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wetsuit optional at a open water race

I did the upton upon severn OD yesterday which went well for a B list race for me. But the orgnisers had said wetsuit was optional so I thought I'd give it a go but after a mile walk to the start I found that I was on the only one in my wave doing this. So is it more of an advantage to wear a wetsuit ie more streamlined etc my swim split was about 30 seconds faster than in training which I put down to being downstream. As a b list race I was willing to try out without the wetsuit and just in tri suit but would be interested to know if there is any difference as I have no idea how much the downstream helped plus the water was cold but in someways just right temp wise and I didn't have to mess about taking the wetsuit off.


  • risris Posts: 1,002
    i think many people find that the additional buoyancy of the wettie helps with their positioning in the water and so swim a bit quicker. i've not swum enough in ow to know if that is the case for me.

    in a race the additional help from the suit may be offset with the potential for overheating and the time used up taking it off in t1. i did the cowman sprint last weekend and it was wetsuits optional there, too. i'd not raced in a wetsuit before so took the opportunity to do so, but if i'd done a load of races before in it i might have opted for the tri-suit.
  • ZacniciZacnici Posts: 1,385
    Well according to the blurb as far as I recall it the wetsuit material is 20 times more hydrodynamic than skin. A quote from 2XU
    Water is 1000 times denser than air, and has a drag coefficient 10 times greater than air. Buoyancy is the ultimate component of speed
    Think of a hydroplaning boat; the more of the hull that rises out of the water the less drag, the same is true for genus homo triathalonicus. Archimedes, a body immersed in water displaces its own mass; so if I at 66Kg can get as much of my lump out of the water that is not actually doing anything , i.e. everything other than arms and legs then I have less water to shove out of the way.

    In order to achieve this the wetsuit has different thickness of neoprene from 5mm to 1mm to give varying degrees of bouyancy. Chest 5mm, arms 2mm, legs 3mm are typical sort of values but vary according to model.

    I know I am faster (being a relative term for me) in a wetsuit than au natural even taking into account the time to take it off.

    Thermal insulation:

    Normal body temp is about 36.5 degrees; hypothermia is defined as a core temperature below 35 degrees. I seem to remember somehwere that swimming or even treading water results in 50% increase in heat loss than just floating for an unprotected person but can't remember where I read that. Anyway by swimming you are expending energy, generating heat and that heat is being sucked away by the water. So it i is a fine balancing act, how long will you be in the water, what is your BMI, what is the water temperature? If the dry air temperature is high the body is working like made to shed heat, when it is suddenly plunged into cold water in extreme circumstances the body can go into shock. Similarly when said body is trying to shed heat we then clad it in neoprene. All pretty hazardouse stuff really.
    The ITU set out these guidleines, the temperature is water temperature:

    [attachment=0:37zhnkjk]Wetsuit guidlines.jpg[/attachment:37zhnkjk]

    Blue Seventy brought out the swim skins for warm water use but they are expenseive, have a limited life and have now been banned I believe? Stand to be corrected.

    So there you go, you pay your money and you take your choice. Personally I am so slow that I will need a wetsuit where optional as I will be in the water so long.
  • ZacniciZacnici Posts: 1,385
    Whoops - sorry Arhimedes - a submeregd object displaces its own volume of water
  • md6md6 Posts: 969
    its very interesting that for shorter races the banned temperature is lower than long races, surely the chances of overheating are greater in a long distance swim than a sprint swim? Or is it more that people will get cold if in the water for longer without a suit? I'm confused, its too early for me
  • largeadelargeade Posts: 166
    Recent race stats tell me that a wetsuit makes me 3 minutes faster over 1900m than in the pool. (34 vs 37mins)

    Either I responded really well to the taper, or I guess that implies I've got a technique issue which the wetsuit is fixing.

    Whatever, it means for now I'll always wear a wetsuit if the option is there.
  • ZacniciZacnici Posts: 1,385
    MD6 - its a simple matter of water being a better conductor of heat than air. Being immersed in water at lower than body temp means that we lose body heat quicker. The longer the immersion the more core heat is lost before hypothermia sets in and we are only talking about a 2 deg loss in core temp for that to occur. When engaged in swimming activity the heat loss increases by 50% over the heat loss from simply floating in water, so if struck by an iceberg simply float in your life jacket rather than tread water.

    If you come out of the water without a wetsuit where the water temp is just at optional then depending on a. your BMI and b. how long you have been in you may have lost enough core temp to impair performance. What does the body do when it is cold? shuts circulation to the extremities to preserve core temp i.e those leg bits that you need to pedal with. OK we are not talking about you turning blue or anything but it may be enough to slow you down on the start of the bike leg whilst your body readjust the thermostat.

    Again you pays your money ... pretty delicate things really aren't we?
  • Morg007Morg007 Posts: 54
    thanks for the feedback, its made for an interesting read.

    And Zacnici its interesting that you say how the water temp effects you more at the start of the bike leg as I felt fine coming out of the water but when pushing the bike up a ramp to get to the point of where I have to get on the bike my legs felt more heavy than normal and I struggled as I faffed about getting onto the bike.... it felt almost like a drag so this may have been down to my body temp being lower than if I had wore a wetsuit.

    I think if I have this option again I'll go for wetsuit as the only thing you're gaining by not wearing one is the 20-30 seconds saved not messing about taking one off.
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