Thursday, 23 June 2011

Westerlies

Yesterday was the first opportunity Chris, Rob & I had to get on the water, all in our Tarans, with nearly all of the fit out complete for our expedition. We were hoping for a nice 15 knot wind day, some head & following seas & a 35-40km paddle just to get a feel for the boats & our group cruising speed.
The best laid plans etc etc meant that instead we were served up a day with a honking westerly, the most dangerous local wind for paddlers. Rather than mess around doing a slog inside the bay, we decided to run out to sea & stay under the lee of the cliffs as far north as we could in an hour-forty, mindful of the slog we'd encounter on our return west to La Perouse.
Westerlies in Sydney do strange things in the coastal environment. Where we could tuck under the cliff line we had sometimes refracting following winds, sometimes headwinds. Where we broke into open sections like Maroubra & Coogee, we were hit with the sledgehammer of 20 knots plus, from the beam, producing demanding paddling requiring a good level of fitness & strength to negotiate. 
Westerlies tend to magnify the further away you get from land, so it's not very long before you're past the point of being able to make it back to safety. The dangerous thing about these winds is the very small margin for error. If a problem occurs, you'll very quickly be blown to seaward and then face a tough job getting back to the lee of the land. 
How tough? The graph below shows the speed vs heart rate of my paddle, showing the brief blast out to Cape Banks at the beginning & then various wind influences as we made our way north & then south again. 
Check out the final 5km, just under an hour of serious slog into a wind which had come up to a steady 25-30 knots, with more than 15km of fetch to throw up nasty little head seas.
Wind strengths get thrown around kayakers blogs, tall stories in the bar & into folklore, but it's important that we all remember just how serious a wind above 25 knots can be. Local observation stations are usually a poor indicator of wind strength for a kayaker - part of the reason they get exaggerated so badly in paddling stories. A wind recorded 60m up on North Head is not going to be anywhere near as strong at water level for a kayaker, so we can be lulled into thinking an observation reading is really what we were out in, when it's rarely the case. The airport station at Sydney is however a good reliable source as it's down at ground level. Yesterday during our paddle it registered between 19 & 30 knots, with the highest readings pretty much coinciding with our rounding of Cape Banks for the trip back into the wind. The best laid plans. I personally find making headway once things hit 30 knots very physically & mentally taxing, & beyond a very short period of time, nearly impossible.
I'm pleased to report that aside from the dastardly end to the trip, we managed a very sustainable 8.4kmh despite the unhelpful conditions. I also spotted an early season Humpback off the coast of St Micks Golf Course. It was a good start as a team to our expedition planning.

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