Thursday, 12 March 2015

Man Overboard - Improving The Odds


Moneypenny On The Wind / Photo : David Wallace
An email last year from my brother Peter showed his crew on the way to another race win aboard the very slippery Moneypenny - but also underlined the changes in crew behaviour that are needed to improve our odds of survival at sea.  In the photo Peter is wearing a PFD - here are his words on the issue :

"As you'll see from the photo, I've taken to wearing a PFD all the time now. We rescued a guy from the water a month ago after he was hit by the boom on his boat and ended up in the water, face down and unconscious. 
We managed to get to him before his own boat could turn around and it's lucky we did. He survived and it was a good test for me and my crew in rescue and first aid etc. He wasn't wearing a PFD but a guy on his boat was so he jumped in, inflated, swam to him and held his head above water as best he could. He'd been face down for about 90 sec before his crew mate got to him, and we got to them about 2-3mins after that. He was indeed lucky.

It underlined the theory that without a PFD your odds of survival, or of helping someone else survive, are severely limited. Also, as you'll see, the width of the cockpit on our new boat is pretty big for a 35 footer, I have really struggled on big weather days to get across to the opposite side in the tacks, there isn't much to hang onto. So, PFD's from now on for me."

So, great teamwork from the Moneypenny crew certainly helped save a life. But what happens aboard a typical cruising boat, with only two people on board ? How can we handle man overboard (MOB) situations better ? With the off-watch crew member most likely asleep, even when wearing a PFD, how can we survive a fall overboard mid-ocean ?
Three Fundamentals For Survival

Going overboard mid-ocean is a chancy endeavour, specially if nobody knows about it for four or five hours.  Even a modern 406 EPIRB will not get you rescued quickly - and maybe not at all.  By the time the messages are validated and then relayed to the responsible authority you might just find that they "have no rescue assets in that area".  Sorry....... 

Its clear to me that the best chance of rapid rescue is by the boat you've just fallen off.  For that to happen there are three fundamental things needed :

1: Stay Afloat   2: Wake The Other Crew Person Immediately  3: Show The Crew Exactly Where You Are

If you can do these three things then you have a much better chance of survival.


Wearing a PFD (personal flotation device) is fundamental to satisfying that first requirement.  The next two issues are handled by adding a compact personal AIS beacon to the PFD, and using the existing AIS receiver system on the vessel to detect the distress call and to wake the off-watch crew.  We use a Kannad Safelink R10 MOB Beacon, that can be manually activated or fitted to a PFD for automatic activation.  Once transmitting, it sends a unique identifier and an exact GPS derived position to all vessels within range.  Operating life is about 24 hours. 

Our existing Comar AIS system will receive the distress message and pass it over to a Digital Yacht AIS Lifeguard MOB alarm.  This device constantly monitors the AIS traffic and sets off a very loud alarm when it sees the unique MOB message. On Crystal Blues we've also added a very loud piezo siren in each sleeping cabin, which no human being could sleep through (even me).

The AIS message is also fed to our Transas chart plotter, which displays the MOB position immediately, as will most modern AIS equipped charting systems.  The rudely awoken crew member can now steer the boat to the exact MOB location.  The Kannad beacon updates its position every 60 seconds, so drift and current are dealt with automatically.

Ocean Signal AIS Beacon With VHF DSC

Later model beacons (by other manufacturers) can also transmit a VHF DSC distress message.

We hope never to need it, but the system is now in place to give us our best chance of survival.  Its also nice to know that we're now equipped to react to MOB emergencies from other nearby vessels.

The availability of these compact MOB beacons is another reason why cruisers should be fitting AIS to their vessels.


2 comments:

Daria Blackwell said...

Thanks for this. Excellent advice. I have posted it on the OCC Facebook page as an instigator to generate other ideas.

SV Crystal Blues said...

Thank you Daria ..... The other thing I wanted to discuss was the importance of crotch straps on the PFD's. recent testing in the UK and elsewhere has underlined this, but it was a little sideways from my main topic. Cheers, N./