RIGGING, LIFTS, CHAIN, WIRE & TACKLES
(Extracts courtesy of A.N.T.A. publications, Ranger Hope © 2008 www.splashmaritime.com.au)
Flexibility is introduced into a wire rope by building the strands around a fibre heart and the wire in each round a fibre core, or by building the strands around a fibre heart and increasing the number of wires while reducing their individual thickness.
Properties of Steel Wire Rope
Type of Core
Steel Wire Rope (SWR) is described by the number of strands in the wire and the number of wires in the strand.
Shown above is a 6/7 Steel Wire Rope (the 7 representing 6 over 1), ie., 6 strands of 7 wires each.
Ropes are referred to by diameter. The correct way to measure is shown below.
Type of core
The centre core of the rope is named the HEART and the centre of the strands the CORE.
The purpose of the heart is to:-
1. Act as a lubrication sponge.
2. Provide support for strands enabling the rope to keep it's shape.
There are two CORE types:
Fibre (natural or synthetic).
a. Fibre Cores
Generally made from hemp, jute, polypropylene or nylon. They provide a resilient foundation for the strands and are used for ropes not subject to heavy loading. Used where flexibility in handling is required.
They are inadequate where wire rope is subjected to heavy loading, prolonged outdoor exposure, and crushing on small drums and sheaves.
Natural fibre - acts as a good sponge, but if re-lubrication is not adequate, rot and rust may form.
Synthetic - rot proof, chemically resistant and more flexible than wire cores.
Used chiefly for standing ropes (guys or rigging). They offer high tensile strength, and have a greater resistance to corrosion failure due to larger wires in the core.
Lay refers to the way the wires in the strands, and the strands in the rope are formed into the completed rope.
Steel wire ropes are conventionally produced with Right Hand lay unless special circumstances require Left Hand.
Ordinary or Regular Lay
Right Hand Ordinary Lay (R.H.O.L.) wires laid left handed, strands laid right handed.
The strands are laid up in the same direction as that in which their constituent wires are twisted, ie., both wires and strands Right Handed or both Left Handed.
Right Hand Langs Lay
Langs lay makes for a more flexible rope and wears well when used for hoisting, due to wear being spread over a larger area of wire. It can only be used when both ends are anchored and prevented from rotating, (eg., Crane Topping Lifts), because it is liable to unlay when under stress if one end is free to rotate. Not as easy to handle as ordinary lay.
Non Rotating Wire Rope
The outer strands may look like a LANGS LAY formation, but all the wires and strands are very much smaller in size. The inner strands are arranged so that any tendency for the rope to rotate under load is reduced to a minimum. It is very flexible and well suited to crane whips (runners).
During the manufacture of pre-formed wire rope, the wires and strands are given the exact spiral form they take up in the finished rope. They lie naturally in position, free form internal stress, and will not spring out of place like ordinary rope, where the wires are held forcibly in position.
Describing Steel Wire Rope
A full description includes the following details.
a. Rope diameter (mm)
b. Number of strands x the number of wires per strand
c. Direction of lay - R.H. or L.H.
d. Type of lay - O.L / L.L / N.R
e. Pre-formed or non pre-formed
f. Type of core
20 mm Diameter
6x24 Rope Construction
R.H.O.L Direction & Type
F.S.W.R with Fibre core
NB: Wear eye protection when inspecting wire rope.
Care and Maintenance
Reeling rope from reels and coils.
Incorrect handling of rope from reels and coils can result in springing of wires and strands and kinking of the rope. The above damage can seldom be entirely rectified and can greatly reduce the effective life of the rope.
With easy to handle coils it can be rolled like a hoop.
If the coil is too large to be handled manually, it should be mounted as above.
When coiling ropes down by hand, R.H. lay coil down clockwise and secure by lashing to prevent coils working open.
1. Ropes should be stored on reels wherever possible.
2. Coils should be kept on gratings to prevent corrosion and turned from time to time to prevent drainage of lubrication.
Removed ropes waiting further use, should be thoroughly cleaned, inspected, lubricated and stored under the same conditions as new ropes.
Wire Rope Life
The basic factors affecting rope life are:-
1. Basic equipment design and installation (sheave size & drums)
2. Operating environment. Corrosion - Internal and External
3. Wear generally caused by:-
a. Drum, sheaves and obstructions
b. Drum creeping
c. Acceleration and breaking
4. Fatigue - broken wires are bent back & broken off, not snipped.
6. Spiralling due to being wound on a drum of too small a diameter.
Occurs both internally and externally. Caused by:-
a. Friction over sheaves, leads, sharp or rough objects. Indicated by deposits of fine brown powder between strands
b. Dirt, dust, grit lodging within strand wires.
Generally caused by lack of lubrication. When wire rope is under tension, the fibre heart and cores are also compressed, releasing oil to overcome friction.
End for Ending and Cropping
Both these methods will give longer rope life due to the wear points being re-located. If additional rope can be accommodated on the drum, then this will allow for cropping, bringing 'new' rope into the system, and will re-locate wear points.
The normal methods of protecting S.W.R. against corrosion in the MARINE environment are galvanising and regular lubrication.
During manufacture the rope is impregnated with oil but is generally insufficient to last the rope's life. Additional lubrication should be carried out during service with a light bodied penetrating lubricant.
Inspection of Wire
A visual and physical examination should take place at regular intervals. Under normal conditions of use, wire rope can be inspected every 3 months. If a broken wire is discovered, then it should be inspected more often.
A thorough inspection is given below.
1. termination of rope at the drum and other points.
2. or broken wires.
3. or corrosion.
5. surface wear.
6. defective coiling.
7. for deterioration due to snatch loading.
8. lengths that run through blocks, particularly those which lie on the sheaves when the appliance is in the loaded condition.
Open the lay.
1. Check internal lubrication.
2. Degree of corrosion.
3. Indentation caused by pressure of wear.
4. Presence of broken wires.
An accurate log should be kept of inspection dates, rope condition, end for ending, replacement, etc. Broken wires are usually the result of fatigue and wear.
Discard if: Marine Order (part 32) "The total number of broken wires visible in a length of S.W.R. equal to 10 times it's diameter should not exceed 5% of the total number of wires constituting the rope".
Chain is well suited for use as slings, lashings, preventers etc., as they withstand corrosion and abrasion better than steel wire ropes.
Properties of Chain
Chains are made of mild or special steel, and are of short link, long link and stud link type. Those used for CHAIN BLOCKS are CALIBRATED ie., the link sides are made parallel.
Chain identification depends on material composition. Welded chains, if tested and marked in compliance with I.S.O. are graded 3 upwards to 9 (higher the number, better the grade).
The grade numbers are usually stamped on the chain approximately. Some manufacturers may use letters. Unmarked chains should be treated as grade 3 (mild steel).
ISO Chain markings (Grade 3 or L)
Care And Maintenance
Faults in chain are not easily seen and should be examined frequently for wastage due to rust, missing studs or distorted links.
The following is a list of DON’TS when using chain.
a. Cross, twist, knot or kink a chain.
b. Drag from under a load.
c. Use around sharp corners, without protective padding.
d. Use bolts or 'bull-dogs' for joining or shortening.
e. Use if over 10% wear in links.
f. Use if links are elongated AT ALL.
g. Use any chain for slinging without approved S.W.L. tags.
h. Make up a sling assembly from separate components, unless you are sure which components are the correct ones. Wrought iron chain needs annealing because it is subject to surface embrittlement, which deepens with time. If not annealed regularly it becomes dangerous.
Inspection of Chain
"Regularly" is every 6 months up to 12 mm diameter and every 14 months above 14 mm diameter.
Chains of mild steel should be checked for the flexing or bending of links. Damage to links where a chain has been used around sharp edges, causing cuts or nicks, is a good reason for condemning.
High tensile and alloy chain have great ability to stretch under shock loads and revert to normal size. If elongation is apparent while not under load, it has been seriously overloaded and should be discarded.
Splicing fibre or wire ripe is a skill that can only be learned through practice. For a comprehensive treatment of splicing, consult one of the many books on marline spike seamanship.
Before splicing - seize the ends of unlaid strands, and seize the rope at the point to which you plan to unlay it.
An eye splice is formed by unlaying the end of a rope, then turning the end back to from an eye, and tucking the separated strands into the standing part.
Natural fibre uses three full tucks and synthetic fibre, a minimum of four full tucks. If splicing round a thimble, tie the rope securely to the thimble with light twine, then splice as shown below.
This is used to join two ropes when not required to pass through a block. Unlay the two ropes and clutch them together, so that the strands of one rope go alternately between the strands of the other. Tuck each strand over one strand and under the next, take tow or more tucks with each strand, then turn the line and do the same with the other rope. Pull each strand up taught. A minimum of three full tucks for each rope.
Back splice is used in the means of finishing off the end of a fibre rope to prevent fraying. It is commenced with a CROWN KNOT, then the strands tucked as in the short splice.
Wire Rope Splicing
There are many types of wire splicing. Where wire has a tendency to spin use the Liverpool Splice.
The splicing tail should be about 40 diameters of the wire. Whip the wire at this point, and form the eye and seize to the main part. Unlay strands of each tail down to the seizing and whip each strand with twine, then cut away the heart.
The diagrams give the sequence for the first tuck of an eye splice in common 6 strand rope. After completion of the first tuck, continue tucking each strand over one and under two, against the lay, until 3 full tucks and 2 reduced tucks (with each strand halved) have been completed.
Stress denotes the load put on material, and strain is the molecular disturbance made evident by a change of shape or a fracture of the material due to the stress which has been applied. The term Breaking or Ultimate Strength is the load or weight applied to material when testing to destruction. Every item used in rigging has a B.S. (Breaking Strength), from which a S.W.L. (Safe Working Load) may be found by dividing the B.S. by a factor of safety for the function of the gear. An alternate termimology for SWL is WLL (Working Load Limit).
relative order of strength is Coir, Sisal,
Splicing a rope reduces its strength by at least 10%. Knots reduce a rope's strength by at least 50%. The ultimate strength of fibre ropes depends much upon the quality of fibre and manufacture.
The diameter of fibre and steel wire rope is in mm. The safety factor of fibre and steel wire rope is 1/6. Thus S.W.L. can be taken to be 1/6 of the breaking strength for fibre and wire rope. (See the table on the next page).
Approximate S.W.L. Rope = D2 x F kgs.
D is diameter of rope in mm.
F is a factor of safety.
Polyamide (nylon) < 50 mm
Polyamide (nylon) > 50 mm
The safety factor is taken as 1/6
The S.W.L. is taken to be (1/6 x B.S.) tonnesExample
Find SWL of 30 mm Nylon
SWL (kgs) = 3D2
= 3 x 302
= 2700 kgs
Find SWL of 12 mm Wire Rope (6 x 24)
SWL (kgs) = 8D2
= 8 x 122
= 1152 kgs
It is common practice to allow a 'Factor of Safety' of 6 in general marine work for both fibre and wire rope. Wire slings can have a 'Safety Factor' of 5 in some cases.
It is common practice to allow a 'Factor of Safety' of 5 for chain.
Grade 1 - Mild Steel
Grade 2 - Special Quality Steel
Grade 3 - Extra Special Quality Steel
B.S. (Breaking Strength)
12.5 mm to 120 mm
12.5 mm to 120 mm
12.5 mm to 120 mm
D is the diameter of the material expressed in mm.
The S.W.L. = B.S. x 1/5 tonnes.
With the I.S.O. standards - Grade 3 is mild steel
Grade 4-9 is tensile steel.
In this case the S.W.L. = 3D2 x Grade (kgs)
10 mm Grade 3 chain
SWL (kgs) = 3D2 x Grade
= 3 x 102 x 3
= 900 kgs
When calculating SWL of chain, beware of two different identification systems. If in doubt, assume the chain is the lowest grade, ie mild steel.
A purchase is any mechanical device which can increase output power. A tackle is a simple device comprised of rope and blocks. The lifting power of a tackle is referred to as the Mechanical Advantage (MA). MA of a tackle depends on the number of sheaves in the block, how the rope is moved and whether it is rigged to advantage or disadvantage.
To find the MA of any purchase, count the number of parts of rope at the moving block. (This assumes no friction in the sheaves).
Parts of a Tackle
When hauling from the moving block, the tackle is rove to advantage. In comparison, rove to disadvantage is when hauling, from the standing block.
Below a ‘Gun Tackle’ is shown to advantage and disadvantage.
MA 3 MA 2
It should be noted that where the tackle is rigged to 'disadvantage' the mechanical advantage is the same as the number of sheaves in the tackle, therefore when rigged to 'advantage' it becomes the number of sheaves plus one.
Types of Tackle
Special names are given to the various types of tackle used at sea, many of which owe their origin to their former use in the sailing ships of the last century.
Chain Hoists (Chain Blocks)
They are ordinarily constructed with the lower hook as the weakest part, so the hook will start to spread before the hoist is overloaded. Any evidence of spreading or wear on the hook is cause for replacement. Any distortion of the links in the chain means the lift has been overloaded and is probably unsafe for further use.
Chain blocks are more generally used for lifting machinery and found in the engine room. Due to the slow movement of the load, it can be placed with reasonable precision.
A derrick provides a way to lift and handle cargo in a similar way to cranes.
NB: The safe working load is painted on the derrick.
Even though this derrick is seldom seen on smaller trading vessels, the principles are applied to fishing and sailing rigs.
Retractable jib hydraulic cranes, eg HIAB or Palfinger types are being widely used as general purpose cranes.
1. This crane may be slewed in either direction through 360o. Usually by means of a manually driven gearbox. To prevent movement when net in use it is fitted with a locking device.
2. Hoisting is achieved by operation of an electric/hydraulic motor mounted on the davit.
3. Raising and lowering is affected by a remote control with separate buttons for 'UP' and 'DOWN'.
4. Winch is equipped with a centrifugal brake.
A small hydraulic crane for store handling, tanker pipelines, etc.
Code of Signals For Working Cranes or Derricks
NB: Be aware of the Code of Signals. You do not need to know these signals unless you operate a crane or derrick.
a. Whenever signals are needed to guide a crane driver, those in the diagram over page should be used.
b. Only one person signals a driver at a time, however the driver should obey anyone who gives the 'STOP' signal as this may indicate an emergency.
c. High visibility gloves or armbands may be worn by the signallerto show his/her authority and to make the signals clear.
Recommended Crane Signals
General Lifting Precautions
a. The operator must not pass a loaded boom over personnel.
b. Motion with heavy weights should be slow to avoid creating momentum.
c. Heavy weights should never be allowed to drop no matter what the distance.
d. Never keep a load in the air any longer than necessary.
e. Avoid swinging the load. If you're lifting something off a wharf, drag it until the load is directly under the head of the crane or boom.
f. Attach steady lines to heavy unwieldy loads.
g. Avoid sudden shocks or strains, and be aware of side pulls. These put great stress on a boom or crane.
h. Stay out from under booms and cranes while lifting operations are in progress.
i. Don't stand between a load in the air and a rail, stanchion, ratch coaming or any solid object against which you could be crushed.
j. Never use running gear as a handhold.
k. Listen for changes of sound in a wire, rope or block. Wire or cordage normally hums under strain. If it starts to squeak or squeal, watch out. A faulty block may give warning by squeaking or groaning.
Safe use and Maintenance of Lifting gear.
There is always an inherent danger whenever weights are to be lifted or moved by means of cranes, booms, tackles, topping lifts or other appliances due to the unevenness of the working platform and changes in dynamic loadings on the gear. Therefore the correct and safe use of the gear, machinery and associated hardware is of vital importance, as is its care and maintenance.
General Procedures in Moving Loads
The following can be adapted to any lifting operation irrespective of the type of lifting appliance or method of attaching the load to the appliance.
1. Determine weight of load and position of the centre of gravity in relation to the lifting points.
At No Time Must The Load Exceed The Safe Working Load (SWL) Of The Equipment In Use.
2. Decide upon the method of slinging and lifting the load. Take into account whether the lift requires 'Tag Lines' and packing or chafing pieces.
3. Inspect all equipment for defects.
4. Ensure the load is free to be lifted ie., not still bolted down or lashed, and any loose parts secured or removed.
5. Make sure there is a clear method of communication between the operator and the signal man
6. The greatest force must be applied at the time of starting a load, in order to overcome inertia. Apply the load gradually to avoid exceeding the S.W.L. Check the load's balance and general security. If this is satisfactory speed may be increased once the load is moving.
Speed of loading is controlled by safety and smoothness of operation
7. When lowering, stop a short distance above the landing site to allow steadying, to check position for landing, dunnage, and to make sure the slings will not be caught under the load.
8. Check lifting equipment before returning to stowage.
A lifting appliance is only as safe as its weakest part.
Shackles are used to connect objects: one wire to another, as sling to a load, a hook to a block or a hook to a wire rope eye.
They are usually made of forged alloy steel, high tensile steel, or mild steel. The nominal size of a shackle is given by the diameter of the material in the shackle body.
Types of Shackles
The 2 principal shapes are 'D' and 'BOW' shackles.
Bow Shackle with screw pin.
Bow Shackle - Used when more than one attachment is to be made to the body.
Other types of shackles are usually named in relation to the pin type.
Forelock - used for standing rigging, or where vibration is present. The pin is unthreaded, but it has a flat split pin as a keeper.
Safety and Operation Checks
a. Any shackles used in lifting purchases must be tested and have the SWL marked on the body.
b. Never use a pin that is bent, strained or damaged in any way.
c. If the crown or pin is worn to more than 10% of its original diameter it must be discarded. Fig 6.57 shows inspection areas.
d. All permanently attached shackles should be the locking type or should be "MOUSED" or secured against accidental opening.
Avoid using a common shackle where the pin can roll and unscrew under load.
e. DO NOT allow shackles to be pulled at an angle. Pack the pin to hold it square on the hook.
Hooks are used to attach the load. Because of its open construction, the hook is usually the weakest part of the lifting rig. New hooks are stamped with their S.W.L. Parts of the hook are shown below.
Types of Hook
When used for raising or lowering cargo or stores, should have a device to stop the slings jumping off – use a Safety hook with a gate. Open hooks should be “Moused”
Safety and Operation Checks
1. Hooks should be free to rotate under all conditions of loading. Swivels should be inserted wherever a twist is possible.
2. If the hook throat opening has stretched more than 5% it must not be used.
3. Damaged, distorted or bent hooks must not be used.
4. The throat opening must be large enough to fit the largest rope, ring or shackle to go on it.
5. Do not overcrowd the hook. Use a bow shackle or ring.
Slings and Strops
They can be made from:-
a. Fibre rope
b. Wire rope
a. Fibre Rope
Lifts without scratching.
Protects load surfaces.
Typical fibre rope slings are shown below.
b. Wire Slings
Steel wire rope slings are more suitable for lifting machinery or material that will cut easily into fibre ropes. Size for size they are much stronger than fibre rope slings but are more expensive.
When bought in they will have their S.W.L. stamped on them.
c. Chain Slings
They are stronger than both wire and fibre rope and are often used in combination with them, especially the two, three and four legged variety, when lifting bulky loads and machinery.
The 'Collar' sling can have different sized end links so that one may be rove through the other to act as a Choke Hitch.
To shorten a chain sling if no clutches available, pull slack of chain through the large ring to form a bight. Pass one hand through the bight, catch hold of standing part, let everything else drop and place standing part over the cargo hook ready for heaving.
Chains will have their S.W.L. stamped on them.
These are frames of wood or steel fitted with one or more sheaves. They are designated as single, double or treble depending on the number of sheaves, or from some special shape or construction eg., snatch block.
Fibre Rope Blocks
1. The older wooden blocks had steel sheaves and plain axles.
The later type have a steel strap or band running outside the shell, with the sheave pin going through both strap and shell.
The modern type tend to be all metal.
2. If no S.W.L. is marked on them, then it is equivalent to that of
the largest diameter rope that can be reeved through comfortably.
3. The diameter of sheaves used for fibre rope should be at least
six times the diameter of the rope used when hand operated.
When power operated the sheaves should be 12 times the rope diameter. (Diameter in mm).
Parts of a block
Wire Rope Blocks
Generally referred to as steel blocks and more often used for heavier applications on board a vessel. There should be a small plate affixed to the cheek of the block showing:
Safe Working Load
Last Test Date
Some typical wire rope blocks are shown below.
Cargo Gin - Purchase Blocks for Heavy Lifts
One special type of block that the mariner will come in contact with on occasions is the Snatch Block. This is a small strong steel block with hinged side. This permits the fall to be put over the sheave through an opening in the side, without reeving the end through. They are very handy as lead blocks when moving cargo, or gear around the decks.
Care And Inspection Of Blocks
a. Check the swivel eyes for free movement.
b. Grease swivel, shank and bearings.
c. Examine side plates for distortion.
d. Sheaves should turn freely by hand, examine for cracks and bush wear, check grooves for wear.
e. Check axle pins cannot work loose.
f. Oil all surfaces rather than paint. Paint may clog oil holes and hide marks and defects.
g. Check wooden blocks for splitting.
h. Never drop a block on the deck.
Matching Rope And Sheave Sizes
Rope must match the size of the sheave to avoid crushing, kinking and deformation.
The diameter of a sheave is measured to the bottom of the groove. (Diameter in mm).
For wire ropes the sheave diameter should be 20 times the rope diameter for power operated blocks and it can be 10 times on non power operated blocks.
Types of cable
Short or Close Link Chain
Used in small vessels in preference to rope.
Stud Link Chain with Joining ShackleUsed by tugs and landing barges.
Stud link chain has the greater strength and the studs help to prevent distortion, forming of kinks, and knots thus making it easier to handle.
A length of cable is known as a Shackle or Shot, the standard length being 15 fathoms, ie 90 feet.
The shackles are joined together using a special joining shackle, as shown below.
Lugged joining Shackle. - Lugless joining shackle or
The lug faces inboard. Kenter Shackle.Cable Marking
The cable is marked from either side of each joining shackle as shown below.
Windlass/capstans, winches and other machinery must be operated in accordance with set procedures established by the master/vessel owner.
Safe operation of a windlass/capstan during anchoring is covered in in “Precautions when using a Windlass”.
Warping Drum Operation
Always test winch prior to using.
Normally pass 3 turns around the drum.
Always tail keeping at least ½-1 metre away from the drum,
If a riding turn develops, stop and remove with caution (riding turns usually develop because of incorrect lead or tailing).
Never surge a synthetic line on a rotating drum.
Always surge in a controlled manner.
Surging causes friction, heat is generated and synthetic fibres may melt onto the drum and even part.
Avoid standing, if possible, in the direct line of the hauling part.
Wear good safety footwear,
Never stand in the bight of lines.
Keep area clear of unnecessary crew/passengers.
Take extra precaution when working in wet weather.
Always inspect prior to operating.
The winch is clear and not fouled.
Trace the wire rope to see it is roved correctly.
Check associated fittings are serviceable.
The controls are not bostructed
Always inform crew. Before operating test the winch.
controls are operating correctly
Always operate safely within the designed limits of the winch.
Keep personnel clear.
Wire rope is correctly spooling onto the drum.
Do not allow overwinds.
Always leave a minimum of 2 turns on the drum.
Never use the winch end terminal as a stop.
Continually check the system whilst operating.
If you need to guide wire rope onto a drum, ie when loading a new rope, always use a guide, never your hands. You should not be operating a winch manually guiding the wire rope onto the drum. This is a very dangerous practice.
Important factors regarding wire ropes being wound onto drums as in the case of cranes, winches etc.
Right hand for R.H.O.L. Left hand for L.H.O.L.
Above shows the Rule of Thumb. This rule is used to determine how to start winding the wire or rope onto a winch drum. With the pad of the index finger touching the over wound or underwound wire, the thumb will point to the correct side of the drum.
Hydraulic double drum and Winch with warping drum.
Where the winches run on electrically-operated hydraulic pumps, they can be run out under power. This gives the operator much greater control and eliminates the ever-present risk of brake failure which can result in lost or damaged gear.
In most cases careful manipulation of the hydraulic control allows them to be slowed right down to a bare 'crawl' and, in the neutral position, acts as a brake when the hydraulic motor is running. All such winches have a manual brake as standard.
The operator is directly responsible for the safety of gear handling operations. If there is any doubt about safety, stop the machinery immediately and rectify the problem or isolate the system The operator be competent in all phases of machinery operation and know the Safe Working Loads of the equipment.
Operators should never leave machinery unattended with gear running, or with a load suspended. Always be sure everyone is clear of the danger zone before applying a load, and never pass a suspended load over another crewman.
Machinery should be provided with a means to prevent over-hoisting and to prevent the accidental release of a load if the power supply fails. Check you know where the Emergency Stop button is for all machinery.
Machinery guards should always be in place, except when carrying out repairs. Never work on running equipment, it must be stopped and rendered incapable of accidental restarting.
Be sure the area around the controls is unimpeded, and that your view is as unobstructed as possible. Make sure that all lighting is in working order and that guards protect the globes.
One method of securing the end of the stage is shown below.
Rigging a Stage
The practical handiest size line for a stage rope is 20 mm. This is known as a “gant” line. It must be long enough to reach the waterline on the bight when working over the ship's side.
In the above method the rope tail is made fast to the standing part after the hitch is completed, using a bowline. If the stage is extra long, it is advisable to rig a centre line to prevent sagging in the middle.
The standing part should be reeved through a lizard, shackle or best of all a tail block to enable it to be lowered and adjusted by those working from the stage.
Take two full turns of the hauling part around the end of the stage and one full turn around the horn as a means of lowering.
Check stage for defects.
Inspect all lines and fittings.
Correctly rig the stage.
Load test the stage to 4 times the intended load.
Gantlines must trail in the water to be used as lifelines.
Stages should only be rigged over water.
Do not use whilst underway.
Always set down before raising and lowering.
Rig a rope ladder for access.
Be positively tended and have a life buoy available.
Rigging a Bosun's Chair
In most work done aloft a bosun's chair and gantline is used, the gantline is always attached to the chair by means of a double sheet bend and end seized to the standing part (Fig 6.88). The gantline should be reeved through a tail block or lizard for ease of hauling and lowering oneself.
How to make a Lowering Hitch whilst on a Bosun’s Chair
A long bight of the hauling part is pulled through the strop of the chair, passed over the head and allowed to drop behind to the feet. It is then passed under the feet and brought to the front. The slack on the hauling part is pulled tight forming the hitch. When ready to lower, render slack on the hauling part through the hitch, which it will easily do.
The practice of holding on with one hand and making the lowering hitch with the other hand is dangerous.
NB: Grip with hand and seize both parts of the gantline together before making the lowering hitch.
Check bosun’s chair for defects.
Inspect all lines and fittings.
Corrrectly rig the gantline,
Load test 4-5 times the intended load.
When hauling aloft in a bosun’s chair it should be done by hand.
Riding a stay
When riding a stay ensure the bow of the shackle rides the stay not the pin. Always seize (mouse) the shackle pin.
Wear a safety harness if more than 2 metres aloft.
The person working aloft should make sure all tools etc., have safety lines attached.
Rope ladders/side ladders are used to access stages over the vessels side, over hatch coamings to access parts of a hold etc. They are light and handy ladders easily carried around the decks. The top of the ladder can be left with the rope ends whipped or a thimble can be used. This enables it to be shackled to a boom if necessary.
Pass a Stopper
A stopper is used to transfer the weight on a line from one fitting to another, ie a warping drum to a bollard.
The stopper is secured to bollard or strong point and lead towards the strain.
The tail is half hitched around the line against the lay.
Then dogged around the line with the lay.
The end is either held or whipped.
Transfer the load.
Use synthetic stoppers on a synthetic line and natural fibre stoppers on a natural fibre line - do not use a nylon line as a stopper.