Floating dredge motion compensator

Claim 2

In dredging apparatus: a vessel floating in a body of water; a cutter mechanism carried by and extending forwardly from said vessel and movable with respect thereto, said mechanism including a cutter device for cutting a formation submerged in the body of water; cylinder means; piston means slidable in said cylinder means; both of said means being located above and overlying said mechanism; means extending forwardly of said vessel and supporting one of said means from said vessel; means operatively connecting said other of said means to said cutter mechanism; means for maintaining a fluid medium under pressure in said cylinder means on one side of said piston means as said piston means and cylinder means move longitudinally with respect to each other to provide an upwardly directed force on said cutter mechanism supporting at least a portion of the weight of said cutter mechanism and thereby retaining the drilling weight of said cutter device against the formation at a selected value; and means for maintaining said fluid medium in said cylinder means at a substantially constant selected pressure.

Claim 3

In dredging apparatus as defined in claim 1; said one of said means being said cylinder means; said other of said means being said piston means.

Claim 4

In dredging apparatus: a vessel floating in a body of water; a cutter mechanism carried by and extending forwardly from said vessel and movable with respect thereto, said mechanism including a cutter device for cutting a formation submerged In the body of water; cylinder means; piston means slidable in said cylinder means; both of said means being located above and overlying said mechanism; means supporting one of said means from said vessel; means operatively connecting said other of said means to said cutter mechanism; means for maintaining a fluid medium under pressure in said cylinder means on one side of said piston means as said piston means and cylinder means move longitudinally with respect to each other to provide an upwardly directed force on said cutter mechanism supporting at least a portion of the weight of said cutter mechanism and thereby retaining the drilling weight of said cutter device against the formation at a selected value; and means for maintaining said fluid medium in said cylinder means at a substantially constant selected pressure; said supporting means including means for raising and lowering said one of said means with respect to said vessel, said supporting means extending above and connected to the upper portion of said one of said means.

Claim 5

In dredging apparatus: a vessel floating in a body of water; a cutter mechanism carried by and extending forwardly from said vessel and movable with respect thereto, said mechanism including a cutter device for cutting a formation submerged In the body of water; cylinder means; piston means slidable in said cylinder means; both of said means being located above and overlying said mechanism; means supporting one of said means from said vessel; means operatively connecting said other of said means to said cutter mechanism; means for maintaining a fluid medium under pressure in said cylinder means on one side of said piston means as said piston means and cylinder means move longitudinally with respect to each other to provide an upwardly directed force on said cutter mechanism supporting at least a portion of the weight of said cutter mechanism and thereby retaining the drilling weight of said cutter device against the formation at a selected value; and means for maintaining said fluid medium in said cylinder means at a substantially constant selected pressure; said supporting means including means for raising and lowering said one of said means with respect to said vessel, said supporting means extending above and connected to the upper portion of said one of said means.

Claim 6

In dredging apparatus: a vessel floating in a body of water; a cutter mechanism carried by and extending forwardly from said vessel and movable with respect thereto, said mechanism including a cutter device for cutting a formation submerged in the body of water; cylinder means; piston means slidable in said cylinder means; both of said means being located above and overlying said mechanism; means supporting one of said means from said vessel; means operatively connecting said other of said means to said cutter mechanism; means for maintaining a fluid medium under pressure in said cylinder means on one side of said piston means as said piston means and cylinder means move longitudinally with respect to each other to provide an upwardly directed force on said cutter mechanism supporting at least a portion of the weight of said cutter mechanism and thereby retaining the drilling weight of said cutter device against the formation at a selected value; and means for maintaining said fluid medium in said cylinder means at a substantially constant selected pressure; said one of said means being said cylinder means; said other of said means being said piston means; said supporting means including means for raising and lowering said cylinder means with respect to said vessel; said supporting means extending above and connected to the upper portion of said cylinder means.

Claim 7

In dredging apparatus: a vessel floating in a body of water; a cutter mechanism carried by and extending forwardly from said vessel and movable with respect thereto, said mechanism including a cutter device for cutting a formation submerged in the body of water; cylinder means; piston means slidable in said cylinder means; both of said means being located above and overlying said mechanism; means supporting one of said means from said vessel; means operatively connecting said other of said means to said cutter mechanism; means for maintaining a fluid medium under pressure in said cylinder means on one side of said piston means as said piston means and cylinder means move longitudinally with respect to each other to provide an upwardly directed force on said cutter mechanism supporting at least a portion of the weight of said cutter mechanism and thereby retaining the drilling weight of said cutter device against the formation at a selected value; and means for maintaining said fluid medium in said cylinder means at a substantially constant selected pressure; said one of said means being said cylinder means; said other of said means being said piston means; said supporting means including means for raising and lowering said cylinder means with respect to said vessel; said supporting means extending above and connected to the upper portion of said cylinder means.

Claim 8

In dredging apparatus: a vessel floating in a body of water; a cutter mechanism carried by and extending forwardly from said vessel and movable with respect thereto, said mechanism including a cutter device for cutting a formation submerged in the body of water; cylinder means; piston means slidable in said cylinder means; means supporting one of said means from said vessel; means operatively connecting said other of said means to said cutter mechanism; means for maintaining a fluid medium under pressure in said cylinder means on one side of said piston means as said piston means and cylinder means move longitudinally with respect to each other to provide an upwardly directed force on said cutter mechanism supporting at least a portion of the weight of said cutter mechanism and thereby retaining the drilling weight of said cutter device against the formation at a selected value; said supporting means including means for raising and lowering said one of said means with respect to said vessel; and releasable lock means for securing said cylinder means and piston means to each other whereby raising and lowering of said one of said means raises and lowers said cutter mechanism with respect to said vessel.

Claim 9

In dredging apparatus: a vessel floating in a body of water; a cutter mechanism carried by and extending forwardly from said vessel and movable with respect thereto, said mechanism including a cutter device for cutting a formation submerged in the body of water; cylinder means; piston means slidable in said cylinder means; means supporting one of said means from said vessel; means operatively connecting said other of said means to said cutter mechanism; means for maintaining a fluid medium under pressure in said cylinder means on one side of said piston means as said piston means and cylinder means move longitudinally with respect to each other to provide an upwardly directed force on said cutter mechanism supporting at least a portion of the weight of said cutter mechanism and thereby retaining the drilling weight of said cutter device against the formation at a selected value; said supporting means including means for raising and lowering said one of said means with respect to said vessel; and releasable lock means for securing said cylinder means and piston means to each other whereby raising and lowering of said one of said means raises and lowers said cutter mechanism with respect to said vessel.

Claim 10

In dredging apparatus: a vessel floating in a body of water; a cutter mechanism carried by and extending forwardly from said vessel and movable with respect thereto, said mechanism including a cutter device for cutting a formation submerged in the body of water; cylinder means; piston means slidable in said cylinder means; means supporting one of said means from said vessel; means operatively connecting said other of said means to said cutter mechanism; means for maintaining a fluid medium under pressure in said cylinder means on one side of said piston means as said piston means and cylinder means move longitudinally with respect to each other to provide an upwardly directed force on said cutter mechanism supporting at least a portion of the weight of said cutter mechanism and thereby retaining the drilling weight of said cutter device against the formation at a selected value; said one of said means being said cylinder means; said other of said means being said piston means; said supporting means including means for raising and lowering said cylinder means with respect to said vessel; and releasable lock means for securing said cylinder means and piston means to each other whereby raising and lowering of said cylinder means raises and lowers said cutter mechanism with respect to said vessel.

Claim 11

In dredging apparatus: a vessel floating in a body of water; a cutter mechanism carried by and extending forwardly from said vessel and movable with respect thereto, said mechanism including a cutter device for cutting a formation submerged in the body of water; cylinder means; piston means slidable in said cylinder means; means supporting one of said means from said vessel; means operatively connecting said other of said means to said cutter mechanism; means for maintaining a fluid medium under pressure in said cylinder means on one side of said piston means as said piston means and cylinder means move longitudinally with respect to each other to provide an upwardly directed force on said cutter mechanism supporting at least a portion of the weight of said cutter mechanism and thereby retaining the drilling weight of said cutter device against the formation at a selected value; said one of said means being said cylinder means; said other of said means being said piston means; said supporting means including means for raising and lowering said cylinder means with respect to said vessel; and releasable lock means for securing said cylinder means and piston means to each other whereby raising and lowering of said cylinder means raises and lowers said cutter mechanism with respect to said vessel.

Claim 12

In dredging apparatus: a vessel floating in a body of water; a cutter mechanism carried by and extending forwardly from said vessel and movable with respect thereto, said mechanism including a cutter device for cutting a formation submerged in the body of water; cylinder means; piston means slidable in said cylinder means; both of said means being located above and overlying said mechanism; means supporting one of said means from said vessel; means operatively connecting said other of said means to said cutter mechanism; means for maintaining a fluid medium under pressure in said cylinder means on one side of said piston means as said piston means and cylinder means move longitudinally with respect to each other to provide an upwardly directed force on said cutter mechanism supporting at least a portion of the weight of said cutter mechanism and thereby retaining the drilling weight of said cutter device against the formation at a selected value; and means for maintaining said fluid medium in said cylinder means at a substantially constant selected pressure; said supporting means extending above and connected to the upper portion of said one of said means; said supporting means including one or more lower sheaves connected to said one of said means, one or more upper sheaves carried by said vessel, a winch, and cable means passing over said upper and lower sheaves and connected to said winch to be moved thereby for raising and lowering said one of said means with respect to said vessel.

Claim 13

In dredging apparatus: a vessel floating in a body of water; a cutter mechanism carried by and extending forwardly from said vessel and movable with respect thereto, said mechanism including a cutter device for cutting a formation submerged in the body of water; cylinder means; piston means slidable in said cylinder means; both of said means being located above and overlying said mechanism; means supporting one of said means from said vessel; means operatively connecting said other of said means to said cutter mechanism; means for maintaining a fluid medium under pressure in said cylinder means on one side of said piston means as said piston means and cylinder means move longitudinally with respect to each other to provide an upwardly directed force on said cutter mechanism supporting at least a portion of the weight of said cutter mechanism and thereby retaining the drilling weight of said cutter device against the formation at a selected value; and means for maintaining said fluid medium in said cylinder means at a substantially constant selected pressure; said supporting means extending above and connected to the upper portion of said one of said means; said supporting means including one or more lower sheaves connected to said one of said means, one or more upper sheaves carried by said vessel, a winch, and cable means passing over said upper and lower sheaves and connected to said winch to be moved thereby for raising and lowering said one of said means with respect to said vessel.

Claim 14

In dredging apparatus: a vessel floating in a body of water; a cutter mechanism carried by and extending forwardly from said vessel and movable with respect thereto, said mechanism including a cutter device for cutting a formation submerged in the body of water; cylinder means; piston means slidable in said cylinder means; both of said means being located above and overlying said mechanism; means supporting one of said means from said vessel; means operatively connecting said other of said means to said cutter mechanism; means for maintaining a fluid medium under pressure in said cylinder means on one side of said piston means as said piston means and cylinder means move longitudinally with respect to each other to provide an upwardly directed force on said cutter mechanism supporting at least a portion of the weight of said cutter mechanism and thereby retaining the drilling weight of said cutter device against the formation at a selected value; and means for maintaining said fluid medium in said cylinder means at a substantially constant selected pressure; said supporting means extending above and connected to the upper portion of said cylinder means; said supporting means including one or more lower sheaves connected to said cylinder means, one or more upper sheaves carried by said vessel, a winch, and cable means passing over said upper and lower sheaves and connected to said winch to be moved thereby for raising and lowering said cylinder means with respect to said vessel.

Claim 15

In dredging apparatus: a vessel floating in a body of water; a cutter mechanism carried by and extending forwardly from said vessel and movable with respect thereto, said mechanism including a cutter device for cutting a formation submerged in the body of water; cylinder means; piston means slidable in said cylinder means; both of said means being located above and overlying said mechanism; means supporting one of said means from said vessel; means operatively connecting said other of said means to said cutter mechanism; means for maintaining a fluid medium under pressure in said cylinder means on one side of said piston means as said piston means and cylinder means move longitudinally with respect to each other to provide an upwardly directed force on said cutter mechanism supporting at least a portion of the weight of said cutter mechanism and thereby retaining the drilling weight of said cutter device against the formation at a selected value; and means for maintaining said fluid medium in said cylinder means at a substantially constant selected pressure; said supporting means extending above and connected to the upper portion of said cylinder means; said supporting means including one or more lower sheaves connected to said cylinder means, one or more upper sheaves carried by said vessel, a winch, and cable means passing over said upper and lower sheaves and connected to said winch to be moved thereby for raising and lowering said cylinder means with respect to said vessel.

Claim 16

In dredging apparatus: a vessel floating in a body of water; a cutter mechanisM carried by and extending forwardly from said vessel and movable with respect thereto, said mechanism including a cutter device for cutting a formation submerged in the body of water; cylinder means; piston means slidable in said cylinder means; means supporting one of said means from said vessel; means operatively connecting said other of said means to said cutter mechanism; means for maintaining a fluid medium under pressure in said cylinder means on one side of said piston means as said piston means and cylinder means move longitudinally with respect to each other to provide an upwardly directed force on said cutter mechanism supporting at least a portion of the weight of said cutter mechanism and thereby retaining the drilling weight of said cutter device against the formation at a selected value; said supporting means including one or more lower sheaves connected to said one of said means, one or more upper sheaves carried by said vessel, a winch, and cable means passing over said upper and lower sheaves and connected to said winch to be moved thereby for raising and lowering said one of said means with respect to said vessel; and releasable lock means for securing said cylinder means and piston means to each other whereby raising and lowering of said one of said means raises and lowers said cutter mechanism with respect to said vessel.

Claim 17

In dredging apparatus: a vessel floating in a body of water; a cutter mechanisM carried by and extending forwardly from said vessel and movable with respect thereto, said mechanism including a cutter device for cutting a formation submerged in the body of water; cylinder means; piston means slidable in said cylinder means; means supporting one of said means from said vessel; means operatively connecting said other of said means to said cutter mechanism; means for maintaining a fluid medium under pressure in said cylinder means on one side of said piston means as said piston means and cylinder means move longitudinally with respect to each other to provide an upwardly directed force on said cutter mechanism supporting at least a portion of the weight of said cutter mechanism and thereby retaining the drilling weight of said cutter device against the formation at a selected value; said supporting means including one or more lower sheaves connected to said one of said means, one or more upper sheaves carried by said vessel, a winch, and cable means passing over said upper and lower sheaves and connected to said winch to be moved thereby for raising and lowering said one of said means with respect to said vessel; and releasable lock means for securing said cylinder means and piston means to each other whereby raising and lowering of said one of said means raises and lowers said cutter mechanism with respect to said vessel.

Claim 18

In dredging apparatus: a vessel floating in a body of water; a cutter mechanism carried by and extending forwardly from said vessel and movable with respect thereto, said mechanism including a cutter device for cutting a formation submerged in the body of water; cylinder means; piston means slidable in said cylinder means; means supporting one of said means from said vessel; means operatively connecting said other of said means to said cutter mechanism; means for maintaining a fluid medium under pressure in said cylinder means on one side of said piston means as said piston means and cylinder means move longitudinally with respect to each other to provide an upwardly directed force on said cutter mechanism supporting at least a portion of the weight of said cutter mechanism and thereby retaining the drilling weight of said cutter device against the formation at a selected value; said supporting means including one or more lower sheaves connected to said cylinder means, one or more upper sheaves carried by said vessel, a winch, and cable means passing over said upper and lower sheaves and connected to said winch to be moved thereby for raising and lowering said cylinder means with respect to said vessel; and releasable lock means for securing said cylinder means and piston means to each other whereby raising and lowering of said cylinder means raises and lowers said cutter mechanism with respect to said vessel.

Claim 19

In dredging apparatus: a vessel floating in a body of water; a cutter mechanism carried by and extending forwardly from said vessel and movable with respect thereto, said mechanism including a cutter device for cutting a formation submerged in the body of water; cylinder means; piston means slidable in said cylinder means; means supporting one of said means from said vessel; means operatively connecting said other of said means to said cutter mechanism; means for maintaining a fluid medium under pressure in said cylinder means on one side of said piston means as said piston means and cylinder means move longitudinally with respect to each other to provide an upwardly directed force on said cutter mechanism supporting at least a portion of the weight of said cutter mechanism and thereby retaining the drilling weight of said cutter device against the formation at a selected value; said supporting means including one or more lower sheaves connected to said cylinder means, one or more upper sheaves carried by said vessel, a winch, and cable means passing over said upper and lower sheaves and connected to said winch to be moved thereby for raising and lowering said cylinder means with respect to said vessel; and releasable lock means for securing said cylinder means and piston means to each other whereby raising and lowering of said cylinder means raises and lowers said cutter mechanism with respect to said vessel.

Claim 20

In dredging apparatus: a vessel floating in a body of water; a ladder pivotally connected to said vessel and extending therefrom; a cutter mechanism carried by said ladder and including a cutter device for cutting a formation submerged in the body of water; cylinder means; piston means slidable in said cylinder means; both of said means being located above and overlying said ladder; means extending forwardly of said vessel and supporting said cylinder means from said vessel; means operatively connecting said piston means to said ladder; and means for maintaining a fluid medium under pressure in said cylinder means on one side of said piston means as said piston means and cylinder means move longitudinally with respect to each other to provide an upwardly directed force on said ladder and cutter mechanism to support at least a portion of the weight of said ladder and cutter mechanism and thereby retain the drilling weight of said cutter device against the formation at a selected value; and means for maintaining said fluid medium in said cylinder means at a substantially constant selected pressure.

Claim 21

In dredging apparatus: a vessel floating in a body of water; a ladder pivotally connected to said vessel and extending therefrom; a cutter mechanism carried by said ladder and including a cutter device for cutting a formation submerged in the body of water; cylinder means; piston means slidable in said cylinder means; both of said means being located above and overlying said ladder; means extending forwardly of said vessel and supporting said cylinder means from said vessel; means operatively connecting said piston means to said ladder; and means for maintaining a fluid medium under pressure in said cylinder means on one side of said piston means as said piston means and cylinder means move longitudinally with respect to each other to provide an upwardly directed force on said ladder and cutter mechanism to support at least a portion of the weight of said ladder and cutter mechanism and thereby retain the drilling weight of said cutter device against the formation at a selected value; and means for maintaining said fluid medium in said cylinder means at a substantially constant selected pressure.

Claim 22

In dredging apparatus: a vessel floating in a body of water; a ladder pivotally connected to said vessel and extendIng therefrom; a cutter mechanism carried by said ladder and including a cutter device for cutting a formation submerged in the body of water; cylinder means; piston means slidable in said cylinder means; both of said means being located above and overlying said ladder; means supporting said cylinder means from said vessel; means operatively connecting said piston means to said ladder; and means for maintaining a fluid medium under pressure in said cylinder means on one side of said piston means as said piston means and cylinder means move longitudinally with respect to each other to provide an upwardly directed force on said ladder and cutter mechanism to support at least a portion of the weight of said ladder and cutter mechanism and thereby retain the drilling weight of said cutter device against the formation at a selected value; and means for maintaining said fluid medium in said cylinder means at a substantially constant selected pressure; said supporting means including means for raising and lowering said cylinder means with respect to said vessel; said supporting means extending above and connected to the upper portion of said cylinder means.

Claim 23

In dredging apparatus: a vessel floating in a body of water; a ladder pivotally connected to said vessel and extendIng therefrom; a cutter mechanism carried by said ladder and including a cutter device for cutting a formation submerged in the body of water; cylinder means; piston means slidable in said cylinder means; both of said means being located above and overlying said ladder; means supporting said cylinder means from said vessel; means operatively connecting said piston means to said ladder; and means for maintaining a fluid medium under pressure in said cylinder means on one side of said piston means as said piston means and cylinder means move longitudinally with respect to each other to provide an upwardly directed force on said ladder and cutter mechanism to support at least a portion of the weight of said ladder and cutter mechanism and thereby retain the drilling weight of said cutter device against the formation at a selected value; and means for maintaining said fluid medium in said cylinder means at a substantially constant selected pressure; said supporting means including means for raising and lowering said cylinder means with respect to said vessel; said supporting means extending above and connected to the upper portion of said cylinder means.

Claim 24

In dredging apparatus: a vessel floating in a body of water; a ladder pivotally connected to said vessel and extending therefrom; a cutter mechanism carried by said ladder and including a cutter device for cutting a formation submerged in the body of water; cylinder means; piston means slidable in said cylinder means; means supporting said cylinder means from said vessel; means operatively connecting said piston means to said ladder; means for maintaining a fluid medium under pressure in said cylinder means on one side of said piston means as said piston means and cylinder means move laterally with respect to each other to provide an upwardly directed force on said ladder and cutter mechanism to support at least a portion of the weight of said ladder and cutter mechanism and thereby retain the drilling weight of said cutter device against the formation at a selected value; said supporting means including means for raising and lowering said cylinder means with respect to said vessel; and releasable lock means for securing said cylinder means and piston means to each other whereby raising and lowering of said cylinder means raises and lowers said ladder and cutter mechanism with respect to said vessel.

Claim 25

In dredging apparatus: a vessel floating in a body of water; a ladder pivotally connected to said vessel and extending therefrom; a cutter mechanism carried by said ladder and including a cutter device for cutting a formation submerged in the body of water; cylinder means; piston means slidable in said cylinder means; means supporting said cylinder means from said vessel; means operatively connecting said piston means to said ladder; means for maintaining a fluid medium under pressure in said cylinder means on one side of said piston means as said piston means and cylinder means move laterally with respect to each other to provide an upwardly directed force on said ladder and cutter mechanism to support at least a portion of the weight of said ladder and cutter mechanism and thereby retain the drilling weight of said cutter device against the formation at a selected value; said supporting means including means for raising and lowering said cylinder means with respect to said vessel; and releasable lock means for securing said cylinder means and piston means to each other whereby raising and lowering of said cylinder means raises and lowers said ladder and cutter mechanism with respect to said vessel.

Claim 26

In dredging apparatus as defined in claim 13; said cylinder means including a guide; said piston means including a piston in said cylinder means, an upper piston rod portion secured to said piston and extending from said cylinder means, a lower piston rod portion pivotally connected to said upper rod portion and slidable in said guide; said lower rod portion being connected to said ladder; said releasable lock means securing said guide to said lower rod portion whereby raising and lowering of said cylinder means raises and lowers said ladder and cutter mechanism.

Claim 27

In dredging apparatus: a vessel floating in a body of water; a ladder pivotally connected to said vessel and extending therefrom; a cutter mechanism carried by said ladder and including a cutter device for cutting a formation submerged in the body of water; cylinder means; piston means slidable in said cylinder means; means supporting said cylinder means from said vessel; means operatively connecting said piston means to said ladder; means for maintaining a fluid medium under pressure in said cylinder means on one side of said piston means as said piston means and cylinder means move laterally with respect to each other to provide an upwardly directed force on said ladder and cutter mechanism to support at least a portion of the weight of said ladder and cutter mechanism and thereby retain the drilling weight of said cutter device against the formation at a selected value; said cylinder means including a guide; said piston means including a piston in said cylinder means; an upper piston rod portion secured to said piston and extending from said cylinder means, a lower piston rod portion pivotally connected to said upper rod portion and slidable in said guide; said lower rod portion being connected to said ladder.

Claim 28

In dredging apparatus: a vessel floating in a body of water; a ladder pivotally connected to said vessel and extending therefrom; a cutter mechanism carried by said ladder and including a cutter device for cutting a formation submerged in the body of water; cylinder means; piston means slidable in said cylinder means; means supporting said cylinder means from said vessel; means operatively connecting said piston means to said ladder; means for maintaining a fluid medium under pressure in said cylinder means on one side of said piston means as said piston means and cylinder means move laterally with respect to each other to provide an upwardly directed force on said ladder and cutter mechanism to support at least a portion of the weight of said ladder and cutter mechanism and thereby retain the drilling weight of said cutter device against the formation at a selected value; said cylinder means including a guide; said piston means including a piston in said cylinder means; an upper piston rod portion secured to said piston and extending from said cylinder means, a lower piston rod portion pivotally connected to said upper rod portion and slidable in said guide; said lower rod portion being connected to said ladder.

Claim 29

In dredging apparatus: a vessel floating in a body of water; a ladder pivotally connected to said vessel and extending therefrom; a cutter mechanism carried by said ladder and including a cutter device for cutting a formation submerged in the body of water; cylinder means; piston means slidable in said cylinder means; means supporting said cylinder means from said vessel; means operatively connecting said piston means to said ladder; means for maintaining a fluid medium under pressure in said cylinder means on one side of said piston means as said piston means and cylinder means move laterally with respect to each other to provide an upwardly directed force on said ladder and cutter mechanism to support at least a portion of the weight of said ladder and cutter mechanism and thereby retain the drilling weight of said cutter device against the formation at a selected value; said supporting means including one or more lower sheaves connected to said cylinder means, one or more upper sheaves carried by said vessel, a winch, and cable means passing over said upper and lower sheaves and connected to said winch to be moved thereby for raising and lowering said cylinder means with respect to said vessel; said cylinder means including a guide; said piston means including a piston in said cylinder means, an upper piston rod portion secured to said piston and extending from said cylinder means, a lower piston rod portion pivotally connected to said upper rod portion and slidable in said ladder; and releasable lock means for securing said guide to said lower rod portion whereby raising and lowering of said cylinder means raises and lowers said ladder and cutter mechanism.

Claim 30

In dredging apparatus: a vessel floating in a body of water; a ladder pivotally connected to said vessel and extending therefrom; a cutter mechanism carried by said ladder and including a cutter device for cutting a formation submerged in the body of water; cylinder means; piston means slidable in said cylinder means; means supporting said cylinder means from said vessel; means operatively connecting said piston means to said ladder; means for maintaining a fluid medium under pressure in said cylinder means on one side of said piston means as said piston means and cylinder means move laterally with respect to each other to provide an upwardly directed force on said ladder and cutter mechanism to support at least a portion of the weight of said ladder and cutter mechanism and thereby retain the drilling weight of said cutter device against the formation at a selected value; said supporting means including one or more lower sheaves connected to said cylinder means, one or more upper sheaves carried by said vessel, a winch, and cable means passing over said upper and lower sheaves and connected to said winch to be moved thereby for raising and lowering said cylinder means with respect to said vessel; said cylinder means including a guide; said piston means including a piston in said cylinder means, an upper piston rod portion secured to said piston and extending from said cylinder means, a lower piston rod portion pivotally connected to said upper rod portion and slidable in said ladder; and releasable lock means for securing said guide to said lower rod portion whereby raising and lowering of said cylinder means raises and lowers said ladder and cutter mechanism.