Diary of a Clipper Racer Around the world in 333 days with Mark Osgood Supporting my chosen charity - "Dreams Come True" Final Diary entry, 54, added Monday 6th October 2003. |
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Latest Diary News 36
- Notes from the Southern Ocean - June 2003 Below is a summary of the notes prepared by Colin de Mowbray, the Race Director, to forewarn us of the extreme conditions possible in the race from Mauritius to Cape Town, as we pass the southern tip of Africa. At the end of Colin's notes is a message from Sir Robin Knox-Johnston, Clipper's chairman, followed an extract from the Admiralty pilot book on "Abnormal waves". The area around the tip of southern Africa is one of the three areas in the world that report abnormal waves and they can be highly dangerous if not treated carefully. Here is what we have in store! Sailing
Notes - Race 12 Intro 1. Mauritius to S of Madagascar 2. S of Madagascar to Agulhas Current (East London area) 3. East London area to Agulhas point 4. Agulhas point to Cape Town Overriding
Considerations Weather The
Agulhas Current The strong SW to W flowing current along the coast is both a friend and an enemy. This is the cause of the much-publicised "Abnormal Waves" feature that is well documented in this area. The
Problem The problem arises when the sudden and strong Sou'westers hit the fast flowing ocean current. Because the current is in the region of 80 to 120 miles wide if you are near the coast and the inner edge of the current it is not possible to get well to seaward in time. It is extremely dangerous and unseamanlike to remain in the current and so the only alternative is to go inshore below the 100-metre line and beat down a narrow coastal ribbon. The band between Durban and East London is literally 3 to 4 miles and so what looks like an ocean passage can end up like beating down a river. There is no shelter, ports or bays, between these ports which are 240 miles apart. This course of action is against one's upbringing of getting offshore and making sea room in dirty weather and hence I am stressing the point here. The inshore beat in the stretch out of the current is no great fun but the demarcation when you go out across the 100/200 metre line and start mixing it with the very steep waves quickly becomes apparent. The prudent skipper will not wish to poke his nose out to experience the validity of this information. When it gets nasty, either stay well offshore and outside the current or get inside it. The 100/200-metre line starts to diverge from the coast from East London onwards and so the problem of having such a narrow strip eases. There are also a selection of bays where refuge can be taken. Route
Notes The following are purely my thoughts on the route gathered from the last three races and are passed on in the spirit that they may be of use. Mauritius
to S of Madagascar The only observation I would make is that in previous races some boats have come badly stuck by going too close to the capes on the south of Madagascar. I remember the currents being strong and tiresome to the S and SW of Madagascar. We also had severe and most dramatic electrical storms. S
of Madagascar to Agulhas Current (East London area) Sooner or later you will have to cross the current and where and how you do this is going to be a judgment call by you. The rule is DO NOT GET CAUGHT IN THE CURRENT WHEN THE SW BELTER COMES. There is a health warning on this. We are not talking about being uncomfortable or being brave. We are talking about abnormal waves which demand the greatest respect and therefore GOOD SEAMANSHIP takes precedence over everything. East
London area to Agulhas Point Much the same call as above regarding the current. When you end up on the inner edge of the current, as you will, taking shelter in the bays is a real option. There can be times when the racing has to wait and you do the sensible thing of sheltering in these bays. This is standard practice for yachts transiting this coast. Bertie Reed talks about sheltering in bays during various races in his book. They do not come much tougher than Bertie so please have no hesitation in riding out the fronts in a bay even if you go in and motor round in circles for three hours - providing everything is properly logged, you will not get penalised for using your engine in these circumstances. Your course over the Agulhas Bank is an interesting decision. The current is obviously strongest along the 200-metre line but as it diverges from the direct route, sooner or later you must take the plunge and go over the Agulhas bank. Agulhas
Point to Cape Town Rounding the successions of capes can be a lengthy and time consuming task when you are relatively near the end of the race and be aware that this bit can drag itself out. The weather at the Cape can be anything between calms and 70 knots so just keep saying your prayers and making the sacrifices. From
Sir Robin Knox-Johnston Please emphasise to the skippers the dangers along the SA coast. With the exception of Roger and Simon (Cape Town and Jersey skippers who are both South African), they will not have experience of this area. If a real gale comes in they are best seeking shelter in one of the bays like Mossel Bay and anchoring until it passes. To stay at sea means damage and a very sick and frightened crew. The freak wave is not a joke and has been the subject of considerable research. A 17,000 ton Ben Line ship had its forward 120 feet bent down 7 degrees when one dumped on its foredeck and Ben Line built well. Two tankers in recent years have broken in half and no-one knows what happened to the Waratah. The shallow waters over the Agulhas bank, with the current flowing west and south, and then meeting a SW storm is my worst nightmare. Dive for cover! Admiralty
Pilot Book for Africa on "Abnormal Waves" "Under certain weather conditions, abnormal waves of exceptional height occasionally occur off the SE Coast of South Africa, causing severe damage to ships unfortunate enough to encounter them." (Para 1.110) Abnormal waves, which may reach a height of 20 metres (very big!) and may occur all year round if the weather conditions are right are fast-moving, steep-fronted waves followed by deep troughs. They haven’t been reported inside the 100/200 metre contour referred to by Colin in his notes above but, outside that contour, they are caused by a combination of sea and swell waves moving NE against the Agulhas current. In the worst case scenario, a ship steering SW and meeting such a wave would find its bow still dropping into the trough with increasing momentum when she encounters the steep-fronted face of the next on-coming wave, the wave eventually breaking over the fore part of the ship with devastating force. It’s probably worth avoiding! My
thoughts on the challenge ahead Rounding the bottom of South Africa is one of the big challenges of this race and despite all the warnings of caution, I’m looking forward to the coming week. Inevitably, I’m apprehensive about the conditions we’ll face as I suspect that large parts of the trip will be extremely uncomfortable, but it’s comforting to see the advice available to us. As with our journey into Japan, I suspect that I’ll look back on the experience with a sense of achievement at having survived it. Watch this space! |
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