Section 2 Offshore Personnel Transfer System types

2.1.1 This Section briefly describes the main types of an OPTS which are currently in use in the industry. A systematic overview of an OPTS is shown in Figure 1.2.1 Systematic overview of OPTS types and features.

Figure 1.2.1 Systematic overview of OPTS types and features

2.2.1 ST-A system types which provide a permanent active compensation may be described as systems where:

1. the roll, pitch and yaw rotations and the surge, sway and heave motions are compensated by means of an active mechanical system enabling full compensation; or
2. only certain degrees of freedom of movement are compensated, e.g. by compensation using telescoping, slewing and luffing motions only; and
3. the connection time may be limited.

2.2.2 ST-P system types which provide a passive compensation may be described as systems where:

1. the positioning of the gangway towards the landing area takes place by means of a manually operated but powered system;
2. the gangway is finally landed on and safely connected to the target structure and the powered positioning system is deactivated, and all brakes are disconnected and/or valves are opened and the passive compensation of the gangway is realised; and
3. the connection time may be unlimited.

2.2.3 ST-H system types are defined as hybrid systems in cases where a combination of passive (ST-P) and active (ST-A) systems is used and where:

1. in the initial pre-operation phase the gangway is actively compensated until a connection to the target structure is established which allows safe transfer; and
2. the system subsequently switches over to allow for passive compensation.

2.2.4 ST-C system types combine the personnel transfer capability (using the gangway as a conventional jib) with a dedicated cargo handling capability (e.g. using hoisting falls and a winch) and are also required to be designed as a conventional offshore crane complying with all relevant requirements.

2.2.5 ST-A and ST-H system types may combine personnel transfer capability with cargo transfer capability where the cargo is stored in dedicated cargo baskets at the tip of the gangway.

2.2.6 ST-M system types combine the personnel transfer capability (using the gangway as a conventional jib) with the personnel handling capability (using falls and a winch). In such cases the system is also required to be designed as an offshore crane with handling of personnel capability complying with all relevant requirements.

2.2.7 There may be combinations of the above defined systems types, e.g. ST-HM which defines a hybrid type system with crane cargo handling and personnel handling capability.

2.2.8 Systems other than those described in the above will be specially considered on the basis of this Code and the Code for Lifting Appliances in a Marine Environment, July 2022 as applicable.

2.3.1 Three types of access systems are defined for the purposes of this Code:

1. A-GU

   OPTS which are designed to allow for unrestricted, unattended and/or uncontrolled access are abbreviated as A-GU. The system needs to be capable of being manually detached from the target structure and the OPTS and its gangway be brought to the stowage position.

2. A-GR

   OPTS where the access and the number of persons simultaneously allowed is restricted by defined means are abbreviated as A-GR. The system needs to be equipped with landing arrangements which can self-disconnect and the OPTS and its gangway be brought to the stowage position.

3. A-BPC

   OPTS which transfer personnel in a personnel containment (e.g. basket, platform, or other type of containment) designed for that purpose are abbreviated as A-PC. For a definition of personnel containment reference is made to Ch 1, 1.10 Terms and definitions 1.10.38.

2.3.2 Access types other than described in the above will be specially considered on the basis of this Code and the Code for Lifting Appliances in a Marine Environment, July 2022 as applicable.

2.4.1 For the connection between the gangway and the target unit the following connection types are defined:

1. Loose connection system

   The connection is made by means of pushing the gangway tip or the contact part of the personnel containment against the target structure with a defined pushing force compatible with the capacity of the target structure and the OPTS structure and gangway tip or personnel containment;

2. Fixed connection system

   The connection is made by a structural and/or mechanical arrangement ensuring permanent and safe connection between the target structure and the gangway tip or personnel containment.

2.5.1 Apart from its main purpose to provide safe transfer of personnel, the OPTS may have additional functions or special design features, such as:

1. Cargo handling capabilities either on the gangway, inside the personnel containment or by using the gangway or personnel containment supporting structure as a crane jib or similar designs.
2. Personnel handling capabilities where the personnel are inside a suspended basket being hoisted and lowered by the OPTS using falls and a winch.
3. Systems where non-telescoping gangways are used, e.g. personnel containment type systems or fixed gangway type systems.
4. Systems where special luffing or heave compensation devices are employed, e.g. robotic structures supporting the personnel containment.
5. Aiding, enabling or providing a secondary means of evacuation of the target unit to the mothership or vice versa.
6. Operation of the system in arctic conditions (see Ch 1, 8.27 Winterisation).

2.5.2 The above and other features will be specially considered during the actual design appraisal of the individual project on the basis of this Code and the Code for Lifting Appliances in a Marine Environment, July 2022 as applicable.

2.6.1 The OPTS usually comprises the following components and systems:

1. The gangway and related systems and structure which are necessary to enable safe passage and transfer of personnel from the mothership to the target unit and vice versa.
2. The system and structure which is supporting the gangway or personnel containment structure which is defined as the base frame for the purposes of this Code.
3. The system and structure which enable the luffing of the gangway structure or vertical movement of the personnel containment structure to enable compensation of mainly vertical mothership motions.
4. The system and structure which provide the possibility of varying the length and reach of the gangway and using this for compensating for mainly horizontal mothership motions in the gangway direction.
5. The system and structure which enable slewing of the gangway or personnel containment structure and system to compensate for horizontal motions in the transverse direction of the gangway/personnel containment structure.
6. Any compensation system which is not realised by a combination of luffing, slewing and telescoping. It is possible that such a compensation system may still be combined with luffing and/or slewing and/or telescoping compensation systems.
7. The walkways and waiting areas.
8. The personnel containment system and structure for systems where no gangway is used to transfer personnel.

2.7.1 Machinery components of an OPTS may comprise (but are not limited to) the following items:

1. winches;
2. hydraulic cylinders;
3. mechanical actuators;
4. slewing rings; and
5. hydraulic power units.

2.8.1 Electrotechnical systems and components of an OPTS may comprise (but are not limited to) the following items:

1. electrical wiring system;
2. electrical switchboard/cabinet including busbars;
3. control system, including alarm and safety systems;
4. electrical motors and actuators;
5. Operator station and control panel;
6. controlling devices;
7. indicating/sensing devices;
8. limiting devices;
9. observation devices; and
10. access control systems.