US3817041A

US3817041A - Ship slipping system

Info

Publication number: US3817041A
Application number: US00358944A
Authority: US
Inventors: F Pownall
Original assignee: Individual
Current assignee: Individual
Priority date: 1973-05-10
Filing date: 1973-05-10
Publication date: 1974-06-18
Anticipated expiration: 1991-06-18

Abstract

A system for slipping ships which comprises grading an area of the sea floor extending from the shore to water sufficiently deep to float the ship to be slipped, providing the graded area with a smooth surface, attaching one or more supporting pads to the hull of the ship, said supporting pads being provided with one or more openings through which water can be discharged downwardly onto said smooth surface to provide a ''''ground effect'''' to support said ship and means for pulling the ship up the smooth surface onto the shore.

Description

United States Patent 1191 1111 3,817,041 Pownall June 18, 1974 [5 SHIP SLIPPING SYSTEM 2,896,564 7/1959 Wright 61/67 x [7 Inventor: Francis Anthony Powna", 45 3,681,926 8/1972 Thatcher etal. 61/67 Applecross Primary Examiner-Jacob Shapiro PP N04 358,944 A system for slipping ships which comprises grading an area of the sea floor extending from the shore to 52 us. 01. 61/67, 272/565 Water sufficiently deep to float the Ship to he slipped, [51] Int. Cl B63c 3/00, A63g 21/04 1363b 1/34 providing the graded area with a smooth surface, at- [58] Field Of Search 61/67, 48, 66, 64; 9/41; taching one or more Supporting P to the hull of the 1 14/67 R, 67 A; 272/565 SS, 56 h p, said Supporting pads being provided with one or more openings through which water can be discharged [56] References Cited downwardly onto said smooth surface to provide a UNITED STATES PATENTS ground effect" to support said ship and means for pulling the ship up the smooth surface onto the shore. 2,415,805 2/1947 Atwood et al. 61/67 2,742,288 4/1956 Brunel 272/565 R 6 Claims, 5 Drawing Figures f x; J lb If l4 l3 'filV /Z 2 SHIP SLIPPING SYSTEM The invention relates to an improved system for slipping ships.

The object of the present invention is to provide a system for slipping ships which eliminates the need for expensive and costly structures and which can be installed in any suitable location with a minimum of cost.

In one form the invention resides in a system for slipping ships which comprises grading an area of the sea floor extending from the shore to water sufficiently deep to float the ship to be slipped, providing the graded area with a smooth surface, attaching one or more supporting pads to the hull of the ship, said supporting pads being provided with one or more openings through which water can be discharged downwardly onto said smooth surface to provide a ground effect to support said ship and means for pulling the ship up the smooth surface onto the shore.

The invention will be better understood by reference to the following description of one specific embodiment shown in the accompanying drawings wherein FIG. I is a plan view of the slipway;

FIG. 2 is a side elevation of the slipway;

FIG. 3 is a sectional view of the ramp;

FIG. 4 is a plan view of an assembly of supporting pads; and

FIG. 5 is a side elevation of the supporting pads.

As shown in FIGS. 1 and 2 of the drawings a suitable area ll of the shore adjacent the water line represented by line 12 is graded to a slope of 1 in 100 to provide for water to run off into the sea whilst a ramp or slipway 13 is graded to a slope of l in 20 for a distance of approximately 400 feet, the depth of water at the end of the ramp remote from the shore being of the order of 20 feet sufficient to float the vessel to be slipped. A 100 foot long smooth transition curve 14 is provided between the shore end of the ramp l3 and the shore area 11. The graded areas are provided with a smooth surface either by covering them with a thin layer of reinforced concrete or by covering them with plastic sheeting (polyvinyl chloride sheeting or polyethylene sheeting) of approximately l/l6 inch thickness. In the case of concrete the sides of the ramp are provided with buttresses 15 as shown in FIG. 3 of the drawings. In the case of plastic the edges thereof are anchored under pieces of rock or concrete blocks in the form of kerbing or by burying them in sand. If desired the graded area may be rendered smooth by applying a layer of asphalt or bitumen to the area and then coating the asphalt or bitumen with a water resistant plastic material such as expoxy resin. If desired the concrete may be coated with a water resistant plastic. A winch represented by the block 16 is provided in a suitable location on the shore area whilst a pumping unit represented by block 17 is also provided in a suitable location on the shore area.

The supporting pads shown in FIGS. 4 and 5 comprise a frame 20 having a plurality of annular pads mounted on the underside thereof. The pads comprise a pair of

annular members

21 and 22 of approximately 10 feet diameter positioned one above the other and formed of a flexible materialso that when inflated with a fluid such as air or water they assume a toroidal shape. If desired the upper annular member 21 may be inflated with air whilst the lower annular member 22 is inflated with water. A series of the assembly of supporting pads is fixed to the underside of the hull of the ship to be slipped and water at a pressure of approximately 10 psi. fed to the lower annular members 22 through flexible hoses (not shown) connected to the pump 17. The inflated annular member 22 forms what can be best described as a skirt so that water discharging downwardly from the centre of the annular member provides a ground effect" which is sufficiently deep to allow the vessel to glide smoothly over the smooth surface of the ramp as it is winched toward the shore by the winch.

When it reaches the shore area it can be provided with suitable braces and any desired work carried out on the hull. To permit access to the hull supporting pad assemblies may be removed one at a time. If it is desired to lift the ship clear of the ground the upper annular member may be inflated with compressed air or water.

With the system of the present invention the expensive foundations and cradles of conventional slipping systems is obviated. With the support pads of the present system the load is distributed over a very large area so that expensive foundations are not necessary. It is only necessary to provide a smooth surface over which the vessel can, in effect, glide.

I claim:

1. A system for slipping ships which comprises grading an area of the sea floor extending from the shore to water sufficiently deep to float the ship to be slipped, providing the graded area with a smooth surface, attaching one or more supporting pads to the hull of the ship, said supporting pads being provided with one or more openings through which water can be discharged downwardly onto said smooth surface to provide a ground effect to support said ship and means for pulling the ship up the smooth surface onto the shore.

2. A system as claimed in claim 1 wherein the graded area is rendered smooth by covering it with plastic sheeting.

3. A system as claimed in claim 1 wherein the graded area is rendered smooth by covering it with a layer of concrete.

4. A system as claimed in claim 1 wherein the graded area is rendered smooth by coating it with bitumen or asphalt and then covering the bitumen or asphalt with a water proof plastic material.

5. A system as claimed in claim 1 wherein the supporting pads comprise an annular member inflated to a toroidal shape the water being discharged downwardly through the centre thereof. a

6. A system as claimed in claim 5 wherein a second annular member inflated to a toroidal shape by compressed air or water is positioned about said first annular member.

Claims

1. A system for slipping ships which comprises grading an area of the sea floor extending from the shore to water sufficiently deep to float the ship to be slipped, providing the graded area with a smooth surface, attaching one or more supporting pads to the hull of the ship, said supporting pads being provided with one or more openings through which water can be discharged downwardly onto said smooth surface to provide a ''''ground effect'''' to support said ship and means for pulling the ship up the smooth surface onto the shore.

5. A system as claimed in claim 1 wherein the supporting pads comprise an annular member inflated to a toroidal shape the water being discharged downwardly through the centre thereof.