Hydraulic Pivoting Davit: PRH 55 AP (Hydraulic Pivoting)
The NED-DECK MARINE hydraulic pivoting davits have been designed for long time operation under adverse and extreme conditions in a highly corrosive marine environment.
The hydraulic pivoting davits of the PRH series are so-called “plug-in and play units” all guaranteeing easy installation on board.
The PRH davit is a freestanding deck mounted davit consisting of a base frame, davit arm, cylinders, winch and hydraulic power pack unit.
The system has been designed to meet the latest IMO requirements and is suitable for safe and efficient launching and recovery of a fully manned fast rescue boat even under severe and adverse weather conditions (wind force 6 on the Beaufort-scale, in association with a significant wave height of at least 3 m).
The PRH series are all provided with a constant wire tensioning system and hydro-pneumatic shock absorber.
The launching procedure can be controlled in two (2) ways, i.e.:
From control stand (normal procedure for rescue operations);
From inside the rescue boat (emergency operations).
During normal operations, all system functions are hydraulically controlled and actuated from the davit’s operating console which is placed on deck near the railing.
In case of an emergency, pivoting out the rescue boat from its stowed into launch position is realised by means of so-called “stored-power” obtained from an accumulator.
Lowering is realised by means of gravity. Both motions, pivoting and lowering, are controlled from within the rescue boat by means of remote control pull wires.
Recovery of the rescue boat is realised by means of the hydraulic driven winch.
In case of a power failure or malfunctioning of the electric system, hoisting can also be done manually by using the ratchet handle of the winch.
Since the safe working load and outreach of the davit are normally determined by the size of the rescue boat, NED-DECK MARINE have chosen for a limited range of standard designs which can be adapted to some extent in order to meet individual and specific needs.
The PRH series meets the latest IMO/SOLAS requirements and recommendations on Ro-Ro Passenger ships, LSA Code and the European Council Directive 96/98 EC on Marine Equipment (M.E.D.).
Demo Movie: http://neddeckmarine.com/08_specialproducts/prhap/movie.php
The PRH AP series of hydraulic pivoting Fast Rescue Boat davits is designed for long time reliable operation in a tough and corrosive marine environment.
The davits are standard delivered with an hydraulic power unit and an hydraulic operated winch, optionally an hydraulic painter line boom is available.
The davit is delivered as a complete unit, fully tested, adjusted and ready for installation onboard. The davit system PRH AP is available in two (2) versions;
1) Work Boat Davit System
2) (Fast) Rescue Boat Davit System; this version of the PRH AP is manufactured in accordance with the latest IMO/SOLAS requirements, LSA Code and European Council Directive 96/98 EC on Marine Equipment (MED)
The davit is equipped with its own hydraulic power pack which is placed in the engine room. The davit will be supplied as a complete, independent unit. It only requires to be connected to the power pack and the electric power source in order to become operational. Only the highest quality equipment has been chosen and installed to ensure the lowest possible emission, sound and maintenance, as well as good and safe access for service.
The davit is equipped with a well dimensioned “shock absorber” system to avoid overload of the davit system in rough operation conditions. The winch is also equipped with a full hydraulic constant tension system.
The launching procedure can be controlled in two (2) ways, i.e.:
1. From control stand (normal procedure for rescue operations/deployment);
2. From inside the rescue boat (emergency operations – under Solas regulations).
Davit steel structure:
The davit structure is built as a totally enclosed hollow box structure with a bearing support in lower end. The lower end is prepared for connection to the king pivot point bracket by means of two self aligning steel bearings. The outer end is equipped with a wire sheave bracket. The winch is located on top of the intermediate beam structure. The electric motor and the hydraulic pump assembly is installed on the hydraulic oil reservoir.
Davit swing out cylinder:
The davit is equipped with high quality hydraulic cylinder, built especially for use in the marine environment. A double load holding valve is mounted to the cylinder to maintain a constant luffing speed independent of hook load and to block the jib in case of a hose/pipe failure.
The winch consists of a steel drum with a flanged on planetary gearbox driven by a fixed displacement hydraulic motor. The gear box is fitted with a fail-safe multi disc brake . The brakes are dimensioned to take the full load plus any additional dynamic forces acting on the winch. In the case of a hose or pipe failure, the brakes block the load immediately.
A counter balance valve is mounted in the winch loop ensuring smooth and accurate winch
The winch drum is of the grooved type while a pushing roller is applied for smooth coiling.
The winch is equipped with a constant tensioning system
The tension system is activated by the operator at the control station. The winch will automatically hoist or lower the MOB with tension speed and follows the MOB
movements in the sea. If the self tension is actuated before the MOB reaches sea level the
tension system will be overridden. The system is based on a fully hydraulic operated system
without use of any sensors which gives the system an unique and reliable operation.
An easy to install control panel is included in the scope of supply. The panel is fully assembled and contains the main control valve and operation instruction signs.
Cable work between control panel and davit is not included in scope of supply.
The winch is equipped with a galvanised, non-rotating wire rope and a high quality wedge
socket with buffer pipe in the outer end. The free end of wire is double secured by one “iron
grip” wire clamp. The inner end of the wire is secured to the winch drum by means of a
wedge wire clamp. The clamp system is easy to inspect.
Shock absorber / Anti-pendulum system:
A well dimensioned shock dampener is installed in top of the davit arm. The shock dampener is a hydro-pneumatic cylinder connected to a pre-charged accumulator. The cylinder rod is made of stainless steel with a Ceramic coating.
For proper retrieval and operation of the boat a well proven hydraulically operated anti-pendulum system will be mounted onto the davit head.
- Overload protection of all motions by pressure limiting valves
- Mechanical/hydraulic hook stop in upper hook position
- Mechanical limitation of cylinder stroke
- Double load holding valve direct in cylinder ports on main cylinders
- Fail-safe, oil submerged disc brake on winch gearbox
- Counter balance valve on winch motor
- Shock dampener (hydro-pneumatic type)
See MFR site: http://neddeckmarine.com/01_rescue_boat/index.php