US3463114A

US3463114A - Method for maneuvering a vessel with respect to its station

Info

Publication number: US3463114A
Application number: US723855A
Authority: US
Inventors: Jack Lovell
Original assignee: STANWICK CORP
Current assignee: STANWICK CORP
Priority date: 1968-04-24
Filing date: 1968-04-24
Publication date: 1969-08-26
Anticipated expiration: 1986-08-26

Description

J. LOVELL Aug. 26, 1969 METHOD FOR MANEUVERIN G A VESSEL WITH RESPECT TO ITS STATION Filed April 24. 1968 v INV ENT OR Jar/r Zara-[Z Y semmesandsemmes ATTORNEY 5 g- 26, 1959 Q J. LOVELL 3,463,114

METHOD FOR MANEUVERING A VESSEL WITH RESPECT TO ITS STATION 2% f4 w w w 7 .4 i 67 INVENTOR 745 7454 [4141/ BY smmesandsemmes ATTORNEYS J. LOVELL 3,463,114

METHOD FOR MANEUVERING A VESSEL WITH RESPECT TO ITS STATION Aug. 26, 1969 5 Sheets-Sheet 5 Filed April 24, 1968 INVENTOR 74!? /d/ BY semmesandsemmes ATTORNEYS J. LOVELL Aug. 26, 1969 METHOD FOR MANEUVERING A VESSEL WITH RESPECT TO ITS STATION Filed April 24 1968 5 Sheets-Sheet 4 I {NVNTOR 740? /4/// BY semmesandsemmes ATTORNEYS J. LOVELL Aug. 26, 1969 METHOD FOR MANEUVERING A VESSEL WITH RESPECT TO ITS STATION Filed April 24, 1968 5 Sheets-Sheet 5 l NVEN TOR .740? [4/[// BY semmesandsemmes ATTORNEYS United States Patent US. Cl. 114-230 Claims ABSTRACT OF THE DISCLOSURE Method for maneuvering a vessel with respect to its station, particularly a method for fending the vessel horizontally and vertically with respect to a rigid station, such as an offshore oil well drilling platform. According to the method an extensible boom and suctorial cup assembly mounted upon a station is used to draw a vacuum upon integral portion of a maneuvering vessel freeboard. The boom is raised and lowered in horizontal alignment with the maneuvering vessel prior to drawing of the vacuum and is supported for free vertical movement corresponding to boat action after drawing the vacuum. The boom is telescoped with respect to the station, so as to control movement of the vessel about the station through the boom.

CROSS-REFERENCE TO RELATED APPLICATIONS None.

BACKGROUND OF THE INVENTION Field of the invention A great deal of difficulty has been experienced in maneuvering a work boat with respect to a station such as an offshore drilling rig. This difficulty is compounded when the working platform of the rig is considerably elevated with respect to sea level. The distances involved preclude ready use of conventional fending devices. As a result, injury both to the rig and to the work boat is such that offshore drilling rigs prefer service and resupply via the less accident prone method of helicopter.

An effective method for fending a work boat with respect to its station, such as a canal lock or offshore drilling rig in any type of sea has not been devised. A primay requirement of such a method would be its capability of horizontal and vertical flexibility, so as to permit movement of the Work boat vertically with the sea and horizontally with respect to an offshore oil rig and enable servicing by a crane or the like. A secondary requirement would be in the rigidness and reliability of the fending so as to preclude injury to its station. Additional requirements of the method reside in its capability of quick, remote-controlled disengagement from the vessel, as well as the capability of absorbing shock.

Description of the prior art Assignee of the present invention has obtained the following patents issued on related methods and devices: Method and Apparatus for Maneuvering Ships (Pat. No. 3,322,091); Ship Maneuvering Method (Pat .No. 3,345,971).

According to both methods, an extensible boom with a suctorial cup is used to position or maneuver one vessel with respect to another. A vacuum is drawn within the cup and through the boom, the cup being placed against the freeboard of a vessel being maneuvered. In the 3,322,091 patent the telescoping boom and cup may be mounted upon a tug, the cup being attached to the freeboard of a larger vessel. In the 3,345,971 patent the extensible boom and suctorial cup include a resupply conduit for the supply of gasoline or the like via pumping through a conduit extending through the extensible boom and cup. Neither patent teaches modes of vertically adjusting the entire boom assembly, of employing a plurality of suctorial cups at spaced positions on the freeboard of the vessel being maneuvered, of positioning the device on a rigid station or of shock absorbing the device with respect to the vessel being maneuvered.

SUMMARY OF THE INVENTION Applicants method for station keeping involves a plurality of extensible boom and suctorial cup devices, so as to position or fend a work boat with respect to its station. Once the vacuum is drawn through the boom and the suctorial cups, the boom is released vertically so as to be movable with respect to swells in the sea and corresponding movement of the work boat. Maneuvering is terminated by breaking of the vacuum, resulting in a disengagement of the extensible boom with the vessel being maneuvered. Refinements of the method consist in pneumatically shock absorbing the boom assembly, supporting the boom for free vertical movement, while limiting lateral movement of the boom, with respect to its station.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a work boat being maneuvered with respect to an offshore drilling rig by a pair of extensible booms;

FIG. 2 is a top plan, partially in section, showing a single extensible boom and suctorial cup assembly;

FIG. 3 is a side elevation of the assembly;

FIG. 4 is a sectional view, taken along section line 4-4 of FIG. 2;

FIG. 5 is a sectional view taken along section line 5-5 of FIG. 3;

FIG. 6 is a fragmentary vertical section of the telescoping boom end fitting within its housing;

FIG. 7 is a sectional view taken along section line 77 of FIG. 6;

FIG. 8 is a sectional view taken along section line 88 of FIG. 6;

FIG. 9 is a front elevation of the vertically movable steel truck 26 supporting boom and suctorial cup elements 83 and FIG. 10 is a like front elevation with the extensible boom and suctorial cups removed;

FIG. 11 is an enlarged side elevation, partially in section, showing the dish 36 and skirt 104 defining vacuum chamber 112 in the suctorial cup assembly;

FIG. 12 is an enlarged fragmentary section of the suctorial cup skirt element;

FIG. 13 is a fragmentary perspective, showing installation of a proposed station keeping device within a canal lock so as to assist in locking of the vessel;

FIG. 14 is a fragmentary end elevation, showing the FIG. 13 device wherein the truck 26 containing suctorial cups 88', 90', 92' and 94 is lifted above the lock upon inclined tracks 16 and 18' when not in use, tracks 16' and 16 being set or recessed Within the concrete lock walls when parallel to the vessel freeboard;

FIG. 15 is a fragmentary front elevation of truck 26' containing the suctorial cups;

FIG. 16 is a fragmentary top plan thereof with the suctorial cups in retracted position; and

FIG. 17 is a top plan thereof with the suctorial cups in extended freeboard engaging position.

3 DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, a station keeping device generally designated as 2 is shown vertically movably positioned in offshore drilling rig platform 6 by means of vertical channels or

tracks

16, 18, 20 and 22 secured to the rig superstructure 24.

The station keeping device includes a pair of like extensible boom assemblies 12 and 14 having at their respective ends

suctorial cups

88, 90, 92-94 engaging the freeboard of work boat vessel 4.

A suggested assembly for carrying out the method is illustrated in FIGS. 2, 3, 9 and 10 as comprising truck 26 vertically movable in

tracks

16 and 18 by means of radially extending

rollers

28, 30, 32 and 34 mounted respectively in radially extending

arms

36, 37, 38 and 39, secured at the corners of the truck assembly 26. Additionally,

top rollers

40, 42,

lower middle rollers

44, 46 and

bottom rollers

48, 50 may be positioned at the truck sides at right angles to the

corner rollers

28, 30, 32 and 34.

Rollers

40, 42, 46, 48 and 50 engage the interior walls of track or

channels

16 and 18.

The extensible boom assembly 12 is more particularly illustrated in FIGS. 2 and 3, as comprising housing 52 secured pivotably at one end to truck 26 by means of ears 56 engaging lugs 58 and secured thereto by means of pin 60. Extensible piston rod 54 is supported rotatably within the housing 52 by means of

outer rollers

114 and 116 mounted, respectively, upon

pins

118 and 120 supported in housing 52 and

inner rollers

122 and 124 secured on piston 54 inner end by means of

pins

126 and 128. Stops or

lugs

130 and 132 secured respectively to the interior wall of housing 52 and the exterior of piston 54 may be positioned for limiting horizontal extensibility of rod 54.

A pneumatic shock absorber assembly housing 70 supplied by air line 64 includes extensible piston rod 82 secured to piston 54 by means of ear 78 and pin 80 at one end and secured to housing 52 by means of

ears

72, 74 and pin 76 at the other end. Piston rod 54 is extended horizontally by means of hydraulic fluid fed through supply line 62.

Piston rod 54, as illustrated in FIGS. 2 and 3, terminates in clevis assembly 138 which movably supports yoke 134 by means of pin 136. At either end of yoke 134,

suctorial cups

88 and 90 are universally mounted by means of

brackets

144 and 146, secured by identical pins 140 and 142. The

cups

88 and 90 include

rear brackets

98 and 98 secured respectively to

brackets

144 and 146 by

pins

148 and 150.

Each suctorial cup consists of dish 96, outer or peripheral rubber or neoprene skirt 104 defining an inner vacuum chamber 112, vacuum being drawn through interiorally threaded conduit 102 by means of vacuum fitting 100 to which the

vacuum lines

112 and 112 may be secured. Skirt 104 may include inner serrations 106, middle flange 110 and outer peripherally extending flange 108, the serrations and flanges enabling the cup to seal with respect to the irregularities of the work boat freeboard.

The boom may be rigidized with respect to truck 26 by means of vertically extending strut 68, secured to the truck by means of lug 66, and laterally extending strut 84, secured to truck 26 by means of lug 86.

In FIG. 1 control house 10 is generally illustrated as including a winch, such as a 5,000 pound constant tension winch used to position vertically the extensible booms 12 and 14 prior to engagement of the work boat freeboard and drawing of the vacuum. Drawing of the vacuum through the cup assembly may be accomplished by a ten horsepower 177 cubic foot per minute 29 inches mercury vacuum device having a 15 cubic foot vacuum tank. The hydraulic system for extending and retracting piston rods 54 may include a g.p.m. at 1,500 p.s.i., two to three gallon piston accumulator for shock absorption. A steel lifting cable 50 may be secured to truck 26 by means of bracket 48 for lifting of the assembly prior to drawing of the vacuum.

The suctorial cups may be approximately 4 square feet, each developing 10 p.s.i. (5 p.s.i.a.) vacuum. Such a suctorial head would have a holding capability of 5,760 pounds or assuming that two extensible booms with four cups were employed a total of 23,040 pounds for four cups in a direction transverse to the work boat keel. Holding capability parallel to the boat keep would be approximately based on the friction force developed between the suctorial cup and the boat hull. In a proposed extensible boom assembly, as illustrated in FIGS. 2 and 3, the boom assembly may be eight feet retracted, eleven feet in its holding position and twelve feet in its extended position.

In operation, work boat 4 would achieve its station with the booms 12 and 14 in retracted position. The booms would be vertically adjusted by movement of trucks 26 by cables 50 and the individual piston rods 54 extended hydraulically to contact the work boat freeboard. Vacuum would be drawn through the

cups

88, 90, 92 and '94, the vacuum system operating continuously to hold a 5 p.s.i. to 14.7 p.s.i. vacuum on the work boat. Winch 50 could be automatically disengaged by a device for sensing the drawn vacuum. As the booms 12 and 14 are extended hydraulically to eleven feet in length, two hydraulic accumulators could be cut into the circuit, one at each end .of the hydraulic rams 12 and 14 to give an air spring load absorption. Disengagement of the suctorial cups could be instantly accomplished by breaking the vacuum through control lines 112. Disengagement due to overload would be automatic as the work boat could break away from the cups without power failure by simply breaking the vacuum at seal 104.

According to the FIGS. 13-17 adaptation truck 26 front is lifted vertically by means of cables 50 extending to a power winch with housing 10. The entire truck is shown in stowed position in FIG. 14. The mid ships truck 26 includes a horizontal track 216, attached to cable 50', which enables the truck 26' to travel horizontally approximately 40 feet in order to position the ship and start the ship in motion.

Truck 26 is essentially similarly constructed as in the basic device with radially extending track engaging wheels 28', 30, 32' and 34', as well as top rollers 40' and 42 and bottom rollers 48' and 50. The individual suctorial cups are mounted upon a pair of identical yokes 134 to which gate 212 is attached by means of

pins

214 and 215. A hydraulic power assembly 206 is connected to truck 26 by means of pin 218 and includes piston 208, having an end clevis 210, engaging pin 215. As the hydraulic cylinder is actuated so as to distend piston 208, the entire yoke 134 is distend outwardly of the lock wall and against the vessel freeboard 4, as illustrated in FIG. 17.

As suggested in FIG. 13, twenty-four suctorial cups may be employed, twelve on each side of the vessel. In such an arrangement each truck could develop a force capability of 54,000 pounds transverse to the lock, three such trucks developing a force capability of 162,000 pounds transverse to the lock on each side of the vessel, based upon the use of 3 foot square suctorial paths. Conventional commercial vacuum hydraulic systems and hydraulic winches may be employed. There is no necessity for reduction in the lock width, inasmuch as individual rails 16' and 18 are recessed in the concrete walls. It is estimated that an operation cycle would be one minute consisting of fifteen seconds to lower the truck on the rail to position opposite the freeboard, fifteen seconds to gate the cups onto the freeboard, as illustrated in FIG. 17, fifteen seconds to effect vacuum attachment and fifteen seconds for inspection.

Manifestly, the extensible boom and vertically movable truck assemblies may be varied, for example by mounting on a vessel, without departing from the spirit and scope of invention.

I claim:

1. Method for maneuvering a vessel with respect to its station comprising the steps of:

(A) horizontally telescoping a rigid boom and suetorial cup, which is mounted upon the boom end for universal movement, with respect to said station, so as to contact said vessel;

(B) raising and lowering said boom in horizontal alignment with said vessel;

(C) ditferentiating pressure between ambient and an integral portion of said vessel which is in contact with said station by means of said rigid boom and suctorial cup by drawing a vacuum through said suctorial cup;

(D) supporting said boom for free vertical movement corresponding to boat action, as said vacuum is drawn;

(E) shock absorbing said boom by fluid means; and

(F) controlling movement of said integral portion of said vessel about said station through said boom.

2. Method for maneuvering a vessel with respect to its station as in claim 1, including distending said boom with respect to said station.

3. Method for maneuvering a vessel with respect to its station as in claim 2, including drawing a vacuum within a plurality of spaced integral portions of said vessel in contact with said station via a plurality of rigid booms.

4. Method for maneuvering a vessel with respect to its station as in claim 3, including limiting lateral movement of said boom within said station, while supporting said boom for free vertical movement.

5. Method for maneuvering a vessel with respect to its station as in claim 4, including breaking said vacuum as a termination of controlling movement of said vessel.

References Cited UNITED STATES PATENTS 2,920,597 1/1960 Dick 114-230 3,322,091 5/ 1967 Stanwick 114235 FOREIGN PATENTS 797,653 7/ 1958 Great Britain.

TRYGVE M. BLIX, Primary Examiner