PIN 4739737 - Caterpillar

Propeller Shafts
Illustration 1 g00744539
Typical propeller shaft and coupling installation (1) Level of the sea water (2) Flexible mounted seal for the propeller shaft (3) Cutless bearing (4) Flexible coupling for the propeller shaft (5) Flexible engine mountsThe engine should be mounted on flexible engine mounts. The flexible engine mounts reduce the transmission of noise and vibration to the hull of the vessel.The OEM is responsible for the design of the propeller shaft and the type of propeller shaft that is used. The systems that are currently active are shown.
Illustration 2 g00744537
One type of seal for the flexible mounted propeller shaft (6) Propeller shaft (7) Stuffing box (8) Graphite string (9) Reinforced rubber hoseIllustration 2 shows one type of seal for the flexible mounted propeller shaft. This type of seal is used when the propeller shaft is supported by the coupling for the gearbox and supported by an outboard bearing that is made of rubber. The support is at the propeller end of the propeller shaft. A seal prevents water from entering the hull. The seal for the propeller shaft must be flexible in order to allow movement of the engine. A flexible coupling for the propeller shaft is mounted to the coupling for the gearbox. This allows momentary angular misalignment in operation.Refer to Illustration 2. The following items must not create a whirling motion:
Speed of the propeller shaft
Diameter of the propeller shaft
Unsupported length of the propeller shaftWhirling is the centrifugal force that is generated by the speed of rotation. Whirling will cause the propeller shaft to bow.
Illustration 3 g00744538
Another type of flexible seal for the propeller shaft (10) Sterntube (11) Oil reservoir (12) Rubber molding (13) Propeller shaftUse the arrangement that is shown in Illustration 4 when the length of the propeller shaft can not be supported by the coupling for the gearbox and the outboard bearing.With this arrangement, one or more additional bearings are mounted on the propeller shaft. The coupling for the propeller shaft should be flexible. This will allow the engine to move on the flexible engine mounts.
Illustration 4 g00744664
Alternative arrangement for the propeller shaft (14) A siphon break is needed when a water lift exhaust system is specified. Refer to Installation Guide, "Exhaust Systems" for more information. (15) A water supply for the bearings is needed. Install a hose from the 1/4 inch BSP tapping on the end cap for the heat exchanger. (16) Level of the sea water (17) Flexible engine mounts (18) Flexible propeller shaft couplings (19) Bearings for the propeller shaft There is an alternative arrangement for the propeller shaft for this type of installation. A thrust block is needed for the propeller shaft. The thrust block should be installed as the propeller shaft enters the engine room. A constant velocity joint is installed at each end of the propeller shaft. The constant velocity joint is connected to the propeller shaft before the coupling for the gearbox. Refer to Illustration 4.Couplings
Flanged Propeller Shaft Couplings
Flanged propeller shaft couplings can be supplied with any marine transmission. The