CA1279532C - Device for laying-out and breaking-out of the sea-bottom and weighing an anchor - Google Patents

Abstract

ABSTRACT

A CHASER OF A HOOK TYPE FOR LAYING-OUT AND
WEIGHING AN ANCHOR AND INTENDED FOR TENSIONING OF
AN ANCHOR LINE TO AN EMBEDDED ANCHOR.

Description

~7~S32 A DEVICE FOR LAYING-OUT AND BREAKING-OUT OF THE
SEA-BOTTOM AND WEIGHING AN ANCHOR.

INTENSIFICATION OF THE EXPLORATION AND EXPLOITATION
OF OFF-SHORE OIL AND GAS FIELDS DURING THE PAST TEN
YEARS HAS CAUSED THESE OPERATIONS TO BE MOVED TO EVER
DEEPER WATERS. THE RESULT OF THIS WAS THAT CONSIDERABLE
SCALING UP OCCURRED WITH RESPECT TO ALL THE MATERIAL
BEING USED FOR OFF-SHORE OPERATIONS.
THUS THE DIMENSIONS OF FOR INSTANCE ANCHOR CHAINS, ANCHOR WINCHES AND OF ANCHORS THEMSELVES ARE
CONSIDERABIY INCREASED. PARTICULARLY THE HOLDING FORCE

IN THE LAST DECENNIUM.

IN THE INITIAL PHASE OF THESE OFF-SHORE ACTIVITIES.
I.E. IN THE PERIOD THAT THE EXPLORATION AND

RESTRICTED TO RELATIVELY SHALLOW PARTS OF THE
CONTINENTAL SHELF, THE ANCHORS BY WHICH FLOATING
OBJECTS SUCH AS DRILLING PLATFORMS, CRANE SHIPS AND
THE LIKE CAN BE ANCHORED TO THE SEA-BOTTOM, WERE PULLED
OUT OF OR FROM THE SEA-BOTTOM AND WEIGHED WITH THE
AID OF SO-CALLED PENNANT WIRES. FOR THIS PURPOSE ONE
TERMINAL END OF SUCH A PENNANT WIRE IS ATTACHED TO THE

,,, ~

3~

ANCHOR AND THE OTHER TERMINAL END TO A SO-CALLED
SURFACE BUOY. AFTER LAYING OUT THE ANCHORS~ WHICH IS
OFTEN PERFORMED ~rJITH TUGBOATS OR SUPPLY SHIPS~ THESE
BUOYS FLOATING ON THE SEA SURFACE INDICATE THE POSITIONS
WHERE THE ANCHORS WERE LOCATED IN OR ON THE SEA-BOTTOM.
UPON COMPLETION OF THE OPERATIONS THESE ANCHORS WERE
WEIGHED AGAIN BY BREAKING THESE OUT OR PULLING THESE
UP FROM THE SEA-BOTTOM WITH THE AID OF THE PENNANT
WIRES. IN ORDER TO DO SO~ THE SURFACE BUOYS TOGETHER
WITH THE TERMINAL ENDS OF THE PENNANT WIRES ATTACHED
THERETO WERE PICKED OUT OF THE WATER AGAIN WITH THE
AID OF THE TUGBOATS OR SUPPLY SHIPS~ AFTER WHICH THE
ANCHORS WERE PULLED OUT BY THEIR PENNANT WIRES. AT THE
SAME TIME THE ANCHOR CHAINS WERE PULLED TAUT FROM THE
FLOATING OBJECT WITH THE AID OF ANCHOR WINCHES AND
SUBSEQUENTLY THE ANCHORSWERE HOISTED ON DECK THERE OR
SECURED TO ANCHOR SUPPORT FRAMES FIXED TO THE SIDE
OF THE OBJECT.

HOWEVER~ IN THE COURSE OF TIME THESE ANCHORS WERE
IMPROVED ON SEVERAL POINTS. ONE OF THESE IMPROVEMENTS
CONCERNS THE ADAPTATION TO HAVE THE ANCHORS PENETRATE
DEEPER. A DEEPER PENETRATION~ HOWEVER~ WOULD NOT ONLY
YIELD AN IMPROVEMENT OF THE HOLDING FORCE CAPACITY~

OUT FORCES~ PARTICULARLY IN SOFTER TYPES OF SOIL. THIS
WOULD IMPLY THAT MUCH GREATER FORCES ARE REQUIRED TO
PULL AN EMBEDDED ANCHOR OUl OF THE BOTTOM. THIS WOULD
FURTHER IMPLY THAT THE PENNANT WIRES HAVE TO BE MORE

BE ENLARGED TO BE ADAPTED TO CARRY THE HIGHER OWN
WEIGHT OF THE PENNANT WIRES.

, . .

~ - ~
i32 IN SEVERAL SEA AREAS, HOWEVER, THESE LARGE BUOYS HAVE
CAUSED ACCIDENTS, WHEREUPON THE USE OF SAID BUOYS
WAS PROHIBITED BY THE AUTHORITIES IN THE COUNTRIES
SURROUNDING THE NORTH SEA IN THEIR SECTORS OF THE
CONTINENTAL SHELF. THE MORE SO SINCE PARTICULARLY
FISHING-BOATS RAN INTO TROUBLES IN THE DARK OF THE
NIGHT DUE TO THE PRESENCE OF SUCH BUOYS.

THIS PROBLEM WAS SOLVED BY MAKING USE OF A SPECIFIC
DEVICE FOR LAYING-OUT AND WEIGHING AN ANCHOR, WHEREBY
THE USE OF SURFACE BUOYS COULD BE ELIMINATED.

A KNOWN DEVICE OF THIS TYPE IS MOSTLY CALLED A "CHASER"
IN THE ART. OF SUCH A DEVICE MAINLY TWO VARIATIONS ARE
KNOWN. ONE TYPE IS GENERALLY REFERRED TO BY THE NAME
J-CHASER". THIS DEVICE HAS, AS THE NAME ALREADY
INDICATES, A J-SHAPE WHICH PROVIDES AN OPEN STRUCTURE
ADAPTED TO BE HOOKED AT ANY LOCATION ABOUT AN ANCHOR
CHAIN OR CABLE. WHEN NOT IN USE, THE DEVICE CAN BE
STORED ON DECK OF THE FLOATING OBJECT AS WELL AS ON
DECK OF THE TUGBOAT OF SUPPLY SHIP.

THE OTHER TYPE IS KNOWN BY THE NAME "PERMANENT CHASER".
BROADLY, THIS DEVICE COMPRISES A RING-SHAPED MEANS
HAVING SUCH INTERIOR MEASURES THAT IT CAN EASILY SLIDE
ALONG THE ANCHOR CHAIN OR CABLE AND ON THE ANCHOR SHANK.
AS THE NAME ALREADY INDICATES. THIS DEVICE IS
PERMANENTLY SITUATED ABOUT THE ANCHOR CHAIN AND, WHEN
NOT IN USE~ RESTS AGAINST AN ANCHOR SUPPORT FRAME.
FOR LAYING-OUT AN ANCHOR FROM A FLOATING OBJECT THAT
HAS TO BE ANCHORED IN A CERTAIN POSITION THE "CHASER"
IS SLID ONTO THE ANCHOR SHANK ("J-CHASER"), IF IT HAS

~, . .

NOT BEEN INCORPORATED PERMANENTLY YET IN THE SYSTEM OF
ANCHOR ~ ANCHOR CHAIN ("PERMANENT CHASER'')AND THIS IN
SUCH A WAY THAT THE "CHASER" IS SITUATED AS CLOSE TO
THE ANCHOR CROWN AS POSSIBLE FOR THE SAKE OF STABILITY.
TO THE "CHASER" A PENNANT WIRE IS OR HAS BEEN ATTACHED, THE OTHER TERMINAL END OF WHICH IS CONNECTED TO A WINCH
ABOARD A TUGBOAT OR SUPPLY SHIP. WITH THE AID OF SAID
WINCH, THE PENNANT WIRE IS KEPT UNDER SUFFICIENT
TENSION AT ALL TIMES SO AS TO PREVENT THE ANCHOR FROM
SLIPPING OUT OF THE "CHASER".

FROM THE FLOATING OBJECT THE ANCHOR CHAIN OR CABLE IS
GRADUALLY PAID-OUT WITH THE AID OF AN ANCHOR WINCH, WHILE AT THE SAME TIME THE TUGBOAT OR SUPPLY SHIP
SLOWLY MOVES AWAY FROM THE OBJECT. BY SIMULTANEOUSLY
PAYING-OUT THE ANCHOR CHAIN OR CABLE AND THE PENNANT
WIRE THE ANCHOR IS LOWERED DOWN TO THE SEA-BOTTOM IN A
CONTROLLED MANNER AND TUGGED TO THE DESIRED ANCHORING
POSITION. THE PENNANT WIRE PREFERABLY SHOULD BE
Z0 1 1/2 TO 2 TIMES THE WATER DEPTH.

WHEN THE ANCHOR HAS BEEN PLACED IN THE DESIRED POSITION, THE TUGBOAT OR THE SUPPLY SHIP IS NAVIGATED BACK TO THE
FLOATING OBJECT, DURING WHICH THE "CHASER" SLIDES OFF
THE ANCHOR SHANK. THEN THE "CHASER" IS TAKEN ALONG
BACK TO THE FLOATING OBJECT WHILE SLIDING ALONG THE
ANCHOR CHAIN.

IF AFTER COMPLETING OR IN ORDER TO INTERRUPT THE
ACTIVITIES SAID ANCHOR HAS TO BE WEIGHED AGAIN, THEN, GENERALLY, IS ACTED IN REVERSED ORDER. THE "CHASER" IS
NOW TUGGED BY THE TUGBOAT OR SUPPLY SHIP WITH THE AID
OF THE PENNANT WIRE FROM THE FLOATING OBJECT SLIDING

~27~353Z

ALONG THE ANCHOR CHAIN OR CABLE IN THE DIRECTION OF THE
ANCHOR ON THE SEA-BOTTOM. WHEN ARRIVING THERE, THE
CHASER" EASILY SLIDES ABOUT THE ANCHOR SHANK DUE TO ITS
ADAPTED CONFIGURATION TO REST AGAINST THE ANCHOR CROWN~
THEN THE ANCHOR CAN BE PULLED OUT OF OR FROM THE SEA-BOTTOM AND BE WEIGHED BY WINDING UP THE PENNANT WIRE
FROM THE TUGBOAT OR SUPPLY SHIP. SUBSEQUENTLY IT CAN
EITHER BE PULLED OR HOISTED ABOARD THE TUGBOAT OR THE
SUPPLY SHIP, OR PULLED TO THE FLOATING OBJECT BY WINDING
UP THE ANCHOR CHAIN OR CABLE FROM THERE SO THAT IT CAN
BE HOISTED ON DECK OR SECURED AGAINST AN ANCHOR FRAME.

THE LAST-DESCRIBED METHOD FOR RETRIEVING AN ANCHOR WOULD
CAUSE PROBLEMS, HOWEVER, AS THE ANCHOR WOULD PENETRATE
MORE DEEPLY INTO THE SEA-BOTTOM. IN THE FIRST PLACE, THE ANCHOR SHANK CAN OFTEN NOT BE REACHED BY THE
"CHASER" SINCE THIS SHANK HAS DUG ITSELF IN TOO DEEPLY.
THUS IT WILL NOT BE POSSIBLE FOR THE "CHASER" TO SLIDE
ABOUT THE ANCHOR SHANK. SECONDLY, THE ANCHOR CHAIN OF
A DEEPLY PENETRATED ANCHOR HAS A RATHER STEEP ANGLE OF
INCIDENCE WITH RESPECT TO THE SEA-BOTTOM. WHEN WINDING
UP THE PENNANT WIRE, THE "CHASER' TENDS TO SLIDE BACK
ALONG THE ANCHOR CHAIN, UNTIL A CERTAIN BALANCE OF
FORCES WOULD BE ESTABLISHED IN THE SYSTEM OF ANCHOR
CHAIN OR CABLE AND CHASER ENGAGING IT. THIS WOULD
CREATE GREAT FORCES IN THE ANCHOR CHAIN OR CABLE. THE
FORCES IN THE CHAIN OR CABLE THUS DIRECTED TOWARDS THE
FLOATING OBJECT AND THE ANCHOR CAUSE, AS A RESULT OF
2ND ORDER EFFECTS,A FAR GREATER RE~SULTING FORCE IN THE
PENNANT WIRE TOWARDS THE TUGBOAT OR SUPPLY SHIP THAN
THE FORCE ACTUALLY REQUIRED FOR BREAKING-OUT THE ANCHOR.

CHAIN OR CABLE AND THE PENNANT WIRE HAVE TO BE DIMENSIONED

3~

DISPROPORTIONALLY MORE HEAVILY AND THAT THE WINCH ABOARD THE
TUGBOAT OR SUPPLY SHIP HAS TO YIELD MUCH GREATER PULLING FORCES.
IN SPITE OF THESE NECESSARY PROVISIONS THERE REMAINS A CHANCE OF
CHAIN OR CABLE BREAKAGE ON ACCOUNT OF THE HIGH LEVEL OF THE ACTING
FORCES, PARTICULARLY IF THE ANCHOR IS EMBEDDED RATHER FIRMLY INTO
THE SEA-BOTTOM.

THE PRESENT INVENTION TENDS TO ELIMINATE THESE DRAWBACKS AND
PROVIDES A DEVICE FOR SUSPENSION FROM A VESSEL FOR LAYING OUT, BREAKING-OUT AND WEIGHING AN ANCHOR, COMPRISING SLIDING SURFACES
FOR PASSAGE OF HORIZONTALLY ORIENTED CHAIN LINKS OF AN ANCHOR
CHAIN, OR A CHAIN LENGTH FORMING PART OF AN ANCHOR CABLE, AND A
ONE-WAY ACTING BLOCKING MEANS OVER WHICH THE PASSAGE OF THE ANCHOR
CHAIN IN AT LEAST ONE WAY IS POSSIBLE, BUT BY WHICH THE LATTER CAN
BE BLOCKED IN THE OPPOSITE DIRECTION, CHARACTERIZED IN THAT THE
ONE-WAY ACTING BLOCKING MEANS COMPRISES STOP CAMS, WHICH ARE
FORMED INTEGRALLY WITH SAID SLIDING SURFACES FOR ONE-WAY
ENGAGEMENT OF THE SAID CHAIN LINKS, SAID SLIDING SURFACES BEING
SEPARATED FROM EACH OTHER BY A RECESSED SECTION FOR UNHINDERED
PASSAGE OF VERTICALLY ORIENTED CHAIN LINKS.

THE USE OF SUCH A ONE-WAY ACTING BLOCKING MEANS OR "CHASER
STOPPER" IN A "PERMANENT CHASER" HAS THE DRAWBACK, THAT THE
"CHASER" AFTER LAYING-OUT THE ANCHOR CANNOT BE TUGGED BACK TO THE
FLOATING OBJECT ALONG THE ANCHOR CHAIN OR THE CHAIN LENGTH OF THE
ANCHOR CABLE DUE TO THE BLOCKING ACTION IN THE OPPOSITE DIRECTION.
ONE OF THE EMBODIMENTS OF THE PRESENT INVENTION TENDS TO SOLVE

,~

~Z7~3532 THIS PROBLEM AND THIS EMBODIMENT IS FOR THAT PURPOSE CHARACTERIZED
IN THAT IT IS PROVIDED WITH AN ANTI-BLOCKING MEANS WHICH CAN
RELEASE THE ONE-WAY BLOCKING ACTION OF THE BLOCKING MEANS. IT
SHOULD BE REMARKED, THAT THE BLOCKING ACTION OF THE "CHASER
STOPPER" CONCERNS ANCHOR CHAINS. THIS DOES NOT

..~.~, ~Z';'95~Z

EXCLUDE THEIR USE IN ANCHOR CABLES, PROVIDED THAT
SUCH ANCHOR CABLES ARE PROVIDED WITH A CHAIN LENGTH
NEAR THE ANCHOR, ON WHICH THE "CHASER STOPPER" CAN BE
OPERABLE. WHEN IN THE FOLLOWING SPECIFICATION THE WORD
CHAIN IS USED, THIS CAN BOTH REFER TO AN ENTIRE ANCHOR
CHAIN AND A CHAIN LENGTH AS A MEMBER OF AN ANCHOR CABLE.

THE INVENTION WILL NOW BE DESCRIBED IN MORE DETAIL IN
VIEW OF THE ATTENDANT DRAWINGS AND BE FURTHER
ELUCIDATED.

FIGURES 1A THROUGH 1D GIVE, IN THIS ORDER, THE
SUCCESSIVE STAGES OF BREAKING-OUT A DEEPLY PENETRATED
ANCHOR FROM THE SEA-BOTTOM WITH A KNOWN DEVICE AND IN
THE PERTAINING FORCE DIAGRAMS THE FORCES OCCURRING
IN EVERY STAGE ARE SCHEMATICALLY SHOWN.

FIGURES 2A THROUGH 2D, IN THIS ORDER, GIVE THE
SUCCESSIVE STAGES OF AGAIN BREAKING-OUT A DEEPLY
PENETRATED ANCHOR FROM THE SEA-BOTTOM WITH THE DEVICE
ACCORDING TO THE PRESENT INVENTION AND AN INDICATION OF
THE FORCES OCCURRING IN EVERY STAGE.

FIG. 3A SHOWS A SIDE VIEW OF A DEVICE ACCORDING TO THE
INVENTION OF THE "J-CHASER" TYPE.

FIG. 3B SHOWS A LONGITUDINAL CROSS SECTION OF THE
DEVICE ACCORDING TO FIG. 3A ALONG THE LINE I-I.

FIG. 3A SHOWS A CROSS-SECTION OF THE DEVICE ACCORDING
TO FIG. 3A ALONG THE LINE II-II IN FIG. 3B.

FIG. 4A SHOWS A SIDE VIEW OF A DEVICE ACCORDING TO THE

INVENTION OF THE "PERMANENT CHASER" TYPE.

FIG. 4B SHOWS A LONGITUDINAL CROSS-SECTION OF THE DEVICE
ALONG THE LINE III-III.

FIG. 4C SHOWS A CROSS-SECTION OF THE DEVICE ACCORDING TO
FIG. 4A ALONG THE LINE IV-IV IN FIG. 4B.

FIG. 5 SHOWS THE CHAIN END NEAR THE ANCHOR, IN WHICH
CHAIN END A FANG MEANS FOR THE "CHASER" IS INCORPORATED.

IN FIG. lA THROUGH 1D THE PROBLEMS ARE SHOWN OCCURRING
WHEN BREAKING-OUT A DEEPLY PENETRATED ANCHOR FROM THE
SEA-BOTTOM WITH THE AID OF A KNOWN DEVICE. IN FIG. 1A
A "CHASER" 1 IS TUGGED BY A PENNANT WIRE 3 FROM THE
FLOATING OBJECT 4 TO BE ANCHORED (DRILLING PLATFORM, CRANE SHIP ETC.) ALONG THE ANCHOR CHAIN OR CABLE 5 IN

OR SUPPLY SHIP. IN THE ENCLOSED DIAGRAM OF FORCES IS
PROPORTIONALLY INDICATED HOW THE FORCES ARE DEVELOPED
AT THE LOCATION OF THE POINT OF ENGAGEMENT OF THE
"CHASER" 1 ON THE ANCHOR CHAIN OR CABLE IN THE PENNANT
WIRE AND IN THE ANCHOR CHAIN OR CABLE.

WITH RESPECT T0 THE SEA-BOTTOM THE "CHASER" IS NOT
CAPABLE TO MOVE TOWARDS THE ANCHOR AND TENDS TO SLIDE
BACK ALONG THE ANCHOR CHAIN OR CABLE WHEN WINDING UP
THE PENNANT WIRE 3 FROM THE TUGBOAT OR SUPPLY SHIP.
THIS SLIDING BACK CONTINUES UNTIL A CERTAIN BALANCE OF
FORCES HAS BEEN REACHED. THIS STAGE IS SHOWN IN FIG. 1B, AS WELL AS THE SCHEMATICALLY INDICATED ACTING FORCES IN

~Z~532 THE BALANCE SITUATION.

IN FIG. lC THE STAGE IS SHOWN IN WHICH BY FURTHER WINDING
UP THE PENNANT WIRE, A BEGIN IS MADE WITH ACTUALLY
BREAKING THE ANCHOR OUT OF THE SEA-BOTTOM. IT CAN BE READ
FROM THEATTENDANT DIAGRAM OF FORCES, THAT THE FORCES IN
BOTH THE CHAIN AND CABLE ENDS AND IN THE PENNANT WIRE
INCREASE CONSIDERABLY.

FIG. lD SHOWS A FOLLOWING STAGE, IN WHICH AS A RESULT OF
THE OCCURRING GREAT FORCES IN THE ANCHOR CHAIN OR CABLE
ENDS AND ON THE BASIS OF THE BALANCE OF FORCES IN THE
POINT OF ENGAGEMENT, THE FORCE IN THE PENNANT WIRE
INCREASES EXCESSIVELY.

ANCHOR, WHEREBY THE DEVICE ACCORDING TO THE INVENTION IS
USED. IN FIG. 2A THE DEVICE IS ABOUT TO SLIDE BACK IN THE
DIRECTION OF THE FLOATING OBJECT 4. AT THAT MOMENT, THE
ONE-WAY ACTING BLOCKING MEANS, "CHASER STOPPER" IN
TECHNICAL TERMINOLOGY, BECOMES OPERATIVE, BY ENGAGING THE
FIRST OCCURRING HORIZONTAL LINK OF THE CHAIN RETURNING
THROUGH THE "CHASER" 1. THUS THE CHAIN IS BLOCKED IN
THE "CHASER" IN THE DIRECTION OF THE FLOATING OBJECT, DUE TO WHICH AS A RESULT OF THE PENNANT WIRE BEING WOUND
UP FROM THE TUGBOAT 2, ONLY THE CHAIN END RUNNING
TOWARDS THE ANCHOR 6 IS PULLED TAUT (FIG. 2B). THE FORCES
IN THE CHAIN END WHICH IS CONNECTED TO THE FLOATING
OBJECT, CAN BE NEGLECTED.
WHEN FURTHER WINDING UP THE PENNANT WIRE, THE ANCHOR CAN
SUBSEQUENTLY BE BROKEN DIRECTLY OUT OF THE SEA-BOTTOM, AS
IS SHOWN IN FIG. 2C. DUE TO THE LACK OF SECONDARY FORCES

~ `~\
lZ7953Z

- 1 o -(2ND ORDER EFFECTS) IN THE CHAIN ENDS, THE REQUIRED
PULLING FORCE IN THE PENNANT WIRE REMAINS RESTRICTED
TO THE BREAKING-OUT FORCE OF THE ANCHOR.

SINCE THE "CHASER'' IS NOW MORE OR LESS SECURED TO THE
CHAIN, THE TUGBOAT OR THE SUPPLY SHIP CAN, IN
PRINCIPLE, PULL THE ANCHOR IN ANY DESIRED DIRECTION, E.G.
AS INDICATED IN FIG. 2D. THIS HAS THE ADVANTAGE THAT
THE ANCHOR CAN BE JERKED FREE OF THE SEA-BOTTOM IN
THE MOST FAVOURABLE DIRECTION AND AT THE MOST
FAVOURABLE ANGLE.

INVENTION OF THE "J-CHASER" TYPE IS SHOWN. THE J-SHAPED
SUPPORT FRAME COMPRISES TWO SLIDING SURFACES ON WHICH
HORIZONTALLY POSITIONED CHAIN LINKS CAN SLIDE. THESE
SLIDING SURFACES ARE SEPARATED FROM EACH OTHER BY A

VERTICALLY ORIENTED CHAIN LINKS. THE SLIDING SURFACES
ARE AT ONE SIDE OF THE DEVICE PROVIDED WITH STOP CAMS 9.
AS LONG AS THE CHAIN 5 ACCORDING TO FIG. 3A RUNS FROM
THE RIGHT TO THE LEFT THROUGH THE "CHASER' , OR RATHER
THE "CHASER" MOVES FROM THE LEFT TO THE RIGHT, THE
HORIZONTAL LINKS CAN PASS ON THE STOP CAMS 9 UNHINDERED.
HOWEVER, AS SOON AS THE DIRECTION OF MOVEMENT OF THE
"CHASER" IS REVERSED, THE FIRST-OCCURRING HORIZONTAL
LINK ENGAGES THE STOP CAMS, WHEREBY THE PASSAGE OF THE
CHAIN THROUGH THE "CHASER' IS BLOCKED. THIS SITUATION
IS SHOWN IN FIG. 3A. IT IS AS IF THE CHASER" SEIZES ON
THE CHAIN, SO THAT THE HOISTING FORCE IS TRANSFERRED
DIRECTLY TO THE ANCHOR VIA THE TENSIONED CHAIN PORTION
(IN FIG. 3A T0 BE RIGHT OF THE "CHASER').

THE ABOVE-DESCRIBED SITUATION OCCURS, WHEN ONE WANTS TO

~'~'79532 WEIGH AN ANCHOR. IN THIS CASE THE TUGBOAT OR THE SUPPLY
SHIP SAILS FROM THE FLOATING OBJECT OVER THE ANCHOR CHAIN
OR CABLE FROM THE LEFT TO THE RIGHT, WHEREBY THE
"CHASER" IS LOWERED INTO THE WATER ON THE PENNANT WIRE
OVER THE STERN ROLLER. THE "CHASER" IS PROVIDED WITH A
ROTARY PLATE 10 AND ROTARY TRIANGLES 11, WHICH UPON
CONTACTINr. THE CHAIN AUTOMATICALLY TURN THE "CHASER"
INTO THE RIGHT DIRECTION, AFTER WHICH THE "CHASER" CAN
BE HOOKED ON THE CHAIN IN A SIMPLE MANNER.
SUBSEQUENTLY THE "CHASER" IS "DRIVEN'' IN THE DIRECTION
OF THE ANCHOR WHEN SAILING AND SUCH UP TO THE EARLIER-MENTIONED MOMENT AT WHICH THE "CHASER" TENDS TO SLIDE
BACK ALONG THE CHAIN. IT IS AT THAT MOMENT THAT THE

DESCRIBED ABOVE.

A RAISED EDGE 12 WARRANTS THAT ONCE A CHAIN IS ENGAGED, IT CONTINUES TO RUN ALSO DURING THE PASSAGE OVER THE
RELATIVELY HIGH STOP CAMS OVER THE SLIDING SURFACES 7.
FURTHERMORE THIS "J-CHASER" IS PIVOTALLY CONNECTED TO
A HOISTING EYE 13 BY MEANS OF A BOLT 13.

AFTER THE "CHASER" HAS ENGAGED THE CHAIN~ THE ANCHOR IS
PULLED OUT OF THE SEA-BOTTOM DIRECTLY VIA THE
TENSIONED WIRE END SITUATED BETWEEN THE "CHASER"AND
THE ANCHOR AND WEIGHED, AFTER WHICH IT CAN BE HOISTED
ABOARD THE TUGBOAT OR SUPPLY SHIP OR ABOARD THE
FLOATING OBJECT.

IF THIS "J-CHASER" IS TO BE USED FOR BRINGING AN ANCHOR
ON ITS LOCATION C.Q. FOR LAYING IT OUT, THIS ANCHOR HAS
TO BE LOWERED FROM THE FLOATING OBJECT, HOISTED ABOARD
THE TUGBOAT OR SUPPLY SHIP AND THEN WITH THE AID OF THE

53;2 "CHASER" LOWERED TO ITS ANCHORING LOCATION. HOWEVER, THIS IMPLIES THAT FOR LOWERING IT FROM THE FLOATING
OBJECT, A PENNANT WIRE SHOULD BE ATTACHED TO THE ANCHOR
TEMPORARILY.

INVENTION OF THE "PERMANENT CHASER" TYPE IS SHOWN. THIS
"CHASER" IS ALSO PROVIDED WITH TWO SLIDING SURFACES 7.
ON WHICH HORIZONTALLY POSITIONED CHAIN LINKS CAN SLIDE, VERTICALLY POSITIONED LINKS OF THE CHAIN 5. THESE

PLATES 15, WHICH ARE KEPT SPACED APART BY MEANS OF A
SPACER 19. ON ACCOUNT OF THE PERMANENT CHARACTER OF
THIS "CHASER" TYPE, THE CHAIN IS ALSO LOCATED
PERMANENTLY BETWEEN THESE SIDE PLATES.

PRECISELY ON ACCOUNT OF THIS PERMANENT CHARACTER OF THIS
"CHASER" IT IS ALWAYS ORIENTED IN ONE PREDETERMINED
POSITION WITH RESPECT TO THE CHAIN. SINCE THE "CHASER"
HAS TO BE USED BOTH FOR LAYING-OUT AND FOR AGAIN
HAULING AN ANCHOR, THIS IMPLIES THAT THE "CHASER"
SHOULD BE ADAPTED TO MOVE IN BOTH DIRECTIONS ALONG THE
CHAIN IF SO DESIRED. FOR, AFTER LAYING-OUT AN ANCHOR
WITH A "PERMANENT CHASER", THIS "CHASER" HAS TO BE
MOVED BACK ALONG THE ANCHOR CHAIN OR CABLE IN THE
DIRECTION OF THE FLOATING OBJECT. HOWEVER, THE "CHASER"
WOULD THEN ENGAGE THE ANCHOR CHAIN OR THE CHAIN LENGTH
OF AN ANCHOR CABLE, WHICH WOULD BLOCK THIS RETURN
MOVEMENT. A SOLUTION TO THIS PROBLEM WAS DEVISED, IN
THE FORM OF AN ANTI-BLOCKING MEANS. IN THIS EMBODIMENT

WHICH CAN PIVOT ABOUT HORIZONTAL PIVOT SHAFTS 17. THEN

, .. .

1~:7~53Z

AND THAT JUST BEFORE THE STOP CAMS 9.

THEY CAN BE LOCKED IN TWO POSITIONS, DEPENDING ON THE
DESIRED "CHASER" ACTION, E.G. BY LOCKING THEM WITH A
PAWL MECHANISM.

WHEN AN ANCHOR HAS TO BE LAID OUT, THE CANTING ARMS 16 ARE LOCKED IN CLOSED POSITION, I.E. CANTED UPWARDS.

OVER THE SLIDING SURFACES 7 IN BOTH DIRECTIONS, DUE
TO WHICH THE "CHASER" AFTER THE ANCHOR HAS BEEN LAID OUT
CAN BE MOVED BACK TO ITS POSITION OF REST AGAINST THE
ANCHOR SUPPORT FRAME OF THE FLOATING OBJECT. THIS CLOSED
POSITION OF THE CANTING ARMS IS SHOWN IN FIG. 4A.

FOR HOISTING AGAIN AN ANCHOR THAT WAS ALREADY LAID OUT, THE CANTING ARMS 16 ARE LOCKED IN OPENED POSITION, I.E.
CANTED DOWNWARDS. NOW THE "CHASER" CAN BE MOVED
UNHINDERED FROM THE FLOATING OBJECT IN THE DIRECTION OF
THE ANCHOR: THE ANCHOR CHAIN OR CABLE RUNS UNHINDERED

THROUGH THE "CHASER". AT THE MOMENT THE CHASER IS NEAR
THE ANCHOR AND ATTEMPTS TO SLIDE BACK ALONG THE ANCHOR
CHAIN OR THE CHAIN LENGTH OF AN ANCHOR CABLE, THE FIRST
OCCURRING HORIZONTAL CHAIN LINK ABUTS THE STOP CAMS 9, AFTER WHICH THE CHAIN END BETWEEN THE CHASER AND THE
ANCHOR CAN BE TENSIONED AND THE ANCHOR CAN BE PULLED
OUT OF THE SEA-BOTTOM. THIS ENGAGEMENT OF A HORIZONTAL

CANTING ARMS 16 IS SHOWN IN FIG. 4C, WHICH FIGURE
REPRESENTS A CROSS-SECTION EXACTLY ALONG THE CENTRE

~Z~ 3;2 LINE III-III OF FIG. 4B.

HOWEVER, FOR CLARITY'S SAKE THE CANTING ARMS 16 ARE NOT
SHOWN IN SECTION IN FIG. 4B. FURTHERMORE THE SIDE PLATES

FOR AN EASIER PASSAGE OF THE ANCHOR CHAIN OR CABLE. THIS
"PERMANENT CHASER" IS ALSO PIVOTALLY CONNECTED TO A
HOISTING EYE BY MEANS OF A BOLT 13 VIA THE SPACER 19.

IN FIG. 5 THE CHAIN END 5 NEAR THE ANCHOR IS SHOWN, IN
WHICH CHAIN END A FANG MEANS IS INCORPORATED SO AS TO
PREVENT THE "CHASER" FROM MOVING BEYOND THIS POINT AND
JAMMING ON THE ANCHOR SHACKLE ("CROWN SHACKLE"). IN THE
EMBODIMENT REPRESENTED HERE THIS FANG MEANS CONSISTS OF
A FANG HOOK 20, ADAPTED TO HOOK BEHIND THE LOWER SIDE
OF THE DEVICE.

IN THE CHAIN END IN QUESTION, A CHAIN SWIVEL 21 IS ALSO
MOUNTED. DUE TO ROTATION OF THIS CHAIN SWIVEL, TURNS IN
THE CHAIN, IF CAUSED BY PULLING THE CHAIN NOT ENTIRELY
STRAIGHT WHEN WEIGHING THE ANCHOR, CAN BE REMOVED FROM
THE CHAIN IN A SIMPLE MANNER. OTHERWISE THE CHAIN SWIVEL
COULD BE MOUNTED BOTH BEFORE AND BEHIND THE FANG HOOK.

FINALLY IT [S REMARKED, THAT THE ABOVE-DESCRIBED
EMBODIMENTS SHOULD BE REGARDED AS NON-RESTRICTIVE
EXAMPLES OF THE INVENTIVE IDEA AND THAT ALL KINDS OF
MODIFICATIONS AND VARIATIONS OF WHAT IS REPRESENTED HERE
COULD BE EMBODIED WITHIN THE SCOPE OF THE INVENTION.

Claims (9)

1. A DEVICE FOR SUSPENSION FROM A VESSEL FOR LAYING-OUT, BREAKING-OUT AND WEIGHING AN ANCHOR, COMPRISING SLIDING SURFACES
FOR PASSAGE OF HORIZONTALLY ORIENTED CHAIN LINKS OF AN ANCHOR
CHAIN, OR A CHAIN LENGTH FORMING PART OF AN ANCHOR CABLE, AND A
ONE-WAY ACTING BLOCKING MEANS OVER WHICH THE PASSAGE OF THE ANCHOR
CHAIN IN AT LEAST ONE WAY IS POSSIBLE, BUT BY WHICH THE LATTER CAN
BE BLOCKED IN THE OPPOSITE DIRECTION, CHARACTERIZED IN THAT THE
ONE-WAY ACTING BLOCKING MEANS COMPRISES STOP CAMS, WHICH ARE
FORMED INTEGRALLY WITH SAID SLIDING SURFACES FOR ONE-WAY
ENGAGEMENT OF THE SAID CHAIN LINKS, SAID SLIDING SURFACES BEING
SEPARATED FROM EACH OTHER BY A RECESSED SECTION FOR UNHINDERED
PASSAGE OF VERTICALLY ORIENTED CHAIN LINKS.

2. A DEVICE AS CLAIMED IN CLAIM 1, CHARACTERIZED IN THAT
THE STOP CAMS ARE LOCATED AT ONE END OF THE DEVICE.

3. A DEVICE AS CLAIMED IN CLAIM 1 OR 2, CHARACTERIZED IN
THAT IT CONSISTS OF AN OPEN STRUCTURE WITH A J-SHAPED FRAME
COMPRISING A HOOK MEANS, WHEREIN THE FRAME IS PROVIDED WITH A
PLATE AT THE SIDE AWAY FROM SAID HOOK MEANS AND TRIANGLES AT EACH
SIDE LATERALLY OF SAID HOOK MEANS FOR AUTOMATICALLY TURNING THE
DEVICE UPON CONTACT WITH THE ANCHOR CHAIN OR CHAIN LENGTH TOWARDS
AN ORIENTATION WHEREIN SAID CHAIN OR CABLE IS AT THE SIDE OF ITS
HOOK MEANS.

4. A DEVICE AS CLAIMED IN CLAIM 1, CHARACTERIZED IN THAT IT
CONSISTS OF A CLOSED STRUCTURE WHICH IS PERMANENTLY AROUND THE
ANCHOR CHAIN OR CHAIN LENGTH, AND WHICH COMPRISES AN UNBLOCKING
MEANS BY WHICH THE ONE-WAY BLOCKING ACTION OF THE STOP CAMS CAN BE
ELIMINATED.

5. A DEVICE AS CLAIMED IN CLAIM 4, CHARACTERIZED IN THAT
THE UNBLOCKING MEANS COMPRISES CANTING ARMS WHICH ARE LOCATED JUST
BEFORE THE STOP CAMS AND CAN PIVOT HORIZONTALLY, SAID CANTING ARMS
IN CLOSED POSITION ENSURING AN UNHINDERED PASSAGE OF AN ANCHOR
CHAIN OR CABLE IN BOTH DIRECTIONS AND IN OPENED POSITION RELEASING
THE STOP CAMS SO THAT THE MOVEMENT OF THE ANCHOR CHAIN OR THE
CHAIN LENGTH IS THEN BLOCKED IN ONE DIRECTION BY THE STOP CAMS.

6. A DEVICE AS CLAIMED IN CLAIM 5, CHARACTERIZED IN THAT
THE SLIDING SURFACES, THE ONE-WAY ACTING BLOCKING MEANS AND THE
UNBLOCKING MEANS ARE SECURED BETWEEN TWO SIDE PLATES WHICH ARE
KEPT SPACED APART AT THE TOP BY MEANS OF A SPACER.

7. A DEVICE AS CLAIMED IN CLAIM 6, CHARACTERIZED IN THAT
THE SIDE PLATES ARE BEVELLED OR RADIUSED AT THEIR INNER SIDE SO AS
TO GUIDE THE ANCHOR CHAIN OR CABLE MOVING THEREBETWEEN.

8. A DEVICE AS CLAIMED IN CLAIM 1, CHARACTERIZED IN THAT IN
THE CHAIN END NEAR THE ANCHOR A FANG MEANS IS INCORPORATED SO THAT
MOVEMENT OF THE DEVICE TOWARD THE ANCHOR BEYOND THIS POINT IS
PREVENTED.

9. A DEVICE AS CLAIMED IN CLAIM 8, CHARACTERIZED IN THAT
THE FANG MEANS CONSISTS OF A FANG HOOK ADAPTED TO HOOK BEHIND THE
LOWER SIDE OF THE DEVICE.