How Wind And Current Makes A Tide Race Go!
I went for a play recently with Tim G and Brenda R. We headed out to run the reef line in the Fishers Island Sound which is famous (infamous?) for it’s races. This is my backyard stomping grounds but it can still has a bucketload to teach me and this run at it left me thinking about the intricate relationship between wind and waves.
To set the scene; it was a springs (full or new moon cycle resulting in relatively higher tides and faster currents) so lots of moving water. 4.5 knts at The Race which is the primary station round here that we gauge both timing and flow rate at the subordinate locations such as The Cans, Wicopesset Passage, Race Rocks, the races along the Ct shore and the reef line we hit this day featuring Catumb Rocks and Sugar Reef. Winds were southeast 5-10knts and while there were small wind waves as the wind had been south for a few days, there was no swell so not really enough energy to effect the races we were headed to.
I’ll get into the gory details on fluid dynamics of a race/overfall in future blogs but, for the sake of this entry, let’s just say that fast moving water does not a race make. There needs to be a countering wind. Along this line, the ebbing Long Island Sound runs south east, meets wind out of the south east (wind direction is described by the direction it comes from), stands up the ripples caused by the water “racing” over the relatively shallow reefs and it forms a field of rideable waves. Quite similar to white water in a few ways. Without the wind, there is plenty of fast moving, swirly current but no waves. On a springs, you need little wind to stand the waves up while on a neaps (mid moon cycle so less current) requires more wind to do the same.
What has really baked my noodle over the years is trying to pin down the perfect balance. How much wind vs how much current? The wind holds the face of the wave up so they are steep enough to ride. Too little wind and the waves are small and fast so may not be possible to ride. You have to paddle your ass off to get on them and keep at it the entire ride. Too much wind (especially gusty wind) makes the field an unconsolidated mess, with waves running into each other or collapsing under their weight. White knuckle, short, bury your bow rides are the best you’ll get. As the current rate increases and decreases over the moon cycle, the optimal amount of wind has an inverse relationship. More current, less wind and vice versa.
You can judge where you are at from quite a distance by looking for the white. When a wave stands up steep enough to ride, it’ll usually have a bit of white foam on top. That part of a wave is called the shoulder. No white means the waves are probably not surfable and too much white means the wave is collapsing (known as dumping) and you are in for a crash-and-burn type ride. Generally.
The three of us hit a sweet spot the other day. Glassy, green waves with just a bit of a breaking edge. The bigger ones were in the 3.5′ area which, keeping in mind that a paddler’s head is at around 2′, made for a super friendly and super fun session. It took a little windmilling your paddle to get on them but once caught, it was a long ride with enough speed to allow you to punch through or ride over the next wave, allowing for another ride. Linking rides is really what a good day in a race is all about.
While it was a Summer Sunday which would normally find half drunk power boaters hammering willy nilly around the sound, the max flow was late enough so we didn’t launch till late afternoon. Most of the boaters had already rushed off the water to go sit in traffic on their painful journeys home. Pretty soon, we had the area mostly to ourselves except for a couple of fishermen working out in front of the fields. They must have assumed we were insane cause they kept their distance. We landed on a fantastic sunset, all of us with the big ass, stupid grins one can only get through dumb luck.
PHOTO CREDIT: Ronny@Quonny by Carl Tjerandsen