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Marine hydraulic gangway, span length 15.5m with active heave compensation (Technical supply specification)


1. General Information (Operating Conditions)

  • The marine hydraulic gangway operates failure-free within an ambient temperature range of -30°C to +40°C.
  • The gangway ensures safe personnel transfer to the wellhead platform deck at heights between 13.7 m and 15.0 m, with wave heights up to 1.5 m and wind speeds up to 15 m/s, without mooring operations.
  • The system provides heave compensation for sea states with wave heights up to 1.5 m.
  • In the wellhead platform area, the mean wave height is 2.9 m, the mean period is 6.9 s, and the mean wavelength is 65.7 m. The prevailing wave direction is southeastern. Maximum wave heights occur during the autumn period.
  • The gangway features a skid-mounted design.
  • Material selection and the coating system are specified for C5-M marine environments.
  • The preservation grease withstands temperature fluctuations from -40°C to +50°C, providing a minimum preservation period of 1 year without grease replacement.
  • The packaging ensures equipment storage in open areas at ambient air temperatures from -40°C to +40°C and a relative humidity of 82%.

2. Purpose

The marine hydraulic gangway ensures safe personnel transfer from offshore supply vessels to the wellhead platform deck / unmanned offshore platforms when aerial transport is unavailable.

Marine hydraulic gangway 15.5 m length overall arrangement drawing operating position
Marine hydraulic gangway 15.5 m length overall arrangement drawing operating position

About

Marine Hydraulic Gangway for Safe Personnel Transfer

Ensuring safe personnel transfer between an offshore supply vessel and an offshore facility is a critical task in offshore infrastructure operations. When aerial transport is unavailable, this function is performed by the marine hydraulic gangway, designed for controlled personnel transfer in open sea conditions.

Operation in Heavy Sea and Wind Conditions

The marine environment is characterized by constant dynamic forces, including fluctuations in wave height, wind direction, and temperature. The marine hydraulic gangway is engineered to operate under these conditions, enabling personnel transfer without mooring operations, which is essential for servicing wellhead platforms and unmanned offshore platforms.

Motion Compensation Principle

The core feature of the hydraulic gangway is its ability to compensate for relative movements between the vessel and the fixed offshore facility. This ensures a stable position of the gangway walkway, reducing risks to personnel during offshore operations.

Design and Control System

The marine hydraulic gangway is an engineered system that integrates structural steelwork, a hydraulic system, and control equipment. Operations are managed via an operator console, enabling precise control over the transfer process and timely responses to changing environmental conditions.

Manufacturing and Practical Application

The design and manufacture of such equipment require specialized expertise in marine hydraulics and industrial safety. Izhora Hydrosystems LLC is a Russian manufacturer developing marine hydraulic gangways tailored to actual operating conditions and industry requirements, making them an essential component of modern offshore infrastructure.


3. Scope of Supply

3.1 Marine Hydraulic Gangway

3.1.1 System Components

ComponentQuantity
Marine hydraulic gangway with auxiliary equipment and foundation fasteners1 pc.
Commissioning SPARE PARTS (commissioning parts)1 pc.
2-year operational SPARE PARTS kit1 pc.
Special tools and appliances kit1 pc.
Technical documentation1 set
Certification package1 set
Marine hydraulic gangway 15.5 m length overall arrangement drawing top view
Marine hydraulic gangway 15.5 m length overall arrangement drawing top view

3.1.2 Technical Parameters

ParameterValue
Personnel weight with cargo on the gangway, max.150 kg
Max. number of persons transferred per cycle20 persons
Extended gangway length15.5 m
Slewing angle (horizontal plane)360°
Luffing angle (vertical plane)+/- 45°
Torsion rotation angle30°
Walkway width0.65 m
Handrail height1.25 m
Distance between handrail longitudinal bars0.4 m
Kickboard height0.15 m
Kickboard-to-decking clearance, max.0.01 m

3.1.3 Spare Parts Kit

Operational SPARE PARTS kit per manufacturer standards for 2-year operation — 1 set.

3.1.4 Documentation

DocumentQuantity
Operation manual / documentation1
Data sheet / Equipment passport1
Operating and installation instructions1
Test and inspection programs and procedures1
Metrological verification procedures for instruments1

3.1.5 Certificates

Russian Maritime Register of Shipping (RMRS) Certificate — 1 copy.

Marine hydraulic gangway 15.5 m length overall arrangement drawing side view
Marine hydraulic gangway 15.5 m length overall arrangement drawing side view

4. Additional Requirements

4.1 General Technical Requirements

  • The marine hydraulic gangway is delivered fully assembled and ready for operation. When the equipment is supplied in separate modules, it features connections that ensure rapid field assembly without requiring manufacturer representatives on site.
  • The marine hydraulic gangway is supplied fully equipped with all components necessary for its operation, including starter and protective devices for the motor-driven pumps, as well as all units, special tools, and appliances required for equipment installation, operation, and maintenance.
  • The equipment complies with the requirements of the Technical Regulation of the Customs Union TR CU 010/2011 “On Safety of Machinery and Equipment”, approved by the Decision of the Customs Union Commission No. 823 dated October 18, 2011.
  • The marine hydraulic gangway is manufactured in accordance with ISO 9001:2008 and ISO 50001:2011 standards.
  • The marine hydraulic gangway is located at the stern of the supply vessels and is designed for removal from the vessel deck with minimal labor (without welding or cutting operations) when its use is not required.
  • The gangway is connected to the deck platform without an additional structural foundation support.
  • Design life of the equipment — 25 years.

4.2 Material Requirements

  • All piping is made of SS316 stainless steel.
  • Pressure gauges are made of SS316 stainless steel with a tempered shatterproof glass front lens.

4.3 Power Supply Requirements

  • The gangway is powered from the supply vessel via a single feeder from a three-phase AC network with an insulated neutral, frequency 50 Hz. Power consumption does not exceed 20 kW.
  • Electric heating is provided for the electrical equipment package and the hydraulic system, with anti-condensation heaters powered by conversion units.
  • Conversion units are fed from a 220V, single-phase, two-wire AC network with a frequency of 50 Hz. A distribution board with voltage status indicator lights is provided to connect power from the external network.
  • The surface temperature of the electric motor anti-condensation heaters does not exceed 200°C.
  • Supply network voltage:
    a) +6% to -10% continuous;
    b) +20% to -20% for 1.5 s.
  • Frequency:
    a) +5% to -5% continuous;
    b) +10% to -10% for 5 s.
  • The electrical equipment is short-circuit resistant: 1.45 kA peak current, 0.72 kA breaking current.
  • The electrical equipment operates reliably at a total harmonic distortion (THD) of the supply voltage up to 10%, as well as during deviations from nominal values.
  • The electrical section of the hydraulic system contains all necessary motor control centers (MCC), fuses, terminal boxes, and other equipment based on the integration logic of the hydraulic gangway with the vessel power system.
  • Connection diagrams are located on the inner sides of the terminal box covers. The electric heaters are switched on and off automatically depending on the ambient temperature.
  • All instrumentation and control equipment features an enclosure protection class of at least IP56.

4.4 Hydraulic System Requirements

  • The hydraulic system is equipped with a redundant pump. Replaceable filters with differential pressure indicators are installed at the pump inlets.
  • In the event of a power failure, the system provides 1 deployment/stowage cycle of the gangway using piston-type accumulators.
  • The hydraulic tank volume is sized based on standard practice for similar systems, but is not less than 1.0 times the total hydraulic system volume.
  • The hydraulic tank is equipped with an inspection hatch, a level gauge glass, a filler neck, a breather valve, a low oil level sensor with signal transmission to the operator console, and a drain plug.
  • All instrumentation for level measurement is connected to the measuring points via isolation valves to allow instrument removal without draining the fluid.
  • The hydraulic system is equipped with pressure transmitters that relay data to the operator monitor with low/high and low-low/high-high pressure alarms. In addition to the transmitters, pressure gauges are installed.
  • All pressure measurement instruments are connected to the measuring points via three-way valves or two-valve manifolds.
  • A manually operated choke-type unloader valve is provided to depressurize the hydraulic system.
  • The hydraulic system is equipped with a heating and cooling system based on the environmental operating conditions at minimum and maximum operating modes. System temperature values are displayed on the operator monitor.

4.5 Motion Compensation and Alarm System

  • The heave, surge, and sway compensation system ensures reliable operation of the personnel transfer complex based on the general operating conditions. In the event of operation at critical motion limits, the system issues an alert to the operator.
  • The gangway is equipped with an audible and visual alarm system.
  • The volume of the sound sounders (loudspeakers) is adjustable, with a maximum level of 117 dB.

4.6 Operator Console Requirements

  • The marine hydraulic gangway is operated from an operator console, which includes the following components: a joystick for gangway extension/retraction; a touchscreen displaying equipment operating parameters; a gangway compensation on/off switch; an alarm reset button; an emergency stop button with accidental activation protection; and a joystick for gangway luffing (hoisting/lowering) and torsion slewing.
  • The operator screen displays the following parameters: actual gangway length; audible alarm status; hydraulic system pressure; structural load on the gangway; motion compensation system status; gangway position (angles); and the event and alarm log.

4.7 Requirements for the Wellhead Platform Docking Area

  • The gangway connection is adapted to the existing deck platform layout. If docking with the existing platforms is not feasible, the Supplier shall propose a modification option requiring minimal material and labor costs. This modification proposal must contain detailed and comprehensive data sufficient for the development of detailed engineering design documentation.

4.8 Installation, Removal, and Transport Requirements

  • The marine hydraulic gangway is installed on the vessel using an offshore crane from the host platform. All equipment components are fitted with lifting lugs (eyes) for handling operations. The rigging arrangement excludes the use of specialized lifting gear. The gangway is transferred in its stowed position.
  • Installation and removal of the gangway to and from the vessel deck are performed with minimal labor and without hot work. Hot work on the vessel deck is permitted only for the installation of embedded fastening components, such as the foundation structural steelwork.
  • Main equipment assemblies and spare parts are preserved for transport and storage for a period of 12 months. A packing list certified by the Supplier is enclosed in each container.
  • The packaging ensures equipment integrity during transit by any mode of transport.
  • Clear, indelible markings in Russian are applied to the packaging.

4.9 Marking Requirements

  • Markings in Russian are applied to the equipment in a visible location for inspection and include the following:
    • Manufacturer name or registered trademark;
    • Equipment type designation;
    • Serial number;
    • Certificate of conformity number;
    • Rated voltage/pressure or rated voltage/pressure range;
    • Maximum continuous operating voltage/pressure;
    • Protection class symbol against electric shock;
    • Enclosure protection class (IP rating);
    • Rated power consumption or rated current;
    • Weight;
    • Overall dimensions;
    • Date of manufacture.

5. Manufacturer

Izhora Hydrosystems LLC


6. Warranty Period

12 months from the date of shipment, unless otherwise provided by the contract.


Contacts

Phone: +7 (812) 339-61-68

Email: contact@i-hydro.tech