Man Over-Board Deployment - Student Project

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JessicaMarais

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Dear Sailors,
Have you ever experienced a 'Man Over-Board' situation, have you wondered what you and your crew would do? In particular have you ever thought how long it might take to deploy your MOB equipment and how far you will be from the swimmer by then?
I'm a Product Design Student at Bournemouth University and a keen sailor. As my final year design project I'm designing a MOB Emergency Deployment Device. This will allow you to deploy all you 'existing' equipment simultaneously at the touch of a button.
To help in my research it would be great if you could fill in this questionnaire about your MOB equipment and procedures. Alternatively if you have any advice to give I'm happy to hear from anyone and everyone :).
Any responses will be anonymous. By filling in this questionnaire you consent to the use of your responses throughout the research and development phase of this project. The link below will take you to the questionnaire.

http://freeonlinesurveys.com/app/rendersurvey.asp?sid=kth4iuz6w8dim3y561817&refer=

Thank you

Jess Marais
 
It's clearly student project time........

Survey filled in. A few notes:
I would consider the mob button on the plotter, and the red button on the dsc VHF to be important devices to be deployed in the event of a mob in anything other than benign conditions.
There is some benefit from gradually throwing floaty stuff over the side as you get the boat under control, such that you can follow the trail back to the casualty, rather than dumping it all over the side as quickly as possible.
Assuming all on board are wearing life jackets, a horse shoe buoy is of little use to the mob. A dan buoy would be very useful though in waves.
You questions about qualifications are interesting - I would consider comp crew and day skip to be course completion certs rather than qualifications.
 
JessicaMarais said:
Dear Sailors,
Have you ever experienced a 'Man Over-Board' situation, have you wondered what you and your crew would do? In particular have you ever thought how long it might take to deploy your MOB equipment and how far you will be from the swimmer by then?
I'm a Product Design Student at Bournemouth University and a keen sailor. As my final year design project I'm designing a MOB Emergency Deployment Device. This will allow you to deploy all you 'existing' equipment simultaneously at the touch of a button.
To help in my research it would be great if you could fill in this questionnaire about your MOB equipment and procedures. Alternatively if you have any advice to give I'm happy to hear from anyone and everyone :).
Any responses will be anonymous. By filling in this questionnaire you consent to the use of your responses throughout the research and development phase of this project. The link below will take you to the questionnaire.

http://freeonlinesurveys.com/app/rendersurvey.asp?sid=kth4iuz6w8dim3y561817&refer=

Thank you

Jess Marais
Click to expand...

Seem to remember a similar system on an Oyster I skippered in the Med.
When button was pressed, it sent a signal to a solenoid in the stern locker. This actuated a co2 bottle (same as LJ one), which sent a pulse of gas along a pipe to a 'knife', which cut the cord releasing a Jonboy from a spring loaded housing, sending the Jonboy off the stern, where it inflated rather violently in the water.

Only time I saw it deployed, was when the owner hit the button, after being advised not too, whilst alongside in Alghero.
The deployment was rather explosive & the sight of the local populace hitting the deck in fright, was something I will never forget!

As part of your project, some attention should be given to actual recovery onboard of MoB, using minimal crew.
 
alant said:
When button was pressed, it sent a signal to a solenoid in the stern locker. This actuated a co2 bottle (same as LJ one), which sent a pulse of gas along a pipe to a 'knife', which cut the cord releasing a Jonboy from a spring loaded housing, sending the Jonboy off the stern, where it inflated rather violently in the water.
Click to expand...

Unless they've changed it, the piston at the end of the CO2 tube actually just knocks the Jon Buoy buckle open to release it, no blades or cutting.

It's always seemed a bizarrely overcomplicated system to me, but I guess the rationale was to avoid having electrical components sitting on the rail getting wet. So the electrics are kept safe below decks and the more robust gas-operated part of the system is all that protrudes above.

I've considered making my own which would use a bowden cable to pull the release handle down, activated either manually (like a red-painted engine-stop knob) or by a substantial solenoid mounted below deck and one or more pairs of trigger buttons (have to hold down both buttons in a pair simultaneously to prevent accidental release).

I'm glad to hear it inflates "violently", as one account of the Prue Nash incident suggested it activated rather sluggishly in that case. I service mine each year but have never tried it - I almost did a trial activation drill last month in fact, but Ocean Safety never responded to my email about getting a replacement cylinder.

Pete
 
My old Merc had hydraulic central locking so it could still be opened with a flat battery.

Does anyone know how many MoB situations there are a year? I'd say there is a bigger risk of falling out of a tender than falling overboard while at sea.

As a singlehander, a system that remotely releases the sheets giving me a fighting chance of getting back on the boat would be good. Otherwise a PLB/EPIRB is ideal for getting rescued. All the Danboys and flotation devices in the world won't help once your boat disappears over the horizon and no-one is coming to get you.

Good luck with the project, hope you get some inspiring answers.
 
Jess did you consider the use of teathers? Better to stay on the boat in a F6 - F10 than go for a swim.
 
I can see why you would want to deign a MOB product but improving what is available will be difficult.

For example, the real problem is how to stop a MOB, we were sailing upwind up current in strong winds and big seas and swells off the Portuguese coast. One of the waves that broke over the boat washed the inflatable danbuoy off it disappeared from sight in 40 seconds behind the waves, thus the MOB would have been out of sight in less time, a danbouy is higher than a MOB. The other issue is the time to turn the boat in big seas and swells single handed if you sail two up as we did, it may not be possible without a big crew. We came to the conclusion that it would have been impossible for me to find Jane or her to find me simply because of the strong wind, wave and swell height.

The solution is to stop MOBs and fit jackstays and a strong point in the cockpit to clip on to. Have one long and one short tether the short tether will stop a MOB the long one is attached around the mast if reefing. We clipped on in bad weather and always at night.

We did carry a six to one block and tackle attached to the mast with a halyard and we did test that we could lift each other in full wet weather gear. It was for peace of mind but pointless really. It is noteworthy that all MOB tests in the yachting mags have four blokes on board in a flat calm. One mag responded that they can only do the tests in the summer, really.
 
Done. Is it advisable to release EPIRB immediately? Depends on circumstances I would suggest, e.g. for us in the Aegean Sea hypothermia is unlikely to be a problem for a long time but finding the casualty in a typical blow could be.
 
I agree that more people probably fall out of tenders, and that most MOB's can be prevented at source by tethers etc.
However, the point remains that people occasionally fall of yachts, and some of them are recovered.
It is clear to me from the boats I've sailed on that many MOB setups could be improved.

I am drawn back to the old RORC rule:
One item of MOB equipment shall be able to be IMMEDIATELY deployed by the HELMSMAN
or words to that effect.

In my view, many yachts could improve their MOB gear.
It must go over the back instantly
The Helmsman must be able to do that with one hand, while keeping control of the boat.

The key thing is to get the horseshoe and danbuoy in the water damn close to the MOB
That means it needs to be over the side in seconds, so the casualty has a chance of swimming to the float.
On my boat, we have a danbuoy in a tube in the transom.
The two horseshoes each have a light and a weighted drogue and some floating line holding it all together.
It is all packed so one hand taking the horseshoe off its bracket dumps the light.
It works, because the wheel is right at the back of the boat.

My instructions are that you dump the nearer horseshoe. If that's not the one with the danbuoy pole, dump that as well if it might help.

Making it all work so quickly in a boat where the helm is not so close to the transom might be interesting.
Or so that it can be done from elsewhere on the boat.

You see a lot of boats with nasty tangles, or even clips that have to be released to get the horseshoes out.
 
Hi Andy B,
Your suggestion of deploying floaty bits gradually is very interesting. I hadn't considered the advantages of leaving a 'breadcrumb trail' to follow back. Whilst an MOB is pretty much a worst case scenario, an MOB without a life jacket is even worse and I will need to design for this scenario. Most MOB situations arise due to negligence and unfortunately the importance of life jackets is one of those things that some neglect. Whilst reading though safety regulations for pleasure vessels, commercial vessels and and racing vessels; from what I can tell, two horse shoe buoys are mandatory. At least one must be 'fixed flotation' (foam) rather than inflatable. No reason is given however I'd assume its to do with the temperamental nature of gas inflation systems and the need for servicing an reloading.

Thanks
Jess
 
Hi Pete,
Thank you for your post. I'm very interested in your suggestion of a bowden cable and release handle. I had hoped to avoid electronics and gas canisters if at all possible, however my problem would be making this one 'action' affect three different fixing points.
 
lw395 said:
In my view, many yachts could improve their MOB gear.
It must go over the back instantly
The Helmsman must be able to do that with one hand, while keeping control of the boat.
Click to expand...

The problem is in a lot of modern cruising boats on passage, there is no helmsman. In fine weather in the middle of the Channel, we might have one person asleep in his bunk, one pottering around the galley / chart table / forward end of the cockpit, and one sitting on the foredeck leaning against the mast. George the autopilot is steering.

This is why I've considered adding an electric trigger to the Jon Buoy, as mentioned above, with buttons in strategic places. But it's all additional effort and complication, on what is a fairly safe activity to begin with.

lw395 said:
You see a lot of boats with nasty tangles, or even clips that have to be released to get the horseshoes out.
Click to expand...

When we used to charter, pretty much every boat had the horseshoes tied to the rail to prevent accidental loss :(. I always used to untie them as soon as we got on board.

Pete
 
All done, If it could fire off all the equipment by the person who fell in the water (proximity) that would be good.

Raymarine already have a basic MOB device, that sounds an alarm on every Raymarine device on board the boat and additional speakers if fitted.

I would get the person on watch to wear this

http://store.switlik.com/products/isplr
 
JessicaMarais said:
Hi Pete,
Thank you for your post. I'm very interested in your suggestion of a bowden cable and release handle. I had hoped to avoid electronics and gas canisters if at all possible, however my problem would be making this one 'action' affect three different fixing points.
Click to expand...

If you mean three different points distributed around the boat, then you're going to need a fitting where one cable pulls three others. However, if you're just talking about releasing a lifebuoy, dan buoy, and drogue at the same time, then you probably don't need three completely separate latches.

Pete
 
prv said:
When we used to charter, pretty much every boat had the horseshoes tied to the rail to prevent accidental loss :(. I always used to untie them as soon as we got on board.
Click to expand...

Having lost a couple of horseshoe buoys we use a pair of bungees with balls on the ends to keep our horseshoes on the boat. Takes no more time to release them than it does to take the buoy off its stand. I can easily imagine a situation in which recovering a lost horseshoe buoy would create some significant issues.
 
It's worth distinguishing between safety equipment, which is supposed to prevent an emergency, and emergency equipment, which is only useful when the safety stuff has failed. Lifejackets, horseshoes etc. are only useful when wet. Binoculars, harnesses, etc. are good preventers of emergencies. VHF is obviously in both categories.
 
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