Monday, July 7, 2008

Foxtrot Course - Local Knowledge

Contender Worlds – Kingston 2008 (August)

I have been asked to give some advice on what to expect of the conditions on the CORK course Foxtrot during the Contender Worlds this August.

There are 5 common wind directions, and each has its own key elements to understand. I will explain my best understanding of each. There are of course transition winds in which the wind direction is shifting between one of these common wind directions and those conditions are a matter of knowing which wind direction is winning or likely to win out. Determining this is usually just a matter of watching the water 500 M to 1 km out and you will know what is likely to happen.

1. South West Wind

This is the wind everyone says is the “standard Kingston wind or the Kingston Thermal”. It is not all that standard but is the most common direction in the summer. If there is an underlying gradient wind from the West in the morning and the daytime temperature is expected to be 8 or more degrees higher than the night time temperature, this wind is likely to be strong by about 1- 2 pm. By strong, I mean it can get up to 25 knots. Without much underlying gradient from the West it is not likely to exceed 15 knots and may only get up to 8-10 knots. As this breeze builds it usually backs to 210 degrees and oscillates 7- 10 degrees either side of that for 2-3 hours. If the wind is right of 210 expect a back. If it is left of 210 expect a veer.

On Foxtrot, the typical strategy once the thermal has set in is to go left. This works because there is a shift to the left as you approach Simcoe Island. I believe that this due to the coriolis effect– wind slows down when it comes over the land due to increased friction and shifts to the left in the northern hemisphere due to the spin of the earth under the wind. There is an additional effect here that is in my opinion even more important and that is there is increased velocity when you get to the zone where the left shifted wind is mixing with the wind that did not get slowed by the land. This convergence zone has more wind and results in boats covering more distance in the left shift and even means you are able to stay in the left shift longer due to a velocity shift in every puff. The velocity shift means that you are able to point higher because of the sudden shift of the apparent wind towards the true wind direction. All you need to know is that it works, but only if you are close enough to shore. Too close and the wind will die. Usually, all you need to do is sail to or slightly past the port layline and you will be in the right place. This is one condition that it usually pays to hit the layline from a long way out. The waves are smaller and boats that will plane upwind will benefit from this as well as the extra velocity and lift on port. It’s a trifecta on the left when it works. The same side is also good on the downwind due to increased velocity. (Right side when you are going downwind.)

Beware of the left. Until the thermal has solidly established itself, going right can pay. It can also pay as the thermal starts to die. The key is to remember to go hard right if you must, but it is usually not preferable to go right, especially because most of the fleet will want the left and it becomes risky to split with them. If you get stuck out there, remember to go big.

2. Northish (about 60 degrees either side of North)

This is completely head-out-of-the-boat sailing. It is usually quite windy (15 knots plus), cold and very shifty (60 degree+ shifts).

Sail to stay in the puffs and get on the lifted tack when you are in a puff. The mistake people often make is to keep going if they are lifted but not in a puff. The puffs will have an extra 10 knots. You must be in the puffs. Often it will not matter what side of the shift you are on as a 10-knot puff will yield at least a 10-degree velocity shift in your favour. Whether or not you should tack on the puff to get onto the lifted tack is usually obvious, because you will be ½ - ¾’s of the way through a tack when the puff hits. – sometimes called an “auto-tack” if you can avoid getting “tea bagged” when the sails back-wind.

3. East (could include about 40 degrees either side of East)

This condition is fairly rare and usually associated with bad weather. It usually pays to stay away from the shore of Simcoe Island. (Go left - towards the south shore = mainland.) Remember, there is a magnetic anomaly in the Kingston Harbour and it seems to me to be most pronounced on Foxtrot in an east wind when sailing close to the shore of Simcoe.

4. Due South

If you get this wind it will be strong early in the morning (6 am and earlier). It almost invariably dies by noon and gets replaced with something else that is rarely as strong unless it shifts to the South West. If it is not dying by 11 am, it may well shift to the South West.
In a South Wind, they sometimes move Foxtrot out into the lake past the lighthouse on Simcoe. The biggest factor there is the size of the waves. Get ready for slow upwind legs and surfing downwind. Basically, in this wind expect oscillating breeze about 10 degrees either side of the median.

This is the most rare type of wind to sail in because it us usually dead by noon and you will have been waiting ashore from 9 am because it is too windy to go out.

5. West

This is more common later in the Fall, but is usually strong and may have a tendency to shift to the left if it gets warm. If it is a true west Wind, left or right can work fine, even the middle can work, depending on how close you are to Simcoe Is. The RC will typically move the course north away from Simcoe Is. and this reduces the effect described above for the South West wind, but watch for that same pattern if your port layline is with in 4- 500 M of the shore of Simcoe.

Good Luck

John Curtis


Remember anything can happen and it probably will. The advice above are rules of thumb and the user assumes the full risk of following them.

A 16-year veteran of the Canadian Sailing Team in both the 470 and Tornado classes, John Curtis represented Canada in the 2004 Olympic Games in the Tornado with Oskar Johansson. In 2005, John was hired as the Canadian Yachting Association's High Performance Manager & General Counsel. Today he practices Sport Law, Mediation and Conflict Coaching. He also continues to coach sailors at all levels.

A resident of Kingston with many CORK regattas under his belt, John was the natural go to guy for advice about what to expect from the Foxtrot course. We'd like to extend a huge thank you to John for his time and comprehensive insight.

No comments: