Water Temparature Affect On Race Times

robhen · Post by **robhen** » February 11th, 2008, 4:46 am

Does anyone know by how much water temparature affects race times?

I just pulled 3:40 for 1k in dead flat conditions but in the middle of summer. I can only guess the water would have been 20 degrees celsius.

How would a 3:40 compare in winter with water temperature of 10 degrees celsius.

Byron Drachman · Post by **Byron Drachman** » February 11th, 2008, 7:54 am

robhen wrote:Does anyone know by how much water temparature affects race times?

I just pulled 3:40 for 1k in dead flat conditions but in the middle of summer. I can only guess the water would have been 20 degrees celsius.

How would a 3:40 compare in winter with water temperature of 10 degrees celsius.

With everything else held constant, the velocity is inversely proportional to the cube root of the viscosity. At 10 degrees C the viscosity is about 1.3 and at 20 degrees C the viscosity is about .98

The cube root of the ratios is about .9, i.e., you go about 9/10 as fast in the colder water. So you would add about 24.4 seconds to your time.

This is all assuming I read the following sources correctly:

http://www.atm.ox.ac.uk/rowing/physics/ ... l#section1

http://www.engineeringtoolbox.com/absol ... d_575.html

I hope I got this stuff right. I'm not an expert.

Byron

Nosmo · Post by **Nosmo** » February 11th, 2008, 11:28 am

Byron Drachman wrote:I hope I got this stuff right. I'm not an expert.

Byron

Didn't check your numbers but that sounds right. The only modification is that about 80% of the drag is due to skin friction and hence dependent on the viscosity, so your number is just a bit high.

PaulS · Post by **PaulS** » February 11th, 2008, 2:23 pm

Nice going, how did the rest of the field do?

robhen · Post by **robhen** » February 12th, 2008, 3:13 am

I won the race by the huge amount of 1.26 seconds.

3:40 was enough to win the Australian Masters "B" single scull last year in winter. Incidently, the winner went on to win the same grade at the Royal Henley Regatta in Canada. In the same race of the Australian Masters last year I got 3:48. I spend a lot more time in my single nowadays and have decent coach.

My conclusion is that unless I know the water temparature it would be hard to compare the times given dead calm conditions. It is easier to compare times on the ergo. If I want to win at the Australian Masters in the single maybe I need to go 2 lengths faster or around 5 to 6 seconds faster than now.

Rockin Roland · Post by **Rockin Roland** » February 12th, 2008, 10:49 pm

Rob,
So do I tell my coach Nick to start worrying about you for this years Aust. Masters or not? Incidently, his sculling skill levels just keep on amazing me. Recently he just came back from a non rowing holiday in New Zealand. He rolled up to a regatta a few days later and won an A grade (1000m) race, easily beating, amounsgt others, two State Masters team reps (Bill Nugent, Peter Searle). I'd hate to think how he'd go if he gave up the booze and got off his lazy butt to do some serious training.

Don't you hate those people with god given rowing skills that train stuff all yet still beat so many blokes that train their butts off.

robhen · Post by **robhen** » February 15th, 2008, 1:48 pm

Roland.

I am not worried about Nick. I am thinking about the guy that won last year, and working on my weaknesses so I can beat him. Nugent and Searle are old, ex-liteweights.

I gave up the grog from 2 Jan until the above result. And have had a couple since then.

I dont have a lot of athletic ability. But throw a lot of hours into rowing.

robhen · Post by **robhen** » February 15th, 2008, 2:34 pm

woops double post!

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Water Temparature Affect On Race Times

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