Blog posts from Gareth, Imogen and Neil
As with all parts of the standardised kit configuration, even the five hoses which are used with the twin cylinder set up have standard lengths. This makes life simple as each piece of equipment will reach exactly to the right place on your kit without excess slack, preventing drag in the water or potential entanglement hazards. An added bonus is any hose can be swapped out with one of your team's in the event of a failure being discovered during the equipment match prior to the dive.
Five hoses are necessary for twin set configuration. The first stage attaching to the right post has the buoyancy compensator/wing inflator hose and the long hose which leads to the primary regulator coming from it. The first stage attaching to the left post has three hoses: the high pressure hose to the submersible pressure gauge (SPG); the low pressure hose leading to the dry suit inflate valve; and finally the shorter backup regulator hose.
In situations which support wetsuit diving in warmer waters, or if the dry suit is being inflated from an independent dry suit inflate bottle, there will only be two hoses leading from the left side.
Use of high quality hoses to reduce the risk of rupture is essential and bubble checks performed on every dive should double check for leaks. Hoses will need checking regularly for signs of wear from kinking and subsequent failure.
The primary regulator (long) hose
The primary regulator (long) hose is the longest in the configuration by far, between 1.5-2.1 metres in length. The long hose configuration has been adopted from diving in an overhead environment, where there is a need to travel in single file yet retain the ability to donate gas. With wider spread use of this configuration, open water divers have found another benefit is reducing stress immensely in an out of gas emergency, especially where there are decompression obligations. Divers in overhead environments MUST have 2.1m (7') length hoses; whereas open water divers may use the shorter 1.5m (5') hose lengths.
The long hose runs from the primary stage on the right post, is tucked underneath the primary torch battery cannister, runs across the diver's chest and forms a loop behind his head running left to right. The primary regulator can then the placed into the diver's mouth. When not breathing from the regulator, the hose is clipped off on the right chest D-ring, by a bolt snap added to the end of the hose.
The backup regulator hose
The backup regulator hose originates from the left post, behind the diver's shoulders, running around the right side of the diver's neck. This should be long enough to allow the regulator to sit comfortably in the diver's mouth without unnecessary bulging at the side of, or behind the diver's head. A necklace made from bungee goes around the diver's neck to keep the regulator in the correct place. The backup regulator hose is 22" or 24" in length depending on the first and second stages.
The BC/wing inflator hose
The BC/wing inflator hose runs from the right post, behind the diver and is kept tight to the corrugated (elephant) hose with two snoopy loops. The inflator hose and elephant hosing from the wing both pass through the rubber ring attached next to the left chest D-ring. This allows the wing hose to be easily found and reattached in the event of it coming detached during the dive. The wing inflator hose is usually around 22".
The dry suit inflator hose
The dry suit inflator hose runs from the left post or from a separate dry suit inflate bottle. The hose type will vary depending on the set up you have in place but those derived from the left post will be about 26".
The high pressure SPG hose
Finally, the high pressure hose that attaches to the SPG is 24". Again a single bolt snap is attached to the gauge end of the hose which allows it to be neatly clipped to the D-ring on the left hip. This allows the SPG to be easily accessed throughout the dive; but when clipped off, the hose is short enough to run close to the diver's body, minimising the chance of entanglement.
The hoses that inflate the wing and the dry suit always originate from different sources - left and right posts, or right post and dry suit inflate bottle. This means in the event of a post failure the diver will retain the ability control buoyancy. Similarly, the primary and backup regulator hoses are also run of different posts. In addition the right post is deliberately chosen to run the primary regulator and BC/wing inflate from as this is unlikely to "roll-off" in the overhead environment.
Ultimately, the lengths given here are a guide, more than a rule, with the exception of the long hose. The take home message is that all hoses should be long enough to comfortable facilitate their function without excess length which may create drag in water or a potential entanglement hazard. It is always a good idea to have at least one spare of each length in your dive kit... there is nothing worse than a wait on the boat while your team goes diving!