FEATURES OF SHIP DESIGN.

Otago Daily Times, Issue 19800, 27 May 1926, Page 16

FEATURES OF SHIP DESIGN.

One of the most difficult matters met with in arranging the disposition of the various features of a passenger liner is that of placing the cargo hatches in suitable positions in relation to the holds which they serve. The ideal arrangement from the stevedore’s point of view is to have a cargo hatch at the centre of each hold, so that the distance over which the cargo must be dragged to bring it under the hatchway is reduced to a minimum. The necessity of finding room for large numbers of passengers amidships, however, calls for a long bridge and promenade decks and deckhouses. These will' considerably overlap the machinery and bunker - spaces, and force the cargo hatches towards the ends of the holds adjacent to the machinery spaces. The adoption of oil fuel and its stowage in. the double bottom, as well as the elimination of boiler rooms in Deisel engined vessels, has the effect of reducing the length of the machinery spaces and so increasing the overlap referred to. If the cargo hatches _ are to be central they must be carried up through the accommodation, making it more difficult to arrange satisfactory dining saloons and public rooms; or the erections must be reduced in length and increased in number. With the former solution cargo has to be lifted to a great height .and possibly swung over the boats; in the latter we have a tower of deck-houses amidships and a call for increase of beam to maintain stability. Another important matter is the provision of a working passage or means of communication from end to end of the vessel for use of the crew, for access to gal*Bys, store rooms, machinery spaces, and crew’s quarters, and for the leads of main steam and water piping and electric cables In earlier types, such means of communication and access was afforded by the passages between the central deckhouse on the upper deck amidships and the vessel’s sides—-pasages exposed _ to the weather. One of the earliest designs for the Lusitania was so arranged, but in this case the ship’s sides were plated above these passages, and the cabins arranged over the fill length of the shiptifaebrke the full breadth of the vessel. The side plating in way of working passages was pierced by a number of long openings with solid plating between with the object of including the top of the shell plating in the- strength girder. _ The favourite arrangement, however, is to place a wide fore and aft working passage on one side of the bulkhead deck, above the tops of the bulkheads and between the machinery the bulkheads and betwen the machinery casings, and a row of crew spaces at the ship’s" sides. In many cases no through fore and aft passage is provided, the various necessary means of communication and access'being worked in locally and independently.—Professor P. A. Hillhouse, in Engineering.