How To Choose Standard Weight BCDs
Look to spend anywhere from 300 to 700 bucks on a decent BC. Don't settle for less than the best: this is essential SCUBA equipment, okay?
Repeat after me: A good BC makes me a fish. A bad BC makes me fish food.
As the name suggests, a Buoyancy Compensator makes positive, neutral or negative buoyancy possible for the SCUBA diver at varying depths and under varying conditions. Your BC unit doubles as the thing that holds your air cylinder to your body. Since these are the device's primary purposes, keep these functions primarily in mind when shopping for a BC.
Of secondary import are non-essential functions: providing maximal surface buoyancy for resting and swimming, as an tackle box for maximal attachments and accessories, and as a neon-colored fashion statement that maximizes your image as a SCUBA sex symbol.
Two BC Types for Two Types of Diver
Today's standard BCs come in two-primary types: Jacket and Back-Inflation (a third type, those old Horse Collar types, aren't worth mentioning here - oops. Guess I mentioned them after all. Never mind them anyway. They're the BCs the Navy UDT divers used during WWII, back when a slathering Crisco all over the diver's body was considered as good as wearing a wetsuit). Both types require a weight belt to provide the additional ballast to keep the diver heavy enough to stay submerged. In an emergency, the diver may ditch the weightbelt to the bottom to increase buoyancy.
Today, Jacket BCs are more commonly used than Back-Inflators, and are better suited for recreational diving; they fit like a vest and allow for inflation around the diver's body. Back-Inflation BCs do what their name suggests - inflate behind the diver's body - and are better suited for more advanced diving or underwater photography. Back-Inflators Photographers are keen on Back-Inflators because they allow the divers more stability and horizontal control. Some recreational divers find that Jacket-type BCs are better able to keep them in a face-up position at the surface.
BC Buyers' Primary Considerations
The important stuff: Buoyancy is the difference between feeling like a fish, and feeding the fish.
How much is that BC in the window's Lift?
Okay. How many pounds of lift do you need to buy? I don't know. A general rule is this: Your BC should be able to hold you comfortably at the surface, without any kicking, in all your gear, while only halfway inflated. How much lift is that? Your mileage will vary. For instance, if you plan to do freshwater diving, you'll need more lift than for marine dives, since saltwater is more buoyant. For tropical diving (sans wetsuit) you'll need a generally-recommended 12 to 24 pounds of lift, for temperate diving (requiring a wetsuit) 20 to 40 pounds, and for hard-core or technical diving, 40 to 80 pounds (but then, you should know if you do this kind of diving). Buy a BC to match the most demanding diving you plan to do, and don't skimp on Lift. The surface can be a long, long way away when your suit is compressed by deep-water pressure and that tropical BC isn't up to the demands your cold-water dive is making on it.
Note that most manufacturers' specs on lift will vary by 10 to 20 percent. If in doubt, just buy the BC that has the higher lift rating. When you want to get to the surface and stay there, you'll be happy if you spent more and bought more lift.
Proper fit is where all that lift meets your body. An ill-fitting BC will function in a sickly fashion. Try on a BC before buying it while wearing your thickest wetsuit/drysuit, and be sure it's not binding or too loose. The BC should allow space for movement - do a few arm circles to feel for any pinches to your armpits - but shouldn't move around. Have someone lift on it to see if it might "ride up" into your chin as it might when inflated underwater. When wearing the BC, see to it that all of your adjustment straps fall into the mid range - neither completely cinched down or completely loosened.
Women: note that some BCs are manufactured with the specific comfort and curvatures of a woman's torso in mind, but they are all, at this writing, weight-integrated designs. Look under What You Should Know About Weight Integrated BCs for a little more information on these models.
Low inherent buoyancy, and no air trapping. These measurements are taken with the BC (supposedly) empty of air. Some BCs float more readily when empty of air (a high inherent buoyancy), and some BCs trap air in pockets, and thus, tend to provide lift when lift ain't wanted. Generally, and not coincidentally, the same BCs that have high inherent buoyancy also tend to trap air.
A Hard Pack for heavier or fatter tanks, with a hard handle to make lugging the tank/BC unit around much easier. Hard packs keep the tank in a stable position, and may or may not have any effect on the comfort of your rig, depending on your body shape. Shorter divers may find that a hard pack mashes their weight belt into their kidneys (and they may want to look into BCs of the weight-integrated variety).
A hard top handle reduces wear on the vest section of the BC proper because you won’t have to grab the BC by the lapels every time you move it.
Get an easy-to-manage Power Inflator. Simplicity of use (are the inflate and deflate buttons easy to distinguish and reach with your fingers/thumb, especially in your dive gloves?), length of hose (is it too short?), and grip size (an inflator grip that feels right in your bare hand may be awkward in your gloved hand). Look for a robust flow rate when inflating and deflating via the handheld valve.
Tank strap. If your pants fell down around your ankles, think how red you’d get. But if your air cylinder slipped down around your ankles, think how blue you’d get. Zero tank slippage is the goal.
Will the tank band on the BC accommodate your tank? If you have a Super 80 or 100, will the tank band fit well around it? Or, if you have a taller tank, will it fit well without hitting you in the back of the head or butt? If you’re a shorter person, a height-adjustable tank strap is a must. Some soft-pack designs don’t allow much room for height-adjustment, and don’t have the rigidity to stop one’s tank from moving around.
And here's where I make the only brand-name recommendation in an otherwise generalized review: the Scubapro Super Cinch tank band has proven itself time and again in various tests to be the simplest-to-use and most secure tank-holding band around.
BC Buyers' Secondary Considerations
Some points to ponder if you also consider your BC a surface-flotation device, gear rack, and fashion statement
As mentioned above, Jacket-type BCs are more apt to allow for more comfortable, face-up floatation than Back-Inflating BCs, which have a tendency to push the diver forward while surfaced, face-into the water. Underwater, this is a plus and makes for an optimal submerged swimming position; on the surface, this can be an annoyance (if you need to wait for a pick up while drift diving, for example). Note that all BCs will roll a diver, and no BC comes with a guarantee that it will float a surfaced diver in a face-up attitude. Jacket BCs seem to make surface swims and conversations a little less demanding, however.
Pockets and D rings. If people have a complaint about their BC, it's usually that their are not enough pockets (or no pockets at all) and/or that the pockets are too inconvenient to actually try to carry anything. While at the dive shop, try to slip in a small flashlight, slate, or Spare Air. Can you do it without having to look at the pocket? Does it secure nicely? Zippered enclosures are more apt to stay closed than velcro enclosures. Also, look for self-draining pockets that can expand to accomodate goodies.
I'm one of those divers who jingles like a sleigh with the D rings on my BC. Having at least four large D-rings, one at each "corner" - top left, top right, lower left and lower right - should be a minimum, I say. If you don't have enough gadgets to completely fill at least four rings, you're not giving out your birthday and Christmas wish lists to the right people.
Color. Who cares what color your BC is? Your buddy might, if you're diving in a crowd, and he's constantly trying to pick you out from the rest of the all-black seal-like forms swimming about. So, you may want to integrate your BC into a divegear color scheme that makes you easy to identify underwater (and makes your gear easier to collect on a junked-up boat deck). If so, keep the ROY G. BIV spectrum in mind; color will drop out underwater in the order of this Red/Orange/Yellow/Green/Blue/Indigo/Violet spectrum. A bright Red BC at the surface might turn gray at 30 feet underwater, whereas an Orange or Yellow BC won't lose its color until maybe 40 or 50 feet. Blues and Purples will maintain their color characteristics the deepest of all.
No comments:
Post a Comment