devashish_paul wrote:
jlh1750 wrote:
For what it's worth, as a weaker female pro swimmer, I really didn't feel like I was struggling against the current yesterday. I could perceive that I was moving more quickly once we turned into the down current, but the first few hundred meters are always a sprint for position anyways, so it kind of just felt par for the course in that regard. I'm​ not saying that what was done was or wasn't right, as I can certainly understand it could have ended some days very early, which would have been unfortunate, just that I personally was surprised​ to learn that we looked like we were having a really hard time, because I didn't perceive it. I normally swim in the 30-31min range, but was a hair under 29 yesterday, so overall a bit faster than normal. I was also glad to have the upstream portion to make the race seem a bit more honest, even if it could be considered a disadvantage for me!
Thanks for your reply. So even for someone with what would be a decent age group swim time, the swim on the pro course was faster. The feedback some are giving is that age groupers would never make it to the turnaround because the current was faster than their swim speed. Do you know your turnaround split. If you are a 30 min swimmer, normally you would be swimming 30 min/19 = 1:35/100m. For faster swimmers, overall time may change very little due to the current and there will be a breakeven swim speed above which the current is advantageous to overall swim time. For slower swimmers it's a completely different story. As current speed approaches swim speed, the upstream section becomes a massive issue. Many swimmer will be unable to complete the course, nevermind within the cut-off.
Let's do a case study!!!
Do feel free to point out if my maths are incorrect.
I'm going to assume a uniform current of 2km/h. Hardly a gushing torrent by any means but very significant relative to typical swim speeds. I'm also going to assume a uniform effort.
Case 1: Weaker Female Pro with typical time of 30mins for 1900m Average pace (speed) = 1:35/100m (3.8km/h)
Upstream 400m @1.8km/h = 13:20
Downstream 1500m @5.8km/h = 15:31
Still water time = 30:00
Race swim leg time =
28:51 So, with a relatively short upstream leg and a reasonable swim speed you save time with a current of this magnitude. Down from 30mins to 28:51 for the same effort. So this is similar to what
jlh1750 described.
All correct?
Case 2: Weak AG swimmer Average pace (speed) = 2:30/100m (2.4km/h)
Upstream 400m @0.4km/h = 60:00
Downstream 1500m @4.4km/h = 20:27
Still water time = 47:30
Race swim leg time =
80:27 So, a slow swimmer spends an eternity going upstream for which the downstream leg can never compensate and in this case increases their time
Break-even point A swimmer doing a 1:44min/100m pace (1900m in about 33 minutes) would be unaffected by the current so long as they swim a constant effort. Anyone faster will benefit from the current. Anyone slower will suffer.
Impact of a 1hr cut-off A 1hr cut-off for a still water race would require a 3:09min/100m pace.
In this current (2km/h) you would need to be a hell of a lot faster. You'd need a 2:18min/100m pace which corresponds to a time of 43:51 in still water. Not fast but I believe there's plenty swimmers around this pace in most HIMs.
If swimmers were to push harder for the upstream leg, rather than adopt a uniform effort, it would greatly benefit stronger swimmers. Weaker swimmers may benefit so long as they can pace it to reach the turnaround before they're exhausted and if they can recover sufficiently during the downstream section to carry on without further impact on their race.