Most vessels of the Tyne and Mersey classes are kept ashore in boathouses ready for immediate deployment. As with the flexible superstructure of navigation and communication aids, the lights need to fold down because in many cases the clearance between boat and boathouse door is very restricted, sometimes being so small that an increase of only 25 mm can make the difference between the boat entering safely or not.

The patented Catchbolt quick-action draw latch or overcentre fastener, designed and manufactured by UK company Protex Fasteners Ltd, gives a closing force combined with rigidity in all three planes. This avoids the hinge-like action common to other overcentre fasteners which apply a load along one axis only.

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 a breaking strength of 600kgf along the longitudinal and lateral axes and 900kgf 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.

MJ Information No: 16715