Thursday, June 25, 2009

Scuba Dry Suit

In this post, I will explain what is a dry suit, its types and a couple of tips on how to maintain it.

As water takes away your body heat 25 times faster than air, it is crucial to choose the appropriate thermal protection when diving. Several dives in a wet suit in colder water than 65ºF/20ºC will diminish your abilities and efficiency seriously. Under 55ºF/16ºC a scuba dry suit is essential.
The main function of dry scuba suits is to keep the diver dry: the suit has several seals that prevent the water from coming in. Frequently divers wear undergarments under the scuba dry suit because they create layers of air inside the suit that improve thermal insulation. This means that a dry scuba suit can be used in a wide variety of water temperatures needing only to adjust the underwear type to go underneath. We must also consider when making the choice of underwear, the type and intensity of the activity we are planning to do and our body size.
Scuba dry suits are easier to put in and off than wet suits, but they also required specific and professional training (do not try to figure it out on your own!) and some practice to learn how to use them.
Scuba dry suits have a buoyancy control system incorporated to help you maintain neutral buoyancy. This is achieved through valves: an inflator valve (usually in the middle of your chest) and an exhaust valve (usually in the outside of your left bicep). On top of this, you must always wear a buoyancy compensator as a back up to guarantee you a surface flotation device (in the rare case that the one on the suit would not work). It is important to remember that it is very difficult to control both systems at the same time and to do so could distract you from the basic measures to have a safe dive, so do never use them together!

Types of Scuba dry Suits

There are basically two types of scuba dry suits:
  • Membrane suit: a material called trilaminate. This material is very thin (1mm) so it requires more protective thermal underwear than a neoprene one.
  • Neoprene. The material is very thick (7/8mm) which allows lighter on non underwear. In deep dives, neoprene can be compressed to 2mm, loosing part of its insulation properties. However, it is possible to buy pre-compressed neoprene to avoid this inconvenience.
A Couple of Tips about Scuba dry Suits

You may want to consider the following recommendations when planning to dive with a dry suit.
  • Check your suit a few days before the immersion: make sure waterproof zippers, seals and valves are in good condition and if not send them to repair.
  • When wearing the suit, your seals and neck seals must be correctly trimmed and adjusted. Latex seals are trimmed often till they are 15% smaller than your neck and wrist circumference. Neoprene seals need to be stretched over night: the neck on the widest part of the scuba tank and the wrist over a tin can.
  • Use the minimum amount of weight possible to help you achieve neutral buoyancy.
  • Make sure you choose a body that understands how your scuba dry suit works.
  • Practice, practice and practice till it becomes a second nature for you.
How to Maintain your Scuba Dry Suits

Rinse it well with clean fresh water after every dive. Check that seals, valves and zippers work correctly and have them fixed it not. You don´t need to rinse the inside unless is wet or damp (pay special attention to the bottom of the boots). Dry it out of the sun and without hangers. Do not storage it till it is fully dried to avoid mold and mildew.
The zippers should be lubricated wit bee´s or parafine wax.
For the seals you can use talcum powder or if you don´t have any, soapy water.
To storage it, roll it and put it in a sealed bag in a cool dry place, away from sources of ozone (like hot water heaters or electric motors).
In any case, consult your scuba dry suits manual for care instructions.

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