Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
  • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
  • B63B3/00—Hulls characterised by their structure or component parts
  • B63B3/14—Hull parts
  • B63B3/16—Shells
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
  • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
  • B63B3/00—Hulls characterised by their structure or component parts
  • B63B3/14—Hull parts

Definitions

• the present invention concerns a hull particularly for ships and similar marine structures of the type stated in the introduction to Claim 1.
• the plating and bracing system is arranged so that the external pressure primarily is carried by bending stresses in the hull plating. Loads are led from the plating to the primary braces (usually longitudinal braces) then to the secondary braces (usually transverse frames) and finally to the ship ' s side/- longitudinal bulkhead for distribution along the "ship's beam". In smaller vessels the plating is often given a double curvature. In a double curved plate the external pressure will mainly be carried by compressive in-plane stresses (shell stresses).
• a weight optimized structure is characterized by relatively thin hull plates and a dense framework of primary and secondary braces. This results in a complicated structure with high production costs.
• the complicated structure introduces several problems. It brings about a range of complicated connections between the various bracing components in steel and aluminium hulls, as well as in glassfibre hulls (GRP). This can easily lead to cracking because of fatigue or delamination in GRP hulls.
• the main objective of the present invention is to create a hull for ships, barges and other marine structures, that permits weight and cost reductions in the production of hulls made of steel, aluminium or composites.
• the invention also has the objective of reducing the number of structural details which are particularly exposed to damage. It is also an object to simplify the connections between the plating and the braces. A further objective of the invention is to find new methods of fabricating hulls that will help to reduce costs.
• the invention is based on the use of what is known as membrane tension, i.e. a concave section of plating that supports external pressure by means of tensile membrane stress.
• the concave plates are placed between and fixed to longitudinal braces which are supported on transverse frames that in principle are not attached to the skin hull plates of the ship.
• the hull plating is connected to other members than the longitudinals, by for example a transverse bulkhead, this is achieved without any real forces being transferred directly from the hull plating to the transverse member.
• the use of membrane sections can be combined with parts of a hull where a traditional bracing system is used.
• the invention is particularly favourable where weight reductions are essential such as in high-speed vessels.
• a membrane section When a membrane section is used, it is the maximum permitted tensile stress in a material that decides the load carrying capacity. This means that steel, aluminium and glassfibre can be loaded at about the same stress level.
• the invention results in considerable weight savings when glassfibre or aluminium are used.
• the problems associated with the connection of internal bracing to the hull will be reduced.
• the problems related to cracking and redistribution of stresses will be almost avoided when a hull section is overloaded.
• the invention can be used for all types of ships hulls, hulls for barges and other marine structures. The only precondition is that the hull must generally only be exposed to external lateral pressure. This is particularly the case for high-speed vessels, either catamarans or single-hulled ships and naval vessels, for example.
• Fig. 1 shows a schematic cross-section of a small vessel
• Fig. 2 shows a detail of a catamaran cross-section with a laminated skin, (sandwich construction).
• Figs. 3-5 show details of the hull in Fig. 2, with the bottom, side and transition of the deck/side respectively, in different variants of materials and design details, while
• Fig. 6 shows a cross-section from the hull of a larger vessel.
• Fig. 1 shows a design where the present invention is used on a single hull, in a small high-speed vessel such as a patrol craft.
• the figure shows a midship frame in the hull.
• the hull structure consists of a transverse frame 11 that is connected to a deck beam 12 and an internal brace 13, that if necessary can be used as a support for the interior deck.
• the transverse frames 11 are connected to the longitudinals 14.
• the example shows two longitudinal braces 14a and 14b on each side, and a V-shaped keel 16.
• the keel 16 is further braced by transverse plates 17 at each transverse frame.
• the membrane section 18, that is the concave plating section, is connected to the longitudinal 14 so that they extend from the bow to the stern.
• the membrane sections are welded in the longitudinals 14 and the keel 16 by continuous longitudinal welds.
• the hull plates form concave sections between the longitudinals. The plates have a radius of curvature that is sufficient to give pure tensile stress.
• the longitudinal frames 14 are placed so they follow the lines of the hull.
• the transverse frames 11 can be welded only to the longitudinals 14. Thus the transverse frames 11 will only be exposed to compressive forces under normal load conditions.
• metal plates are used as the membrane sections 18.
• a similar type of structure can be used for hulls with glassfibre hull plates.
• the plating or the membrane sections 18 must here be laid continuously over the longitudinals 14.
• the fibres in such a glassfibre membrane are to be laid in the direction that gives the optimal utilization of the tensile strength of the material.
• the forces that are transferred from the plating to the braces will mainly be forces acting perpendicularly to the hull surface.
• the strength reguirements on the connection between the hull plating (membrane sections) and the longitudinal braces are not high.
• Fig. 2 shows a catamaran hull with a laminated outer hull plating (sandwich plates).
• the hull consists of a transverse bulkhead 20 that acts as a support for a deck beam 21 and outer transverse frames 24 and inner transverse frames 25 that extend down towards the keel area.
• the deck beams 21 are attached to a longitudinal 26. Similar longitudinals 27 and 28 are located one under the other along each side of the ship.
• the deck 30 is built in a traditional manner. From the deck next to frame 26 and down towards the keel area (longitudinal 29) the hull plates are laid as membrane sections 31.
• keel 33 Traditional means of construction are used by the keel 33 and the longitudinal frames are connected to a local web 33 in the keel region. From the longitudinal 29B close to the keel membrane sections 32 cover the hull up to the centre line 22. Longitudinal braces 27B and 28B are found as indicated in Fig. 2. In the central part of the hull (wet deck) the hull plates are attached to the transverse bulkhead 20.
• Fig. 3 shows the details of the area that are close to the keel region.
• the transverse brace 24 in this example has a quadratic section, and can be made of glassfibre for example.
• the hull plate 31 has a sandwich construction with covering layers of glassfibre-reinforced plastic and with foam as the core material.
• Fig. 4 shows the equivalent details as Fig. 3 for the attachment of the hull plates 31 at the transition to the deck.
• the transverse frames are alsomade of glassfibre profiles 24, with longitudinals 26 and 27 built into the transverse frame structure.
• Fig. 5 shows the arrangement of a longitudinal 27 used in a modified hybrid design where an aluminium transverse frame 25 is used.
• the longitudinal 28A is attached with two aluminium brackets 49 that are welded to the transverse frame 24.
• laminated single hull plates 31 are used, These could be made of glassfibre.
• Fig. 6 shows a section through a tanker designed in accordance with the invention.
• the hull has a transverse frame 34 that is divided into sections with intermediate longitudinals 35.
• the transverse frame sections 34A-E support the bottom plates 36, that form the inside base of the tank 37.
• the longitudinal frames 35A-F that support the concave skin plates 38 are welded to the transverse frames.
• the transverse frame 34F has closely spaced longitudinal braces 351 using known methods, and is covered by an extension of the hull plates 38.
• the ship's sides have two sections 34G and 34H with a transverse frame and interior walls 39 in a known manner.
• the outer part of the longitudinals 35G-J is welded to the hull plates 40.
• the hull plates are formed so that a concave arched membrane section 41 is formed in an equivalent manner as at the bottom.
• the topside of the vessel is designed by known means, with a transverse frame 42, longitudinal braces 43 and plates 44 midship.
• membrane sections 45 and 46 at the sides of the midship plates 44 and a traditional braced plate section 47 in the upper part of the ship ' s side, between the outer membrane section 46 and membrane section 41.
• the bottom plates 36 can be shaped as membrane sections, with or without connection to the transverse frames.
• the interior wall, or parts of this can be shaped as membrane sections, with or without connection towards the transverse frames along the sides of the ship. This gives the same advantages as when a membrane section is used for the outer hull plating.
• the invention will provide a basis for a simplified production that will in turn give considerable reductions in cost.
• the frames are correctly positioned it is possible for example to lay the hull plates out by being unwound from a plate spool. Further, the invention enables more rational assembly of machinery, equipment and the like before the hull plates are attached.
• the invention can be combined with parts of hulls that are designed by traditional means.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• Ocean & Marine Engineering (AREA)
• Laminated Bodies (AREA)
• Physical Or Chemical Processes And Apparatus (AREA)
• Gyroscopes (AREA)
• Pressure Vessels And Lids Thereof (AREA)
• Body Structure For Vehicles (AREA)
• Electroplating Methods And Accessories (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Helmets And Other Head Coverings (AREA)

Priority Applications (7)

Applications Claiming Priority (2)

Publications (1)

Family

ID=19892722

Family Applications (1)

Country Status (12)

Cited By (1)

Citations (4)

Family Cites Families (1)

• 1989
  • 1989-12-29 NO NO895316A patent/NO175811C/no not_active IP Right Cessation
• 1990
  • 1990-12-17 ES ES91900970T patent/ES2094806T3/es not_active Expired - Lifetime
  • 1990-12-17 DK DK91900970.4T patent/DK0536130T3/da active
  • 1990-12-17 KR KR1019920701552A patent/KR920703387A/ko not_active Application Discontinuation
  • 1990-12-17 WO PCT/NO1990/000188 patent/WO1991009768A1/en active IP Right Grant
  • 1990-12-17 JP JP91501378A patent/JPH05505360A/ja active Pending
  • 1990-12-17 DE DE69028318T patent/DE69028318T2/de not_active Expired - Fee Related
  • 1990-12-17 AU AU69140/91A patent/AU651329B2/en not_active Ceased
  • 1990-12-17 EP EP91900970A patent/EP0536130B1/en not_active Expired - Lifetime
  • 1990-12-17 CA CA002072570A patent/CA2072570A1/en not_active Abandoned
• 1992
  • 1992-06-26 FI FI922987A patent/FI98288C/fi active
• 1996
  • 1996-11-27 GR GR960402885T patent/GR3021534T3/el unknown

Patent Citations (4)

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