SE526949C2 - Ways to manufacture hulls - Google Patents

Abstract

A ship hull, especially intended for oil and chemical ships, passenger ships are fishing ships, comprising a hull made of steel or aluminium built on a supporting structure of frames, stringers and longitudinals, having improved buoyancy and energy absorbing capability, and a method of manufacturing such a ship. Between an outer hull ( 200 ) and an inner hull ( 202 ) a layer ( 204 ) of a cellular plastic material is applied having chiefly closed cells. The outer hull is made of a high strength steel, wherein at external strain the outer hull and the cellular plastic material are adapted to jointly constitute an energy absorbing deformation zone.

Description

co soon coon o. 1 n oss n (k: .no- .c @ IQ I I I 0 00 q q 00 no ecco 526 949 and collision is reduced or eliminated.

There is also a great need for a ship's hull with improved buoyancy or alternatively which is unsinkable. This applies to tankers but especially also to passenger ships for obvious reasons.

EP-B1-473587 describes a method of providing an improved hull, in which sheets or mats of a cellular material are glued to an aluminum hull, and to this a glass fiber layer is applied. This method provides a number of benefits and opportunities.

Old rust-damaged or corroded hulls can be easily renovated. Thermal insulation is achieved which provides several manufacturing advantages in the yacht industry, e.g. as the condensation problems disappear. In addition, a sound-absorbing effect is achieved, which is bidirectional. The cell material also has an energy-absorbing ability that protects the metal hull and provides a local increase in stiffness.

The invention An object of the present invention is to provide a method of manufacturing ship hulls with eliminated or at least substantially reduced risk of leakage in the event of grounding and collision.

Another object of the present invention is to provide a method of manufacture or conversion of ship hulls which makes ships with this hull substantially unsinkable. Even in a damaged condition, it must float so that, for example, an oil load can be pumped to another ship or passengers can be evacuated from the wreck.

A further object of the present invention is to provide a method of manufacturing ship hulls which independently 10 15 20 l \) UI Jolo 0 I u now 0:00 u; .ø ;. .;:. ....

CD 00 coon o: a 0 gu 0 0 0 0 nc OO 00 5 2 6 9 4 9 'of hull shape provides optimal adhesion between different layers of the hull at the least possible cost and without requirements for precise adaptation such as mechanical measures in the form of grinding, milling and the like.

The above and other objects of the invention are achieved with the method according to the invention which is characterized in that between a inner hull of steel or aluminum built on a support structure of frame, scales and longitudinals, and an outer hull of high-strength steel a structure is arranged which fixes the hulls to each other. desired distance, but which is softer than the support structure of the inner hull, to form a gap, and to inject a foam material forming material into the gap, preferably foam balls together with an adhesive, thereby forming a foam layer which adheres to the inner and outer hull.

According to an advantageous embodiment of the invention, a thickness of 0.005 - 0.30 m is selected for the high-strength steel in the outer hull.

According to another advantageous embodiment of the invention, the gap between the two hulls is formed 0.05 - 3.0 m wide.

According to a further embodiment of the invention, the density of the foam layer including adhesive is brought to 60 - 400 kg / nf, preferably not more than 200 kg / m 3, preferably 100 - 150 kg / m 2. adhesives that give rise to a dilatation joint or viscoelastic adhesive joint, such as a two-component polyurethane adhesive, epoxy resin and moisture-curing one-component polyurethane adhesive or various types of prepegs. According to a further embodiment of the invention, polypropylene foam, polyethylene foam, polystyrene foam are selected as materials in the foam balls. , PET foam, PPO foam, PVC foam or mixtures thereof, other polymeric materials can also be used.

According to a further embodiment of the invention, a thermosetting plastic, or other hardening adhesive, is used as the adhesive.

Detailed description of the invention The combination of the properties of the cell material (foam) and the outer hull has a decisive function. The hull's unique structure means that the outer layer and the cell material form a deformation zone so that it takes up sufficient load for the inner hull to collapse before the outer hull. Foam with a high yield strength and progressive curing modulus in combination with an outer layer with high tensile strength and high allowable stress is preferred.

The company SSAB, Luleå, Sweden manufactures and sells a high-strength steel, called Domex 500, which has the desired properties for the outer layer.

When the mechanical stresses are so high that the inner hull is deformed, the structure inside the inner hull breaks. Only when the deformation in the outer hull passes the yield strength of the high-strength steel does crack formation occur, whereby leakage can still be prevented due to the sealing ability of the cell material.

It is essential that the structure holding the outer hull at the intended distance from the inner hull be dimensioned so that it is deformed by a force below a force which causes deformation of the inner hull. Thereby it is achieved that the cellular plastic can fulfill its function as energy absorption and 00 0000 0000 0 0 I O OO O 0 0 00 0000 00 0000 00 I I I l 0 0 0 0 0 0 0 0 00 00 sze 949 ga energy distribution zone.

When rebuilding existing double-hull vessels, there is already a structure that fixes the two hulls to each other. These structures can then suitably be weakened in a suitable manner, preferably in places particularly exposed to grounding. In these places, softer plates can be welded in which should fold in case of damage and not be pushed in through the inner structure. The injected foam can then work as intended. The distance between the two plates in double-hull vessels is usually about 3 m. very large.

It is also conceivable that shipyards that are built to build double-hull vessels will continue with this, but with adapted mid-hull construction, whereby the shipyard's conversion costs can be minimized.

According to an embodiment of the invention, a layer of a highly elastic material is arranged between the inner and the outer metal hull, next to either or both of these. This highly elastic material can also be one formed by an adhesive used in the gluing of the cell material to the inner and / or the outer hull.

When injecting foam in the form of particles together with a binder, a cohesive foam layer is formed and bonding is achieved to the hull surfaces facing the foam material. Preferably, the hull surfaces are glued with an adhesive that gives rise to a dilatation joint or viscoelastic adhesive joint between foam material and metal sausage, e.g. a two-component polyurethane adhesive. Other examples of useful adhesives are epoxy resin and moisture-curing one-component polyurethane adhesives, various types of prepegs. 10 15 20 nu: 0 :: 0: (15 .I:. .N :. ...- C oc! Ha 000! 00 IOO 0 IO II 526 949 6 åë be made of several different types of materials, and also mixtures thereof, eg polypropylene foam, polyethylene foam, PVC foam, polystyrene foam, PET foam, PPO foam, or mixtures thereof.

The cell material should preferably also be flame-retardant, and thereby expanding graphite particles can be introduced into the particles and / or into the binder, which in the event of a fire expands and forms a non-combustible layer.

The thickness and density of the cell material layer including binder can vary depending on the current conditions, and can for instance be between about 0.05 and 3 m and 60 - 400 kg / m 2, respectively up to about 200 kg / m 2, preferably 100 - 150 kg / m 2 The thickness and density of the cell material layer are important for the function as a deformation zone and the energy absorption that is sought, but also for the buoyancy. By adapting the thickness and density of the cell material layer to the current conditions, the total weight of a vessel can be completely compensated and the vessel becomes unsinkable.

The method according to the invention has a number of essential advantages. Regardless of the shapes of the inner and outer hull, an optimal filling and adhesion to both the inner and the outer hull is achieved. In addition, it is possible to vary the thickness of the foam layer by making the gap between the inner and the outer hull different in size in different places of the vessel, if the need arises.

The thickness of the hull plates is determined when dimensioning the vessel in accordance with international classification rules. Use of 10 15 CO OO OIII C000 II 0 IOOI 0 Inc 00 00 00 I 0 0 I 0 I 0 0 1 OI 00 0000 II 000 526 949 high-strength steel provides a weight saving by being able to decrease in thickness while still obtaining excellent properties such as very high tensile strength in the event of deformation due to grounding, collision, explosion, etc.

Flame retardancy can be achieved by mixing expanding graphite particles into the plastic material and / or into the binder.

It is also possible to arrange a flame retardant in the form of a layer of expanding graphite particles next to the outer and the inner hull, respectively. in the glue.

Claims (10)

10 15 20 25 30 526 949 8 Patent claims 1. l. Methods of manufacturing a hull, in particular for oil and chemical vessels, passenger vessels and fishing vessels, comprising an inner hull of steel or aluminum built on a support structure of frames, scales and longitudinals, and an outer hull of high-strength steel, characterized by: that between the inner hull and the outer hull a structure is arranged which fixes the hulls to each other at the desired distance to form a gap, which structure is weaker than said support structure for the inner hull, or in that when rebuilding a double hull, a structure existing between the inner and the outer hull is adapted so that said construction is softer than the support structure of the inner hull, and that a foam layer-forming material, preferably foam balls together with a binder, is injected into the gap between the inner hull and the outer hull. a layer of foam material adhering to the inner hull and the outer hull, wherein the structure between the inner hull and the outer hull is dimensioned so that it is deformed by a force less than a force which causes deformation of the inner hull, so that the foam material can form an energy-absorbing and energy-distributing zone. A method according to claim 1, characterized in that the outer hull and the foam material are designed to form an energy-absorbing deformation zone which, in the event of external stress, absorbs sufficient load for the inner hull to collapse before the outer hull. Method according to claim 1 or 2, characterized in that when rebuilding a double hull, the construction between the inner hull and the outer hull is weakened, preferably in places particularly exposed to grounding. 10 l5 20 25 30 526 949 9 Method according to one of Claims 1 to 3, characterized in that a thickness of 0.005 ~ 0.30 m is selected for the high-strength steel in the outer hull. characterized by being 3.0 m wide. A method according to any one of claims 1-4, the gap between the two hulls is formed 0.05 - Method according to one of Claims 1 to 5, characterized in that the density of the foam layer including binder is brought to a level: iii 60 - 400 kg / m 2, preferably not more than 200 kg / m 2, preferably 100 - 150 kg / m 2. Method according to one of Claims 1 to 6, characterized in that a layer of a highly elastic material is arranged between the inner hull and the outer hull next to either or both of these. 8. A method according to claim 7, characterized in that said layer of highly elastic material is formed of an adhesive by gluing the inwardly facing surfaces of the hull with said adhesive giving rise to a dilatation joint or viscoelastic adhesive joint, such as a two-component polyurethane adhesive, epoxy resin and moisture-curing one-component polyurethane adhesive or various types of prepegs. A method according to any one of claims 1 to 8, characterized in that the foam material comprises foam balls whose material is selected for polypropylene foam, polyethylene foam, polystyrene foam, PET foam, PPO foam, PVC foam, or mixtures thereof. Method according to one of Claims 1 to 9, characterized in that a hardening adhesive such as thermosetting plastic is used as binder.