Innovative Shortsea Vessel Fitted With Unique MacGregor-Navire CAE
MacGregor-Navire (MGN), the leading designer of cargo access equipment (CAE), has supplied the innovative shortsea RO/LO vessel Alster Rapid with a shipset of CAE that for originality and the mix of cargo made possible by its use, must stamp it as unique. The 2,515-dwt vessel, though small, is equipped so that it offers the cargo-handling capabilities of ships much larger.
The recently delivered Alster Rapid was built by the Hamburg yard of J.J. Sietas for the West German owner Henry Stahl, who immediately deployed the vessel in his U.K.-trading Washbay Line.
The new ship will form part of a thrice-weekly service operated by the line for more than 20 years. All four of the vessel's cargo decks above the tanktop level are entirely composed of removable flush-fitting panels. Each level, in fact, is a stowable MGN hatch cover that completely spans the hull to constitute a deck. Each deck includes an individual panel (or panels) that also does duty as interdeck ramps.
When the cargo to be loaded requires the removal of any deck, the panels of which it is formed can be rolled into stowage and stacked, both movements being performed automatically ; the only exception is the four panels on the forward part of the upper deck, which fold into stowage. Replacement of a deck is also automatic, the unstacking and rolling (and unfolding) being performed in reverse order.
Long cargo (up to about 148 feet) can be loaded vertically using shoreside cranes but the principal mode of access is horizontal, cargo being rolled over the stern via a 200-toncapacity ramp that, in keeping with the singular nature of all this ship's CAE, is adjustable in length, width, and height. Width and height adjustment were included to cater for specific berthing conditions at ports on the destined routes; height adjustment, in which the ramp can be hinged at any one of the four decks above the tank top, enables the ship to be worked at any quay height or tidal level, thus eliminating the need for link span berthing.
Another unusual feature of the Alster Rapid, which the MGN access equipment is designed to facilitate, is its ability to load fiat-bottomed floating cargo such as small barges, these being floated/winched aboard through the stern in what the owner calls the slip-on/slip-off (SO/SO) mode. For this operation, one of the main deck panels is placed athwartships (there is a 5- ton crane fitted aft for this purpose) to form a watertight bulkhead located about 59 feet forward of the stern ramp, thus creating a separate section. For embarking floating cargo, the stern ramp is lowered to an angle of —20 degrees below the horizontal, its end reaching about 10 feet below the waterline. This exposure of the stern—the so-called "open air" section—also enables the loading of cargo of unlimited height when the upper deck panels within the sternmost section are removed. Flexibility in cargo operations is greatly enhanced by the multiangled ramp situated within the 59- foot-long sternmost section. This ramp, the two ends of which are separately height-adjustable by means of four jigger winches, is used as an extension or continuation of the external stern ramp. This facility, together with ramps on the main and weather decks (which may or may not have to be brought into use), permits direct access for wheeled cargo to any deck. The criteria for use of the main/weather deck ramps will depend on the gradient to be climbed, which in turn is determined by the quay height.
The Alster Rapid has an overall length of 290.6 feet, beam of 46.9 feet, depth to main deck of 16.6 feet, and draft of 16.7 feet. Propulsion is provided by a MAN B&W 8L 28/ 32-FVO diesel engine with an output of 1,530 bhp, giving a speed of 13 knots.
For complete literature fully describing all MacGregor-Navire equipment,