Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 09-03-2009, 01:15   #1
CF Adviser
Moderator Emeritus
 
TaoJones's Avatar

Cruisers Forum Supporter

Join Date: Dec 2006
Location: Montrose, Colorado
Posts: 9,850
Freak Wave - Compound Leg Fracture

Many of you are probably familiar with Peter Goss and his Spirit of Mystery blog. The following is from his account of a knockdown they recently suffered, and the consequences:

"I put the washing up liquid by the hatch, reach out and clip on before leaving the safety of below, glance up and there it is. A huge wall of water that towers over the boat and there is nothing breaking about it. Its solid, dark green, dangerous and a freak; 'HOLD ON' I am aware of Mark bracing himself as I duck my head and tense. The noise is as shocking as the blow, I am aware of it going very dark and I am disorientated. I am under water and can't breathe, there is a huge weight pushing me down and the rush of solid water through the hatch has my legs straining in resistance. It feels like I am trying to push the wrong way up a storm drain in full flood and that is what I am trying to do for I know that this is going to leave us badly damaged and I am fighting to get to Mark who is my first concern. My chest is protesting, I need to breath, how much longer is this going to go on for. Come on Spirit this is it, this is the moment of truth, you can only swallow so much before the physics that have sustained us don't add up."

To read the entire riveting account, from the March 8 update headlined "The knock-down," go to:

Latest Weblog

TaoJones
__________________

__________________
"Your vision becomes clear only when you look into your own heart. Who looks outside, dreams; who looks within, awakens."
Carl Gustav Jung (1875-1961)
TaoJones is offline   Reply With Quote
Old 09-03-2009, 02:13   #2
Registered User
 
Vida Nova's Avatar

Join Date: Oct 2007
Boat: Catalina 250 WB - Vida Nova
Posts: 21
The source of Freak Waves

I thought these were folklore, and so did the scientific community for a long time. However such occurrences do happen more often than one might think. I stumbled on a series of highly interesting BBC videos that proved me wrong. The linear model dictates that even in a fierce storm where the average wave height might be 12 meters (40 feet) that the chance of hitting a 30 meter wave (100 feet) is practically ZERO. Using the linear model the chances of hitting such a wave is 10 to the -5, which is 0.0001%. To put things in perspective that means that a freak wave comes once every 10,000 years.

However they do occur. The combination of wave directions against the current is what gives life to these monsters. In fact there are 2 kinds of waves, the ones who do follow the stable linear model and the unstable non-linear waves that feed off the energy of other waves around them. A few places in the world are known to have the right conditions to summon these beasts. Fortunately most of our cruising grounds are nowhere near there.

You may view the high res videos on my web site:
http://vidanova1.mysailboatblog.com/2009/03/09/freak-waves/
__________________

__________________
Steve Blackburn
VIDA NOVA, Catalina 250WB
Vida Nova is offline   Reply With Quote
Old 09-03-2009, 05:45   #3
Moderator Emeritus
 
GordMay's Avatar

Join Date: Mar 2003
Location: Thunder Bay, Ontario - 48-29N x 89-20W
Boat: (Cruiser Living On Dirt)
Posts: 31,583
Images: 240
Quote:
Originally Posted by Vida Nova View Post
... Using the linear model the chances of hitting such a wave is 10 to the -5, which is 0.0001%. To put things in perspective that means that a freak wave comes once every 10,000 years.

However they do occur...


Ship-sinking monster waves revealed by ESA satellites
Goto:
ESA Portal - Ship-sinking monster waves revealed by ESA satellites

Once dismissed as a nautical myth, freakish ocean waves that rise as tall as ten-storey apartment blocks have been accepted as a leading cause of large ship sinkings. Results from ESA's ERS satellites helped establish the widespread existence of these 'rogue' waves and are now being used to study their origins...
... radar data from the North Sea's Goma oilfield recorded 466 rogue wave encounters in 12 years - helped convert previously sceptical scientists, whose statistics showed such large deviations from the surrounding sea state should occur only once every 10000 years...
__________________
Gord May
"If you didn't have the time or money to do it right in the first place, when will you get the time/$ to fix it?"



GordMay is offline   Reply With Quote
Old 11-12-2009, 17:22   #4
Long Range Cruiser
 
MarkJ's Avatar

Cruisers Forum Supporter

Join Date: Dec 2007
Location: Australian living on "Sea Life" currently in England.
Boat: Beneteau 393 "Sea Life"
Posts: 12,828
Images: 25
Just going back over this thread... at the time they were in the Southern Ocean, and Gords figers come from the North Sea.

I am sure they do occur in the extreems but we should not the locations are not often sailed by our mob
__________________
Notes on a Circumnavigation.
OurLifeAtSea.com

Somalia Pirates and our Convoy
MarkJ is offline   Reply With Quote
Old 11-12-2009, 17:52   #5
Registered User

Join Date: Sep 2009
Location: the golden state
Boat: pilot cutter
Posts: 289
There was a show recently on one of the education channels (Discovery?) detailing how these huge waves occur and how they are much more common than even more recently suspected, and showing how the phenomena has been replicated in the lab using wave tanks. Basically, wind and currents conspire to join many many many many little waves into one big giant wave, forming a 'rogue' wave. All that is required is the correct wind/current conditions that cause the small waves to pile up on one another.
__________________
Not Sure is offline   Reply With Quote
Old 12-12-2009, 05:16   #6
Moderator Emeritus
 
GordMay's Avatar

Join Date: Mar 2003
Location: Thunder Bay, Ontario - 48-29N x 89-20W
Boat: (Cruiser Living On Dirt)
Posts: 31,583
Images: 240
Quote:
Originally Posted by MarkJ View Post
Just going back over this thread... at the time they were in the Southern Ocean, and Gords figers come from the North Sea.
I am sure they do occur in the extreems but we should not the locations are not often sailed by our mob
They occur everywhere.

Excerpted from the article (Ship-sinking monster waves revealed by ESA satellites):

“... So far some patterns have already been found. Rogue waves are often associated with sites where ordinary waves encounter ocean currents and eddies. The strength of the current concentrates the wave energy, forming larger waves – Lehner compares it to an optical lens, concentrating energy in a small area.

This is especially true in the case of the notoriously dangerous Agulhas current off the east coast of South Africa, but rogue wave associations are also found with other currents such as the Gulf Stream in the North Atlantic, interacting with waves coming down from the Labrador Sea.


However the data show rogue waves also occur well away from currents, often occurring in the vicinity of weather fronts and lows. Sustained winds from long-lived storms exceeding 12 hours may enlarge waves moving at an optimum speed in sync with the wind – too quickly and they'd move ahead of the storm and dissipate, too slowly and they would fall behind.”

Wave climatology information services ~ ESA
http://earth.esa.int/applications/da...sk/ssc/ssc.htm

World Wave Atlas (WWA)
World Wave Atlas, a PC MS-Windows Application for Geographical Presentation of Wind and Wave Statistics World-wide

WWA - World Wave Atlas - Wave and Wind Atlases for any country worldwide
__________________
Gord May
"If you didn't have the time or money to do it right in the first place, when will you get the time/$ to fix it?"



GordMay is offline   Reply With Quote
Old 12-12-2009, 06:23   #7
Moderator
 
nigel1's Avatar

Cruisers Forum Supporter

Join Date: Oct 2009
Location: Manchester, UK
Boat: Beneteau 473
Posts: 5,190
Quote:
Originally Posted by GordMay View Post

Portal - Ship-sinking monster waves revealed by ESA satellites

... radar data from the North Sea's Goma oilfield recorded 466 rogue wave encounters in 12 years - helped convert previously sceptical scientists, whose statistics showed such large deviations from the surrounding sea state should occur only once every 10000 years...
In March 2003, we did a trip from Aberdeen to Bergen, had to push the boat quite hard in ordėr to get to Bergen to pick up a rig.
Wind was Force 10 from the NE, and I decided to "tack" the boat across the seas rather than hitting them head on. We were rolling about 20 degrees, but not so bad. At about 2300, vessel was cresting a sea/swell, but instead of pitching down the backside of the wave, it felt that we had fallen in a hole, 6000 tonne of tug in free fall. It felt like we landed on beam ends , but that was probably disorientation. When we had pick ouselves up, the port shoulder of the tug had been set in 6 inches, with frames buckled.
Tops my list of things I dont want to experience again.
__________________
Nigel
Beneteau 473
Manchester, UK
nigel1 is online now   Reply With Quote
Old 12-12-2009, 06:55   #8
Registered User

Join Date: Jan 2007
Posts: 497
Images: 1
Anybody watch Deadliest Catch? There is an episode on there were a 130 foot crabber was sitting nose into a 40 knot blow when a huge wave came aboard directly from starboard. This rolled the boat quite badly and most of their systems went down, it did not go over. It was all caught on film. Changed my mind completely about rogue waves. Nothing like film at 11 to convince you stuff happens.
__________________
jdoe71 is offline   Reply With Quote
Old 13-12-2009, 17:53   #9
Registered User
 
paradix's Avatar

Join Date: Oct 2009
Location: Australasia
Posts: 284
Here's that Deadliest Catch footage:

__________________
paradix is offline   Reply With Quote
Old 13-12-2009, 18:15   #10
Registered User

Join Date: Aug 2009
Posts: 8
Downside:
Lost two friends swept over while crabbing.
Another paralyzed below waist falling onto railing on lower back.

Upside:
Captain friend began as crew,ended as owner of 2 boats as well as 5 acres on Olympic Peninsula,private island in inside passage AK/BS,5 acres Maui.

Nothing ventured, nothing gained.
Faint heart never won fair maiden.
__________________
divelly is offline   Reply With Quote
Old 14-12-2009, 14:33   #11
elf
Registered User
 
elf's Avatar

Join Date: Nov 2006
Location: North Carolina
Boat: Catalina 30
Posts: 105
Quote:
Originally Posted by paradix View Post
Here's that Deadliest Catch footage
Holeee crap! My heart leapt up into my throat...
__________________

__________________
elf is offline   Reply With Quote
Reply

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Yanmar 3GM30F to Buhk Saildrive leg Z7 Uncle Braddah Construction, Maintenance & Refit 0 01-10-2008 14:21
Yachtsmen 'died in freak accident' sctpc Pacific & South China Sea 21 14-08-2008 15:49
Witnesses tell of freak death of Steve Irwin CaptainK Off Topic Forum 7 04-09-2006 16:06
Bedding Compound/Sealer SkiprJohn Construction, Maintenance & Refit 9 30-06-2006 13:02
Sillette leg outdrive problems? Talbot Multihull Sailboats 2 21-10-2004 10:17



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 11:21.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.