An area of significant difference between recreational diving equpiment and cave diving equipment is that of exposure protection. Recreational divers tend to severely underestimate the amount of exposure protection necessary to be comfortable in the 72-degree water of north-central Florida’s freshwater springs, or the 77- to 78-degree water of the Yucatan’s cenotes.
For short, shallow dives in the north-central Florida springs, it is a rare diver who can be truly comfortable in anything less than a 7mm, farmer-john style wetsuit. For similar dives in Yucatan cenotes, a 5mm full-length, one-piece wetsuit may suffice. Nevertheless, we frequently see recreational divers in both environments attempting to get by in 3mm shorty wetsuits — or less. (Apparently these are the same divers who missed that part of their beginning scuba course which explained how water conducts heat away from the body 25 times faster than air.)
Cave divers in these same environments need substantially more exposure protection than recreational divers do. This is because they go deeper (where suit compression limits the effectiveness of wetsuits), and remain far longer. Where the typical recreational dive seldom lasts longer than 30 to 40 minutes, cave dives can last up to 90 minutes or more — plus decompression.
In the Yucatan, cave divers typically use a minimum of a 7mm, farmer-john style wetsuit, with a hood. In north-central Florida, it is a rare cave diver than does not use a dry suit and thermal undergarments.
Modern dry suits offer a further benefit to cave divers in that most come with large thigh pockets. These make excellent places to store items such as slates, dive tables, clothespins, line arrows and guideline spools. By keeping these items stored out of the way, in pockets, cave divers substantially reduce the risk such items causing guideline entanglement.