# US 5,704,307 A · Taut leg mooring system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,704,307 A - Document ID: US5704307A - Status: Granted - Kind: A - Application number: 08/745,865 - Filed: 1996-11-08 - Granted: 1998-01-06 - Earliest claimed: 1996-03-21 - Assignees: Aker Marine, Inc. - Inventors: Johannes Jacobus Treu; Peter George Scott Dove - Web page: https://patentgrep.com/patent/US5704307A ## CPC - D07B 1/14: Ropes or cables with incorporated auxiliary elements, e.g. for marking, extending throughout the length of the rope or cable - B63B 21/50: Anchoring arrangements {or methods} for special vessels, e.g. for floating drilling platforms or dredgers - D07B 1/165: {characterised by a plastic or rubber inlay} - D07B: ROPES OR CABLES IN GENERAL (joining ropes or cables to one another or to other objects B65H69/00, F16G11/00; {mountaineering ropes A63B29/02}; mechanical finishing or dressing of ropes D02J; {braiding D04C}; decorative ropes or cords D04D; suspension cables for bridges E01D19/16; specially adapted for driving, or for being driven by, pulleys or other gearing elements F16G9/00; electric cables or joints insofar as electrical aspects are essential H01B, H01R) - B63B: SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING (arrangements of vessel ventilation, heating, cooling, or air-conditioning B63J2/00; floating substructures as supports of dredgers or soil-shifting machines E02F9/06) ## Abstract A taut leg bow mooring system (40) includes an anchor (42) positionable on the floor of the sea. A riser line (44) secured to and extending upwardly from the anchor, and a submerged buoy (46) secured to the end of the riser line from the anchor. The ratio of the net buoyancy of the surface buoy to the buoyancy of the submerged buoy is at least 2 to 1. A buoyant connector line (50) is secured to and extends upwardly from the submerged buoy. A surface buoy (52) is secured to the end of the connector line remote from the submerged buoy, and a hawser (56) is secured to and extends from the surface buoy. ## Claims ### Claim 1 A taut leg bow mooring system comprising: an anchor having a total weight sufficient to remain fixed on the water body floor under predetermined maximum riser line tension, said anchor positionable on the sea floor; a riser line secured to and extending from the anchor; a submerged buoy secured to an upper end of the riser line, said submerged buoy positioned substantially below the surface of the water body both when the mooring system is connected to a vessel and when said mooring system is not connected to a vessel, said submerged buoy having a first predetermined buoyancy sufficient to maintain the riser line in tension and in a substantially vertical position when said mooring system is not connected to a vessel, thereby minimizing flexure wear of a lower portion of the riser line; a floating connector line having a proximate end secured to the submerged buoy and extending therefrom; and a surface buoy positioned on the surface of the water and having a second predetermined buoyancy sufficient to prevent submergence of the surface buoy at a maximum vessel offset, said surface buoy secured to a distal end of the floating connector line remote from the submerged buoy, said surface buoy adapted to float on the surface of the water body. ### Claim 2 (depends on 1) The taut leg mooring system of claim 1 further including: a hawser connected to and extending from a distal end of the connector line secured to the surface buoy, said hawser for connection to a vessel to be moored. ### Claim 3 (depends on 1) The taut leg mooring system of claim 1 further including: a first length of chain positioned between the anchor and riser wire, said chain having a proximal end connected to the anchor and a distal end connected to the riser wire, wherein said chain reduces flexure in the riser wire. ### Claim 4 (depends on 3) The taut leg mooring system of claim 3 having a buoyancy of the submerged buoy around 10 to 20 kips above the combined weight of the riser line and first length of chain. ### Claim 5 (depends on 1) The taut leg mooring system of claim 1 further including: a second length of chain positioned between the riser wire, and the submerged buoy, said chain having a proximal end connected to the riser wire and a distal end connected to the submerged buoy, wherein said chain reduces flexure in the riser wire. ### Claim 6 (depends on 5) The taut leg mooring system of claim 5 having a buoyancy of the submerged buoy around 10 to 20 kips above the combined weight of the riser line, the first length of chain and the second length of chain. ### Claim 7 (depends on 1) The taut leg mooring system of claim 1 having at least a 2 to 1 ratio of buoyancy of the surface buoy to the bouyancy of the submerged buoy. ### Claim 8 (depends on 1) The taut leg mooring system of claim 1 wherein the anchor has a submerged weight of between about 60 and about 75 tons. ### Claim 9 (depends on 1) The taut leg mooring system of claim 1 wherein the system has a stiffness factor of about 450 pounds per foot, said stiffness factor being defined as the increase in bow mooring tension per unit of boat displacement. ### Claim 10 (depends on 1) The taut leg mooring system of claim 1 wherein the submerged buoy is positioned about 100 feet below the surface of the water to isolate said submerged buoy and riser line from surface wave action. ### Claim 11 A taut leg bow mooring system comprising: an anchor having a total weight sufficient to remain fixed on the water body floor under predetermined maximum riser line tension, said anchor positionable on the sea floor; a riser line secured to and extending from the anchor; a submerged buoy secured to an upper end of the riser line, said submerged buoy positioned substantially below the surface of the water body both when the mooring system is connected to a vessel and when said mooring system is not connected to a vessel, said submerged buoy having a first predetermined buoyancy around 10 to 20 kips above the weight of the riser line, said first predetermined bouyancy sufficient to maintain the riser line in tension and in a substantially vertical position when said mooring system is not connected to a vessel; a connector line having a proximate end secured to the submerged buoy and extending therefrom; and a surface buoy positioned on the surface of the water and having a second predetermined buoyancy sufficient to prevent submergence of the surface buoy at a maximum vessel offset, said surface buoy secured to a distal end of the connector line remote from the submerged buoy, said surface buoy adapted to float on the surface of the water body. ### Claim 12 A taut leg bow mooring system comprising: an anchor having a total weight sufficient to remain fixed on the water body floor under predetermined maximum riser line tension, said anchor positionable on the sea floor; a riser line secured to and extending from the anchor; a submerged buoy secured to an upper end of the riser line, said submerged buoy positioned substantially below the surface of the water body both when the mooring system is connected to a vessel and when said mooring system is not connected to a vessel, said submerged buoy having a first predetermined buoyancy sufficient to maintain the riser line in tension and in a substantially vertical position when said mooring system is not connected to a vessel; a connector line having a proximate end secured to the submerged buoy and extending therefrom; a surface buoy positioned on the surface of the water and having a second predetermined buoyancy sufficient to prevent submergence of the surface buoy at a maximum vessel offset, said surface buoy secured to a distal end of the connector line remote from the submerged buoy, said surface buoy adapted to float on the surface of the water body; and having a ratio of buoyancy of the surface buoy to the ratio of the bouyancy of the submerged buoy of at least 2 to 1. ### Claim 13 A taut leg bow mooring system comprising: an anchor having a total weight sufficient to remain fixed on the water body floor under predetermined maximum riser line tension, said anchor positionable on the sea floor; a riser line secured to and extending from the anchor; a submerged buoy secured to an upper end of the riser line, said submerged buoy positioned substantially below the surface of the water body both when the mooring system is connected to a vessel and when said mooring system is not connected to a vessel, said submerged buoy having a first predetermined buoyancy sufficient to maintain the riser line in tension and in a substantially vertical position when said mooring system is not connected to a vessel, thereby minimizing flexure wear of a lower portion of the riser line; a floating connector line having a proximate end secured to the submerged buoy and extending therefrom; and a surface buoy positioned on the surface of the water and having a second predetermined buoyancy sufficient to prevent submergence of the surface buoy at a maximum vessel offset, said surface buoy secured to a distal end of the floating connector line remote from the submerged buoy, said surface buoy adapted to float on the surface of the water body. ### Claim 14 (depends on 13) The taut leg mooring system of claim 13 further including: a hawser connected to and extending from the surface buoy, said hawser for connection to a vessel to be moored. ### Claim 15 (depends on 13) The taut leg mooring system of claim 13 wherein the anchor has a submerged weight of between about 60 and about 75 tons. ### Claim 16 (depends on 13) The taut leg mooring system of claim 13 wherein the anchor is a clump weight type anchor. ### Claim 17 (depends on 13) The taut leg mooring system of claim 13 further including: a length of chain positioned between the anchor and riser wire, said chain having a proximal end connected to the anchor and a distal end connected to the riser wire, wherein said chain reduces flexure in the riser wire. ### Claim 18 (depends on 13) The taut leg mooring system of claim 13 further including: a length of chain positioned between the riser wire and the submerged buoy, said chain having a proximal end connected to the riser wire and a distal end connected to the submerged buoy, wherein said chain reduces flexure in the riser wire. ### Claim 19 (depends on 13) The taut leg mooring system of claim 13 wherein the system has a stiffness factor of about 450 pounds per foot, said stiffness factor being defined as the increase in bow mooring tension per unit of boat displacement. ### Claim 20 (depends on 13) The taut leg mooring system of claim 13 wherein the submerged buoy is positioned about 100 feet below the surface of the water to isolate said submerged buoy and riser line from surface wave action.