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Old 20 November 2002, 15:32   #31
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As I understand it (and my opinion does not count for much here), Alan P is talking about a LIFE THREATENING and EXTREME situation.

If the choice is between drowning immediately and loosing your instruments due to water ingress, then the choice would be to risk your instruments etc. You would at least be alive to worry about it!

Recent story on the TV about a fisherman whose arm was caught in his wynch. He had a choice, cut off his arm or die. He cut off his arm. He lived. He has lost an arm, but he is only alive today because he made that choice.

Hopefully most of us will NEVER be in such a situation.

Keith (oooh, serious for a bit then eh) Hart
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Old 20 November 2002, 15:44   #32
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Keith, but would YOU throw the BACON SARNIES overboard if it would save your life?!

But seriously Keith makes a good point there, if it's a choice between financial loss and loss of life, or putting up with severe discomfort or pain versus losing your life, then I think we'd all agree and go for choice numbero uno.

Matt
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Old 21 November 2002, 03:55   #33
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Now, this IS getting interesting.

Yesteryear's accepted wisdom for sail boat survival in deep sea heavy weather conditions was to slow the boat down and use a sea anchor.

A vast amount of practical experience by world renowned mariners showed that this was the way to go. Sea anchor development became very sophisticated and included variants like those that consisted of a very long line with hundreds of mini drogues at close intervals.

When water ballast came along there were those that recommended flooding the tanks as well.

But then along came a French sailor called Christophe Augin who achieved victory in three consecutive round the world races and he changed all this. Another French Open Class racing superstar, Yves Parlier, did the same the same thing.

And what they did was to lighten the boats and let SPEED be their saviour. They flew faster than the seas that threatened to overwhelm them.

I chose to follow this example in my own "rocket ship" during the 1998-99 Around Alone and it served me well.

Approaching Cape Horne from the west in what was the worst storm on the planet at the time I chose to give my boat her head and we outran the storm.

The 50 foot boat weighed only 6 tons, and which was no more than a giant wind-surfer, was able to speed down the back of waves and up the other side before crossing the breaking tops to out-run them down the far side.

Now, I have to admit that my experience of heavy weather sailing in RIBs is very very limited and I read Alan's and Julian's advice with serious interest. But why, if an extreme sail boat can outrun heavy following seas, why can't a RIB do the same?
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Old 21 November 2002, 04:18   #34
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Mike, I am not 100% sure of this but did Magalen Alpha have some sort of keel and how heavy was it? Unfortunatly a RIB is reliant on is't centre of Gravity / Bouyancy. Interesting thought though. Can we go out in Alpha and do a back to back test off of Lands End in a force 12? We could try Your way first and if it works than we have created another altenative Alan P
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Old 21 November 2002, 04:32   #35
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Quote:
Originally posted by Mike Garside
. . . able to speed down the back of waves and up the other side before crossing the breaking tops to out-run them down the far side.
This is fine so long as you are absolutely sure that your boat, whwtever it happens to be, will go up the other side.

The real problem comes when you are going fast (as you will by definition in this scenario!) and your boat tries to go through the next wave, not over it.

Whether it works or not will depend on various factors such as the wave shape and pattern, along with the type and design of boat. Most ribsters caught in heavy weather are unlikely to be mid ocean, so waves will tend to be relatively steep and short, making a stuffing more likely.

The faster you're going when things go wrong, the more it hurts!

John
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Old 21 November 2002, 06:47   #36
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Food for thought

I found Alanís comments very interesting and have been thinking about this matter since. I will not begin to dispute experience as this technique has obviously worked for Alan, his crew and others like Julian for some time. But although I donít doubt and understand the principle I canít get my head around the details?

How many of those who post on this site would be happy to go out to sea and flood their boat and be confident that there systems would continue to function and get them home? Mike?

If you decide to fill your boat you will lower its water line by? Say 100mm. Lowering the CoG by the same amount. Now I would guess that the centre of gravity for a RIB, with a console and inboard is just above deck level. By filling your boat with 400 mm of water, Will you not be placing the weight above the CoG? hence raising the boats CoG, making it more unstable. This is not to mention the effect of the FSE that can significantly reduce the stability of a vessel. When a RIB heels over the centre of buoyancy moves outboard quickly because of the sponsors. So I am unsure how this effects the standard equations concerning the FSE but I am sure it is still a relevant consideration.

As Mike said a number of offshore sailors like himself who have chosen to run before the weather. I understand that stuffing could then become a problem but is the serious of this only proportional to the speed you are travelling in comparison to the wave not through the water. So can you not reduce your speed and run at the same speed as the wave systems? Alan. Making this a feasible option.

Just a thought but this is the sort of article that would be good to see in RIB Int. They could take a RIB out in steep over falls and test these different techniques! Maybe.

Toby
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Old 21 November 2002, 07:59   #37
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Toby, I understand everything you are saying but what I am suggesting is what to do in a life threatening condition, not steep over falls. I fully aggree with Mike's theory but not nessesarly for a RIB that has a great big bubble on the front. A sail boat with go under on the back / front of a wave where as a rib will proberbly rip it,s bow off in a short time.As for the increase in weight, a typical 6 metre RIB will hold around 2.5 ton of water. That is one hell of a keel. As I said, you have to sink the boat and make it part of the sea Alan P
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Old 21 November 2002, 08:36   #38
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Valve

With regard to ripping the tubes off the bow. Could you not fit a preasure release valve to stop this happening? Like on liferafts.

Toby
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Old 21 November 2002, 08:41   #39
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Hi folks

This is all very good info, given me info that I would have never tried before. I think if it got really bad before I would have been pumping out like mad to keep the boat dry, how wrong I would have been.

Everyone talks about how would the boats survive, and that Scorpion do this test as standard, does anyone know if Ribcraft do this test or how Ribcrafts stand up to being flooded. If its a problem for them maybe I can change some things before my new boats fully built. Being a inboard there is lots of extra things to go wrong when flooded. eek:

Would love to see peoples faces at the maina when all the RIB oveners are stood up their knees filling their boat with water, they they will think these funny RIB folks have really lost the plot

Regards Gary:
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Old 21 November 2002, 08:48   #40
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Flooding

Hi Garygee

I'm not sure if Ribcraft sink there boats when built but I do know they make very good boats and very strong boats. Just make sure that the engine box is watertight. Diesel engines and sea water do not mix all that well.

Julian
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