SailNet Community

SailNet Community (
-   Racing Articles (
-   -   Southern Ocean Weather for The Race (

Bill Biewenga 01-28-2001 07:00 PM

Southern Ocean Weather for The Race
<HTML><!-- eWebEditPro --><TABLE cellSpacing=0 cellPadding=0 align=right border=0><TBODY><TR><TD width=8></TD><TD vAlign=top align=left width=274><IMG height=215 src="" width=274><BR><DIV class=captionheader align=left><FONT color=#000000><B>Watch Captain Neal MacDonald drives the 110-foot <EM>Club Med </EM>down a wave in the Southern Ocean.</B></FONT></DIV></TD></TR><TR><TD colSpan=2 height=8></TD></TR></TBODY></TABLE><P>As <I>Team Legato</I> plunges into the Roaring Forties and <I>Team Adventure</I> gets underway again, all of the competitors in The Race are now joined in battle with the Southern Ocean. The competition between the boats is as fierce as ever, but the emphasis has shifted to what the ocean will throw at each of them. The weather is now their enemy, and it will try to wreak carnage on the unwary.<BR><BR>The South Indian Ocean is a tough neighborhood. Go too far south and your crew risks 50 or 60-knot winds with 40 to 50-foot seas on a weekly basis. And it can get worse. Head too far north and the wind can vanish, leaving those slightly farther south to sprint hundreds of miles ahead in a matter of a day or two. The choices are significant and the risks are huge.<BR><BR>Spinning in a clockwise direction from the west, the Southern Ocean low-pressure systems will overtake the fleet like a series of bowling balls gyrating around the world. Imagine an upside-down mirror image of the northern hemisphere where the fronts of these lows extend toward the equator to the north. As the fronts approach, typically the winds preceding it fit some description of northwesterly, with the boats on a port tack headed slightly north of east. As the front passes, often the wind shifts to a more southwesterly direction, and the crews scramble to jibe to starboard.</P><TABLE cellSpacing=0 cellPadding=0 align=center border=0><TBODY><TR><TD vAlign=top align=middle width=335><IMG height=270 src="" width=335><BR><DIV class=captionheader align=left><FONT color=#000000><B>The speed potential of the big cats like <EM>Club Med </EM>allow them to remain with a particular weather system much longer than monohulls have in previous 'round the world races. </B></FONT></DIV></TD></TR></TBODY></TABLE><P>In earlier 'round the world competitions, the fronts overran the competitors on a regular basis. Jibing kept the fleet tracking along latitudes that generally took the boats in an easterly direction through the Southern Ocean. The huge multihulls in The Race have the speed potential to increase the time that they stay with the fronts. The sustained speeds of these large cats can help to place them in a weather system that they prefer at times or allow them to keep up with a fast-moving system. But if they stay on the backside of a front with southwesterlies for too long, they can be forced to make a decision between going too far to the south or taking a bad jibing angle to get north. When it comes to strategy in the southern ocean, timing and placement within a weather system are everything; with boats and weather patterns moving quickly, there is little time for error.<BR><BR>As the competitors cross the Indian Ocean, they will be forced to decide whether to go north or south of Kerguelen Island. Located at about 49 degrees south and 70 degrees east, Kerguelen's banks extend about 75 to 100 miles to the south and about 150 to 200 miles to the north. While the boats can sail over the 150-meter deep water, the sea state can be horrific in extreme conditions. For multihulls, the steep seas associated with heavy weather can push both stability and equipment right to the edge.<BR></P><P><TABLE cellSpacing=0 cellPadding=0 align=center border=0><TBODY><TR><TD vAlign=top align=middle width=386><IMG height=256 src="" width=386><BR><DIV class=captionheader align=left><FONT color=#000000><B>Vignettes like this aren't too uncommon in the remote Southern Ocean.</B></FONT></DIV></TD></TR></TBODY></TABLE>Veteran mariners know that sea state is a function of wind speed, how long the wind has been blowing from a given direction, the fetch of the wind, the depth of the water, and any ripple effect given off by nearby coastlines. Upwellings caused by underwater currents and ocean floor topography can also affect the surface conditions. In storm-force winds, all of these variables give rise to mountainous, steep seas around Kerguelen Island. With wind speeds potentially exceeding 60 knots, the storm systems rolling around the entire world unimpeded by any land masses, and the water's depth coming up abruptly to less than 200 meters, steep, short-period waves can easily be 50 feet or<BR>higher and breaking at the tops.<BR><BR>In those conditions, competitors will need to be set up to leave the islands to starboard and pass on their northern side. To do otherwise would put them in even worse conditions, closer to the center of the passing lows. Once past Kerguelen, the fleet will continue in the Southern Ocean, under Tasmania, into the Tasman Sea and toward Cook Strait between the North and South Islands of New Zealand. It's well known that these waters can throw a wide variety of conditions at the sailors. During the 1998 Sydney to Hobart Race, numerous vessels ran into extreme conditions and lives were lost despite heroic efforts on the parts of many participants and rescue services. While the typically heavy seas of the Southern Ocean can be huge, widely spaced rollers, waves in the Tasman Sea can be short and steep. Rapid slamming into waves by the fast moving monster multihulls will again test the strength and reliability of hull construction as well as deck hardware, sails, rigging, and crew.<BR><BR>However, the Tasman Sea can also put boats into a drifting mode for days. High-pressure systems coming across southern Australia's Bight, crossing the Bass Straight and Tasmania can settle across the Tasman Sea, creating mirror-like lake conditions. These potentially light and variable conditions would provide testing of a different sort as crews scramble to change sails repeatedly. <P><TABLE cellSpacing=0 cellPadding=0 align=right border=0><TBODY><TR><TD width=8></TD><TD vAlign=top align=left width=320><IMG height=203 src="" width=320><BR><DIV class=captionheader align=left><FONT color=#000000><B>For the Polish crew aboard <EM>Warta-Polpharma</EM>, a night on the Southern Ocean isn't too drastically different than a winter evening in Warsaw.</B></FONT></DIV></TD></TR><TR><TD colSpan=2 height=8></TD></TR></TBODY></TABLE>Now that <I>Team Adventure</I> is sailing with only 10 crew, Cam Lewis and company could be in for a nightmare of back-to-back sail changes and reefing drills should they encounter these conditions. For the next month, navigators will be looking behind to see what kind of weather is approaching and how best to get into a favorable place in the system.<BR><BR>Once through the Tasman Sea, the boats will enter Cook Strait, a narrow body of water separating North and South Island of New Zealand. Home to "Windy" Wellington, the Straight funnels the raging Southern Ocean winds through its narrowest point, about 30 miles across. Winds can be shifty as well as gusty.<BR><BR>As the boats clear Cook Strait, they will be headed back down in a southeasterly direction as they set themselves up for Cape Horn. It's unlikely that they will go as far south as some of the earlier Whitbread boats did for fear of getting on the wrong side of the Southern Ocean low-pressure systems. In some ‘round the world races, monohulls have ventured so far south that when the low-pressure circulation passed their positions, they were confronted with headwinds. In some cases they overstood Cape Horn and had to beat north into the South Atlantic. While going to the south shaves miles off the course and is closer to the Great Circle route from Cook Straight to Cape Horn, it doesn't always provide the fastest elapsed time if the boat runs smack into headwinds. <P><TABLE cellSpacing=0 cellPadding=10 width=160 align=right border=0><TBODY><TR><TD><IMG height=2 alt="" src="" width=160 border=0></TD></TR><TR><TD vAlign=top align=middle width=160><FONT face="Arial, Helvetica, sans serif" color=black size=+1><B><I>"Rounding Cape Horn will be the crowning achievement for the racers."</I></B></FONT></TD></TR><TR><TD><IMG height=2 alt="" src="" width=160 border=0></TD></TR></TBODY></TABLE>Rounding Cape Horn will be the crowning achievement for the racers as they run at fast forward to get out of the Southern Ocean. With the fast current, continental shelf, and irregular coastline adding to the often chaotic sea state here, the lucky competitors will pass unimpeded into the South Atlantic. If a deep, monster low times its arrival with that of a boat in The Race, these sailors would be well advised to consider standing off and leave Diego Ramirez to port, giving Cape Horn a wide berth as they remain in deeper water. This small island about 50 miles southwest of Cape Horn marks the edge of the South American continental shelf.<BR><BR>While The Race doesn't end at Cape Horn, an almost audible sigh of relief will be heard from crews as they 'round the corner and start making tracks to the warmer climes farther north. Once in the lee of South America, the huge Southern Ocean swells will diminish, and the boats will at last be pointed toward the finish in Marseilles. Keep an eye on&nbsp;SailNet for frequent updates. </P><HR align=center width="75%"><P clear=all><P><STRONG>Suggested Reading:</STRONG></P><P><A class=articlelink href=";report=biewen0004">T he Race, The Weather, The Route</A>&nbsp;by Bill Biewenga</P><P><A class=articlelink href=";report=hancoc0016">P reviewing The Race</A>&nbsp;by Brian Hancock</P><P><A class=articlelink href=";report=ddcksn0353">L iving Large on Club Med</A>&nbsp;by Dan Dickison</P><P>SailNet Buying Guide: <A class=articlelink href="">Personal Flotation Devices</A></P><P><TABLE cellSpacing=0 cellPadding=0 align=center border=0><TBODY><TR><TD height=8></TD></TR><TR><TD vAlign=center><A href=""><IMG height=100 src="" width=320 border=0></A></TD></TR></TBODY></TABLE><P><P>&nbsp;</P><P>&nbsp;</P><P>&nbsp;</P></HTML>

All times are GMT -4. The time now is 07:17 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging v3.1.0 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
(c) LLC 2000-2012

For the best viewing experience please update your browser to Google Chrome