ship equipments | ship navigation equipment 

1)    HYDROMETER:

• Hydrometer is used to find the  (DW) density.
• Hydrometer is used:
  1.  To calculate dock water allowance (DWA)
  2.  for a draft survey

 STEPS TO BE FOLLOWED WHEN USING A HYDROMETER: 

1.     Hydrometer must have approved certificate and how to use it. 
2.     Must to be in good condition and ready for use without any damage.
3.     find errors of hydrometer.
4.     Take a clean bucket and get samples from 6 points around the vessel.
5.     Make sure bucket doesn’t touches the bottom and floats freely.
6.     Let water be calm.
7.     Put hydrometer inside bucket.
8.     Make sure it  doesn’t touches the sides of the bucket.          
9.     Get the measurement  from the lower meniscus

2)    HYGROMETER:

Hydrometer is used:

1.    To find the humidity in air and predict fog.
2.    To decide whether to make ventilations or not.

How to predict fog?

1.    Take the wet bulb and dry bulb temperatures for any given time.
2.    Calculate their different  known as depression of wet bulb.
3.    find dew point temperature  from table using dry bulb temperature. and depression of wet bulb.
4.    from engine room find sea temperature for that.
5.    Plotting these temperatures against time axis for successive hours
6.    Extend these lines, wherever dew point temperature and sea. temperature meet each other that is the predicted time of fog.

•    DEFITNITIONS:

Humidity 

 the water vapor Quantity present in the atmosphere

Relative humidity (RH

It is ratio percentage of the present water vapor a sample can hold to the maximum quantity of water vapor that sample can hold at that temperature

Dew point 

 When Relative humidity is 100% saturated

•    How to decide ventilate or not?

Cold to Hot – no Ventilation
Hot to Cold – Ventilation the HOLD 

3)    PRECISION ANEROID BAROMETER (PAB):

It is used to measure the pressure at any position.

•    How to use a PAB?

•     close the damper .
•     Press push button and turn the dial.
•     Stop when show green light breaks. Take the reading.
•    Apply the correction.Use temperature and height correction, and apply to a table in the box or mariners handbook.
•     Pressure taken on the ship is above sea level and we know that pressure decreases as altitude increases, therefore this correction is always added.

6) AZIMUTH RING:

 Parts of azimuth ring:

1.     Mirrored prism 
2.     Magnifying lens 

• How to test error in an exceedingly azimuth ring? 

•    Select a terrestrial object.
•    Take a control of the thing “arrow down”.
•    Take an impact of the identical object “arrow up”.
•    Compare the two readings – If same then there’s no error within the azimuth ring if not then there’s a error.
•    If bearings are different then it mustn’t be used and sent ashore for repair.

 How to use an azimuth ring?

1.    Use “arrow down” for terrestrial objects.
2.    View reflected image of magnetic compass and actual terrestrial object just in case of terrestrial objects.
3.    Use “arrow up” for celestial objects.
4.    View reflected image of natural object and actual mariner’s compass just in case of celestial objects.