At least Six Good Reasons to Dive Dry in Tropical Waters – Or, “No I am not crazy”

We did raise some eyebrows when we took our drysuits (see the companion sidebar article “Fusion is truly a Polar to Tropics drysuit”) to dive the in the “warm” waters around Grand Cayman. But we were in absolute comfort the whole trip and quickly found a lot of good reasons for diving dry in the tropics.

  1. One obvious sign that we made a wise choice was evident in the form of a lot of cold divers shivering in the wind during the first surface interval. It was a particularly windy spring in the gulf this year. Not only did we avoid the surface interval “wind chillys,” we also used our undergarment layer to keep comfortable in the cooler evening breezes après-dive.
  2. Even though the water was 79 degrees F (26C) the diver masters and many divers were wearing 6 mils of neoprene around their core. With our thin Fourth Element Xerotherm undergarments, were had much more flexibility than even those few in their 3 mil suits.
  3. Just for comparison, we took one dive in wetsuits. It reminded us that we do not like the sticky salt water feel that lingers until your post dive fresh-water shower.  After the dive, our fellow divers all were hungry, but most made a detour back to their rooms for a quick shower before lunch. We dropped our gear and took our place at the front of the lunch line.
  4. Our drysuits are lighter than our wetsuits and took a smaller bite out of our limited luggage weight allowance. In many moist tropical places it can take time to dry the water out of your wetsuit in the remaining time between your last dive and your packing time. Water is 8.6 lbs per gallon, so every ounce left in the suit is important. With a quick towel burrito and a little breeze our drysuits are often back to their dry weight in a couple of hours.
  5. You can save a lot of money buy just buying one drysuit and using it for all dives. Drysuits, especially shell suits can last forever, while a wetsuit’s insulating bubbles degrade a little with every dive.
  6. This last one is minor but most wetsuit divers admit hating the stretch battle you have to wage every time you get into and out of a wetsuit. Not the case with a drysuit.

How warm is too warm for diving dry?

We spoke with Allen Aboujeib, with the grand title of “Director of Happiness,” from Bluewater Divers.

Allen has 300+ dives over the last few years in the DUI 30/30 Tropical Drysuit in areas all over such as Australia, Fiji, Chuuk, Curacao, California. He says he was only too warm once while on a shallow dive in 85+ degree water. But not for long, because he just stretched open a seal and let in a bit of water. Remember that a shell drysuit’s only purpose is to keep you dry. It has no insulating value. That is why it can be used in warm waters without overheating. With only a thin wicking layer inside, even if the water is quite warm you should be able to release excess body heat to the water.

Allen pointed out this quote on the DUI website

“Repeated exposure to temperate waters can cause minor discomfort to turn into hypothermia. By staying dry even in warm waters, your comfort level increases and you can maximize the length and number of your dives. After all, you are on vacation.”

Many divers are not aware of the phenomenon called “warm water hypothermia”. Many of the really active tropical divers I spoke with said they had experienced it at some level. The NOAA Diving manual states the following on the subject:

“Divers also have to be wary of hypothermia in warm environments. A phenomenon called “warm water hypothermia” can occur even in the tropics, especially during long dives and repetitive dives made without adequate re-warming between dives. In warm water hypothermia, long slow cooling can take place in water temperatures as warm as 82 degrees F – 91 degrees F. Although warm water hypothermia is not easily recognized as its cold water counterpart, it definitely warrants attention.

What kind of suit can be used for tropical diving

If you only dive warmer waters, the DUI 30/30 Tropical Drysuit is the perfect tool for the job. The “30/30” stands for 30 degrees north latitude, to 30 degrees south latitude, hinting at the locations you can find the waters that this suit was designed to dive. It is made with a durable but breathable/waterproof trilaminate material and does not have the attached boot or dry socks found on other “cold water” suits. All 30/30 divers we interviewed loved this suit.

Any other shell drysuit should also be a fine warm water drysuit. However, the Whites Fusion drysuit is particularly well suited for tropical diving. Its thin shell is compressed against your body by and outer lycra or superstretch neoprene layer. If you own the “bullet” or “tech” skin model, you can even swap out the Velcro attached compression outer layer with the thinner “sport” layer. Owning a Fusion is a great money saver, because this one suite is at home in any temperature waters, so you can skip the common practice of owning a drysuits and one or more wetsuits for vacations (See our companion article Whites Fusion Lives Up to its Claim of TROPICAL TO POLAR ).

Neoprene and crushed neoprene suits should still be an acceptable solution. But they are heavier and do provide some insulation, thus would not be as good for really warm waters.

While browsing a dive shop on Grand Cayman, we heard that the shop owner was just approached by the Cayman police interested in ordering Whites Fusion drysuits for their staff.

The Caveat

One issue may be a challenge diving dry. Many dive charters in tropical location do not have a marine head (boat toilet) and expect diver to “pee in the pool.” With a drysuit, this means you have to either hang over the side to pee, jump in the water between dives, or have a pee valve (or a she-pee for women). We did manage fine, even though my female partner was the only woman dropping her rear off the side of the boat between dives, but are considering the pee valve for  future dives.

From our experience we came home wondering why anyone would choose to dive a wetsuit and will likely only dive wet in waters that are so warm you do not need a wet suit. But, no matter how strong the case for diving dry in the tropics, scuba is a world of strongly embedded traditions and we do not expect to see a mass movement of divers willing to buck that tradition and peer pressure anytime soon. But if you do don the drysuit on your next tropical trip and your fellow divers are shivering on deck feel free to gloat a bit.