Marine Davit System
Ships carry Marine A-Frame Davits for raising small boats. As far as retracting and launching a boat is concerned, there are three types of retracting and launching: gravity, swing-out, and roll-out.
Specifically, the specification requires that the davit be able to quickly put the small boat on the water and retract it inboard, as well as be strong when tilted 15 degrees to any side and longitudinally. When the speed is 5 knots and the inclination is 5 degrees, the small boat can be turned outboard while carrying all equipment and two crew members. Set at least two safety lines to ensure that all crew members safely land on the cross-tension cable of the surface davit. Marine davits equipped with safety devices, such as limit switches, are designed so that when the davit reaches its peck position, the power is automatically cut off.
It is possible to divide type A-frame davit cranes into electric and hydraulic types. For recovering rescue boats (or fast rescue boats) in rough seas, the hydraulic type has a wave compensation system (tension system).
Classification and Function of Marine Davit Cranes
On seagoing vessels, davits are divided into gravity type and inverted pole type (rotating type no longer used). There are two types of gravity davits: slide rails and tipping davits. Because of their different positions, the two types can be divided into a variety of structural shapes. Inverted rod davits come in two types: straight rod type and sickle type. The two types can also be divided into a variety of structural shapes based on their layouts and needs.
Gravity davits, which are typically used on seagoing vessels, launch boats quickly and are safe and reliable. The davit releases the boat under gravity when the brake device is opened. A disadvantage of this system is that lifeboats are usually hoisted on the davit, which raises the ship’s center of gravity.
Inverted-pole davits or swivel davits are usually lifted to a certain height when launching a boat. Due to this, the boat launches slower and occupies a larger deck space. Since the davit is placed directly on the deck, the ship’s center of gravity can be lowered. Davits with inverted poles are typically used on inland river boats.
How to choose a marine davit crane?
In addition to considering the layout and operation of the davits, the selection of life-saving equipment for marine vessels is also based on the following criteria: passenger ships, aquatic processing vessels, scientific survey ships and oil tankers with a gross tonnage of 1600 tons and above. Gravity-type davits are required.
Other ships’ davits: when the lifeboat weighs more than 2.3 tons in the operating state, the gravity type should be adopted; when the weight does not exceed 2.3 tons, either the inverted pole type or gravity type can be used; if the weight does not exceed 1.4 tons, spiral can be used.
Marine A-Frame Davit Standard
- The A-frame davits are designed and manufactured according to the requirements of SOLAS currently being implemented.
- It complies with the requirements of resolution MSC.47 (66) (the amendment to the International Convention for the Safety of Life at Sea in 1974) and resolution MSC.48 (66) (the International Life-saving Equipment Regulations).
- According to the requirements of MSC81 (70)-life-saving equipment testing, all equipment has passed the test and accepted.
Marine A-Frame Davit Types
- Hydraulic type: NM30 (with manual constant tension and anti-sway system).
- Electrical type: NMAR30, NMAR30-1, NMAR60.
Marine A-Frame Davit Feature
- Gosea Marine A-frame davits can provide a series of options according to operational requirements.
- The equipment adopts a rigid A-frame structure, which is stable and safe in operation, and takes into account later maintenance and maintenance.
- The davit winch and derrick movement are operated by a nearby console or remote control.
- Start/stop and emergency stop are also located on the console or remote control.
- Whether a ship is involved in rescue operations, stand-by operations, or other related activities, the davits can be equipped to perform the task.
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