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Key Features and Benefits of Rigid Life Raft

• The surface of the rigid liferaft is painted in an eye-catching color, usually orange. The rigid life raft is generally thrown into the water from the storage place, or when the ship sinks or floats, any side ofthe rigid life raft can be used after entering the water and has a certain stability.

  
  

• There are rope nets or wooden grids in the floating ring for the victims to stand or sit down, and there are hanging ring lifelines on the periphery for grasping. The number of hanging rings is the rated capacity of passengers of the rigid type life raft. lts storage should be convenient for throwing, and when stacked,  it should not exceed one layer.

  
  

• The occupant quota of the rigid liferaft takes the integer value of the smaller of the following two calculation results: the weight of the iron block that the life float can support in freshwater(kg) divided by 14.5, or the circumference of the life float's outer edge(mm) divided by 305, but not less than 6 and not more than 20 persons. The weight of the rigid liferaft should not exceed 180kg. The rigid liferaft is effective and stable when floating upwards on either side. Its stability should be such that a 7kg weight is hung every 300mm on one edge of the buoyancy device, and the upper edge of the side where the weight is hung should not be submerged in the water.

  
  

• There are also simple accessories such as buoyant ropes and hand paddles in the rigid life raft, but the life float does not store food, fresh water, or seats. People in distress can only stand in it or soak in the water and hold the lifeline tightly, waiting for rescue. So it is only allowed to be used on inland river or coastal short voyage ships.

Specification of Rigid Life Raft

What is the difference between rigid and inflatable life rafts?

Rigid Liferaft (Rescue Float)

A rigid life raft, also known as a life float, is typically made of foam (polyurethane) plastic. It can maintain buoyancy and durability despite changes in sea temperature or climate.

Definition:

A type of lifesaving equipment that can support the rated number of people floating in the water and maintain its shape and function.

Lifesaving equipment is designed to support multiple people floating in the water while maintaining its structural integrity and performance. Generally, it refers to rescue floats and benches.

Description:

A rescue device that supports survivors floating in the water while maintaining a certain shape and performance. The float is typically oval or cone-shaped with easy-to-grip features and is designed to support up to 30 people. It should not exceed the specified weight and is commonly used on larger vessels, automatically floating free in case of sinking. The 1983 amendment of the "Convention" canceled the use of rescue floats due to the lower body of the user being submerged in water. However, China’s 1983 "Regulations" still allow their use on certain ships.

Basic Requirements:

• Generally made of foam plastic, maintaining buoyancy and durability in varying sea temperatures or climates.

• Must have a synthetic fiber life rope encircling the entire float, with enough handles for the rated number of occupants.

• Must withstand the total weight in freshwater (calculated at 14.5 kg per person) for at least 24 hours.

• The rated capacity must not be less than 6 people and not more than 20 people, with a total weight not exceeding 180 kg.

• The float must not be damaged or permanently deformed when launched from its storage place or from a height of 10 meters into the water.

Inflatable Liferaft

Inflatable liferafts are made of rubber-coated nylon fabric.

Definition:

A raft is set on board for lifesaving when the ship encounters distress.

Description:

An inflatable liferaft is stored uninflated in a fiberglass container on a cradle. When needed, pulling the activation cord opens the CO2 cylinder, inflating the raft in about 60 seconds. The inflated raft forms an oval shape with a canopy, providing buoyancy through two independent air chambers.

Inflatable liferafts are effective survival equipment, second only to motorized lifeboats, and often superior in certain situations, such as severe longitudinal and transverse tilts where lifeboats cannot be launched. Therefore, liferafts hold the same importance as lifeboats on ships.

Advantages and Types:

Inflatable liferafts take up less storage space, are less prone to damage, provide better protection for occupants, can be thrown overboard, and are compatible with automatic release mechanisms. They are widely adopted, replacing traditional rigid liferafts. Inflatable liferafts are classified into davit-launched and throw-over types. For the throw-over type, the fiberglass container is thrown into the water, and the raft inflates automatically. Davit-launched rafts inflate on the deck, and occupants board before the raft is lowered into the water. These are extensively used on passenger ships. The 1983 amendment to the "Convention" requires passenger ships to have davit-launched liferafts. Inflatable liferafts now feature automatic inflation, automatic release, and automatic floating mechanisms.

General Requirements for Liferafts:

• The liferaft structure must withstand exposure and float in all sea conditions for 30 days.

• The liferaft must function satisfactorily when dropped from a height of 18 meters.

• The floating liferaft must withstand repeated jumps from at least 4.5 meters above the raft bottom, with and without the canopy deployed.

• When fully loaded with occupants and equipment and with a sea anchor deployed, the liferaft must be able to be towed in calm water at a speed of 3 knots.

• The liferaft must have a canopy that automatically deploys upon launching and reaching the water, providing protection from the elements and rainwater collection.

• The liferaft must have an effective painter line at least twice the distance from the storage location to the light load waterline or 15 meters, whichever is greater.

• Each liferaft must be equipped with the required accessories.

• Liferafts must be equipped with a float-free device.

Common Deficiencies in Liferaft Inspections:

• Certification issues.

• Failure to undergo periodic inspections.

• Illegible markings (ship name, port of registry, inspection tags, etc.).

• Expired hydrostatic release units.

• Poorly visible or incorrectly placed embarkation instructions.

• Damaged or moldy embarkation ladders.

• Severely corroded storage cradles.

• Damaged outer packaging of life rafts.

• Life rafts are secured with additional ropes.

• Incorrect connections of hydrostatic release units, painter lines, and weak links.