"From birth man carries the weight of gravity on his shoulders ... But man has only to sink beneath the surface and he is free. Buoyed by water, he can fly in any direction — up, down, sideways — by merely flipping his hand. Underwater, man becomes an archangel." - Jacques-Yves Cousteau
Tropical Minimalist (“TM”) scuba diving is diving within recreational limits in a tropical environment using as little gear as possible. TM has no application in overhead environments, at depths greater than 130 feet/40 meters, or where a decompression obligation is planned. It can only be accomplished in the benign conditions of tropical waters possessing good visibility, little if any current, and a water temperature which makes a wetsuit unnecessary.
It gives you a feeling of freedom in the water akin to free-diving. You are faster and more maneuverable, but expend less energy and use less air. It’s the most natural way to dive. TM diving just feels right.
TM diving is as much about what you don’t bring as about what you do.
No wetsuit: In tropical waters, you just don’t need one. Really. For example, in the Cayman Islands (where I live), the sea temperature has not dipped below a toasty 81 degrees in the last year. The 12-month average is 83. (Ref.: http://www.aoml.noaa.gov/cgi-bin/trinanes/searchmaps1.cgi?month=10&day=1&year=2007 ) At these temperatures, why coat yourself in neoprene? Take some advice from the diving pioneers: “Use a rubber suit when the surface water is below 70 degrees F.” (Ref.: “Diving With the Aqua-Lung”, U.S. Divers Co., 1958, p. 17).
No weights or weight belt: Without a wetsuit, your weight requirement should fall to a manageable 2 to 8 lbs. and will be provided by a back plate (see below). No need to hang lead blocks around your waist.
No wing or BC: With this little weight (and assuming you use the ubiquitous single AL80 tank), you really don’t need an inflation device underwater. You will be pleasantly surprised at how much drag you eliminate by leaving it behind. Control your buoyancy using your IBD – your internal buoyancy device, i.e., lungs. The lack of a BC or wing will feel strange at first but become second nature after a handful of dives. It may help to remind yourself from time to time that BCs did not come into common use until the 1970s; most long-time divers learned without one.
Back Plate + STA: This attaches your tank & reg set to your back in a secure manner and satisfies your weighting requirement. A back plate will distribute the weight evenly across your back and enhance your trim. Back plates are available in various weights (see Table); it is CRITICAL to buy the one which is right for your weighting requirement. Don’t forget to include the weight of a Single Tank Adapter (STA) in your calculation.
Harness: A simple "Hogarthian" harness made from 2” nylon webbing, a buckle, and a couple of D rings will do.
Reg Set: No surprises here. A 2-stage balanced regulator, alternate air source (octopus), dive computer (or depth gauge and timepiece), and submersible pressure gauge (or air-integrated computer) are needed. Throw in a compass and a knife while you’re at it.
Mask: No change here. A low-volume mask which fits your face. A snorkel is unnecessary; leave it behind.
Fins: Full-foot fins, of course. Since you’re not wearing a wetsuit, you have no need for open-heel fins. Full-foot fins will give you better maneuverability because of the tighter fit.
Doffing your wetsuit and reducing your weight requirement really pose no risks. The lack of a BC or wing does present some additional risk because an inflation device allows you to rest during long surface swims, planned or unplanned. You will have to weigh the added risk factor against TM’s benefits by considering the diving conditions you are likely to encounter. Personally, I will wear a wing whenever I consider that a long surface swim or a moderate to strong current is a reasonable possibility. And, of course, when acting as a PADI DM I wear a BC to avoid setting a bad example.
No additional skills. Well, it does take a bit of getting used to. But only a bit. Your buoyancy feels different without a BC and even more so sans wetsuit. Two or 3 dives should be enough to master it. Make the first dive a shallow one.