MacGregor's Novel Solution To Quay Height Variation

The Claymore, a ro-ro passenger/ vehicle vessel capable, when fully loaded, of carrying up to 527 passengers and 47 cars or six 40- foot trailers and 24 cars, was recently launched from Robb Caledon's Leith, Scotland, yard. When delivered to her owners, Caledonian Macbrayne of Gourock, Scotland, she will supplement that company's sizeable f l e e t which services the large number of Scottish islands with passengers, vehicles, freight and mail.

The Claymore, a stabilized vessel of 450 dwt and 77 meters (about 253 feet) overall length, is fitted with MacGregor ro-ro equipment of a type which represents a rather unusual yet simple solution to the problem of the wide range of quay heights met with at the various Scottish island ports of call. It includes (a) a stern ramp and (b) a hoistable platform or cargo-lift embodying turntables (one port, one starboard), access to which is via side ramps, one on each side of the vessel.

In its lowest position, the platform is flush with the cardeck, entry to which, when quay height permits, is via the stern ramp.

Often however, the quay height may not permit stern access; then vehicles will drive on to the cargo lift — raised to the appropriate height — via a side ramp from either port or starboard, depending upon the side the vessel is moored. Platform with vehicle then descends to cardeck level, the turntable is manually operated to point the vehicle longitudinally, and the vehicle driven off and parked.

Operation of the platform is by hydraulic jigger winch, and of the side ramps by two hydraulic cylinders. Duplicated, joysticktype controls for both ramps and platform are located adjacent to the forward port and starboard platform guide and support pillars.

Indicator lamps show the "in" and "out" condition of side ramps, the position of the platform and the direction of its travel. Interlocked safety limit switches are provided on all movements plus, for warning purposes when the system is energized, revolving indicator lamps and a klaxon operable during raising and lowering.

The MacGregor hydraulic stern ramp provides a 3.83-meter-wide (about 121/a feet) vehicle way and is comprised of an inner and outer leaf with a single finger flap, giving total length of over 7.5 meters (about 25 feet). It is suitable for a twin-axle loading of 13.5 tons per axle.

Operation of both inboard and outboard sections of the ramp is by hydraulic cylinder, and control is by joystick situated adjacent to the ramp.

Power for both stern ramp and lifting platform/side ramps is supplied from the same power pack. Briefly, this hydraulic pump station comprises three main pumps, all mounted on a common tank and powered by a 68-hp 1,500 rev/min motor.

Other stories from October 1978 issue


Maritime Reporter

First published in 1881 Maritime Reporter is the world's largest audited circulation publication serving the global maritime industry.