sail-world.com -- Melbourne to Osaka Double-Handed Yacht Race - A weather perspective
Melbourne to Osaka Double-Handed Yacht Race - A weather perspective
Tue, 2 Apr 2013
Melbourne to Osaka Double-Handed Yacht Race 2013. A two-time Melbourne to Osaka veteran and with 29 Melbourne to Hobart Westcoasters under his belt, sailed on his beloved Yoko, Robin Hewitt knows a thing or two about the weather. In this article he explains why this race is so challenging and so special.
This race is unique because it crosses the weather climate systems of the world. Basically it starts from Melbourne in the Autumn Westerlies wind belt. Next as the yachts move North, they must cross through the centre of the southern belt of high pressure systems which is basically light winds or calms. Here there are two strategies possible-aim for ocean eddies and currents for a lift North or stick close to shore to hopefully avoid the Eastern Australian south flowing current and gamble on coastal breezes.
These are individual decisions which require knowledge of the individual boat and it's performance characteristics combined with a personal interpretation of the current weather situation. Hopefully the cyclone zone of Latitude 20 deg. to 10 deg. South is quiescent.
After breaking out of the light weather the equator side of the highs gives rise to the South-East trade winds and glorious spinnaker runs until meeting the Tropical Convergence Zone of light winds and calms often termed 'The Doldrums' . This lies roughly in the Solomon Seas area at this time of the year and the yachts must also squeeze through the 'Gate' between Islands and New Guinea- a navigational challenge. In the tropical areas, convection storms plague the yachts with blasts of high winds and tactical challenges to produce the best directional gains. Battling exhaustion combines with these difficulties to test the sailors further. Ocean currents and wind effects are further decision points in this area perhaps illustrated by New Ireland which is a narrow, razor backed, yet very high island with many influences. Also there is the Northern Typhoon area between 10deg and 20deg. N.
Breaking through this frustrating zone, yachts next enter the southern side of the Northern High Pressure belt otherwise known as the 'North-East Trades' . Here the miles and passage to Japan quickly mount with a series of tremendous daily runs before once again having to get through the light winds of the high pressure systems centre and preparing for the strategic approach to Japan in the fringe of the Northern Westerlies zone. By now the much fabled North Pole Star will have been visible in the night sky for some time. Usually somewhere around here, a vigorous low pressure system will bring strong winds. For southern hemisphere sailors, the weather systems now operate in the opposite directions requiring interpretation skills and unusual (to them) weather planning.
Japan lies not only in the fringe of the northern Westerlies, but it's weather is highly influenced by the continental land mass of Asia and Siberia particularly. In addition it has it's own version of the East-Australian Current termed the 'Kuroshio' which has to be negotiated carefully in order not to be swept away from Osaka.
Fortunately, the Japanese weather bureau produces excellent information and mapping to enable good decision making. Negotiating a crowded shipping route to Osaka Bay brings the final challenge of traversing an area filled with vessels of all kinds and differing shorelines unusual to first time visitors. Winds here can be strong but more usually very light and the finish is near a river mouth which after heavy rain can result in adverse currents requiring persistence and determination so close to finishing after so long at sea and so many obstacles.
The elation of accomplishment and the wonderful welcome at Hokko Yacht Club completes this 'Yachtsmans Everest'