Just out of curiosity, given all things equal do you see a pace difference between salt and fresh water? I've heard differing things. I train in fresh water and almost always race is salt water, but I'm rarely training in a wetsuit and I'm always slowing in fresh water. Also, I just try harder on race day so my pace is faster. So given all things equal is there a pace difference from salt to fresh water?

Just for the record, I was thinking of a pool with seawater in it, not a "saltwater pool" as they exist today. Don't know if the pool still exists but when I was swimming in HS we swam somewhere on the east coast where they had a pool filled with seawater. I say we swam there but it was just for fun, not a meet or anything. The actual swim meet was held in a regular chlorinated pool. If I could recall where the hell that was, it would be the ideal place to test this out but alas all those meets blur together. :)

I think there are too many variables in open water swimming to be able to detect any difference. Personally, despite having raced in the ocean numerous times, I never even knew that salt water makes you slightly more buoyant until I read it here on ST. The diff is quite small though, much less than a pull buoy or wetsuit. The only way to say for sure would be to have a salt water pool and freshwater pool right next to each other and swim equal efforts for say 500 yds in each. I would guess the diff to be maybe 1 sec/100 yds at most. YMMV.

I think there are too many variables in open water swimming to be able to detect any difference. Personally, despite having raced in the ocean numerous times, I never even knew that salt water makes you slightly more buoyant until I read it here on ST. The diff is quite small though, much less than a pull buoy or wetsuit. The only way to say for sure would be to have a salt water pool and freshwater pool right next to each other and swim equal efforts for say 500 yds in each. I would guess the diff to be maybe 1 sec/100 yds at most. YMMV.

The diff in buoyancy in going from
freshwater to seawater is not *super* small relative to adding a pull buoy or wetsuit, though it is somewhat smaller.

Remember that the buoyant force is equal to the weight of the displaced fluid. At 9”x6”x4” a pull buoy displaces about 0.12 cuft and thus has a buoyancy of ~7.5 lb (fresh water has a density of ~62 lb/cu ft). A wetsuit averaging 3mm thickness with 1.5 m^2 of area will displace about 10 lb of water and thus have a buoyancy of 10 lb.

Seawater has a density about 2.5% greater than that of freshwater. A full swimmer’s weight is supported by the displaced weight of fresh water, so the buoyant force of changing the displaced fluid to saltwater is about 2.5% of the weight of the swimmer, or perhaps 4 lb for a lean male triathlete.

So this is pretty non-negligible - and has a nice uniform distribution over the body. But it’s probably counteracted in terms of real-world swim speeds by the effects of waves and currents, which can easily decrease your swim speed by much more than 4lb buoyancy gain increases your speed…

The best experiment in feeling the difference is competing in the Laguna Phuket Tri where the swim is broken up between the ocean and a lagoon. First 1,300'ish meters in the ocean and the last 500'ish meters in the elephant bath/lagoon. You start with that ocean swim which is awesome and then you run over the beach and hit the lagoon and you can feel the difference straight away.It feels so different and so much slower.

Aloha. I swim west side Hawaii Island every morning, and vacationed in Maine in August. Salt content is so different in these two states, plus the fresh water lakes in Maine added a third “water feel” sampling.
I was trained as a physiologist in school, so dug through some old texts. Found it to be mildly different for speed of swim in different waters, and it’s all about the buoyancy factor.
Trust me- one feels much more buoyant here in Hawaiian waters.[/reply]

The diff in buoyancy in going from
freshwater to seawater is not *super* small relative to adding a pull buoy or wetsuit, though it is somewhat smaller.

Remember that the buoyant force is equal to the weight of the didplaced fluid. At 9”x6”x4” a pull buoy displaces about 0.12 cuft and thus has a buoyancy of ~7.5 lb (fresh water has a density of ~62 lb/cuft). A wetsuit averaging 3mm thickness with 1.5 m^2 of area will displace about 10 lb of water and thus have a buoyancy of 10 lb.

Seawater has a density about 2.5% greater than that of freshwater. A full swimmer’s weight is supported by the displaced weight of fresh water, so the buoyant force of changing the displaced fluid to saltwater is about 2.5% of the weight of the swimmer, or perhaps 4 lb for a lean male triathlete.

So this is pretty non-negligible - and has a nice uniform distribution over the body. But it’s probably counteracted in terms of real-world swim speeds by the effects of waves and currents, which can easily decrease your swim speed by much more than 4lb buoyancy gain increases your speed…