Ropes and hawsers for general cargo ships

Ropes and hawsers used on board a general cargo vessel

Ropes on board : Ropes are made of short fibres that are spun into yarns, which are then made into flat or twisted strands. And the strands are spun or braided to make the finished rope . The two main types of rope are:

i) Laid rope: three-strand rope (two- and four-strand ropes also exist) is made of strands twisted together in the opposite direction to that of the yarns, normally to the right (Z-laid), but sometimes to the left (S-laid).

ii) Braided rope is made in different ways. The yarns are normally braided to form a sheath covering an inner core of yarns, which may again be braided or lightly twisted together.

Z laid and S laid or braided ropes

Ropes of many different types and sizes have continued to play a major role in the working of ships throughout history. Clearly, the era of the sailing ships, where cordage, in virtually every form, could be found from anchor warps to ratlines, was a dominant period in history for rope manufacturers.

Times have marched on, with the container ship, the tanker, the Ro-Ro vessels, where a limited amount of cordage is found on board. Of course, the standard ropes remain, namely, the mooring ropes which virtually all ships still retain. However, even these have suffered from the development in wire ropes, tension winches and fixed mooring positioning methods. This is not to say that ropes have disappeared, far from it, but the need for ropes has diminished.This need has been met with improved synthetic ropes, while the natural ropes are difficult to obtain and in some cases not as strong as the manmade products. No wonder that change has occurred. From the seafarers point of view, the rigging of stages and boatswains chairs will still arise and the mariner will still need to throw a bowline into an end, though possibly not as often as his historical counterpart.

Ropes may be of a right-hand lay or left-hand lay, but the most common is right-handed. It is essential to realise that each of the components is turned (twisted) up in an opposite direction to that of its predecessor, e.g. in right-hand lay, strands are laid up right-handed (clockwise), yarns laid up left-handed, and fibres laid up right-handed.

When using steel wire ropes it is important that they are properly installed, maintained and lubricated as appropriate to their use. Manufacturer's guidelines and recommendations for use should be followed. Where eyes are formed they should be made by eye splicing or using appropriate compression fittings (using swages or ferrules). The use of Bulldog grips is discouraged, and they must not be used on lifting wires and mooring wires.

Care of Ropes and wires

Mooring ropes, wires and stoppers that are to be used in the operation should be in good condition, Ropes should be frequently inspected for both external wear and wear between strands. Wires should be regularly treated with suitable lubricants and inspected for deterioration internally and broken strands externally. Splices in both ropes and wires should be inspected regularly to check they are intact. Where wire rope is joined to fibre rope, a thimble or other device should be inserted in the eye of the fibre rope. Both wire and fibre rope should have the same direction of lay.

Mooring ropes

Ropes and wires which are stowed on reels should not be used directly from stowage, but should be run off and flaked out on deck in a clear and safe manner, ensuring sufficient slack to cover all contingencies. If there is doubt of the amount required, then the complete reel should be run off.

Personnel should not in any circumstances stand in a bight of rope or wire. Operation of winches should preferably be undertaken by competent personnel to ensure that excessive loads do not arise on moorings.

When moorings are under strain all personnel in the vicinity should remain in positions of safety, i.e. avoiding all `Snap-Back' Zones. It is strongly recommended that a bird's eye view of the mooring deck arrangement is produced (an aerial view from a high point of the ship can be utilised) to more readily identify danger areas. Immediate action should be taken to reduce the load should any part of the system appear to be under excessive strain. Care is needed so that ropes or wires will not jam when they come under strain, so that if necessary they can quickly be slackened off.

Where moorings are to be heaved on a drum end, one person should be stationed at the drum end, backed up by a second person backing and coiling down the slack. In most circumstances three turns on the drum end are sufficient to undertake a successful operation. A wire on a drum end should never be used as a check wire.

A wire should never be led across a fibre rope on a bollard. Wires and ropes should be kept in separate fairleads or bollards.When using steel wire ropes it is important that they are properly installed, maintained and lubricated as appropriate to their use. Manufacturer's guidelines and recommendations for use should be followed. Where eyes are formed they should be made by eye splicing or using appropriate compression fittings (using swages or ferrules). The use of Bulldog grips is discouraged, and they must not be used on lifting wires and mooring wires.

When stoppering off moorings the following applies:-

(i) Natural fibre rope should be stoppered with natural fibre.

(ii) Man made fibre rope should be stoppered with man made fibre stopper (but not polyamide).

(iii) The `West Country' method (double and reverse stoppering) is preferable for ropes.

(iv) Wire moorings should be stoppered with chain, using two half hitches in the form of a cow hitch, suitably spaced with the tail backed up against the lay of wire, to ensure that the chain neither jams nor opens up the lay of the wire.

Maintenance of mooring Ropes

All mooring ropes used on board cargo ships should be properly maintained in good condition for safe berthing / unberthing. Characteristic of Mooring ropes , Material and Type of Thread, Safe Working Load , Stretching ratio Anti-abrasion, Water-tightness against Sea water, etc should be monitored carefully. For all mooring ropes, record of certificates, replacement date and specific winches to which they are fitted, is to be maintained. If mooring ropes are observed major damage, should be replaced immediately.

Careful inspection of man-made fibre ropes for wear externally and internally is necessary. A high degree of powdering between strands indicates excessive wear and reduced strength. Ropes with high stretch suffer greater inter-strand wear than others. Hardness and stiffness in some ropes, polyamide (nylon) in particular, may also indicate overworking.

Unlike natural fibre ropes, man-made fibre ropes give little or no audible warning of approaching breaking point.

Rope of man-made material stretches under load to an extent which varies according to the material. Polyamide rope stretches the most. Stretch imparted to man-made fibre rope, which may be up to double that of natural fibre rope, is usually recovered almost instantaneously when tension is released. A break in the rope may therefore result in a dangerous back-lash and an item of running gear breaking loose may be projected with lethal force. Snatching of such ropes should be avoided; where it may occur inadvertently, personnel should stand well clear of the danger areas. The possibility of a mooring or towing rope parting under the load is reduced by proper care, inspection and maintenance and by its proper use in service, but it can nevertheless still happen without warning.

Man-made fibre ropes may easily be damaged by melting if frictional heat is generated during use. Too much friction on a warping drum may fuse the rope with the consequential sticking and jumping of turns, which can be dangerous. Polypropylene is more liable to soften than other material. To avoid fusing, ropes should not be surged unnecessarily on winch barrels. For this reason, a minimum of turns should be used on the winch barrel; three turns are usually enough but on whelped drums one or two extra turns may be needed to ensure a good grip; these should be removed as soon as practicable.

Rope splice guideline

The method of making eye splices in ropes of man-made fibres should be chosen according to the material of the rope.

(i) Polyamide (nylon) and polyester fibre ropes need four full tucks in the splice each with the completed strands of the rope followed by two tapered tucks for which the strands are halved and quartered for one tuck each respectively. The length of the splicing tail from the finished splice should be equal to at least three rope diameters. The portions of the splice containing the tucks with the reduced number of filaments should be securely wrapped with adhesive tape or other suitable material.

(ii) Polypropylene ropes should have at least three but not more than four full tucks in the splice. The protruding spliced tails should be equal to three rope diameters at least.

(iii) Polythene ropes should have four full tucks in the splice with protruding tails of three rope diameters at least.

Mechanical fastenings should not be used in lieu of splices on man- made fibre ropes because strands may be damaged during application of the mechanical fastening and the grip of the fastenings may be much affected by slight unavoidable fluctuations in the diameter of the strands.

Man-made fibre stoppers of like material (but not polyamide) should be used on man-made fibre mooring lines, preferably using the `West Country' method (double and reverse stoppering).

All Ropes should be inspected internally and externally before use for signs of deterioration, undue wear or damage.

More on general cargo ship :

Rope handling safe procedure

Ropes and hawsers used on board a general cargo vessel

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