Are you Hydrodynamic? BC Basics Part II
Are you an underwater sports car, sleek and streamlined?
We explored the history, variety, evolution and functionality of BCs in February. Now we’ll discuss BCs as a platform for mounting a range of diving accessories in the most hydrodynamically efficient manner possible. We'll approach each section based on general groupings of dive environments we encounter. Every Dive - Whistle and cutting devices
A whistle is a cheap, effective signaling device every diver should have secured to their BC or harness. Fishing line entanglement can be a hazard on any dive. Shipwrecks are often shrouded in fishing tackle and their interiors pose numerous entanglement hazards. Severing and retrieving the line or cable is easy with a quality cutting device.
Shears, also worn in a sheath on one's BC or harness, are useful when diving wrecks where cutting electrical cables or metal fishing gear may be required.
Paying a few bucks more for high quality cutting devices is a good long-term investment. The blade must perform when called upon.
Ocean, Lakes & Rivers - Surface Marker Buoys
Surface Marker Buoys (SMB) have become standard equipment when diving in large bodies of water. Wind and current can move ascending divers away from their intended surfacing point. High visibility SMBs, usually orange or yellow, help captain and crew spot and recover drifting divers more easily.Deploying an SMB attached to a dive reel at depth just prior to ascending is an effective means of signaling the boat captain that the dive team is preparing to ascend. Attachment points include in your BC or exposure suit pocket, D-ring, back plate or butt plate rail, or a strap-on thigh pocket.
Drift, Planned Decompression, Search and Recovery Dives
Have you ever lifted something from depth by adding extra gas to your BC or wings? The guide is to employ a lift bag when lifting five pounds or more. If you drop your load while being overinflated you risk a lung overexpansion injury. Consider signing up for the PADI Search and Recovery Specialty. You'll get hands-on experience conducting search patterns to find objects, knot-tying techniques to secure the objects, and lift bag deployment techniques to recover your trash or treasure from depth. BoN divers had great fun using lift bags to retrieve hundreds of pounds of heavy objects from the river bottom during the October 2017 Project AWARE Cleanup.
Lights (Torches) and Strobes
Underwater lights (or torches for our Commonwealth friends) are essential tools for night dives and in overhead environments like caverns, caves and wrecks.Lights used in daylight bring back color lost below 30' when diving on a beautiful reef or wall and are particularly useful for peering into crevices to glimpse nocturnal animals or those with perfect camouflage like octopi and scorpionfish.
Recreational diving with two lights has become commonplace as lights are fairly inexpensive and backups are always desirable. Cave and wreck divers always carry three lights on every dive. Attachment points are many. Placement depends on the dive and diver preference. The last thing you want to do is to let your lights dangle during the dive. You risk damaging aquatic life...and your light! Nobody wants to be "that guy."
Recreational divers normally secure their lights to their wrists using a lanyard, storing the light in a pocket (with the backup light) when not in use. However, more recreational divers are using small canister lights due to their flexibility, falling prices and incredible power.
Technical diving in an overhead environment calls for powerful, long-duration lights. That used to mean canister lights which have light heads attached to their power source (NiMH or Li-Ion batteries) via a strong, watertight cable. The canister is secured to a back plate or harness while the cable is run in a manner that doesn't interfere with stage or bailout cylinders.
The photo at left shows a "can" light with its light head attached to a Goodman handle which has a small stainless steel bolt snap for attaching the light to the diver's harness pre and post-dive.
Technical divers usually carry two backup lights in a thigh pocket of their exposure suit, secured inside using stainless steel snap bolts. Another option is to attach one light longitudinally on each harness shoulder strap using surgical tubing or shock cord.
Strobe lights are useful on shore dives to mark a specific spot, such as an ingress, egress point or in the water attached to a boat's anchor line. Chem lights, or purpose-built lights designed to be attached to one's cylinder, mark each diver's presence on night dives, particularly useful on moonless nights.
Recreational divers normally secure their lights to their wrists using a lanyard, storing the light in a pocket (with the backup light) when not in use. However, more recreational divers are using small canister lights due to their flexibility, falling prices and incredible power.
Technical diving in an overhead environment calls for powerful, long-duration lights. That used to mean canister lights which have light heads attached to their power source (NiMH or Li-Ion batteries) via a strong, watertight cable. The canister is secured to a back plate or harness while the cable is run in a manner that doesn't interfere with stage or bailout cylinders. The photo at left shows a "can" light with its light head attached to a Goodman handle which has a small stainless steel bolt snap for attaching the light to the diver's harness pre and post-dive.
Technical divers usually carry two backup lights in a thigh pocket of their exposure suit, secured inside using stainless steel snap bolts. Another option is to attach one light longitudinally on each harness shoulder strap using surgical tubing or shock cord.
Powerful Handheld Primary Lights
Dive Rite’s ingenious HP50 light system is a terrific advancement in dive light technology. The Handheld version slips into a Quick Release Mount (QRM) wrist mount for a completely cordless experience with a 3-hour burntime on medium setting using four 18650 3400 mAH Li-Ion rechargeable batteries. The light head also can be mated to the Dive Rite Slimline and Expedition canister lights which provide 6.5 and 10 hours of burn time respectively on medium setting.
I regularly cave dives with a Dive Rite LX20 (four hours of burn time on high) handheld primary in a QRM mount (in the foreground) and two Dive Rite BX backup lights. The BX2 is powered by a single rechargeble 18650 battery.
I regularly cave dives with a Dive Rite LX20 (four hours of burn time on high) handheld primary in a QRM mount (in the foreground) and two Dive Rite BX backup lights. The BX2 is powered by a single rechargeble 18650 battery.
Strobe lights are useful on shore dives to mark a specific spot, such as an ingress, egress point or in the water attached to a boat's anchor line. Chem lights, or purpose-built lights designed to be attached to one's cylinder, mark each diver's presence on night dives, particularly useful on moonless nights.
Compass
Often an overlooked piece of gear, a good compass is an essential tool. Magnetic compasses are still the norm. A good quality compass will last for decades and always point to magnetic north.If your wrists are occupied with dive watches and computers, consider mounting your compass in an automatically retracting mount which you can attach to your BC or harness. The reel keeps the compass close when not in use.
More dive computers are coming standard with an electronic compass. The diver calibrates the compass before the dive on the surface. The electronic compass in the Shearwater Perdix and Petrel computers is easy to use, reliable, and lets you shed your conventional compass...or put it in your pocket as a back-up, helping you streamline yourself even more.
Attaching and Streamlining Additional Cylinders
Continuing Education
As always, seek training and experience with the Bubbles or Not Diving instructor staff before attempting dives beyond your skill or current level of training. PADI Night, Cavern and Wreck Specialties are exciting courses that will inject variety and excitment in your diving repertoire and open up new worlds of local, US and international dive destinations.
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Coming in April: Dive Like a Pro - Advanced Streamlining Techniques
Coming in May: Compressed Gas Cylinders 101
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