Catamaran MOB

[GordMay]

Practice has shown that different man-overboard manoeuvres may be required, depending upon the situation prevailing and the type of boat involved.

1. Single turn: (270º will take the ship back to the scene of the casualty most quickly.
Rudder hard over (in an "immediate action" situation, only to the side of the casualty) .
After deviation from the original course by 250º, rudder to midship position and stopping manoeuvre to be initiated.


2. Williamson turn: Rudder hard over (in an "immediate action" situation, only to the side of the casualty) requires more time, and will temporarily take the ship farther away from the scene of the casualty; but will take the ship to the scene of the casualty most surely.
After deviation from the original course by 60º, rudder hard over to the opposite side.
When heading 20º short of opposite course, rudder to midship position and ship to be turned to opposite course.

3. Scharnow turn: (not to be used in an "immediate action" situation.), cannot be carried out effectively unless the time elapsed between the occurrence of the casualty, and the commencement of the manoeuvre is known.
Rudder hard over.
After deviation from the original course by 240º, rudder hard over to the opposite side.
When heading 20º short of opposite course, rudder to midship position so that ship will turn to opposite course.

Pictured below: (2) Williamson, and (3) Scharnow turns.

[Factor]

In my Training with the Coast Guard, the I recall that the williamson turn was developed for larger ships, the idea being that if a MOB goes over on the port side of the vessel, the call is MOB - PORT side, the helm is directed to that side, the aft of the ship obviously moves to starboard, the idea being to get the props and vessell away from the MOB by the time the stern of the vessell gets to them, the vessell is then turned in the opopsite direction. It also was based on the fact that the large vessel couldnt be stopped all that quickly.

I dont think the williamson turn has much application to small boats such as ours, by the time the helm is put over we have gone well past the person overboard. On a sail vessell, I still believe that getting the life ring etc into the water is priority 1 and then getting the vessell head to wind is next, two key points are get the life saving gear in and get the vessell to not make way and then determine appropriate straegies from there.

A nice piece of cut and paste, but what the heck does it have to do with a caramaran under sail?????

Originally Posted by GordMay

Practice has shown that different man-overboard manoeuvres may be required, depending upon the situation prevailing and the type of boat involved.

1. Single turn: (270º will take the ship back to the scene of the casualty most quickly.
Rudder hard over (in an "immediate action" situation, only to the side of the casualty) .
After deviation from the original course by 250º, rudder to midship position and stopping manoeuvre to be initiated.


2. Williamson turn: Rudder hard over (in an "immediate action" situation, only to the side of the casualty) requires more time, and will temporarily take the ship farther away from the scene of the casualty; but will take the ship to the scene of the casualty most surely.
After deviation from the original course by 60º, rudder hard over to the opposite side.
When heading 20º short of opposite course, rudder to midship position and ship to be turned to opposite course.

3. Scharnow turn: (not to be used in an "immediate action" situation.), cannot be carried out effectively unless the time elapsed between the occurrence of the casualty, and the commencement of the manoeuvre is known.
Rudder hard over.
After deviation from the original course by 240º, rudder hard over to the opposite side.
When heading 20º short of opposite course, rudder to midship position so that ship will turn to opposite course.

Pictured below: (2) Williamson, and (3) Scharnow turns.

[catty]

Originally Posted by GreatKetch

A nice piece of cut and paste, but what the heck does it have to do with a caramaran under sail?????

Great Catch, I see you own a mono. While I see nothing wrong with you owning a mono, I do think you really need to take a fully laden cruising cat out in trade wind conditions ( ie 20-25 knots, 2M sea/ 2M swell) and actually try doing a few maneuvers under sail , by your lonesome (imagine crew/partner fell overboard whilst running before the trades), and then tell us about not using your motors.

Firstly, being a cat and running ,you've probably got the main in the bag and either a head-sail or small kite up ( minimizing chafe).
Geeze, a lot of cruising cats are battling to tack in these conditions with main and jib sheeted correctly, let alone with jib only.
So hop off your high horse, go for a sail,and tell us how you go.

[Joli]

I don't I think I said they were either or choices and I don't think I said I would sail away and call the next of kin but the reality of the situation is pretty dismal when there are large waves and big wind.

After racing well over 100k miles I will tell you that when a 12 foot wave has a period of 5 seconds and it's blowing 35 knots it will be very difficult for even a very experienced fully crewed boat to pick up a 250 pound man in daylight.

Originally Posted by GreatKetch

I don't mean to be rude, but using a tether and practicing MOB recovery procedures are not exactly an either/or choice. It is not MORE prudent to do one or the other. Doing BOTH is just plain good prudent seamanship. Not doing BOTH is foolish.

My situation is a bit different than most. I teach sailing pretty much full time. In the last year I have probably personnelly done well over 100 MOB drills myself and coached students through well over a thousand. Sometimes on J-24s in 30 knots, and sometimes on Catalina 36's in 5 knots. And boats and conditions in between. Believe me, I know just about everything that can go wrong (but there is always that new twist!).

There are many boats on which a singlehanded MOB would be very difficult or damn near impossible. I can do it on my own 40' ketch, so can my wife. Everyone of our certified students has to bring a boat back to a MOB and stop the boat at least three out of four times. They do this with one crew onboard to help. So I know that any good, well trained sailor WITH PRACTICE can bring a wide variety of boats back to an MOB quickly and efficiently. The key here, is that it is a skill, not an intellectual exercise. It really takes practice, and frequent practice, to be good at it. I should be realistic, and realize that if somebody doesn't think they need to practice this, me preaching at them isn't going to change their mind, so I really should get off this soapbox, at the end of this post...

The very idea that "if you fall overboard you're dead anyway" I find to be incredibly silly. If you really believed that your MOB plan would be to look over your shoulder, wave goodbye, and phone the next of kin. I doubt anybody would not TRY to go back and pick up a crew in the water. If you would try it, you should practice it. It is harder than you think but not impossible. Believe me, you should practice it even if your plan is to use the engines. It WILL take longer than you think it will, and there will be problems you didn't anticipate.

One of the things I think is frequently missed, is that nobody is ever "ready" for a crew in the water. It's always a shock and a surprise. If you don't have a drill ready to go, things will get bad quickly. One of the key techniques, IMHO, is RIGHT AWAY coming to a course that is 90 degrees off the true wind--no matter what your initial point of sail. If you do this you can always sail an accurate reciprical course and have a very good chance of finding the victim. If you go sailing off upwind, or down, the chances of finding somebody get smaller every second.

[Eleven]

Just picked this thread up by chance. An old one but good for a new sailor owner.
I'd thought of tying my bucket to a fender to provide a chuckable float that won't blow down wind. I'm doing that before I go out again. On a bright yellow float.
Also I usually carry a dinghy. I'm tying that to a long line attached to the boat so I/crew can sail upwind of the MOB and drift down to it. Floating line to be purchased and dedicated to this task.
I have trouble tacking reliably in over twenty knots, (31' Prout Cat and I think battened main has moved the C of P aftwards and un-balanced the trim but I'm just starting on sail trimming) but gybing is reliable if the genoa doesn't wrap around the forestay. If it does then at least then the boat is stable and slow.
Making a 270 to downwind allows me to stay in close range and hopefully in sight.
During the 270 I can get the dinghy over the back on the long line. It will blow down wind faster than the boat drifts so a 'catch' is likely.
Engine(s) started will ensure I can hold head to wind upwind of MOB and allow him to board the dinghy.
If he's not conscious then it's going to take time to roll the genoa, drop the main and secure from flapping and maintain visual, and heading and distance.
Hopefully then a wrap around course will secure him until I go in the water to recover all.
Not a good prospect - so a tether running line around the deck and short tethers on the lifebelt harnesses will be standard in all weathers. At least then the MOB will be at worst be towed beside the cockpit in a position where I can get the boom over him to lift the dead weight of a big waterlogged man. At best he's bumped battered and bruised but still on deck and inside the netted safety rails. I love cats. I wish they manouvred better, and sailed to wind a bit better, and were faster in light airs, but I ALWAYS feel safe. So safe I don't wear life belt / harness, practice MOB.
Many thanks for this thread.

[Talbot]

One problem with a cat mob that is not understood by the half boat crowd is the speed at which a cat will be blown under bare poles sideways, forwards or backwards.

In a very strong wind this is a major problem that has to be taken into account in your procedure.

An advantage that you have is that you only have a single engine which (provided the single arm steering system is connected), makes it very simple to manoeuvre stern to the wind, just upwind of the guy in the water. While using the engine to balance the thrust of the wind, You should then get a ladder over the side (not at the stern) and then use one of the weighted throwing lines to get a line to the casualty, and get him to tie on, and you secure your end, then switch off the engine. pull him into you as quickly as possible before the boat really gets up to speed. If necessary, use a winch.

The ladder needs to project below the water line by at least 3 feet to make it possible to use the legs to climb the ladder, rather than relying on arm strength for the first part. people who have been in the water for a while do not have the strength in their arms to climb up, but probably do have the strength in their legs. (if not - on to Plan C!)

You will noy find this procedure in the RYA manual, but for a cat, particularly one with a single steerable leg, it is really good

How do I know - I used it while single handed picking up a guy from another boat - how windy was it - well it needed full astern on a 27hp diesel to stay alongside the guy in the water. If I had done the RYA thing I would have drifted right over the top of him - which probably would not have helped a lot

[Eleven]

Thanks again Talbot. I understand. You think bows downwind and use reverse to hold station.
I can fully appreciate that system and it makes a lot of sense. Its impossible to hold the bows into much of a wind as rudders need boat speed to work, I've tried it picking up a mooring bouy.

[Talbot]

Yes
also works well when securing to a buoy - its a system that really works well with a single steerable leg. PBO did a series in Jan and Feb 2006 on manoeuvring alongside on a single engined cat - it was my boat, and was an intentional method of getting more cat articles in PBO, although the day was a lot of fun, and even the wind assisted on the day, coming from a direction that it had never done before!

My requirement was an easy system that enabled me to secure alongside single handed even when the wind was blowing off. - which is actually the same problem as the MOB - understanding what your boat will do in different conditions, and the best way to operate her.

For the first few times each season, I would keep the engine cover off so that I could actually see which way the leg was pointing.

[dialdan]

Hi ,
Last nights ABC tv program (OZ) the Inventors featured the Mobilarm V100 , a very useful piece of equipment imho and will be on my shopping list .
Worth checking out Google ,Mobil V 100
Al

[Intentional Drifter]

Al --

Googled as instructed and got lots of hits for a cell phone. Is this what you meant? I'm not getting it, please help.

ID

[Islander]

Here:
Mobilarm Crew Locating and Tracking Solutions - Mobilarm V100 | Mobilarm - Man overboard safety systems

At $750 I think I'll try and stay tied on to the boat!

Cheers

[sandy daugherty]

I found a Switlik MOM-8 at a boaty flee market, and $250 got it renovated and recertified. This is my first action in the even of a MOB event

[Robertcateran]

I must admit that in doing my training for my coxwains ticket, I killed the dummy a few too many times. This was on a 33' power boat. While sailing a small tri, I used various occasions to practices MOB drills, Like losing a hat overboard. We used to treat it as a game that someone would see a piece of flotsam and yell seaweed overboard and we had to keep track and retrieve it. I found it worked if for downwind I would immediately come round pointing fairly high and after about 10 or 15 seconds would head on the other tack. I would then drift down steering backwards and recover the flotsam over the stern. Other points would have different responses but I would always finish by drifting down backwards. Different boats will behave very differently.
My next boat planned takes this idea of sailing backwards even further. It is a Harryproa. This allows very easy reversing and even crabbing up wind. A dinghy ramp allows relatively easy hauling out of the water. There is even less chance than on most multis of MOB as the cockpit is on the lw side of the ww hull thus most sailing strings to pull are a long way from the water.
I have had experience of two serious MOBs while professional fishing. One was while tuna poling and a laarge yellowfin was in a patch of 35lb bluefin and one of the crew was pulled in with the strop on the pole wrapped around his wrist. He managed to get it clear but was dragged a fair way from the boat and was pretty knackered by the time we got to him. Another was someone fell overboard while steaming and wasn't noticed till the next watch. The boat spun round on a reciprocal course with people in the crows nest on the look out and he was found about 4 hours later.
A reciprocal course for a sailing boat needs a very accurate idea of the leeway and there would be a much greater margin of error

[rjrendemd]

This thread started with a very simple question. What is the best way to perform a MOB maneuver in a cat? I will give a very simple answer. I am still laughing at some of the answers from people who have never sailed a cat. Their turning characteristics are obviously different than a monohull. I have a wife and 4 kids and insist on doing a MOB drill 2 or 3 times before we sail EVERY Time. It also helps to know how to do one when you hook on to a trophy catch. Simply heave to. You don't have to move a thing. Simply turn the bow into the wind, do not touch the jib and backwind the jibsail and the boat will sit there for hours until you decide to jibe the main to resume sailing. Fig of 8's will not get you to the MOB like a heave to will. The kids love to practice it so they can see who gets to "save" the life vest. Additionally I have always been taught and will continue to insist that the motors should be OFF when someone is in the water.