Skip to main content

Ship Anchor

An anchor is used by a ship to make itself fast to the sea-bed so that it will stay in one place and will not drift due to wind and current. A shop normally carries three anchors, two working anchors, one on each bow, attached to cables and stowed up the hawse pipes. These are called Bower Anchors. One Spare Bower anchor lashed and well secured in the vicinity of the forecastle deck. If one of the working bower anchors is lost, this spare anchor is shackled on to the anchor cable and used.
A fourth anchor may also be carried on small vessels known as Stream anchor, lashed and secured at or near the stern of the vessel. It is meant to be used in narrow channels for preventing the stern of the vessel from swinging. But these days it is hardly ever used for this purpose.

Earlier all anchors had a stock, which was just before anchoring, fixed in position at right angles to the arms. The stock helped the anchors to turn itself so that the arms became vertical and one of the flukes dug itself into the seabed. But this type of anchor was difficult to stow, as it could not heave up the hawse pipe, unlike the stockless anchors.

Nowadays a stock anchor is used on ships only for a stream anchor. Small boat anchors are also stock anchors. Both the Bower and the Spare Bower are stockless anchors. A stock anchor holds better but a stockless anchor is easier to stow as it can be hove up the hawse pipe.

Anchor Parts:


Ring (Shackle): The device used to shackle the anchor chain to the shank of the anchor. The ring is secured to the top of the shank with a riveted pin.

Shank: The long center part of the anchor running between the ring and the crown.

Crown: The rounded lower section of the anchor to which the shank is secured. The shank is fitted to the crown with a pivot or ball-and-socket joint that allows a movement from 30 to 45 degrees either way.

Arms: The parts that extend from each side of the crown.

Throat: The inner curved part of an arm where it joins the shank.

Fluke or palm: The broad shield part of the anchor that extends upward from the arms.

Blade: That part of the arm extending outward below the fluke.

Bill or pea: Tip of the palm or fluke.


Comments

Popular posts from this blog

Load Line & Why it is Important

Merchant ships have a marking on their hull know as the Plimsoll line or the Plimsoll mark, which indicates the limit until which ships can be loaded with enough cargo, internationally, the Plimsoll line on a ship is officially referred to as the international load line. Every type of ship has a different level of floating and the Plimsoll line on a ship generally varies from one vessel to another.  All vessels of 24 meters and more are required to have this Load line marking at the centre position of the length of summer load water line. There are two types of Load line markings:- Standard Load Line marking – This is applicable to all types of vessels. Timber Load Line Markings – This is applicable to vessels carrying timber cargo. These marks shall be punched on the surface of the hull making it visible even if the ship side paint fades out. The marks shall again be painted with white or yellow colour on a dark background/black on a light background.  The comp

Difference Between A, B & C-Class Divisions?

IMO Symbol A Class Division  IMO Symbol B Class Division  SOLAS has tables for structural fire protection requirement of bulkheads and decks. The requirements depend on the spaces in question and are different for passenger ships and cargo ships. The Administration has required a test of a prototype bulkhead or deck in accordance with the Fire Test Procedures Code to ensure that it meets the above requirements for integrity and temperature rise. Types of Divisions: "A" Class "B" Class "C" Class "A" Class: "A" class divisions are those divisions formed by bulkheads and decks which comply with the following criteria: They are constructed of steel or equivalent material They are suitably stiffened They are constructed as to be capable of preventing the passage of smoke and flame to the end of the one-hour standard fire test. they are insulated with approved non-combustible materials such that the average tempera

Gravity Disc

Oils containing water can only be de-watered in a perfect manner if the bowl is accurately adjusted to the difference in densities of oil and water. The gravity disc with proper inner diameter i.e. with the diameter that corresponds to the difference in densities of the oil-water mixture to be treated should, therefore, be inserted in the bowl, This disc can be chosen from the set of disc provided with the separator. The inner diameter of the disc to be chosen can be determined by:  Calculation   Experiment The general rule is : Small diameter gravity disc when treating heavy oil Large diameter regulating ring when treating light oil Determining the size of gravity disc by calculation: For a given separating temperature, the inner diameter of the gravity disc and if the desired density of the oil can be determined from the diagram, provided that the density of the oil at a temperature ranging 15℃ and 90℃ is known. For example; Given: Density of oil at 20℃            ρ oil