towed log vs bottom log

What are the advantages of Bottom Speed Logs over Towed Speed Logs?

Advantages of Bottom Speed Logs:
  1. Can be retracted /lowered faster viz a viz a towed logs.
  2. Bottom logs do not foul up with surface objects
  3. Bottom Logs can provide direct inputs to other equipment like Radar, AIS etc.
  4. Can provide inputs to multiple displays on the bridge or Captain’s cabin etc.
  5. More accurate
  6. Measures slow speed also (towed need > 5 kts)
  7. Astern speeds can also be measured.

VIKASH KUMAR