Primary Gas Supply
In addition to the normal buoyancy control and performance expected of our previous commercial jackets, the Mk.4 offers direct feed supply to the jacket from the diver’s main gas supply delivered from the helmet via a cross connect hose with Swagelok quick-connect fittings at both ends.
This offers a key safety feature in that two divers have the ability to buddy breathe from one umbilical supply (
see animated demo) in an emergency.
Helmet Side-Block
The Mk.4 Jacket has been designed to be used in conjunction with a KMB.17/18 b/c diving helmet or any subsequent model with a suitable 3/8” UNF low pressure port on its side-block. Note: The DSI Side-block (Part No. 505-024) can be retro-fitted to any KMB. 17/18 helmet if not already supplied. The Swagelok 90° swivel elbow and female quick-connect fitting (both supplied) is fitted to the LP port and the cross connect hose feeds buoyancy gas from the side-block to the inflator on the jacket.
Secondary & Tertiary Gas Supplies
Secondary buoyancy gas is available via the pneumo hose inflator on the opposite side of the jacket. The pneumo hose is the primary inflator on earlier models such as the Mk.3 Jump Jacket.
A third option is to inflate from the emergency bailout gas supply cylinders on the diver's back. This should only be used in the event of losing the umbilical supply. One inflation of the jacket from a fully charged bailout set at a depth of 160m would reduce the bailout duration of 5.5 mins by 34 seconds.
Over-pressure / Dump Valves
The Mk.4 features 3 over-pressure dump valves – one at each shoulder and a third at the lower rear for dumping in an inverted position. Operating either dump will empty all gas from the jacket in three seconds. Buoyancy control at depth is very gradual. For example, at typical working depths of 100-150m plus, a fully inflated Jump Jacket will make the diver only slightly positively buoyant. The diver is able to adjust their buoyancy extremely accurately using a combination of the multiple inflate and deflate options.
All 3 O.P. / Dump valves are fitted with mesh filters to prevent grit ingress and all jacket valves can be stripped down and serviced.
Surface Orientated Diving & The 0.4 litre Emergency Cylinder
The Mk.4 Jacket has been specifically designed to be used with a surface umbilical supply, but can be used independently with conventional scuba if required.
When diving from the surface with either umbilical or scuba, the 0.4 litre 232 bar emergency mini-cylinder offers another inflation option.
NOTE: The mini-cylinder is NOT TO BE USED when bell diving due to the possibility of gas contamination.
The Integral Diver Recovery Harness
The integral harness features lifting points at front and rear. These can be used to recover a diver in distress back into the bell, aid the rapid removal of kit and to manoeuvre the diver into the ideal position to perform E.A.R. and cardiac massage. (
see animated demo)
Diving Helmet Safety Harness
The Mk.4 is unique in providing helmet-retaining webbing safety strops with clips attached to shoulder D rings and the helmet. This does away with the need for an independent helmet harness and secures the helmet to the diver in the event of a neckdam failure.
Supercam Twin-Cylinder Cambands
The Mk.4 comes with a Twin-Cylinder webbing Camband system to mount bailout cylinders on the diver’s back.
Supercam cambands are available in 3 sizes to fit 5.5" (140mm), 7" (178mm) or 8" (203mm) diameter cylinders. (please specify) Note: There is a reasonable amount of leeway on the band length to cater for unusual cylinder diameters.
Correctly fitted, the Supercam system will hold twin cylinders rigidly and with absolute security without the need to fit either a double boot or a manifold. The bands are fitted or removed by a simple threading procedure that does not require the use of tools. Single cylinder camband kits are also available.
Full Servicability
The Jump Jacket Mk. 4 is a twin-bag design with a rugged outer bag and an airtight inner bladder. Our patented stud construction ensures that the major stresses are transferred to the stronger outer bag which means greater product durability and longevity.
The outer bag features a service zip around the backplate allowing access to the inner bladder for routine washing, maintenance and regular service. All valves can be stripped down and serviced and replacement parts are readily available.
