Stainless steel fasteners secure lifeboat lights

The versatile Protex Catchbolt in stainless steel is specified by the Royal National Lifeboat Institution to secure two folding, deck worklights fitted on RNLI Mersey and Tyne class lifeboats

The versatile Protex Catchbolt in stainless steel is specified by the Royal National Lifeboat Institution to secure two folding, deck worklights fitted to the forward end of the wheelhouse top on RNLI Mersey and Tyne class, all-weather lifeboats.

The pair of Aquasignal broadbeam worklights type 013, each giving a power output of 50W and light emission of 500 lumens, are used primarily to illuminate the foredeck of the lifeboat when the crew are performing tasks such as mooring, anchoring, and launch and recovery from the slipway or carriage.

Most vessels of the Tyne and Mersey classes are kept ashore in boathouses, ready for immediate deployment.

The lights need to fold because in many cases the clearance between boat and boathouse door is very restricted, sometimes being so small that an increase of only 25mm can make the difference between the lifeboat entering safely, without damage, or not.

The unique, patented, Catchbolt quick-action draw latch or overcentre fastener, designed and manufactured by British company Protex Fasteners, gives a closing force combined with rigidity in all three planes.

This avoids the hinge-like action common to all other overcentre fasteners which, since they apply a load along one axis only, are unsuited to securing bonnets, covers, other enclosures, doors, flaps, hatches or panels.

The initial closing action of the Protex Catchbolt pulls the keeper in towards the main body.

Continued operation of the lever drives a spring-loaded bolt under the keeper and, since the bolt has a tapered nose, a positive "clamp-down" is achieved against the rubber seal it compresses.

The bolt provides the fastener with excellent rigidity and alignment in all three planes.

Although the description is complex, the fastener is simple to use.

With an impressive breaking strength of 600kgf (5.88 kN) along the longitudinal and lateral axes and 900kgf (8.82 kN) in the vertical axis, the stainless steel version of the Protex Catchbolt is specified widely by the RNLI for deck and wheelhouse applications where a secure and rigid fastening with quick action is essential.

In mild steel for less hostile environments where seawater corrosion would be absent, the device gives 400kgf (3.92 kN) along the longitudinal and lateral axes, 900kgf (8.82 kN) in the vertical axis.

100mm long X 45mm wide X 18mm deep, the Protex Catchbolt serves as its own template for accurate fixing.

Facilities can include pin sealing, padlock, safety catch and, for flush fitting, a convenient split, recessed dish.

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