Wetsuits for Different Temperatures
Every swimmer knows that warm weather can be accompanied by cold water. And even if the water is warm at the surface, temperatures drop rapidly once you descend. Proper body temperature maintenance is an absolute must while underwater!
Water temperature is tricky business. While 70°F might feel like the perfect spring day on the surface, under water it can be deadly. Water pulls heat away from your body 20 times faster than air, which means that your body has to work 20 times harder to maintain your 98.6°F internal temperature. This means that, even though the water will be warm while diving in the Bahamas, you'll still want some protection from the cold. Fortunately, wetsuits are the answer, and they come in a variety of different forms for various levels of protection.
Wetsuits are generally made of neoprene - a type of foamed rubber - that traps water close to your skin. Your body heat warms this trapped water next to your skin, essentially allowing you to swim in your own self-heated suit. Because the water needs to be trapped for the suit to work effectively, wetsuits should be snug, especially at the neck, arm, and leg openings.
If the water is warm enough, you can probably get away with a "shorty." This type of wetsuit is a single piece garment that covers your torso, shoulders and part of your upper arms, and legs to your knees. These suits offer excellent freedom of movement at the expense of thermal protection. Thanks to the warm water, this will probably be your suit of choice while diving in the Bahamas!
The next most common category of wetsuit is the "full suit," which is a single piece garment that covers your torso and your arms and legs to the wrists and ankles. These suits are often constructed with thicker neoprene in the torso and thinner neoprene at the extremities, so be sure to weigh the mobility and temperature trade-offs!
Beyond these two primary categories of wetsuits, there are also other pieces and accessories that can help keep you warm. Boots are often worn to help provide a platform for fins, while gloves, vests, and hoods can provide both additional warmth and some protection from the environment.
Be aware that a wetsuit that feels comfortable at the surface may well feel freezing underwater! Neoprene foam is an excellent insulator because of the high concentration of trapped nitrogen in the material. This nitrogen compresses at depth, which means that you lose some thermal protection as you descend. This compression when combined with lower temperatures at depth can send some divers back to surface looking for more protection.
Finally, thanks to the nitrogen, neoprene is buoyant, and becomes more buoyant as thickness and coverage increases. While this may make surface swims a bit easier, keep in mind that maintaining neutral buoyancy with a thick wetsuit may be a challenge. You may need to compensate with extra weight, which can in turn make you more tired and cause faster air use. Also note that buoyancy decreases at depth - a warmer suit can certainly lead to a more challenging dive!
Above all, be sure to check with a local dive shop about what solution works best for your dive area. You'll have plenty of options while diving in the Bahamas, and all of the dive centers want to make sure that you have a fun and safe time!