ROPEWORK QUESTIONS 1

ROPEWORK QUESTIONS NAME:

1 Name three types of natural and synthetic fibre ropes and give their characteristics and properties.

2 Explain the following 'Lay' of fibre rope.

a) Hawser

b) Shroud

c) Cable

3 Describe how you would uncoil cordage.

4 Describe how you would inspect rope for internal and external damage?

5 When using fibre rope, list four things to avoid.

6 What are the properties of steel wire rope?

7 How should a wire rope be wound on a drum if it is R.H.O.L.?

8 What is the purpose of the Core and Heart?

9 Practice making the various knots, bends and hitches also splicing in cordage

ROPEWORK QUESTIONS 2

1 What are the properties of steel wire rope determined by?

2 Explain 'Langs' lay and where this type would be used.

3 Give some examples of wire rope deterioration.

4 How are rope sizes measured?

5 Explain the uses of the following:-

a) Figure of eight knot

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b) Bowline

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c) Sheepshank

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6 What is the S.W.L. of -

a) 20 mm Manila

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b) 15 mm Polypropylene

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c) 12 mm 6/24 wire

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7 What factors affect wire rope life?

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8 What should you look for when carrying out an inspection of wire rope?

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9 What is S.W.L. and B.S.?

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ROPEWORK ANSWERS 2

1 What are the properties of steel wire rope determined by?

Properties of Steel Wire Rope are determined by:

                   Size
                   Construction
                   Type of Core
                   Lay
                   Flexibility

The size of steel wire ropes are referred to by diameter

Construction identifies the ‘Make up’ of a rope and shows the number of strands in the wire, then the number of wires in the strand.

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 at sea basically 2 types of Core.

A. Fibre (natural or synthetic).

B. Wire Strand.

The lay of the rope refers to the way the wires in the strands, and the strands in the rope are formed into the completed rope.

2 Explain 'Langs' lay and where this type would be used.

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.

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.

3 Give 8 examples of wire rope deterioration or damage.

Fatigue

Kinking

Spiralling

Crushing

Strand Distortion

Abrasion

Corrosion

4 How are rope sizes measured?

Ropes are referred to by diameter. The correct way to measure is shown below

5 Explain the uses of the following:-

a) Figure of eight knot

Used as a stopper to prevent the line from running through a block. Does not jam so readily as an overhand knot. Can also be used to keep an unwhipped line from unlaying.

b) Bowline

May be used to put a temporary eye in a rope, secure a safety line, join two hawsers.

c) Sheepshank

Used for shortening a rope.

6 What is the S.W.L. of -

a) 20 mm Manila

Manila formula = D²

= 20²

= 20x20 = 400 Kg

b) 15 mm Polypropylene

polypropylene formula = 1.8 D²

= 1.8 x 15²

= 1.8 x 15 x 15 = 405 Kg

c) 12 mm 6/24 wire

Wire formula = 8D²

= 8 x 12²

= 8 x 12 x 12 = 1152 Kg

7 What factors affect wire rope life?

The basic factors affecting rope life are:-

1. Basic equipment design and installation ie., sheave size and 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

5. Kinking

6. Spiralling

7. Crushing

8 What should you look for when carrying out an inspection of wire rope?

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.

Externally

1. Inspect termination of rope at the drum and other points.

2. Inspect for broken wires.

3. Inspect for corrosion.

4. Inspect for deformation.

5. Inspect for surface wear.

6. Inspect for defective coiling.

7. Inspect for deterioration due to snatch loading.

8. Inspect lengths that run through blocks, particularly those which lie on the sheaves when the appliance is in the loaded condition.

Internally

Open the lay.

1. Check internal lubrication.

2. Degree of corrosion.

3. Indentation caused by pressure of wear.

4. Presence of broken wires.

9 What is S.W.L. and B.S.?

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 or Strain), 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.

The Safe Working Load is the maximum load that the rope should be used to lift, taking into account a safety factor of 6.