US3385069A - Mobile marine platform apparatus - Google Patents

Description

y 8, 1968 J. c ESTES 3,385,069

MOBILE MARINE PLATFORM APPARATUS Filed Oct. 7, 1966 I 2 Sheets-Sheet 1 h. "r; QQWMQMMWWW F7 John C Estes May 28, 1968 J. c. ESTES 3,385,069 A MOBILE MARINE PLATFORM APPARATUS Filed 001;. 7, 1966 2 Sheets-Sheet 2 United States Patent 3,385,069 MOBILE MARINE PLATFORM APPARATUS .l'ohn C. Estes, Beaumont, Tcx., assiguor to Bethlehem Steel Corporation, a corporation of Delaware Filed Oct. 7, 1966, Ser. No. 585,119 2 Claims. (Cl. 61-465) ABSTRACT OF THE DISCLOSURE The hull of a mobile marine platform comprises two or more horizontally spaced, parallel ballastable pontoons aligned parallel to the direction of tow. Bracing elements extend between and are secured to the top surfaces of the pontoons. Two vertical columns are secured to the pontoons and one vertical column to the midpoint of a bracing element. An operating platform is mounted to the columns in vertically adjustable relationship to the hull.

This invention relates broadly to mobile marine platform apparatus. More specifically, this invention relates to mobile marine platform apparatus having a divided hull assembly to reduce towing resistance when the apparatus is being moved from one location to another.

Mobile marine platform apparatus, such as the wellknown offshore drilling barges to be found in great profusion in the Gulf of Mexico, are employed to perform various operations in a marine environment and, as their name implies, are regularly and sometimes quite frequently moved from one location to another location which may be a great distance away. Some of these mobile marine platforms are of the type employing a hull or a mat which is a large pontoon structure usually submerged below the water surface and sometimes actually bottomed on the marine floor when one particular kind of platform is set up on location. This hull or mat can create tremendous resistance to towing when the platform is being moved. This has proven to be quite expensive for several reasons which will be apparent to those familiar with this art.

One of the objects of this invention is to provide improved mobile marine platform apparatus.

Another object of this invention is to provide mobile marine platform apparatus having markedly reduced towing resistance over conventional designs.

Yet other and further objects of this invention will be apparent from the specification, the drawings, and the appended claims.

Broadly speaking, I have discovered that the foregoing objects can be attained by dividing the above mentioned hull or mat into two or more horizontally spaced parallel pontoons aligned parallel to the direction of tow and firmly braced to each other by elements which are secured to the top surfaces of the said pontoons.

Referring now to the drawings, in which like numerals represent like parts in the several views:

FIGURE 1 represents a side view in elevation of mobile marine platform apparatus with the improved hull or mat, the particular apparatus shown being of the type which has the hull or mat bearing on the marine floor when the apparatus is set up on location and ready for operation.

FIGURE 2 represents a partial side view in elevation, showing the mobile marine platform apparatus in floating condition with the hull Or mat at the surface of the water, and ready for towing.

FIGURE 3 represents a partial end view in elevation showing the mobile marine platform apparatus in floating condition, with the hull or mat at the surface of the water, and ready for towing.

3,385,%9 Patented May 28, 19-68 ice FIGURE 4 represents a section taken along the line 4-4 of FIGURE 1, and shows in plan the divided hull or mat.

FIGURE 5 represents a view in plan of the operating platform of the mobile marine platform apparatus, the hull or mat being omitted for purposes of clarity.

Mobile marine platform apparatus 1 is seen, in the particular embodiment shown, as comprising hull assembly 2, columns 3 secured to hull assembly 2 and extending upwardly therefrom, and operating platform 4 through which said columns 3 extend.

Mobile marine platform apparatus 1 is of the wellknown two boat type and it will be recognized that operating platform 4 is actually a portion capable of stably buoyantly supporting the entire apparatus during the time hull assembly 2 is below the surface of water 5 and above the marine floor 6. It will also be recognized that hull assembly 2 is a pontoon means capable of stably buoyantly supporting the entire apparatus in floating condition as shown in FIGURES 2 and 3. This particular type of structure, as is well-known, calls for elevating the operating platform 4 above the surface of water 5 to the positiOn shown in FIGURE 1, when setting upon location, and for lowering operating platform 4 to the surface of water 5 pri r to raising hull assembly 2 from the marine floor 6, in preparation for towing to another location. Therefore, jacking means mounted on operating platform 4 in housings 7 and engaging columns 3 are provided. There are many types of jacking means currently used in this art for the same purpose and, as the particular design of jacking means forms no part of the present invention, the same will not be further described herein.

Hull assembly 2 comprises two ballastable and deballastable pontoon elements 8, each extending from the bow (right end of hull assembly 2 as viewed in FIGURE 1) to the stern (left end of hull assembly 2 as viewed in FIG- URE 1) of the said hull assembly 2. Pontoon elements 8 have sufiicient buoyancy when deballasted to collectively support the mobile marine platform apparatus 1 with the said pontoon element 8 having frceboard. Various means for ballasting and deballasting pontoons are well known in this art. As the particular design for ballasting and deballasting means forms no part of the present invention, the same will not be further described herein. Brackets 9 are suitably secured to the upper surfaces of the said pontoon elements 8, and tubular brace elements 10 are suitably secured to the said brackets 9, whereby the said pontoon elements 8 are rigidly maintained in horizontally spaced parallel relation in a common horizontal plane, to provide a structurally secure hull assembly 2. It will be noted that the said pontoon elements 8 are aligned parallel to the direction of tow which is toward the right of FIGURES 1, 2 and 4.

Mobile marine platform apparatus 1 has, in the disclosed embodiment, three columns 3 interposed between hull assembly 2 and operating platform 4, said columns 3 being arranged relative to each other in the form of an isosceles triangle as viewed in plan (see FIGURE 4). Two of these columns 3, defining the base of the isosceles triangle, are secured at their lower ends directly to the pontoon elements 8, one column 3 on each pontoon element 8. The third column 3 is secured at its lower end, and hence is supported by, one pair of tubular brace elements 1t) midway between the pontoon elements 8. This arrangement provides a sturdy, stable and convenient form of construction.

The operation of this invention will now be described. It will be assumed that the mobile marine platform apparatus 1 is set up on location as shown in FIGURE 1, with pontoon elements 8 in at least partially ballasted condition and sitting on marine floor 6. Operating platform 4 is lowered by the herein mentioned jacking means in h usings 7 until it is in floating position on the surface of the water 5. Thereafter, hull assembly 2 is elevated from the marine floor 6. Preferably, this is done initially by employment of the jacking means acting on columns 3 to pull up the hull assembly 2, against the buoyancy of operating platform 4 until brackets 9 engage the underside of operating platform 4. Thereafter, pontoon elements 8 are deballasted to acquire freeboard whereupon tubular brace elements 10 are elevated above the surface of the water 5. Mobile marine platform apparatus 1 may now be towed to a new location. The only resistance during this tow will be that of the relatively small-beam pontoon elements 8. It will be appreciated that this resistance is only a minor fraction of the resistance that would be offered if hull assembly 2 were a unitary pontoon having a beam extending from the outboard or extreme side of one pontoon element 8 to the outboard or extreme side of the other pontoon element 8. It will also be appreciated that the resistance of the hull assembly 2 f the present invention, when afloat and under tow, is only a minor fraction of the resistance that would be obtained if tubular elements 10 or operating platform 4 had draft while under tOW.

At the new location, pontoon elements 8 are ballasted and consequently will sink in water until operating platform 4 becomes afloat and acquires suflicient buoyancy to support mobile marine platform apparatus 1. Thereafter, hull assembly 2 is jacked down to marine floor 6. Continued operation of the jacking means will then elevated operating platform 4 out of the water 5 to the position shown in FIGURE 1.

Hull assembly 2 may be used with other types of mobile marine platform apparatus not of the two boat type herein shown. Thus, hull assembly 2 may be used with the well-known floater type rigs in which columns 3 are actually buoyant ballastable cylinders. In this type of structure, setting up on location is achieved by submerging hull assembly 2 from a floating condition with freeboard to a submerged position intermediate the surface of the water 5 and marine floor 6, stability being provided by the cylinders. When such structures are under tow, hull assembly 2 will be deballasted to acquire freeboard, thereby to reduce towing resistance in the same manner and for the same reasons as in the embodiment of mobile marine platform apparatus herein specifically shown.

Although the specification refers to the mobile marine platform apparatus as being towed from one location to another, it will be understood that the present invention is also intended to be used with self-propelled marine structures.

I claim:

1. Apparatus for marine operations adapted to be positioned at an operating site over water-covered land and further adapted to be moved from one such operating site to another such operating site, said apparatus comprising:

(a) an operating platform,

(b) a hull assembly adapted to buoyantly support said operating platform completely above the surface of the water when said apparatus is being moved between operating sites or selectively to be submerged below the surface of the water when said apparatus is positioned at an operating site, said hull assembly comprising:

two ballastable and deballastable elongated, horizontally spaced parallel ponto n elements, each extending from the bow to the stern of said hull assembly, said pontoon elements being in a common horizontal plane, said pont on elements having sufiicient buoyancy when deballasted to collectively support said apparatus with the said pontoon elements having freeboard,

brace elements extending between said pontoon elements,

fastening means to secure said brace elements to the top surface of said pontoon elements whereby said pontoon elements are rigidly braced to each other,

(c) column means rigidly secured to said hull assembly and extending upwardly therefrom, said column means comprising a column rigidly secured at its lower end to the midpoint of a brace element,

(d) means mounted to said operating platform and engaging said column means above said hull assembly to secure said operating platform to said column means and to vary the vertical distance between said operating platform and said hull assembly,

(e) whereby said hull assembly buoyantly supports said operating platform completely above the surface of the water when said pontoon elements are deballasted to acquire freeboard, the brace elements then being above the surface of the water, and whereby said hull assembly is submerged below the surface of the water when said pontoon elements are ballasted.

2. Apparatus as in claim 1, further comprising:

(g) said fastening means comprising brackets secured to said brace elements and to the top surfaces of said pontoon elements,

(h) said operating platform engaging said brackets when the vertical distance between said operating platform and said hull assembly has been adjusted to a minimum.

References Cited UNITED STATES PATENTS 1,470,459 10/1923 Lonsinger 61-465 X 2,975,747 3/1961 Opie 114-61 3,323,478 6/ 1967 Hunsucker 114-0.5

JACOB SHAPIRO, Primary Examiner.

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