find it easy to pop the fob in and out.

You gotta remember you have it on however > more than once when anchored I have jumped into the water and caused the system alarm. Opps. Additionally, when gassing up or at the dock, its easy to forget and walk off the boat and again, it alarms. So, I have learned to take it off when anchored / docked but its easy to forget to put it back on! There is a lanyard for the fob but i do not like that option.

Frankly I am not good at remembering to put it back on after going swimming, etc. mitigating its utility. But I am glad for it due to the concern over the dog. And while my boating is always accompanied by DW, but in the future that may not always be, in which case, I am glad for this device.

My bottom line: glad I have it. Hope others find this info useful who are considering it.
 

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
42,056
Installed in my boat and it would not kill the starboard motor. Removed and did not reinstall

Note: the documentation which comes with the unit states something to the effect it doesn't meet the requirements for a kill switch.

I'm going to return at the same time to see if Merc will test/repair/refund/replace, If they replace I won't even open the box, I'll just sell it on ebay
 
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