How to replace Doppler Log transducer?

To replace Doppler Log sensor:

1. Switch off unit's power. Disconnect the transducer cable from the Signal Processor. Dismantle the cable.
2. Measure the distance from the mounting flange surface up to a white grove of the transducer. Release nuts that secure positioning bracket
   
3. Release gland packing nuts
   
4. Lift the sensor all the way up. The upstroke is about 158 mm for the NKF-531E transducer.
   
5. Close the sea chest valve
6. Release the mounting flange nuts but do not remove them. Check sea chest valve tightness, there should be no leakage from under the flange.
   
7. If the sea chest valve is holding, remove the mounting flange with the transducer.
   
8. Inspect the gasket, renew if necessary
   
9. Remove the old transducer from the mounting flange. Clean the flange and V-packing. Install a new transducer into the mounting flange. Lubricate new transducer and V-packing with vaseline and install V-packing on the transducer first, then push V-packing stack into the gland.
   
10. Install the mounting flange with the transducer onto the sea chest valve and tighten the flange bolts. Slightly tighten the gland packing
    
11. Fully open the sea chest valve and push the transducer down. It should go easily so you will fill when it reaches its seat. Reconfirm the transducer vertical position by comparing the distance from the mounting flange surface up to a white grove of the transducer with the measurement obtained at step 2.
    
12. Make sure the white mark at the top of the transducer is pointing the FORE direction of the vessel. Rotate if necessary.
    
13. Tighten gland packing and positioning bracket nuts.
14. Secure the transducer cable and reconnect it to the Signal Processor.