Method for hauling a vessel alongside a mooring platform

Claim 3

The method of claim 1 wherein the vessel is hauled along the mooring structure by shortening and lengthening respective ones of the cables utilizing said hauling devices while retaining the connections between said hydraulic drive motors and the respective rotary hauling devices.

Claim 4

The method of claim 2 wherein said hauling devices are winches having drums drivable by both said existing drive means and said hydraulic drive motors.

Claim 5

The method of claim 2 wherein one of said hydraulic drive motors functions as a motor to aid in the shortening of the respective cable and the other of said hydraulic drive motors is driven by its respective hauling devices and functions as a pump to supply hydraulic fluid to said one hydraulic drive motor.

Claim 6

The method of claim 1 wherein said hauling devices are winches having drums drivable by both said existing drive means and said hydraulic drive motors.

Claim 7

The method of claim 1 wherein said hydraulic drive motors are constantly coupled to said rotary hauling devices for rotation as said rotary hauling devices are rotated.

Claim 8

A method according to claim 1 wherein the high pressure line is kept at a constant value by a pump with an overflow valve connected in parallel with it, while the low pressure line is connected to a vent reservoir.

Claim 9

Apparatus for positioning a vessel alongside a mooring structure comprising a pair of winches each including a drum, cables extending from said drums for individual shortening and loosening, each of said winches including first rotary motor means for selectively driving said drum, each of said winches including second rotary motor means for exerting a like cable tensioning torque on said drum thereof independently of said first rotary motor means to normally apply a like tensioning force on each of said cables, said second motor means being a hydraulic motor, high and low pressure lines connected to both of said second motor means, and control means maintaining a constant pressure in each of said high and low pressure lines, said control means includes a source of substantially constant pressure hydraulic fluid, identical control valves for said second motor means selectively providing for opposite directional driving of said second motor means and isolation of said second motor means from said hydraulic fluid source, and said first motor means being in the form of hydraulic motors, a separate source of hydraulic fluid under pressure, and interconnected valve means for selectively independently connecting and isolating said first motor means relative to said separate source.

Claim 10

Apparatus for positioning a vessel alongside a mooring structure comprising a pair of winches each including a drum, cables extending from said drums for individual shortening and loosening, each of said winches including first rotary motor means for selectively driving said drum, each of said winches including second rotary motor means for exerting a like cable tensioning torque on said drum thereof independently of said first rotary motor means to normally apply a like tensioning force on each of said cables, said second motor means being a hydraulic motor, high and low pressure lines connected to both of said second motor means, and control means maintaining a constant pressure in each of said high and low pressure lines, said control means includes a source of substantially constant pressure hydraulic fluid, identical control valves for said second motor means selectively providing for opposite directional driving of said second motor means and isolation of said second motor means from said hydraulic fluid source, and said first motor means being in the form of hydraulic motors, a separate source of hydraulic fluid under pressure, and interconnected valve means for selectively independently connecting and isolating said first motor means relative to said separate source.

Claim 11

The apparatus of claim 8 wherein said separate source is a reversible pump.

Claim 12

Apparatus for positioning a vessel alongside a mooring structure comprising a pair of winches each including a drum, cables extending from said drums for individual shortening and loosening, each of said winches including first rotary motor means for selectively driving said drum, each of said winches including second rotary motor means for exerting a like cable tensioning torque on said drum thereof independently of said first rotary motor means to normally apply a like tensioning force on each of said cables, said second motor means being a hydraulic motor, high and low pressure lines connected to both of said second motor means, and control means maintaining a constant pressure in each of said high and low pressure lines, said control means including means for connecting said second motor means high and low pressure lines directly to one another whereby when one of said winches is shortening its respective cables and the other of said winches is loosening its cable, said second motor means coupled to said other winches is driven as a pump to drive said second motor means coupled to said one winch.

Claim 13

Apparatus for positioning a vessel alongside a mooring structure comprising a pair of winches each including a drum, cables extending from said drums for individual shortening and loosening, each of said winches including first rotary motor means for selectively driving said drum, each of said winches including second rotary motor means for exerting a like cable tensioning torque on said drum thereof independently of said first rotary motor means to normally apply a like tensioning force on each of said cables, said second motor means being a hydraulic motor, high and low pressure lines connected to both of said second motor means, and control means maintaining a constant pressure in each of said high and low pressure lines, said control means including means for connecting said second motor means high and low pressure lines directly to one another whereby when one of said winches is shortening its respective cables and the other of said winches is loosening its cable, said second motor means coupled to said other winches is driven as a pump to drive said second motor means coupled to said one winch.

Claim 14

The apparatus of claim 10 wherein said control means includes a separate pump coupled to said high pressure line to compensate for differences in the rotations of said winches.