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-   -   Roll over survival (http://www.sailnet.com/forums/seamanship-navigation/83156-roll-over-survival.html)

davidpm 01-26-2012 10:37 PM

Roll over survival
 
There have been many discussions about the seamanship required to survive a life-threatening storm. Reefing, steaming warps, drogues, and heaving too have all be discussed.

It is also common knowledge that lockers and companionways need to be secured and cockpits need large drains because in the case of boarding seas or knockdown the boat can take on water and flounder.

I've only been on two boats that were pinned down to about maybe 75 degrees.
In both cases I got to tell you we were very busy just holding on.

It is very, very hard to actively sail the boat in these conditions.
In Abby's case according to the book she had just come through a pretty bad storm and was just cleaning up below when a rogue wave rolled the boat. She bounced around the cabin quite a bit and was even knocked out for a few seconds.

So here is the question?
When does the captain make the decision to leave the cockpit?
If the conditions are so brutal that you can't see 6 inches and your hands don't work it is so cold you might as well go below.
If you get so tired it is not safe to be above.

If the boat gets rolled you are very likely going to loose the rig. Not for sure but very possible so staying on deck and actively keeping the boat right side up is a good thing.

But here is my point. If the likelihood of a roll is high do people often survive in the cockpit? Do you remember any reports where people stay tethered and survive? Un-thering is an option, risky but possible if their are other crew boats nearby like in a race but not much of an option for cruising alone.

jackdale 01-26-2012 11:19 PM

Quote:

Originally Posted by davidpm (Post 821909)

But here is my point. If the likelihood of a roll is high do people often survive in the cockpit? Do you remember any reports where people stay tethered and survive? Un-thering is an option, risky but possible if their are other crew boats nearby like in a race but not much of an option for cruising alone.

David

The Fatal Storm and Proving Ground (The 1998 Sydney Hobart Race) should be right next to Fastnet Force 10 on you bookshelf. There are a couple of examples of capsized boats with tethered crews.

When cruising wear a PLB. It "might" help.

davidpm 01-26-2012 11:44 PM

Quote:

Originally Posted by jackdale (Post 821934)
David

The Fatal Storm and Proving Ground (The 1998 Sydney Hobart Race) should be right next to Fastnet Force 10 on you bookshelf. There are a couple of examples of capsized boats with tethered crews.

When cruising wear a PLB. It "might" help.

I read them a long time ago. Will get them again.

I'm not sure I could hold my breath that long?

davidpm 01-26-2012 11:48 PM

Quote:

Originally Posted by jackdale (Post 821934)
David

The Fatal Storm and Proving Ground (The 1998 Sydney Hobart Race) should be right next to Fastnet Force 10 on you bookshelf. There are a couple of examples of capsized boats with tethered crews.

When cruising wear a PLB. It "might" help.

Just bought it. I'm not sure I like it or if it is even a good thing but I can get a book in less that 30 seconds now. At least this one was only 5 bucks.

jlynker 01-27-2012 02:14 AM

The book Desirable and Undesirable Characteristics of Offshore Yachts

http://www.amazon.com/Desirable-Unde...7644337&sr=8-1

has a chapter which describes tests of yachts in wave pools. They capsize boats and measure their ability to right themselves. Of course, if your main is up and sheeted in tight, or if when your boat is capsized it becomes a flat bottom boat, the time to right itself is significantly longer.

Knowing the characteristics of the boat you're sailing should inform your decision of when to go below and how to 'gracefully degrade' from the effort to make way.

Additional good advice in this book includes - having a mast with a Storm Tri-sail bent on and ready to go... for instance, the Lefiell OM3D mast has a 2nd integral track for a storm tri-sail. Cruising Mast & Boom Assemblies.

This book was an easy read... I absorbed it in 3 weeks... Lots of expert knowledge regarding cruising boats.

mikieg 01-27-2012 03:09 AM

this is a damned good thread. these are indeed the very things i think about! i am looking forward to reading all the replies.

smurphny 01-27-2012 08:32 AM

Capsize ratio was #1 on my list of design factors in choosing an Alberg 35 to renovate and sail. It came in WAY ahead of speed, cabin space, and resale value. In the event of an actual 360 degree roll, differentiated from a knockdown, from what I've read, the mast/rigging will almost surely break. The swages/aluminum/s.s. is nowhere near strong enough to absorb the force of water, leveraged against the boat by the length of the rig. Even if you're below, this will require getting on deck to secure the battering ram that is likely still attached by the rigging that did not break. If far from help, saving pieces could be used to jury rig. So, you're going to be tethered to a boat being tossed around by breaking waves, rigging flying about, boat in danger of rolling again with you on deck. Would some sort of small rebreather be a wise thing to have if you ever have to be on deck in these conditions? As long as the hatches and boards are in you KNOW she will right herself eventually. Is it wise to even use an inflatable pfd which may go off at the wrong moment as you're struggling to secure the rig? Do you want one to go off if you're clinging like a barnacle to the inverted boat?

mikieg 01-27-2012 10:51 AM

tell me about this capsize ratio. how is it calculated and what is a good number?

marianclaire 01-27-2012 11:50 AM

This may help. Capsize Formula Dan S/V Marian Claire

mikieg 01-27-2012 03:17 PM

ok, so what is a good number?


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