In the name of ALLAH who is the most beneficient and merciful.
Life Savings Appliances
The life savings equipment carried on board a ship depends upon the number of persons carried and the normal service of the ship. A transatlantic passenger liner would carry considerably more equipment than a coastal cargo vessel.
There must be sufficient life boat accommodation on each side of the ship for the whole of the ship’s complement(number/quantity that make something complete). The lifeboats must be at least 7.3 long and may be constructed of wood, steel, aluminium or fiberglass. They carry rations for several days, together with survival and signaling equipment such as fishing lines, first aid equipment, compass, lights, distress rockets and smoke flares. One life boats on each side must be motor driven.
The lifeboats are suspended from davits which allow the boats to be lowered to the water when the ship is heeled to 15 degrees. Most modern ships is heeled to 15 degrees. Most modern ships are fitted with gravity davits, which when released allow the cradle carrying the boats to run out board until the boat is hanging clear of the ship’s side.(fig.1)
The boat is raised and lowered by mean of an electrically driven winch. The winch is manually controlled by a weighted lever(fig.2) know as dead man handle which releases the main brake. Should the operator lose control of the brake the lever causes the winch to stop. The speed of descent is also controlled by a centrifugal brake which limits the speed to a 36 m/min. Both the centrifugal brake and the main brake drum remain stationary during the hoisting operation. If the main power fails while raising the boats, the main brake will hold the boat.
Each member of the crew is supplied with a lifejacket which is capable of supporting an unconscious person safely.
Lifebuoys are provided in case a man falls overboard. Some are fitted with self igniting lights for use at night and others fitted with smoke signals for pin-pointing positin during the day
Next topic
Conditions of assignment
The load line rules are based on the very reasonable assumption that the ship is built to and maintained at a high level of structural strength and will sail in a safe and seaworthy condition.
Until recently the rules laid down the standard of longitudinal and transverse strength. The classification societies usually found it necessary to increase these standards although in some design considered the rules excessive. It is now felt that the structural strength of the ship is more properly the function of the classification societies who may well be the assigning authority.
Standards of stability are given in the rules for both small and large angles of heel. Details of the information required to be carried on a ship are stated, together with typical calculations, all the information is based on an inclining experiment carried out on the completed ship in the presence of a DTp surveyor.
It is essential that all openings in the weather deck are water tight. Hatch coamings, hatch covers, ventilator coamings, air pipes and doors must be strong enough to resist the pounding from the sea and standards of strength are laid down. The rules also specify the height of coamings, air pipes and door sills above the weather deck, those at the force end being higher than the remainder.
It is important to remove the water from the deck quickly when a heavy sea is shipped. With completely open decks, the reserve buoyancy is sufficient to lift the ship and remove the water easily. When the bulwarks are fitted, however, they tend to hold back the water and this may prove dangerous. For this reason openings knows as freeing ports are cut in the bulwarks, the area of the freeing ports depend upon the length of the bulwark. If the freeing ports are wide, grids must be fitted to prevent crew being washed overboard. In addition, scuppers fitted to remove the surplus water from the deck. The scuppers on the weather deck are led overboard whilst those on intermediate decks are may led to bilges or, if automatic nonreturn valves are fitted, may be led overboard.
Type A ships, with their smaller freeboard are more likely to have water on the decks and it is a condition of assignment that open rails be fitted instead of bulwarks. If the vessel has midship accommodation, a longitudinal gangeway must be fitted to allow passage between the after end and midships with out setting foot on whether deck. In larger ships it is necessary to fit shelters along the gangway. Alternatively access may be provided by an underdeck passage, but while convenient for bulk carriers could prove dangerous in oil tankers.
WRITTEN BY S/C ZEESHAN AHMED (A/C 2988)
INSTRUCTOR: CHIEF ENGINEER YASEEN SAHAB
DATE: 25/10/2009
TIME: 10:05:00 AM
No comments:
Post a Comment