Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 20-02-2010, 15:52   #1
Senior Cruiser
 
maxingout's Avatar

Cruisers Forum Supporter

Join Date: Dec 2006
Location: Fort Pierce, Phoenix
Boat: Privilege 39 Catamaran, Exit Only
Posts: 2,606
Microbursts and Multihulls

I just read an article about a microburst striking SV Concordia off the coast of Brazil. The vessel is 188 feet long, and had at least forty high school and college students on board. The microburst knocked the vessel down pinning the sails to the water, and in fifteen seconds they had to abandon ship as it was taking on water and sinking. Everybody made it into liferafts, and all were rescued.

Here is the question. Do you know of any instances of a microburst hitting a multihull sailing offshore when not racing, and if you do, what was the outcome?
__________________

__________________
Dave -Sailing Vessel Exit Only

http://SailingUNI.com
http://maxingout.com
http://PositiveThinkingSailor.com
maxingout is offline   Reply With Quote
Old 20-02-2010, 16:00   #2
Senior Cruiser
 
maxingout's Avatar

Cruisers Forum Supporter

Join Date: Dec 2006
Location: Fort Pierce, Phoenix
Boat: Privilege 39 Catamaran, Exit Only
Posts: 2,606
The Canadian Press: Captain of floating university: Sudden 'microburst' knocked ship onto side off Brazilian coast

This is a link to an account of the microburst and sinking of SV Concordia.

Additional comment:

I am not so much interested in the behaviour of an overcanvassed multihull in a race during a microburst. I know the multihull will probably flip. I am interested in the behavior of a cruising multihull in a microburst.

Do you know of any cruising multihulls offshore caught in microbursts?
__________________

__________________
Dave -Sailing Vessel Exit Only

http://SailingUNI.com
http://maxingout.com
http://PositiveThinkingSailor.com
maxingout is offline   Reply With Quote
Old 20-02-2010, 17:12   #3
Registered User

Join Date: Dec 2007
Location: Duluth,Minnesota
Boat: Lindenberg 26 & Aloha 8.2
Posts: 984
Dave ,i dont know if it makes much difference if the multi is racing or cruising,any amount of sail is over canvassed if it catches you unawares,we get these things on the great lakes which i would have to call microbursts where you have very light winds and have lots of sail up,then you see this big black wall comming at you and you scramble to get everything down and secured before you get whacked by instantaneous 70 knots,a few minutes later its dropped to 30 or so and you get reefed sail up and plug on.I looked at buying a racing cat that flipped with loss of 2 souls in one of these that struck them at night,they probably never saw it comming, i dont know what sail they had up but main and working jib would have been too much,would a cruising cat have fared better,i dont know,probably more stabilit due to more weight and less sail area.Ive been in 2 of these things, the first in a 24ft uldb i designed and built and we were racing,i had never seen one before and we were a bit late getting the sails down and were knocked down with the mast in the water,we waited it out,reefed,changed to the self tacker and completed the race,no water down below due to the open transom so no real danger,im sure we were down for several minutes,other boats were taking water down the companionway. The second time we were cruising on a 34ft we had built ,this time we recognized it and got everything down in time and the engine running but still ended up with the mast in the water and a stray sheet around the prop.
Steve.
.
__________________
clockwork orange is offline   Reply With Quote
Old 20-02-2010, 18:20   #4
Senior Cruiser
 
maxingout's Avatar

Cruisers Forum Supporter

Join Date: Dec 2006
Location: Fort Pierce, Phoenix
Boat: Privilege 39 Catamaran, Exit Only
Posts: 2,606
Quote:
Originally Posted by clockwork orange View Post
Dave ,i dont know if it makes much difference if the multi is racing or cruising,any amount of sail is over canvassed if it catches you unawares,we get these things on the great lakes which i would have to call microbursts where you have very light winds and have lots of sail up,then you see this big black wall comming at you and you scramble to get everything down and secured before you get whacked by instantaneous 70 knots,a few minutes later its dropped to 30 or so and you get reefed sail up and plug on.I looked at buying a racing cat that flipped with loss of 2 souls in one of these that struck them at night,they probably never saw it comming, i dont know what sail they had up but main and working jib would have been too much,would a cruising cat have fared better,i dont know,probably more stabilit due to more weight and less sail area.Ive been in 2 of these things, the first in a 24ft uldb i designed and built and we were racing,i had never seen one before and we were a bit late getting the sails down and were knocked down with the mast in the water,we waited it out,reefed,changed to the self tacker and completed the race,no water down below due to the open transom so no real danger,im sure we were down for several minutes,other boats were taking water down the companionway. The second time we were cruising on a 34ft we had built ,this time we recognized it and got everything down in time and the engine running but still ended up with the mast in the water and a stray sheet around the prop.
Steve.
.
When you got hit by the 70 knot winds, did you feel the chill of cold air before the full force of the microburst hit?

I've been sailing many times and felt the chill of the high altitude cold air coming my way before the full force of the wind hit. Whenever I feel the cold air, I take my sails down.
__________________
Dave -Sailing Vessel Exit Only

http://SailingUNI.com
http://maxingout.com
http://PositiveThinkingSailor.com
maxingout is offline   Reply With Quote
Old 20-02-2010, 19:05   #5
Elvish meaning 'Far-Wanderer'
 
Palarran's Avatar

Cruisers Forum Supporter

Join Date: Jan 2008
Location: Me - Michigan / Boat - Tenerife
Boat: 56' Fountaine Pajot Marquises
Posts: 2,641
Quote:
Originally Posted by clockwork orange View Post
we get these things on the great lakes which i would have to call microbursts where you have very light winds and have lots of sail up,then you see this big black wall comming at you and you scramble to get everything down and secured before you get whacked by instantaneous 70 knots,a few minutes later its dropped to 30 or so
.
I have seen that exact storm several times on Lake Michigan. Once the black cloud was only maybe a 1/4 mile high and rolling along the water. It was one cool looking front. But, I'm not sure it would be a micro-burst. I think they tend to hit when the storm is already there.

Dave, I'm wondering if you'd be interested in sharing what you think would happen if a cat was hit by a microburst. I thought I'd read somewhere that catamarans sails where designed to basically blow out if hit with to much wind. If they didn't blow out, I wouldn't think the boat would capsize as the inertia would be to great. Rigging failure?
__________________
Not all who wander are lost

http://www.sailblogs.com/member/palarran/
Palarran is offline   Reply With Quote
Old 20-02-2010, 19:12   #6
Senior Cruiser

Cruisers Forum Supporter

Join Date: Aug 2009
Location: between the devil and the deep blue sea
Boat: a sailing boat
Posts: 17,314
I would be very careful with what finished off Concordia. It is not the first training ship that claims microburst. Somehow, neither Gorch Fock, nor any other of the dozen of tall ships or so had this kind of trouble. Why?

Quite recently a Polish training ship lost her sticks. Why?

b.
__________________
barnakiel is offline   Reply With Quote
Old 20-02-2010, 19:23   #7
Registered User
 
Zednotzee's Avatar

Join Date: Jun 2009
Location: Oromocto, New Brunswick
Boat: 1976 Alberg 37 Yawl hull 172
Posts: 394
Quote:
Originally Posted by maxingout View Post
When you got hit by the 70 knot winds, did you feel the chill of cold air before the full force of the microburst hit?

I've been sailing many times and felt the chill of the high altitude cold air coming my way before the full force of the wind hit. Whenever I feel the cold air, I take my sails down.
You may be interested in this article, from the Great Lakes Alberg Association newsletter-

The Great Lakes Alberg Assoc.

From his account, the only warnings were visual & a shift in wind direction. One (fully canvassed) boat was sunk.
__________________
Zednotzee is offline   Reply With Quote
Old 20-02-2010, 19:32   #8
Registered User

Join Date: May 2009
Location: Vancouver, Wash.
Boat: no longer on my Cabo Rico 38 Sanderling
Posts: 1,794
Send a message via MSN to John A
There is no warning when a micro burst will occur. They're the same thing as wind shear around airports.
Its caused by a downdraft from the layer of wind that flows above the surface winds when they flow in the same direction and is the sum of the two.
A very mild micro burst is called a gust of wind.
The following was taken from a google search.
A microburst is a small, very intense downdraft that descends to the ground resulting in a strong wind divergence. The size of the event is typically less than 4 kilometers across. Microbursts are capable of producing winds of more than 100 mph causing significant damage. The life span of a microburst is around 5-15 minutes
__________________
John A is offline   Reply With Quote
Old 20-02-2010, 22:27   #9
Senior Cruiser
 
maxingout's Avatar

Cruisers Forum Supporter

Join Date: Dec 2006
Location: Fort Pierce, Phoenix
Boat: Privilege 39 Catamaran, Exit Only
Posts: 2,606
Quote:
Originally Posted by Palarran View Post
I have seen that exact storm several times on Lake Michigan. Once the black cloud was only maybe a 1/4 mile high and rolling along the water. It was one cool looking front. But, I'm not sure it would be a micro-burst. I think they tend to hit when the storm is already there.

Dave, I'm wondering if you'd be interested in sharing what you think would happen if a cat was hit by a microburst. I thought I'd read somewhere that catamarans sails where designed to basically blow out if hit with to much wind. If they didn't blow out, I wouldn't think the boat would capsize as the inertia would be to great. Rigging failure?
I have wondered many times how a microburst would effect Exit Only. We tend to sail in a conservative manner, but from what I read, any sail that you have up is too much in a microburst.

My catamaran is over-rigged for a 39 foot catamaran in my opinion. So I don't think the rigging would go in a microburst. I am very meticulous about the condtion of my rigging. My sails are 9 oz, and I never blew out a sail since the boat came from the factory. I have never lifted a hull out of the water.

I really don't know what would happen if I got hit by a microburst. Our autopilot steers the boat 98% of the time, and if we ever got him by a microburst, the autopilot would probably be steering the boat when it happened.

I guess how a microburst would affect the boat would depend to a significant degree on our point of sail, and how the autopilot responded.

If a microburst hit Exit Only when there was no sail up, I don't think there would be any problem. In every other situation, I really don't know how things would turn out.
__________________
Dave -Sailing Vessel Exit Only

http://SailingUNI.com
http://maxingout.com
http://PositiveThinkingSailor.com
maxingout is offline   Reply With Quote
Old 20-02-2010, 22:37   #10
Senior Cruiser
 
s/v Beth's Avatar

Cruisers Forum Supporter

Join Date: Oct 2008
Location: Coos Bay, Oregon
Boat: Valiant 40 (1975)
Posts: 4,066
My family and I got caught in a microburst on Utah Lake. Even though our boat was heavily reefed, we broached but popped up immediately afterwards. The only warning we had was the whitecaps racing to us (about 30 seconds worth). About 2 minutes of pure h$!!, then picking up the pieces and going home...
__________________
s/v Beth is offline   Reply With Quote
Old 20-02-2010, 22:37   #11
Registered User

Join Date: Jun 2007
Location: SW Florida
Boat: FP Belize, 43' - Dot Dun
Posts: 3,425
Cruising cats are heavy enough the rig will go before a hull lifts out of the water. My rig is big also, all 14mm, but the engineers at the manufacturer told me the rig would go before wind would flip the boat.

I don't want to test it!
__________________
DotDun is offline   Reply With Quote
Old 20-02-2010, 23:54   #12
Registered User

Join Date: May 2009
Location: Vancouver, Wash.
Boat: no longer on my Cabo Rico 38 Sanderling
Posts: 1,794
Send a message via MSN to John A
Sailing east from Panama I was in the middle of some pretty stiff winds with a full keel cutter. All of a sudden a gust of wind hit the boat and I stood in the cockpit and watched as every plastic sail slug on the main exploded! Faster than you can read this!
The main was attached by the top and bottom metal slugs.

I'd kept my old main but changing it in 15ft seas by myself took awhile, because of the double tether for the safety harness.
__________________
John A is offline   Reply With Quote
Old 21-02-2010, 04:02   #13
Registered User
 
Laidback's Avatar

Join Date: Jun 2007
Posts: 853
In Which Latitudes have so called Micro Bursts been OFFICIALY recorded?

What is the difference between a Tropical Line Squall and a "Micro Burst" ?
__________________
Laidback is offline   Reply With Quote
Old 21-02-2010, 07:15   #14
Senior Cruiser
 
Blue Stocking's Avatar

Cruisers Forum Supporter

Join Date: Dec 2008
Location: St. Georges, Bda
Boat: Rhodes Reliant 41ft
Posts: 4,114
When A square-rigged ship, such a Pride of Baltimore, Marques, (sunk by microburst north of Bermuda in 1984), or Concordia, are sheeted in for windward work, and are knocked flat, the sails fill with water, and the ship cant stand back up.
The sheets and braces are cleated to the submerged rail, and cant be released.
With a centreline sheeted arrangement we would have a better chance of releasing, IMHO
__________________
so many projects--so little time !!
Blue Stocking is offline   Reply With Quote
Old 21-02-2010, 09:06   #15
Registered User

Join Date: May 2009
Location: Vancouver, Wash.
Boat: no longer on my Cabo Rico 38 Sanderling
Posts: 1,794
Send a message via MSN to John A
Laidback,
Please read my post above explaining micro-burst. They can occur anywhere that the wind blows, even in clear air.
A rain squall is a different animal and will travel for only 20 or 30 miles before disappearing.
If I couldn't see thru a rain squall, I'd usually take evasive action - reef down or change course, I've had to evade waterspouts in large rain squalls.
regards John.
__________________

__________________
John A 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
Why I Like Multihulls (Well, One Reason) Jmolan Multihull Sailboats 127 05-12-2012 02:59
multihulls indypopeye Multihull Sailboats 4 17-11-2008 17:22
whither express multihulls? sandy daugherty Multihull Sailboats 4 30-08-2008 21:50
Flying Multihulls delmarrey Multihull Sailboats 11 11-03-2008 04:37
Heavy Weather and Multihulls Sonosailor Multihull Sailboats 13 07-03-2008 10:03



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 03:57.


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.