Safe and Effective use of tugs in Shiphandling

Tugs are very important part in any harbor maneuvering. Today we will strive to know this important team member in detail and how to safely and effectively use them.

We will divide this large topic into following sections:-

1. A typical tug layout and parts of tug

2. Types of tugs- Their limitations

3. Effective usage of tugs

4. Safety precautions when using tugs- Interaction, Girding etc.

A typical tug layout and parts of tug

The ability of tug to handle such a large pulling or pushing force vis-à-vis its size is due to its deep draft and heavy in bottom part (very low VCG).

A typical tug is powered by 2 variable speed diesel engines powering the 2 fixed pitch propellers mounted onto azimuth which can be rotated 360 degrees using hydraulic mechanism.

Tugs bow (stern in case of tractor tugs) is additionally strengthened and fitted with fixed fenders like W-fender, tube –fender, U-fenders made of hard rubber. This Hard rubber is supplemented by installing a softer layer of tyre fenders (Usually discarded Aircraft tyre or Hydra tyre)

Once tugs engines are started, initially they are allowed to run at idle rpm for few minutes, then propellers are clutched with the engine shaft, and then RPM can be varied as required and direction of thrust can be controlled by rotating the Azimuth (Z-peller). Z-peller rotation is mostly hydraulic actuated.

If tugs is fitted with FIFI (firefighting system- Pumps upto capacity 2400 CubM/Hr), there will be either 2 pumps which can be clutched with engine simultaneously with propeller or in case of single fire pump, one of the engine will need to be declutched and to clutch the fire pump. In such case tug will need to be maneuvered with only 1 propeller until FIFI system is being used.

Operation in case of power failure:

In case of Auxiliary engine failure, tugs have adequate battery back up to continue maneuvering for another 1 hour to 3 hour.