Relevant important classification rules on Windlass

-

1. General

1.     Windlass of sufficient power and suitable for the size of chain cable is to be fitted. Where wire ropes are proposed and approved in lieu of chain cables, suitable winches capable of controlling wire rope at all times are to be fitted.
2.     Windlass is to have one cable lifter for each anchor required to be kept ready for use. The cable lifter is normally to be connected to the driving shaft by release coupling and provided with brake.
3.      For each chain cable, a chain stopper is normally to be arranged between the windlass and hawse pipe. The chain cables are to reach the hawse pipe through the cable lifter only.
4.      Electrically driven windlasses are to have a torque limiting device(slip clutch). Electric motors are to comply with the requirements.
5.      The windlass is to be capable of exerting, for a period of 30 minutes, a continuous duty pull corresponding to the grade of chain cable, as follows :-

                             36.8 dc                  for grade CC1
                             41.7 dc                  for grade CC2
                             46.6 dc                  for grade CC3

          Where dc is the chain diameter [mm]. The mean hoisting speed is not to be less than 9 [m]/min.
           The windlass is to be also capable of exerting, for a period of not less than 2 minutes, a pull of not less than 1.5 times the continuous duty pull. The speed in this period can be lower. The above criteria do not require both anchors to be raised or lowered simultaneously on windlass fitted with two cable lifters.

6.   The capacity of the windlass brake is to be sufficient for safe stopping of anchor and chain cable when paying out.The windlass with brakes engaged and release coupling  isengaged is to be able to withstand static pull of 45 per cent of the tabular breaking strength of the chain without any permanent deformation of the stressed parts and without brake slip. If a chain stopper is not fitted, the windlass is to be able to withstand a static pull of 80 per cent of the tabular breaking strength of the chain without any permanent deformation of the stressed parts and without brake slip.
The chain stoppers and their attachments are to withstand a pull of 80 per cent of the tabular breaking strength of the chain without any permanent deformation of the stressed parts. The chain stoppers are to be so designed that additional bending of the individual link does not occur and the links are evenly supported.
7.    Attention is to be paid to stress concentrations in keyways and other stress raisers and also to dynamic effects due to sudden starting or stopping of the prime mover or anchor chain.

Comments

Post a Comment

Popular posts from this blog

Introduction to Mooring Line

-
Image
The mooring refers to any permanent structure to which a vessel/ship may be secured. Examples include quays, wharfs, jetties, piers, anchor buoys, and mooring buoys. A ship is secured to a mooring to forestall free movement of the ship on the water. An anchor mooring fixes a vessel's position relative to a point on the bottom of a waterway without connecting the vessel to shore. As a verb, mooring refers to the act of attaching a vessel to a mooring. Mooring is often accomplished using thick ropes called mooring lines or hawsers. The lines are fixed to deck fittings on the vessel at one end and to fittings such as bollards, rings, and cleats on the other end. Mooring requires cooperation between people on a pier and on a vessel. Heavy mooring lines are often passed from larger vessels to people on a mooring by smaller, weighted heaving lines. Once a mooring line is attached to a bollard, it is pulled tight. Large ships generally tighten their mooring lines using heavy machin
Read more

Anchor Size- rigging table

-
Image
After having found the equipment numeral from previous blog , the details regarding sizes and quality  may be obtained from the rigging tables provided in these regulations. From these table , we can find the following information The Equipment Letter Stockless bower anchors number of anchor Mass per anchor (kg) Stud-link chain cables for bower anchors Total length (m) Grade and Diameter (mm) of chain CC1———— low  strength. CC2———–medium strength. CC3———–high strength Towline Minimum length (m) Minimum breaking strength (KN) Mooring Lines Number Length of each mooring ropes (m) Minimum breaking strength (KN)
Read more

Introduction to Towline

-
Image
A tow line is used with a tug (tugboat or towboat) which is a type of vessel that maneuvers other vessels by pushing or pulling them either by direct contact or by means of a tow line. Tugs typically move vessels that either are restricted in their ability to maneuver on their own, such as ships in a crowded harbor or a narrow canal, or those that cannot move by themselves, such as barges, disabled ships, log rafts, or oil platforms. A tow line is the essential link between tug and ship. This applies to tugs operating alongside a vessel in the push-pull mode as well as to towing tugs fastened with a tow line to the bow or stern of a ship, also called `tugs towing on a line‟. Basic towline requirements A towline must fulfil two basic functions, firstly to function as the load-carrying link between tug and ship and secondly to cope with the dynamic loads resulting from the relative motion between tug and ship. This leads to the following basic requirements for towlines for harbo
Read more