Views: 21 Author: admin Publish Time: 2018-11-20 Origin: Site
LIFE RAFT is a boat that has no self-propelled capacity for lifesaving on board. The life raft is stocked with a certain amount of food and fresh water rations for occupants to use for rafting at sea.
Life rafts can be divided into rigid life rafts and inflatable life rafts according to their structure.
Life rafts can be divided into rigid life rafts and inflatable life rafts according to their structure. The main structure of the former is made of a rigid material; The latter is made of rubber and nylon cloth as the main material.
I. Rigid life raft
The rigid life raft, also known as the traditional life raft, is constructed by using a galvanized iron sheet, an aluminum alloy sheet, a stainless steel sheet or a hard plastic material around the life raft to form a plurality of joint air boxes as the main buoyancy part of the life raft. The outer layer is then covered or not covered with flame retardant material; the top of the crucible is provided with a fixed rigid canopy and an entrance and exit, and the bottom of the crucible is a wooden grate plate. It is usually stored on the ship's side sloping ramp or on the deck of the bridge. When it is applied, the carriage fixing hook is opened, and the carriage is slid down by the carriage or the sling is used to release the water.
The biggest feature of this kind of life raft is its simple structure and low cost; But it is bulky, heavy and has few staff members.
II. Inflatable life raft
Inflatable life rafts are further divided into inflatable life rafts, inflatable lifesaving floats, and inflatable self-righting life rafts.
1. inflatable life raft
These life rafts provide buoyancy from upper and lower floating tires made of rubber material, made of double-layer waterproof nylon cloth, and inflated with gas into circular, oval or polygonal tents with awnings. After the liferaft body is folded up, it is stored in the GRP storage container together with the spare parts. The inflatable life raft is widely used in various civil and military vessels at sea because of its advanced design, compact structure, good safety, convenient movement, simple operation and rapid forming.
There are two types of inflatable liferafts, davit launched and throw overboard. The davit launched type raft has been inflated before entering the water; The throwing overboard life raft is inflated on the sea surface, and the life raft may be overturned during the inflation forming process, so it is necessary to manually turn the life raft to its right position on the water to support the personnel for boarding and use.
2. Inflatable lifesaving float
In addition to the awning, the inflatable lifesaving floats have the same manufacturing materials, main structure, performance requirements, forming process, storage requirements, and attachments, all of which are the same as the inflatable life rafts, but the casting method is only throwing type. Its characteristics are:
(1) There is no canopy. After the life raft is inflated on the water surface, the water persons can take the two boarding platforms symmetrically set on both sides of the floating device or any one side to board the floating device, which is convenient and fast;
(2) The max. capacity is more than inflatable life rafts with tent, and can carry up to 50 people;
(3) The double bottom of the rescue buoy is placed between the upper and lower floating tires. Therefore, no matter what sea conditions are applied, the floating device is in a positive floating state after being inflated and formed on the sea surface (both sides are available), and no artificial righting is required;
(4) Because there is no canopy for such lifesaving floats, the persons are greatly affected by sea conditions and climate, and are mainly equipped on passenger ships.
3. Inflatable self-righting life raft
In order to overcome the overturning situation that the inflatable life raft can form during the sea surface forming process, to avoid the difficulty of people getting in and out of the water, to meet the needs of the sea-based survival persons for safety and rapid response, some manufacturers have developed inflatable self-righting life rafts. Such a life raft is once overturned on the sea surface during the application process. Since the top of the raft is rounded, the contact surface with the water can be reduced. The weight of the raft body and the spare parts is at the center of gravity at the bottom of the life raft. After inflation molding,it can be self-righting.
The main requirements of the LSA Rules for life rafts are:
(1) The liferaft shall be constructed to withstand exposure to all sea conditions for 30 days;
(2) The life raft and its attachments can be used safely and normally after being put into the water from a height of 18 m;
(3) The liferaft body floats on the water and can withstand repeated pedaling from the bottom of the rafter at least 4.5 m without damage, and does not affect normal use;
(4) The life raft carries all the occupants and attachments and releases a sea anchor, which can be towed at a speed of 3 kn in still water without damage;
(5) The life raft shall be provided with a canopy that can be automatically propped up when landing on the surface to protect the occupants from exposure;
(6) The life raft shall have a fixed occupant of not less than 6 persons;
(7) The total mass of lifesaving carcasses, belongings and containers shall not exceed 185 kg. In addition, specific requirements are placed for the installation of the liferaft, the liferaft's deflating facility, the strength of the suspended liferaft, the boarding, the container for the container, and the free floating and lowering.
(1) Life rafts and its storage container shall not affect the use of lifesaving equipment stored in any other location;
(2) As close to the surface as possible, as far as practicable. Life rafts other than life rafts that need to be thrown out of the way should be in such a position that the life raft at the embarkation position, when the full load is at an unfavorable trim of 10° and traverses to any side up to 20 ° or when crossing the angle of the edge of the ship's weather deck into the water (whichever is greater), should be no less than 2 m from the waterline;
(3) When the hoistable life raft is in the ready-to-use state, the two crew members should be able to complete the boarding and landing preparation work within 5 minutes;
(4) Store in a safe and sheltered place and protect it from fire and explosion. Especially the survival craft on the tanker. Should not be stored above cargo tanks, slop tanks or other cargo compartments containing explosive or dangerous cargo.
INSPECTION & MATENCE
(1) Visually inspect the life raft and its storage and discharge equipment weekly to ensure that it is immediately available and to be recorded;
(2) Every month, the quick decoupling, fixing rigging, first cable, rope plug, connecting shackle, seal on the liferaft container on the liferaft storage rack shall be inspected once and found to be damaged or not ready for use. It should be repaired immediately, in a good state of technology, and to be well documented;
(3) The time interval for maintenance of liferafts shall not exceed 12 months and may be extended to 17 months with the consent of the competent authority;
(4) The life raft must be inspected at the inspection station approved by the competent authority, or the certified personnel recognized by the competent authority shall inspect the life raft system on board as required. The main items of maintenance include: inspection of the surface quality of the carcass (sticky, damaged, etc.), inspection of the container of the carcass, inspection of the armor of the carcass, inspection of the life preserver, inspection of the product, and inspection of the inflatable cylinder Check, start the striker, start the drawstring check, perform the inflation test and check. In short, these inspections should not neglect any small parts, any one part, any one of the armor, or any one of them. All bad conditions such as shortage, damage, mildew, etc., must be added, repaired or replaced to keep them in good technical condition;
(5) Under normal storage and use, the life span of the liferaft is 10-15 years, which must be replaced after the service life;
(6) If the hydrostatic release unit can be exchanged on board, the ship must have qualified spare parts. After the use expires, it should be replaced in time;
(7) Hydrostatic release unit(except for self-replacement), the inspection interval is 12 months; with the approval of the competent authority, it can be extended to 17 months;
(8) The surface of the container of the life raft should never be painted. The signs and technical data marked on the container must be clear and obvious. It is not possible to add a cover on the container. It is not possible to add a fixed rigging.