MOB recovery again

[peteandthira]

There was some discussion recently about MOB recovery when short handed.

SWMBO and I have just been out and had a look at the "Oscar" system, with 30m floating line terminating in a floating strop. Various approaches to a fendered bucket ("Bob") showed pretty much foolproof contact with the casualty.

The most certain seemed to be a close-ish pass, followed by a hard 180 and go past again, didn't seem to need to be too close the second time.

The recovery rope was always in contact with the MOB before the strop got there, and on the last occasion the strop actually snagged the fender and enabled me to drag it aboard.

If we tried a tight circle, it seemed to take a bit longer for the rope to touch the fender, although the casualty ended up completely surrounded by it.

There was never any danger of the floating rope snagging anything underwater.

All this was done motoring, but I can't imagine any difference under sail. If anything, it seems to remove the need to be so precise with the sail handling, since you can just sail round and the rope will end up with the casualty, at which point your one remaining crew can faff with sails in slower time.

Any interest out there, or any comments?

Pops

 

[Vara]

I think I said in the post to which you referred,making contact with the casualty is the easiest bit,and the floating line and strop does that very well.
It's getting the poor sod back on board which causes the problem.
For us the problem will be me in the water at 15stone(dry) probably 17 wet, with SWMBO at 7½stone trying to get me back aboard if for one reason or another I couldn't assist from the water.
Sugar scoops and bathing platforms with ladders help in fairly benign conditions but in any sort of sea the stern of a sailing boat is not the place to be.
At present I'm thinking through a davit affair with attached self tailing winch which can be put into a ready prepared socket amidships.(one each side)
Another factor is that you need to get rid of flapping canvas easily so furling sails or lazy jacks would make a tremendous diference.
Work in progress!!!

 

[colvic987]

a couple of years ago, our sailing club organised an event with the local rnli to come out to the boats, and get familiarised with getting the sails down, and getting a bridle attached to the yacht for towing, and using some of the mob aids we had aboard.

We dropped the lifeboatman overboard and deployed the sling and strop system, similar to the oscar you mentioned, the conclusion was that it was a lot easier than using some other methods of mob, and the lifeboatman was very impressed with the system..

if you can ever get an exercise of this nature organised with the rnli, it is very useful for the yachtsmen and the rnli, to get familiarised with yachts and boats of a varied nature...

 

[vyv_cox]

You're quite right. Trying out your MOB recovery system for real on a warm, quiet day really makes you think. For years we assumed that we could unclip the mainsheet from the traveller, lower the free end to the casualty and winch him/her back aboard. Wrong! Even with a six-part tackle it was impossible to pull upwards and lift someone of between 10 and 12 stones weight. Getting the free end to a winch proved to be far more complex than we thought, needing two snatch blocks to give a good enough lead to prevent riding turns. Even then it was no easy matter for me to winch Jill aboard and she really struggled with me.

WE now reverse the mainsheet and find it much easier to pull downwards then upwards. It's still a serious business though and nor one we ever intend to try for real.

 

[Vara]

The securing boom with preventers,and reversing mainsheet is the system I found worked best but that was with a fairly strong crew it would be a nightmare for one person to rig and operate,especially as time is of the essence.Every pair of available hands makes the solution easier.
It would be an interesting exercise for a team of forumites to get together and play through a few solutions even recovering from a jetty/pontoon would be worthwhile.
Unless we could find a forumite with his own dry suit to go in the water.
I'd volunteer but its at the cleaners/the dog eat it/I've got a bad back/I've got hydrophobia.

 

[peteandthira]

colmce

"Another factor is that you need to get rid of flapping canvas easily so furling sails or lazy jacks would make a tremendous diference."

We went that way from the start, and it only takes about a minute to get all sails in, in any wind. The specially-extended topping lift then gets unhooked from the boom (carabina) and oiks the casualty from the water, over the side rails and onto the deck, with ease, from a coachroof winch. I have pulled SWMBO out of the dinghy alongside, and the next exercise is for her to try pulling me out.

We can't think of any easier ways to do it now, apart from simply not going overboard.

regards

Pops

 

[Vara]

Yep that sounds good to me,I was thinking in terms of a vertical lift and swinging the casualty on board.But on reflection a few minor abrasions as cas is dragged in are probably of minor consequence.
This knocking ideas about really works!

 

[alan17]

One problem that nobody seems to have mentioned is the need to lift the casualty horizontally especially if they have been in the water for more than a few minutes.

It does not take long in our waters for a casualty to become hypothermic and then if you lift them in an upright position you are very likely to end up with a corpse on board. I have not got an easy answer to this but my thought is that I would attempt to recover into my RIB which is mounted in snap davits attached to the boarding ladder and can be easily dropped into the water still attached to the transom/boarding ladder.

I must one day try this in a test situation.

 

[peteandthira]

alan17

We thought about that one too, but having seen our dinghy whilst still attached to its snap davits in a rough sea, we thought we would just not bother.

However, if you try it, let me know how you get on! I am always looking for the best answer to this 2-person crew problem.

Pops

 

[William_H]

I have heard recently on this forum of this problem of harm to the victim if you lift vertically after hyperthermia.
I can't help thinking that while that may be a concern in lifting into a helicopter (and a nicety into a proper rescue boat,) that speed of recovery is of primary importance and if a victim comes out of the water vertical on a topping lift that the period of time vertical would be limited and you would soon have him/her horozontal again in the boat.

I am concerned that this concern may be over emphasised to the detriment of speed of recovery in a real rescue drama. ???????????????? olewilll

 

[Searush]

Thanks for that. Very useful as I have never actually tested my system! As you can see from my avatar I spend a lot of time in the 'Oggin.

Interested in the "don't lift out in upright position" isn't that how the ASR choppers do it? Also I'd have thought that most people would be pretty safe from hypothermia in UK waters during the main sailing season.

I would guess 15-20 mins recovery time would not be a serious threat to life - I spend that long in the sea quite often, just for fun. Then climb out for a good rub down to get surface blood flowing again. Don't ever think I've ever had any core cooling problems. Air temps vary a lot in summer but sea temps are pretty stable.

 

[roly_voya]

Re: MOB recovery again - Horizontal lift

The reasoning behind using horizontal lifts from water is for the following reasons
Once in cool water the body shuts down blood flow to the extremities, these then cool rapidly
A body floating in water with feet down will feel increased pressure in legs further reducing blood flow
When lifted vertically the sudden release of pressure means blood flows into the legs causing a sudden drop in BP
The blood is rapidly cooled in the legs so when it returns to the hart it creats a thermal shock
There is a real risk that these factors can trigger a cardic arrest. The risk is increased with the age and circulatory/cardic health of the casualty. As the casualty is also probably highly stressed by the MOB incident as well this risk can get quite high.

This does not apply to an active swimmer because the exercise required keeps circulation going to the legs and keeps them warm.

Hypothermia risk veries significantly in UK waters with early season presenting greates risk as it takes time for waters to warm up. Most people swim close to the shore in shallow waters but 5 miles offshore at the end of May can be very different. Also again health and age play a big part as does cloathing. Cirtainly some casualties will be experiencing significant problems within 30min

So if possible lift horizontally but as you rightly imply say the casualty is going to die if you don't get them out so if its vertical or nothing you have to do it. There are verious methods using sails or nets that 'scoop' the casualy up and roll them onto the deck. This keeps the casualty horizontal and also needs lees effort for the recovery so you win both ways.

Hope this helps

 

[peteandthira]

Searush and Roly

Interesting. This suggests then, that our personal safety brief can be amended. We always want the MOB off our boat to stay still and keep calm, making only a short attempt to reach a danbuoy.

Given that I know I can be back with my casualty within 10-15 mins with my lift ready, should she then keep gently swimming so as not to introduce the vertical lift problem?

Then, if I don't make it within my time, casualtly then keeps calm, still and hopes for the best? We are also looking at fitting a second strop for the legs, but neither of us think we can get our feet into that underwater.

I suppose one could discuss this all day, but it strikes me that it is one of those things worth discussing.

Pops

 

[Vara]

Re: MOB recovery again - Horizontal lift

The nets, scoops, and other devices are pretty good if you have the time and the crew to deploy them.In the situation of a two crew boat you would be balancing the risk of a quick rough and ready vertical recovery against a necessarily much longer horizontal recovery,tricky call!
With Pop's method given good luck you should be able to get the casualty out in 10-15 mins.
Oh I forgot to mention before deploying any of these things hit the alarm buttons,a helicopter or another boat could be an important tool.


Footnote when I was playing with different methods of recovery the improvised foresail lift was very difficult to execute.

Given Pops past life maybe a set of blow up trousers(G suit?) might be the answer to stop the blood flowing to his legs.

 

[Peter_Chennell]

Look out for an article covering this topic in PBO February or March. We did some tests on various methods, with surprising results.

 

[gjeffery]

I have a snatch shackle on the mainsheet lower block for MOB recovery. Having read this thread I will now have a snatch block ready to attach to the boom, enabling the main sheet to be pulled down, rather than up.

My concern has been with the strength of the topping lift fittings at the masthead, specifically a cast crane, and a turning block attached to the crane by a rivet in single shear. If I use the topping lift to recover an MOB, it is likely that the masthead crane/block will carry away, dropping the boom until the topping lift comes up on the masthead sheave.

From an engineering design perspective, it is necessary to stress for foreseeable loads, not merely the loads intended by the manufacturer. (Try defending a criminal or civil action when a lout falls through the roof of a bus shelter!).

It is forseeable that a topping lift will be used in an MOB recovery and it should be strong enough for that purpose. Unfortunately, the manufacturer of my mast does not agree, and when asked, conveniently advises against the use of the topping lift for MOB recovery. The masthead crane appears not to have a designed SWL, and I suspect that like so much boaty, this company is craft led and the design mainly subjective.

Shorthanded, it would probably be impossible for my crew to detatch the main halliard to replace the topping lift. I will make a sling with snap shackles at each end. This will support the boom and attach at each end to the head shackle of the lowered mainsail!

It seems ironic that the RCD over-controls so many aspects of design, in the name of safety, but fails to make requirements for MOB recovery other than a boarding ladder at the stern.

It would be interesting to have an RNLI/MCA view on the need to "design in" provisions for MOB recovery, and it would help if pressure could be brought on boat and spar manufactures to include MOB recovery as an essential within their Product Design Specifications.

 

[jimbaerselman]

I'm surprised that bathing ladders are so quickly discounted. They should always be the first line of defence for recovering an active person (the common situation), mainly because it's the quickest option, and in cold waters, that's probably the most important consideration.

In light seas, there's no contest. Stern ladder every time.

Yes. in moderate seas on some boats the motion can be frightening and look very threatening. But in reality for an active person it's just a matter of timing. I've tried it, and I'm ancient.

In rough seas you can mitigate the motion - go beam to the sea. Which many sailboats tend to do anyway without canvas. Or even heave to, though finding the right balance to minimise boat speed may take an unacceptably long time.

For the rare case - an inactive person (because you've been too long getting the gear ready? Because it took a long time to find them? Because they were injured?), by all means consider an alternative. The alternatives are not easy.

If there's just a single person on deck, the alternatives may not be possible. Just hope the MOB is active enough to clip a line onto his (before the politically correct rebound, for 'his', read 'his/her') harness, or to pass a line around his body. If not, you're probably going to lose this one. Then ignore any possibility of injury as you try to heave them over the rail . . . just get 'em aboard, broken or whatever. Think about cutting the guardrails to ease the task.

But don't let the alternative dominate your thinking. In cold water, that may just create a problem where none existed before.

 

[jimbaerselman]

Sorry, I left out a most important point above.

If you can't use the stern ladder, you next option should be to launch a rubber dinghy (if it's inflated) or chuck the liferaft over, then recover from that. Much, much easier than hauling to the deck with all sorts of rigs . . .

 

[Steve_Bentley]

Experience

We fished someone out of the drink earlier this year (before Easter although I forget the exact weekend- I bet the 'victim' didn't though!) so I thought I'd share the experience. The poor chap in question fell off the boat in front during a race (ironically in the process of stopping someone else fall in during I think an accidental gybe or rolling spinnaker) and we picked him up. Obviously we were following a similar course to the next mark but we were almost upon him before he was spotted in the waves, and so we found him before his own boat did (something to think on...) after a delay of 5 minutes according to the swimmer (although being in a race I don't think the delay was any longer than this).

Anyway, back to the facts: we spotted him paddling (no lifejacket and I don't think any buoyancy?), did the usual with a spotter (not sure when we used the radio to the marina/committe boat as I was busy) and turned under sail with the engine on in standby, I made a snakes nest out of unravelling the throwing line tied to the pushpit and horseshoe (but had it sorted by the time we were in throwing distance) then threw the horseshoe which connected first throw. However when we started hauling him through the water the polystyrene core broke in half with only the canvas cover holding it together. Two of us hauled him to the sugar scoop where he wanted a rest for a minute or two to recover. We then cut the stern lifeline and made a short loop with the throwing line so he could get a leg in (the idea being he could use it as a step but without any strength it just served to help us hang on to him) then two of us manhandled him aboard. I guess he was 30's or 40's 6'4" and a fit 17 stone (maybe I'll ask him next time in the clubhouse)? The marina lifeboat arrived but he said was happy for us to take him back. The lifeboat followed close by.

He told us with the cold water he could only paddle, not swim (ie there was no was he could make it the 1/4 or 1/2 mile (?) to shore), and was finding it very hard work to keep above the waves. The strength just disappeared from him (arms in particular). He said he though his limit was only another 5-10 minutes. He had no strength at all to lift himself onto the boat, but could lift his legs and arms onto the sugar scoop & looped rope. Being a strapping lad he just puked some water and after a 10 minutes (?) lie-down til we got to the marina he could walk to the shower (with someone of course keeping an eye on him all the time).

Many lessons learnt, including 1) make sure you can untie the throwing line in a hurry, and 2) replace your horseshoe regularly before the polystyrene degrades to nothing!

If he hadn't been closely followed in a race .....

 

[peteandthira]

Jimb...

We don't discount the boarding ladder. Its just that our dinghy is often in the way. In a good sea we would drop the boarding ladder no problem. In choppy sea though, the trailing edge of our rudder is only about 2 feet forward of the transom and it looks 'orribly sharp!

Active or passive casualty? We don't think we could help a disabled one much, short of getting in the water with them, whilst tied on.

Would you ever consider both crew in the water at the same time? Even if it was perceived as being the only hope of saving a life?

SWMBO and I have agreed that if either of us is overboard AND disabled in rough seas, the best option is to log the position and call the cavalry. Then spend whatever time you have left pouring warm water over her or something!

There's no easy answer, is there!

Pops