02.02.2006
Shore team commentary Andrew Roberts
Thursday 2 February 2006 14:10
Southern Ocean storms
Aviva is currently battling to windward in horrendous Southern Ocean conditions with the prospect of even worse to come very soon. The website progress tracker illustrates some quite abrupt alterations of course that Dee has, in recent days, made to avoid the very worst onslaughts of the weather fronts as they charge towards her.
Predicting the exact track and speed of fast moving Southern Ocean systems is particularly difficult and Mike Broughton (Dee’s weather adviser) has been masterful in all his predictions and the advice given.
Deciding how to avoid the worst conditions whilst at the same time trying to optimise performance is equally difficult and the consequences of getting it wrong could result in real hardship and possible danger to Dee. Because Aviva is sailing against the prevailing winds her speed made good is relatively slow and therefore her ability to get out of the way is limited.
So far, with accurate advice and good interpretation Dee has managed to avoid the worst of a succession of really bad storms and hurricane strength winds, but with complex systems the options can be very limited and that is what brings about abrupt changes of course.
One result of beating to windward and dodging these systems is that the speed made good and 24 hour speeds appear low when in fact the speed against actual distance sailed is very different. During the last 24 hours Dee actually sailed 168 miles at an average speed of 7 knots where as the distance made good towards the next waypoint off New Zealand was only 86 miles. When considering these figures bear in mind that Dee had 12 consecutive hours of true wind over 50 knots topping out at 58.1. All the time she was still driving to windward at 7 knots.
Very few yachts have the ability to do this but it is essential to try and get out of the way of the next 70-knot storm. The discomfort and risks of keeping going are not as bad as the potential problems of being a sitting target in the way of hurricane strength winds.
As I write this Dee called me and has described the conditions she encountered during the last 24 hours and indeed the last 8 days. Apart from the 60 litre calorifier (hot water) tank breaking loose there is no apparent damage but daylight will allow a close inspection of the rig and deck. Dee spent two hours upside down in the bilge re-securing the calorifier with ratchet straps during the worst of the storm, but other than being battered and bruised she was very upbeat and looking forward to the windspeed dropping below 40 knots.
Confused by any of these terms? Read our Glossary
|
