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What makes a wetsuit "semi-dry"?

Discussion in 'Exposure Suits' started by youngjun, Jun 17, 2002.

  1. youngjun

    youngjun Angel Fish

    Does blindstitching and gluing cause it? A dry-suit zipper? What makes some suits leak through the seams (like the Tilos rental I used this weekend) while others don't.

    The LDS owner told me the thicker O'Neills are semi-dry although I'm not sure if it is advertised as such. I don't remember if he said the 3mm suits are blindstitched because isn't it too thin to blindstitch? Who else makes semi-dry suits?
  2. MikeS

    MikeS Divemaster


    I think that semi-dry is a marketing term. Being semi-dry is like being kind of pregnant, either your dry or your wet. Usually the big difference on “semi-dry” suits is how they seal at the wrists, ankles, neck, and zippers. By limiting the water flow with good seals they keep you warmer. I have an Excel “semi-dry” wetsuit and while I don’t stay completely dry usually about half of my body is after a dive. IMO how well the suit fits is more important than being “semi-dry”! The better the fit the less water is moving around and the warmer you’ll be.

  3. testdrv321

    testdrv321 Garibaldi

    I'm going to agree that semi-dry is a marketing term. I dive in a Mares Isotherm 'Semi-Dry' suit. I did alot of research before purchsing this suit and believed it to be the best 'semi-dry' on the market. The difference between this and, for example, my dive buddies Parkway 7mm wetsuit is the zipper and the extremity opeinings. The zipper is a standard drysuit zipper. It is a excellent seal, but has all of the disadvantages of a dry suit zipper (maintainance, PIA location, and hard to operate). The extremity openings all feature rubber seals approx 6" long. These seals get folded underneath itself. The boot, glove, hood then goes on top of the runner and a neoprene sleeve zippers closed on top. I bought the matching mares boots which are supposed to also be 'semi-dry'. My findings are as follows... the suit stays as dry as a dry suit, allowing almost zero water to enter. The boots get some water in them, not perfect. A little duct tape might fix that though? The challenge is getting the suit on and off as the seals are VERY tight (key to dry) and bleeding out the air. Unlike a dry suit where you keep an airspace inbetween, the semi-dry is worn tight like a wetsuit. Air trapped is bad for bouyancy and seals. Upon entering the water you must careful submerge to your neck and bleed the air out of the neck. This is easy in still water beach dives but a major challenge in rough water on a boat dive. All in all, the semi-dry is the way to go in my opinion. It is much more comfortable than a wetsuit, very warm and has none of the hassles of a full dry suit. The cost was pretty reasonable too. I dove this weekend in low 50 deg water and was warm! not even the slightest hint of chill. I have also used it into the 70's with out gloves and a hood and was still confortable when my buddy was dyign hot in his 7mm wet. The dry seems to allow a wider comfort range for temp too. Anyway, thats my 2 cents worth. Email me if you have questions. P.S. the fit is 10x more critical in any dry type suit so make sure it is very tight around the extremities or it will be a semi-wet!
  4. Scubaroo

    Scubaroo Great White

    Ditto to the previous comments regarding semi-dry being a marketing term. Some suits are better than others at keeping you partially dry, but to do so, the suit must have neck, wrist and ankle seals similar to a drysuit. I have a semi dry that only has neck and ankle neoprene seals, with the arms being lined with a smooth silver material designed to provide a seal, but because of my skinny forearms, doesn't. A semi-dry is best thought of as a bag of warm water IMO - but still better than an unsealed wetsuit in cold water. I dived my leaky 7mm semi-dry at Monterey on Saturday - over an hour in 52 degree water and not cold.
  5. Welshman

    Welshman senior member

    The other semi-dry worth looking at is the ScubaPro Scotia 6.5mm.

    I also looked at the Mares but IMO the wrist and ankle seals are not as good as the ScubaPro.
  6. pt40fathoms

    pt40fathoms PADI Pro

    # of Dives:
    Location: Manitoba, Canada
    What makes a wet suit a semi-dry,,,bladder control.

    But seriously, all of the above. Very good sealed openings, good zipper, sealed seams on the material used to construct the "semi-dry". Most important is how it fits YOU. Loose fit, you get wet.
  7. Guam_Diver

    Guam_Diver Angel Fish

    I agree with the comment, "...like a bag of warm water" I used to dive a semi-dry, (when I was diving in cold water) The wrist, ankle & neck seals worked very well and didn't let water in much at all. I found that I would stay warmer though if I let some water in at the beginning of the dive. That water would warm up & insulate me more against the outside cold water......That first tug at the seals was a shocker!!


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