GB1593860A

GB1593860A - Protective marine structure

Info

Publication number: GB1593860A
Application number: GB4141877A
Authority: GB
Original assignee: Regal International Inc
Current assignee: Regal International Inc
Priority date: 1976-10-15
Filing date: 1977-10-05
Publication date: 1981-07-22
Also published as: DE2745501A1; FR2367873A1; JPS5367201A

Description

(54) PROTECTIVE MARINE STRUCTURE (71) We, REGAL INTERNATIONAL INC., (formerly known as Regal Tool & Rubber Co., Inc.,) a Corporation organised under the laws of the State of Texas, United States of America, of Highway 31 East, Corsicana, Navarro County, Texas, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to offshore platforms.

Offshore platforms which the present invention is designed to protect are semirigid structures subject to damage by excessive shock loading. As drilling progresses to deeper waters in more open seas with the use of heavier supply boats and barges, it has become necessary to develop better protective systems. Such systems are generally attached to individual legs of the offshore platform. In the past, it has been the practice to use cast-off vehicle tires, usually large offthe-road or aircraft tires, mounted on a supporting column next to the platform leg, as shown for instance in Blackman patent No. 2,413,210 or Rolando patent No.

2,952,979, the latter showing the practice of filling the tires with cable or other material to prevent their excessive sagging or collapse.

Some special structures have been built for this purpose, as shown for instance in Roach patent No. 3,005,435 and Schwall patent No.

2,424,635. However, each has attendant drawbacks. The cast-off vehicle tire systems involve the difficulty of finding a plurality of tires of the same large size, as well as the problems which arise when corded tires become waterlogged and sag. Moreover, deflated vehicle tires exhibit very poor shock absorption capabilities. Schwall, supra, resorted to making special rubber bumper moldings for this purpose, but such bumpers are subject to early destruction. Roach shows rotating cushions, but the use of axles and bearings provides too fragile a structure to withstand open-sea battering.

The invention has a setting such as that illustrated in U.S. patent no. 3,564,658 in which an offshore platform is provided with a resiliently supported barrier at the normal sea level.

According to the present invention there is provided an offshore platform comprising: a) A work area having rows of legs extending downwardly therefrom, b) A boat landing structure spanning the distance between two of said legs on at least one side of said platform having an array of horizontally spaced bars whose longitudinal axes extend in the vertical direction and which are faced with resilient material spaced along the interval between said two legs and mounted top and bottom with means to absorb shocks to each of said two legs, and c) at least one vertical bumper column mounted with means to absorb shocks on at least one respective leg.

The invention will now be described with reference to the following detailed description of an illustrative embodiment taken in conjunction with the accompanying drawings, in which: FIGURE 1 is a top plan view of an offshore platform including the boat landing system; FIGURE 2 is an elevation view showing an illustrative embodiment of the landing of FIGURE l; FIGURE 3 is a top view taken along lines 3-3 of FIGURE 2; FIGURE 4 is a partial end view taken along the lines 4--4 of FIGURE 2; FIGURE 5 is a sectional view taken along lines 5-5 of FIGURE 2; and FIGURE 6 is a sectional view taken along lines 66 of FIGURE 5 illustrative of bumper bars of the boat landing.

In FIGURE 1, an offshore platform 400 includes two boat landings 402a and 402b.

The actual work area of platform 400 has not been detailed but is generally indicated by the outline 400a. Platform 400 and boat landings 402a and 402b are supported by legs 406. Bumper assemblies are provided on each of the legs 406. The assemblies each includes a pipe column 410 which supports a stacked series of elastomeric cylindrical bumper rings 412. Each pipecolumn 410 is coupled to a platform leg 406 by two shock cells 420 and 422.

Referring to FIGURES 1-5, boat landing 402a includes horizontally extending frame members 426, 428 and 430 which are vertically spaced and span the distance between legs 406a and 406b and support the boat landing 402a. A plurality of downwardly depending and resiliently faced bumper bars 432 are affixed to and span the distance between horizontally extending frame members 426, 428 and 430. A shield 433 is attached to the lower portion of bumper bars 432 to protect boats adjacent thereto.

The landing 402 further includes a horizontally extending frame member 436 which is parallel to member 426. A support frame member extends between members 428 and 436 to provide support for a walkway 440.

Walkway 440 extends above the surface 443 of the boat landing. Walkway 440 consists of a plurality of cross members 442 which are horizontally spaced and connected between horizontally extending frame members 426 and 436. The walkway 440 also includes a grating surface 443, a fixed hand rail 444 and a ladder assembly 446 leading from the surface of the platform 400 to the walkway 440.

Referring to FIGURES 2, 3 and 4, boat landing 402a also includes flexible tensile bearing support links, such as a chain. Chain 450 extends from horizontally extending frame member 428 to eyelet 452 mounted on leg 406 below the shock cell 422. A second chain 454 extends from horizontally extending frame member 428 to the second leg 406 of boat landing 402a below shock cell 422.

Chains 450 and 454 relieve the side loads imposed on the boat landing 402 due to movement along the length thereof caused by a vessel in contact with the rub strips 434.

The boat landing further includes a pair of chains 456 extending from lifting eye 458 mounted on each vertical support 410 to eyelet 460 mounted to each leg 406 below the shock cell 422. A second pair of chains 462 is mounted from lifting eye 464 mounted to each elbow 466 of vertical members 410 and extends upwardly to eyelet 468 which is mounted to legs 406. Chains 456 and 462 provide vertical support which minimizes the static vertical loads on shock cells 420 and 422.

Referring to FIGURE 6, a rub strip 434 is illustrated having a trapezoidal shaped rubber body 502. The rub strip 434 also includes a cavity 504 extending the length thereof.

The rub strip 434 includes a guide member 505 which in turn slidably encompasses plate 506 of bumper bars 432. The rub strip 434 is clad with a coating of anti-friction material 508. Anti-friction material 508 may comprise a layer of urethane. The layer 508 is bonded and mechanically connected to the rub strip using the mechanical interlocks 510 and 512.

WHAT WE CLAIM IS: 1. An offshore platform comprising: a) A work area having rows of legs extending downwardly therefrom, b) A boat landing structure spanning the distance between two of said legs on at least one side of said platform having an array of horizontally spaced bars whose longitudinal axes extend in the vertical direction and which are faced with resilient material spaced along the interval between said two legs and mounted top and bottom with means to absorb shocks to each of said two legs, and c) at least one vertical bumper column mounted with means to absorb shocks on at least one respective leg.

2. An offshore platform according to claim I wherein such vertical bumper column comprises a vertical column of bumper rings.

3. An offshore platform according to claim I or 2 wherein each resilient facing on each bar of the array of bars is trapezoidal in cross sectional shape and clad with an antifriction layer of material harder than the resilient facing.

4. An offshore platform according to claim 3 wherein said antifriction layer of material is bonded and mechanically connected to said facing.

5. An offshore platform according to claim 3 or 4 wherein said antifriction layer comprises urethane.

6. An offshore platform according to any preceding claim, further including an array of downwardly depending guide members carrying said resilient material, each of said guide members including structure for slidably encompassing each bar of said vertical array of bars.

7. An offshore platform according to any preceding claim, further comprising at least two vertically spaced horizontally extending frame members spanning said two legs and supporting said array of resiliently faced bars.

8. An offshore platform according to any preceding claim further comprising support means extending from the offshore platform to said boat landing structure to relieve the shock mounting of the static load of said boat

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. In FIGURE 1, an offshore platform 400 includes two boat landings 402a and 402b. The actual work area of platform 400 has not been detailed but is generally indicated by the outline 400a. Platform 400 and boat landings 402a and 402b are supported by legs 406. Bumper assemblies are provided on each of the legs 406. The assemblies each includes a pipe column 410 which supports a stacked series of elastomeric cylindrical bumper rings 412. Each pipecolumn 410 is coupled to a platform leg 406 by two shock cells 420 and 422. Referring to FIGURES 1-5, boat landing 402a includes horizontally extending frame members 426, 428 and 430 which are vertically spaced and span the distance between legs 406a and 406b and support the boat landing 402a. A plurality of downwardly depending and resiliently faced bumper bars 432 are affixed to and span the distance between horizontally extending frame members 426, 428 and 430. A shield 433 is attached to the lower portion of bumper bars 432 to protect boats adjacent thereto. The landing 402 further includes a horizontally extending frame member 436 which is parallel to member 426. A support frame member extends between members 428 and 436 to provide support for a walkway 440. Walkway 440 extends above the surface 443 of the boat landing. Walkway 440 consists of a plurality of cross members 442 which are horizontally spaced and connected between horizontally extending frame members 426 and 436. The walkway 440 also includes a grating surface 443, a fixed hand rail 444 and a ladder assembly 446 leading from the surface of the platform 400 to the walkway 440. Referring to FIGURES 2, 3 and 4, boat landing 402a also includes flexible tensile bearing support links, such as a chain. Chain 450 extends from horizontally extending frame member 428 to eyelet 452 mounted on leg 406 below the shock cell 422. A second chain 454 extends from horizontally extending frame member 428 to the second leg 406 of boat landing 402a below shock cell 422. Chains 450 and 454 relieve the side loads imposed on the boat landing 402 due to movement along the length thereof caused by a vessel in contact with the rub strips 434. The boat landing further includes a pair of chains 456 extending from lifting eye 458 mounted on each vertical support 410 to eyelet 460 mounted to each leg 406 below the shock cell 422. A second pair of chains 462 is mounted from lifting eye 464 mounted to each elbow 466 of vertical members 410 and extends upwardly to eyelet 468 which is mounted to legs 406. Chains 456 and 462 provide vertical support which minimizes the static vertical loads on shock cells 420 and 422. Referring to FIGURE 6, a rub strip 434 is illustrated having a trapezoidal shaped rubber body 502. The rub strip 434 also includes a cavity 504 extending the length thereof. The rub strip 434 includes a guide member 505 which in turn slidably encompasses plate 506 of bumper bars 432. The rub strip 434 is clad with a coating of anti-friction material 508. Anti-friction material 508 may comprise a layer of urethane. The layer 508 is bonded and mechanically connected to the rub strip using the mechanical interlocks 510 and 512. WHAT WE CLAIM IS:

1. An offshore platform comprising: a) A work area having rows of legs extending downwardly therefrom, b) A boat landing structure spanning the distance between two of said legs on at least one side of said platform having an array of horizontally spaced bars whose longitudinal axes extend in the vertical direction and which are faced with resilient material spaced along the interval between said two legs and mounted top and bottom with means to absorb shocks to each of said two legs, and c) at least one vertical bumper column mounted with means to absorb shocks on at least one respective leg.

landing structure.

9. An offshore platform according to claim 8 as dependant on claim 7, wherein said support means comprises a flexible tensile bearing support link member extending upward to each of said legs from one of said two frame members to relieve the shock mounting of the static weight of said structure and to relieve the upper shock mounting from outwardly directed tensile forces.

10. An offshore platform according to claim 9, wherein said support means comprises a flexible tensile bearing support link means extending upward to each of said legs from the bottom one of said two frame members.

11. An offshore platform according to claim 8 as dependant on claim 7, 9 or 10, wherein said support means comprises a tensile bearing support link means extending substantially horizontally to each of said legs from one of said frame members.

12. An offshore platfrom according to any preceding claim, wherein said boat landing structure is mounted by means of shock cells.

13. An offshore platform including a protective system substantially as described herein with reference to the accompanying drawings.