SHIP WITH MONOCOQUE HULL MADE OF PLASTIC-BASED COMPOSITE MATERIAL

Abstract: This invention relates to a ship having a monocoque or unitary-construction hull (1) made of a composite material having a base of suitably-reinforced plastics. According to the invention, the longitudinal strength of the hull (1) mainly derives from the monocoque or unitary-construction hull and the decks (4). Optional transverse reinforcing structures may be constituted exclusively by structural transverse bulkheads (5). The thickness of the monocoque hull (1) increases, preferably in a substantially uninterrupted manner, from the stringer area towards the keel (2). The keel (2) and the rolling chocks (3) are integral with, and made of the same material as, the monocoque hull (1). At least some tanks are constituted by cylinders (8, 8', 9) made of a plastics-based composite material and suspended, at a certain height from the bottom of the hull (1), between two successive structural transverse bulkheads (5).

Description: This invention relates to a ship of the type having a monocoque or unitary-construction hull made of a composite material, more particularly a suitably reinforced plastics-based material, such as, for example, sandwiched laminated materials having a base of either plastics material or fiberglass-reinforced plastics material, or the like. The use of plastics-based composite materials when building ships of considerable size and characteristics, such as 30 to 100 metres long, has been limited heretofore by technical and economical factors that have prevented a larger use of said materials. This is due mainly to the fact that, usually, the builders have endeavoured to reproduce by said materials structural shapes which were suitable for wood, steel or light alloys. The main disadvantages of these constructional principles followed heretofore were the poor stiffness of hulls at a parity of weight, due to the low modulus of elasticity of said materials, and the high building costs due to the extensive use of labour as a result of the complicate structure designed according to said principles followed until now. This invention aims to overcome said disadvantages and it resides, substantially, in the fact that the longitudinal strength of the hull mainly derives from the monocoque or unitary-construction hull and the decks, while the optional transverse reinforcing structures may be constituted exclusively by structural transverse bulkheads (either watertight or not), and the thickness of the monocoque hull increases from a certain height towards the keel. A considerable structural stiffness of the hull is thus obtained as a result of the location of the material as spaced as practicable from the neutral axis of the ship. At the same time, a constructional simplification is obtained as a result of the construction principle of the increasing thickness of the hull, to which only the structural bulkheads and decks are to be added. Preferably, according to a further cnaracteristic of the invention, the thickness of the monocoque hull increases substantially uninterruptedly, preferably beginning from the stringer area, towards the keel. Moreover, the keel and/or rolling chooks are integral with, and of the same material as, the monocoque hull and they are formed simultaneously with the hull. According to a still further characteristic of the invention, at least some decks, particularly the internal decks (and the element carried thereon) are supported by the structural transverse bulkheads through longitudinal carrying beams arranged under said decks. Preferably, the decks and structural bulkheads are also made of plastics-based composite materials and, in this instance, the longitudinal carrying beams for the decks are, preferably, integral with, and of the same material as, the respective decks. According to an important characteristic of the invention, at least some of the tanks of the ship, such as the fuel and/or the freshwater tanks, are constituted by cylinders of plastics-based composite materials and are suspended between successive structural transverse bulkheads, at a certain height from the bottom of the hull. Thus, said tanks become a structural part of the ship and act as additional strengthening beams, in addition to the decks. Moreover, said embodiment and arrangement of the tanks render the bilge thoroughly unobstructed and easily inspected. According to a further characteristic of the invention, at least some engines and/or machinery are supported by decks and/or structural bulkheads and/or are arranged on suitable oradles or cells made of a plastics-based composite material and suspended between successive structural transverse bulkheads. These and other characteristics of the invention and the advantages resulting therefrom will be apparent from the following description of a preferred embodiment thereof shown diagrammatically as a non-limitating example in the accompanying drawings, wherein: Fig. 1 is a fore-and-aft section of the structure of a ship according to the invention; Fig. 2 is a midship cross section thereof. With reference to the Figures, the numeral 1 indicates the hull of the ship, of the unitary-construction or monocoque type and made of a plastics-based composite material, particularly of fiberglass-reinforced plastics, or the like. The keel 2 and the rolling chooks 3 of the hull are integral with the monocoque hull 1 and are made of the same material as said hull upon the formation of the latter. The thickness of the monocoque hull 1 increases substantially uninterruptedly, for example, from the stringer to the keel 2. The longitudinal strength of the ship's hull 1 derives only from the monocoque hull and decks 4, while the transverse reinforcing structures are constituted exclusively by structural transverse bulkheads 5 which may be of the watertight type or not. The decks 4 (and, therefore, the elements carried thereon) are supported by the structural transverse bulkheads 5 by means of longitudinal reinforcing beams 6 arranged under said decks 4. Of course, the decks 4 may be provided with transverse reinforcing beams 7 as well. Preferably, the transverse structural bulkheads 5 and decks 4 are also made of a composite material having a base of suitably reinforced plastics. In this instance, the longitudinal beams 6 and transverse beams 7 of the decks 4 are integral with the respective deck 4 and are made of the same material as said deck upon the formation of the latter. The tanks 8, 8' and 9 for fuel and freshwater are constituted by rugged cylinders made of reinforced plastics-based composite material and suspended, at a certain height from the bottom of the monocoque hull 1, between successive structural transverse bulkheads 4, as viewed particularly in Fig. 1. Therefore, the tanks 8, 8', 9 are independent from the bottom of the hull 1 and permit a free access into the bilge for inspection, while constituting additional strengthening longitudinal beams. The engines and machinery are arranged either on the decks 4 or the structural bulkheads 5, or they are supported on suitable cradles or cells 10 made of reinforced plastics-based composite material and suspended between successive structural transverse bulkheads 4 at a certain height from the bottom of the monocoque hull 1. Of course, the invention is not limited to the embodiment shown and described herein, but any modifications, especially of constructional nature and in the practicing details, may be made thereto without departing from the basic principle set forth above and claimed hereinafter.

Claims: 1. A ship having a monocoque hull made of a composite material with a base of suitably reinforced plastics, for example, sandwiched laminated materials having a base of either plastics material or fiberglass-reinforced plasics material, or the like, characterized in that the longitudinal strength of said hull mainly derives from the respective monocoque hull and the decks, and optional reinforcing transverse structures may be constituted exclusively by structural transverse bulkheads (either watertight or not) and the thickness of the monocoque hull increases from a certain height towards the keel. 2. A ship according to Claim 1, characterized in that the thickness of the monocoque hull increases substantially uninterruptedly, beginning preferably from the stringer area, towards the keel. 3. A ship according to Claim 1, characterized in that at least some decks, particularly the internal decks, are supported by the structural transverse bulkheads by means of longitudinal carrying beams arranged under the respective decks. 4. A ship according to Claim 1, characterized in that the the decks and/or structural bulkheads are of a composite material having a base of suitably reinforced plastics. 5. A ship according to Claim 1, characterized in that the longitudinal carrying beams for said decks are made integral with, and of the same material as, the respective decks. 6. A ship according to Claim 1, characterized in that the keel and/or the rolling chocks are made integral with, and of the same material as, said monocoque hull. 7. A ship according to Claim 1, characterized in that at least one of the tanks of the ship is constituted by a cylinder made of a composite material with a base of suitably-reinforced plastics and is suspended between successive structural transverse bulkheads and at a certain height from the bottom of the hull. 8. a ship according to Claim 1, characterized in that at least some of the engines and/or machinery are supported by the decks and/or structural bulkheads and/or they are arranged on suitable cradles or cells made with a composite material with a base of suitably reinforced plastics and suspended between successive structural transverse bulkheads.

Inventors: DE CASA, GIANFRANCO, FANTACCI, GIANFRANCO, Trimming, S.K. Michael
Applicants: INTERMARINE S.P.A.
Application year: 1986
Main classification: B63B5
IPC codes: B63B5