MOB -vs- PLB

[The Apprentice]

I'm currently looking at additional safety equipment to supplement what I already have onboard, and are weighing the merits of MOB and PLB devices. I've looked at McMurdo, ACR and RescueMe, and all appear to have pros and cons.

I would be interested in the experience and thoughts of members as to what they consider to the most appropriate.

[fxykty]

I’m not familiar with the other two units, but we have two McMurdo Smartfind S20 AIS with GPS personal locator beacons that are mounted inside our PFDs for automatic deployment when the PFD inflates. They have a range of about 4 nm and take about 30 seconds to send the first AIS MOB signal and another 30 seconds to send the first GPS signal. After that, it’s continuous AIS and GPS signal. Depends on your nav system, but if you have an AIS receiver and especially if it displays on your plotter then with a good loud MOB alarm your off-watch will be woken up by the alarm when you wash overboard. We’ve tested on our boat with these results (not the range, that’s from the documentation but makes sense based on sea-level antenna).

I believe an AIS unit makes sense as it can be received and action on your boat (and any other with the appropriate equipment), while I’m not sure what use personal EPIRB units as by the time the signal traverses it’s way via satellite and rescue centre they will be recovering your body. YMMV

[svmobert]

It depends on your crew complement or lack thereof and where you are sailing..

If you have a complement of crew (at least one other adult) on board

Then the MOB (DSC/AIS SART) is your first, best option. No one is closer to rescuing you than your own vessel and the MOB1 and similar DSC/AIS SARTs call YOUR boat and alert your crew to you condition.

Once you have a MOB on each persons life jacket, then you can and should add an EPIRB to your boat, or possibly a PLB at minimum just in case you need to request help from authorities a long way off.


If you are a solo-sailor and might need rescuing after falling off your boat (or in any other situation) you really need a PLB (not a MOB)

If you are in inland waters (SF Bay, Puget Sound, Cheasapeake, or something similar) with nearby boats and Coast Guard in VHF range, then a VHF/DSC/AIS MOB might work okay, but you have to manually activate the "all ships distress" call after it automatically activates because by default it only sends the distress call to your own boat first.

If you are offshore, a MOB really won't do anything for you.. It will transmit a distress to your boat but no one is on board to hear it, and you can switch it to all-ships call but the range will be limited to a couple miles.

A PLB on the otherhand sends the distress to the authorities via satellite with your position and they can call other ships, boats, planes, etc in the vicinity to help you.

We have a family on board (4 of us) and we have 4 x MOBs (1 per person) and 3 PLBs (2 for night crew and 1 inside the liferaft), plus a category 1 (auto deploying) EPIRB on the boat.

In any case, the PLB and MOB's solve slightly different problems..
MOB for one crew overboard from a vessel with additional crew.
PLB for all is lost, come get me, no one knows I am here problems.

Just my $0.02.

Originally Posted by The Apprentice

I'm currently looking at additional safety equipment to supplement what I already have onboard, and are weighing the merits of MOB and PLB devices. I've looked at McMurdo, ACR and RescueMe, and all appear to have pros and cons.

I would be interested in the experience and thoughts of members as to what they consider to the most appropriate.

[ggray]

This device seems to be very useful.

Can the batteries be replaced? I suppose it's not the sort of thing that you would expect to use more than once, if at all, and 7 years is a pretty long time for something like this.

Originally Posted by fxykty

I’m not familiar with the other two units, but we have two McMurdo Smartfind S20 AIS with GPS personal locator beacons that are mounted inside our PFDs for automatic deployment when the PFD inflates. They have a range of about 4 nm and take about 30 seconds to send the first AIS MOB signal and another 30 seconds to send the first GPS signal. After that, it’s continuous AIS and GPS signal. Depends on your nav system, but if you have an AIS receiver and especially if it displays on your plotter then with a good loud MOB alarm your off-watch will be woken up by the alarm when you wash overboard. We’ve tested on our boat with these results (not the range, that’s from the documentation but makes sense based on sea-level antenna).

I believe an AIS unit makes sense as it can be received and action on your boat (and any other with the appropriate equipment), while I’m not sure what use personal EPIRB units as by the time the signal traverses it’s way via satellite and rescue centre they will be recovering your body. YMMV

[billknny]

My thought is that a PLB is near worthless for an offshore MOB. I need to find the MOB, not send a signal to a satellite and then on the the Coast Guard 1000 miles away! Even if I was near coastal, it would be at least a half hour, more likely several hours, before assets were on scene.

The AIS beacon uses equipment I already have on board, and is already integrated into my navigation suite. In the event of an MOB, I KNOW where they are in real time relative to my boat within a minute of activation, and can plot a course back to them right on the chart plotter I use everyday. That's a huge benefit to my mind.

[The Apprentice]

Thanks everyone for you comments and thoughts..
I'm leaning to the MOB...more than leaning really...Decision made!
I had it in my mind to go the way of the MOB...it helps to have some discussion to help with thought process..
Thanks once again
Cheers

[a64pilot]

Originally Posted by billknny

My thought is that a PLB is near worthless for an offshore MOB. I need to find the MOB, not send a signal to a satellite and then on the the Coast Guard 1000 miles away! Even if I was near coastal, it would be at least a half hour, more likely several hours, before assets were on scene.



The AIS beacon uses equipment I already have on board, and is already integrated into my navigation suite. In the event of an MOB, I KNOW where they are in real time relative to my boat within a minute of activation, and can plot a course back to them right on the chart plotter I use everyday. That's a huge benefit to my mind.

However as was pointed out, it depends, if there is no one on the boat you fell off of, then an AIS / SART beacon my not be of much use.
I have them for the wife and I after reading an account of a Gentleman who woke up, thinking his wife had let him sleep late for his watch, only to not be able to find her. She was never found, that sent chills through me.

[Eluchil]

Don't forget to consider a handheld radio with DSC and GPS as an option in a MOB situation. It will not trigger automatically if you fall overboard unconsciously, but it can send out the same DSC alert with your GPS position to all receiving stations as an MOB device. It also may not send out an AIS signal, but all DSC enabled radio's have navigation functions and will show the nearby vessels the range and bearing to the MOB, even RIB's or the like who may not have AIS receivers. It also allows the person to communicate with the vessel, which would be very useful in coordinating the recovery. As a bonus, a handheld VHF has numerous uses outside of an MOB situation, making it more fun and useful to purchase, and possibly more likely to be carried by the person falling overboard in the first place!?