GB1386708A - Boats - Google Patents

Abstract

1386708 Acoustic insulation of boats' engines E SAMUELSSON and A SAMUELSSON 5 March 1973 [13 Dec 1972] 10632/73 Headings B7S and B7V A boats' engine 1 is mounted in a box 4 which in turn is smaller than and is mounted within a hull compartment by sound insulating distance means 6 such as rubber blocks the compartment having a cover 3b which when closed is spaced from the upper surface of the engine box 4. The space 7 around the box 4 may be filled with air. Alternatively, the space 7 is filled with a solid insulating material. In the former case, an ejector operated by water flowing past the hull reduces the pressure of air in the gap, Fig. 8 (not shown). The box, along with the engine, can be lowered into and lifted out of the compartment. Further insulation is given by a plastics hood 8a, 8b which covers the outboard drive unit 2 and in the rest position of the boat extends below the waterline. When the boat is under way the bottom of the hood is only slightly above the waterline. An engine air intake may be incorporated in the hood. The hood is mounted on the hull by rubber blocks 9 and any remaining gap between the hood and the hull is filled by insulating material. In a modification, Figs. 3 and 4 (not shown), the hull compartment is located forwardly of the transom and an inboard drive is used. Air for the engine enters the box through a conduit communicating with an opening in the side of the hull, and the rear end of the propeller shaft is supported from a plate which is mounted on the hull by means of insulating blocks. Operating cables or rods enter the box through insulating packings contained in plastics tubes, Fig. 6 (not shown), and such operating elements may themselves include insulating portions, Fig. 9 (not shown).