5 On-load/off-load release gear system

 This section describes the details of the release gear system. Read this section carefully for safe operation. This release gear system consists of fore and aft hooks, a release handle near the steering console, a hydrostatic unit and the associated cables (see Fig. 5.1).

 The releasing operation of the hooks is conducted at the release handle near the steering console through the control cables terminating at the fore and aft hooks. The interlock system including the hydrostatic interlock unit is provided to prevent the release of the hooks when the boat is not waterborne.

 The system also has an on-load release function which makes it possible to over-ride the interlock by the hydrostatic unit. Incorrect on-load release operation may cause fatalities and due precautions should be taken for this operation.

Fig. 5.1 Schematic of release gear system

  5.2.1 Structure and parts names

 The structure and parts names of the fore and aft hooks are shown in Figures 5.2.1.1 and 5.2.1.2. The fore and aft hooks are generally identical except for the direction of installation.

Fig. 5.2.1.1 Perspective of the hook unit

Fig. 5.2.1.2 Internal view of the hook unit

  5.2.2 Releasing

 When the release handle near the steering console is pulled, the cam lever pin is turned by the control cable and the lock piece is then made free. Finally the hook is turned and released (see figure 5.2.2).

Fig. 5.2.2 Release principle of the hook unit

  5.2.3 Resetting

 After the resetting of hooks, the posture of each hook is held by the lock piece and the lock piece is locked by the cam lever pin with the reset lever. To ensure the proper resetting of the fore and aft hooks, the procedures described in paragraph 4.1 should be followed. The fore and aft reset levers must be operated simultaneously. After simultaneous resetting of the hooks, the release handle near the steering console also returns to the closed position (see figure 5.2.3).

Fig. 5.2.3 Reset principle of the hook unit

  5.3.1 Structure and parts names

 The structure and parts names of the release handle are shown in figures 5.3.1.1 and 5.3.1.2.

Fig. 5.3.1.1 Perspective of the release handle unit

Fig. 5.3.1.2 Internal view of the release handle unit

  5.3.2 Operation

 When the lifeboat is fully waterborne, the lifeboat can be released by removing the safety pin and then pulling the release handle fully and quickly to the open position (off-load release). The lifeboat can also be released by the same operation of the release handle even though the lifeboat is not fully waterborne, by opening the interlock cover and lifting up the interlock lever. This over-rides the interlock function of the hydrostatic interlock unit (on-load release).

Fig. 5.3.2 Operation procedure of the release handle

  5.4.1 Structure and parts name

 Structure and parts names of the hydrostatic interlock unit are shown in figures 5.4.1.1 and 5.4.1.2.

Fig 5.4.1.1 Perspective of the hydrostatic interlock unit

Fig. 5.4.1.2 Internal view of the hydrostatic interlock unit

  5.4.2 Operation

 When the lifeboat is fully waterborne, the hydrostatic interlock unit pushes up the interlock lever through the interlock cable by the water lifting the float and thus allowing the release handle to be operated. Contrary to this, operation of the release handle is not allowed by the hydrostatic interlock unit when the lifeboat is not fully waterborne.

Fig. 5.4.2 Schematic diagram of the interlock