Cruisers Forum
 


Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on Cruisers Forums. Advertise Here
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 02-11-2016, 15:24   #61
Moderator
 
Dockhead's Avatar

Cruisers Forum Supporter

Join Date: Mar 2009
Location: Denmark (Winter), Cruising North Sea and Baltic (Summer)
Boat: Cutter-Rigged Moody 54
Posts: 34,319
Re: Cat in 10-15' seas with around 3-4 second period

Quote:
Originally Posted by Kenomac View Post
It's been explained many times on this forum how the Beaufort scale can't be applied to seas such as the Mediterranean and Baltic or even the Great Lakes. We certainly get the high winds, but the corresponding sea state is different from the Beaufort scale, instead we get steep high waves with a short period between them.
Ken is right -- the sea states described in the Beaufort scale are for fully developed ocean waves, blowing across thousands of miles of fetch for long periods of time.

You get very different sea states in smaller bodies of water like Med or Baltic, much less wave height, but shorter periods.

Up to the point where the ocean waves start to break, I think they are actually easier to deal with than the Med/Baltic ones, even though the ocean waves can be much higher for a given wind strength. I actually had part of my rail broken off my boat in a F8 crossing between Sweden and Finland this year, on a reach no less, not bashing into the waves. They were so steep that they were smashing violently onto the deck, but they were not high at all, I would say 3 meters or so, 4 at most. Never get that in an F8 in the Atlantic.


Also a given wind speed, whatever the body of water, won't produce fully developed wave trains instantly -- it takes some time. It it only blows for an hour or two, it won't get enough energy transferred into the water to get the sea up.
Dockhead is offline   Reply With Quote
Old 02-11-2016, 15:26   #62
cruiser

Join Date: Jan 2012
Location: Pangaea
Posts: 10,856
Re: Cat in 10-15' seas with around 3-4 second period

Quote:
Originally Posted by Snowpetrel View Post
^^ utter rubbish

Sent from my SM-G930F using Cruisers Sailing Forum mobile app
Here in this video is 6-8ft steep choppy waves formed by 35 knot winds from a building mistral. If and when the wind increases to 40-45 knots, you would see the 10-12ft steep choppy waves in the catamaran video with the same 4-5 second intervals. Maybe only 200 miles of fetch off the French coastline. If you like, I can show you a second video of us heading the opposite direction the next day with 40 knots behind us with the waves having built up to 10-12ft.

If you don't believe me, come over to the Med and see for yourself. 10-15ft steep waves with short intervals in 40-45 knot winds is not uncommon. Or just look anywhere along the Mediterranean coastline and you'll see all the vegetation and soil washed clean off the rocky coastline for the first 30-40ft of elevation off the water.
Kenomac is offline   Reply With Quote
Old 02-11-2016, 16:53   #63
Registered User
 
rognvald's Avatar

Join Date: Jan 2011
Location: Now based on Florida's West coast
Boat: Pearson 34-II
Posts: 2,621
Images: 5
Re: Cat in 10-15' seas with around 3-4 second period

Quote:
Originally Posted by Kenomac View Post
It's been explained many times on this forum how the Beaufort scale can't be applied to seas such as the Mediterranean and Baltic or even the Great Lakes. We certainly get the high winds, but the corresponding sea state is different from the Beaufort scale, instead we get steep high waves with a short period between them.
Ken,
I won't argue with your above statement, but the sea state pictured in the above video of the Aegean does not even come close to a 10-15 foot wave train. And, the sea state appears to be closer to a 30K blow . . . but not 50K. As far as the Great Lakes, a 30-35K continuous wind(one day) blowing up/down or across the lakes during the Spring/Summer/Fall will produce seas of 10-15 feet with a short fetch and nasty breaking conditions. During the Winter with 30-50K, 18-22 foot seas are common and would not be survivable by a small boat sailor. I believe many sailors tend to exaggerate winds and sea state and ,in all fairness, they are difficult to judge when you're in the soup. Good luck and safe sailing.
__________________
"And those who were seen dancing were thought to be insane by those who could not hear the music."
Friedrich Nietzsche, Thus Spake Zarathrustra
rognvald is offline   Reply With Quote
Old 02-11-2016, 16:59   #64
Moderator
 
Dockhead's Avatar

Cruisers Forum Supporter

Join Date: Mar 2009
Location: Denmark (Winter), Cruising North Sea and Baltic (Summer)
Boat: Cutter-Rigged Moody 54
Posts: 34,319
Re: Cat in 10-15' seas with around 3-4 second period

Quote:
Originally Posted by rognvald View Post
. . . As far as the Great Lakes, a 30-35K continuous wind(one day) blowing up/down or across the lakes during the Spring/Summer/Fall will produce seas of 10-15 feet with a short fetch and nasty breaking conditions. During the Winter with 30-50K, 18-22 foot seas are common and would not be survivable by a small boat sailor. I believe many sailors tend to exaggerate winds and sea state and ,in all fairness, they are difficult to judge when you're in the soup. .
I've heard this before about the Great Lakes. I've sailed extensively in Med and Baltic, but never in the Great Lakes. I wonder why it would be so different? Because of fresh water? Bottom contour? Perhaps the temperature also plays a role -- cold air is denser.

I've never seen 6 meter seas in Med or Baltic, and I've been out in some way nasty weather in both.
Dockhead is offline   Reply With Quote
Old 02-11-2016, 17:13   #65
cruiser

Join Date: Jan 2012
Location: Pangaea
Posts: 10,856
Re: Cat in 10-15' seas with around 3-4 second period

Quote:
Originally Posted by rognvald View Post
Ken,
I won't argue with your above statement, but the sea state pictured in the above video of the Aegean does not even come close to a 10-15 foot wave train. And, the sea state appears to be closer to a 30K blow . . . but not 50K. As far as the Great Lakes, a 30-35K continuous wind(one day) blowing up/down or across the lakes during the Spring/Summer/Fall will produce seas of 10-15 feet with a short fetch and nasty breaking conditions. During the Winter with 30-50K, 18-22 foot seas are common and would not be survivable by a small boat sailor. I believe many sailors tend to exaggerate winds and sea state and ,in all fairness, they are difficult to judge when you're in the soup. Good luck and safe sailing.
It appears we agree on most everything. I also don't see much wind driven spray in the Aegean video, they may have been referring to wind gusting to 50k. There might be some misunderstanding as I was referring instead to the original catamaran video posted by the OP. Not the sea state in the Aegean video.
Kenomac is offline   Reply With Quote
Old 03-11-2016, 15:54   #66
Registered User
 
CbroTheDude's Avatar

Join Date: Oct 2016
Boat: Pogo 10,50
Posts: 189
Re: Cat in 10-15' seas with around 3-4 second period

Quote:
Originally Posted by 44'cruisingcat View Post
That's basically what this forum consists of. A very few sailors posting their experience, and an awful lot of keyboard sailors (the kind of people who don't say what boat they own, because they don't own one) criticising everything they do.

Rich people can be sailors or at least have a boat which doesn't make them anymore clever than people sailing but who can't own their boat...
Stupid harsh stereotypical comment, and you look more like what you call a "keyboard sailor" than anyone with such unjustified intolerance
CbroTheDude is offline   Reply With Quote
Old 03-11-2016, 16:06   #67
Registered User

Join Date: Sep 2009
Location: on board, Australia
Boat: 11meter Power catamaran
Posts: 3,648
Images: 3
Re: Cat in 10-15' seas with around 3-4 second period

Quote:
Originally Posted by CbroTheDude View Post
Rich people can be sailors or at least have a boat which doesn't make them anymore clever than people sailing but who can't own their boat...
Stupid harsh stereotypical comment, and you look more like what you call a "keyboard sailor" than anyone with such unjustified intolerance
Now thats an interesting observation of someone who built their own vessel (catamaran) including their mast and living aboard full time for 12 mths a year for years now.

You could not be more wrong in this case Dude.
downunder is offline   Reply With Quote
Old 03-11-2016, 16:28   #68
Registered User

Join Date: Jan 2010
Location: Canada
Posts: 280
Re: Cat in 10-15' seas with around 3-4 second period

Quote:
Originally Posted by CbroTheDude View Post
Rich people can be sailors or at least have a boat which doesn't make them anymore clever than people sailing but who can't own their boat...
Stupid harsh stereotypical comment, and you look more like what you call a "keyboard sailor" than anyone with such unjustified intolerance
I think you ought to do a bit of research there, my friend. The person you are so quick to be critical of is one of the more respected members here.

44C has been there and done that and speaks from experience. Something you appear to not yet have aquired
rallyman1122 is offline   Reply With Quote
Old 03-11-2016, 18:31   #69
Registered User
 
moepitman's Avatar

Join Date: Sep 2015
Location: Austin, TX
Boat: Seafarer 29
Posts: 17
Re: Cat in 10-15' seas with around 3-4 second period

Quote:
Originally Posted by Dockhead View Post
Ken is right -- the sea states described in the Beaufort scale are for fully developed ocean waves, blowing across thousands of miles of fetch for long periods of time.

You get very different sea states in smaller bodies of water like Med or Baltic, much less wave height, but shorter periods.

Up to the point where the ocean waves start to break, I think they are actually easier to deal with than the Med/Baltic ones, even though the ocean waves can be much higher for a given wind strength. I actually had part of my rail broken off my boat in a F8 crossing between Sweden and Finland this year, on a reach no less, not bashing into the waves. They were so steep that they were smashing violently onto the deck, but they were not high at all, I would say 3 meters or so, 4 at most. Never get that in an F8 in the Atlantic.


Also a given wind speed, whatever the body of water, won't produce fully developed wave trains instantly -- it takes some time. It it only blows for an hour or two, it won't get enough energy transferred into the water to get the sea up.
I've seen the same in the Gulf of Mexico, though the water isn't as pretty. 10 to 12 feet in well under 40 knots, with a nasty, short period.
moepitman is offline   Reply With Quote
Old 03-11-2016, 19:29   #70
Registered User

Join Date: May 2011
Posts: 847
Re: Cat in 10-15' seas with around 3-4 second period

LOL.. yea I think these guys have their meters calibrated in kilometers per hour

As for the comments on Beaufort sea states. With new winds the seas can be completely flat and as others have said the waves build over time. The seas can only reach their full height with sufficient fetch. However the description of the surface of the water; blown streaks, spray, etc.. hold true at any point of the blow's development.

People often quote the highest gust they see as the wind speed .. it aint!

Their anemometers are invariably not calibrated for the height of the sensor on the mast.

Then there is just pissing contests.

Whatever the wind that cat is is nasty sea. Looks like there is sea reflected off the harbour wall mixed up in that too. Wouldn't fancy doing a pick up off a pilot ladder in that.
Littlechay is offline   Reply With Quote
Old 03-11-2016, 20:06   #71
Moderator
 
Jim Cate's Avatar

Join Date: May 2008
Location: cruising SW Pacific
Boat: Jon Sayer 1-off 46 ft fract rig sloop strip plank in W Red Cedar
Posts: 21,295
Re: Cat in 10-15' seas with around 3-4 second period

I wonder if the reported 3-4 second period takes into account that the boat is moving towards the wave motion, and at a significant fraction of the wave train velocity? The resulting Doppler effect will shorten the apparent period considerably; this could help explain some of the conflicting thoughts above.

Jim
__________________
Jim and Ann s/v Insatiable II, lying Port Cygnet Tasmania once again.
Jim Cate is offline   Reply With Quote
Old 04-11-2016, 04:51   #72
Registered User
 
CbroTheDude's Avatar

Join Date: Oct 2016
Boat: Pogo 10,50
Posts: 189
Re: Cat in 10-15' seas with around 3-4 second period

Quote:
Originally Posted by downunder View Post
Now thats an interesting observation of someone who built their own vessel (catamaran) including their mast and living aboard full time for 12 mths a year for years now.



You could not be more wrong in this case Dude.

I was only following your description of CF members, in which your primitive close-minded criticising speech puts you more in the keyboard-sailors category, so maybe you're wrong ;-)
CbroTheDude is offline   Reply With Quote
Old 04-11-2016, 04:59   #73
Registered User

Join Date: May 2011
Posts: 847
Re: Cat in 10-15' seas with around 3-4 second period

Quote:
Originally Posted by Snowpetrel View Post
^^ utter rubbish
Quite!
Littlechay is offline   Reply With Quote
Old 04-11-2016, 05:14   #74
Registered User

Join Date: Jun 2010
Location: Now limited to seasonal NE sailing
Boat: PT-11
Posts: 1,541
Re: Cat in 10-15' seas with around 3-4 second period

Quote:
Originally Posted by CbroTheDude View Post
Rich people can be sailors or at least have a boat which doesn't make them anymore clever than people sailing but who can't own their boat...
Stupid harsh stereotypical comment, and you look more like what you call a "keyboard sailor" than anyone with such unjustified intolerance
You're making friends here everywhere you go.
SVNeko is offline   Reply With Quote
Old 04-11-2016, 05:26   #75
Registered User
 
Suijin's Avatar

Join Date: Feb 2013
Location: Bumping around the Caribbean
Boat: Valiant 40
Posts: 4,625
Re: Cat in 10-15' seas with around 3-4 second period

Quote:
Originally Posted by Jim Cate View Post
I wonder if the reported 3-4 second period takes into account that the boat is moving towards the wave motion, and at a significant fraction of the wave train velocity? The resulting Doppler effect will shorten the apparent period considerably; this could help explain some of the conflicting thoughts above.

Jim
Indeed, that boat seems to be making consistent headway, so the actual wave period could be substantially longer.

Looking at the video there are a couple of things that are immediately obvious. First, it's a big boat. Second, some of the swells are indeed 10'-15', with the cabin top vanishing as the boat slips into the trough (and the vantage point of the video is elevated. And the general wave period is pretty short, even if the larger swells are spaced further apart.

This was probably filmed in the Med, since the poster is Greek and has posted a number of other boat videos of generally similar conditions shot locally.
Suijin is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
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
How to Read the Period of Waves Alecadi Seamanship & Boat Handling 28 21-11-2017 19:33
AIS Targets Disappear After a Longer Period sinbad7 OpenCPN 86 30-04-2012 09:18
Crew Available: Crew Avbailable Over Summer Break Period GregAllum Crew Archives 0 01-08-2011 23:13
Swell Size , Period and Boat Comfort ? Boracay Seamanship & Boat Handling 26 05-06-2011 05:28
Cooling Off Period on New Yatchs ? andy2290 Dollars & Cents 8 18-11-2010 00:41

Advertise Here


All times are GMT -7. The time now is 23:34.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.