When should the Rottmer releasing gear lever be operated?

The Rottmer releasing gear lever should be operated when the lifeboat is waterborne. This is because the mechanism is designed to safely release the lifeboat from the davits into the water. Operating the lever while the lifeboat is floating ensures that the lifeboat can be launched without risk of it being damaged or causing injury to personnel on board or on the deck. Launching from a stable position in the water allows for a controlled release, which is critical for the safety of crew and passengers.

Choosing to operate the lever during preparation for launch or while passengers are still boarding could lead to unforeseen complications or hazards, as the lifeboat would still be connected to the ship and could swing or destabilize. Operating the lever in calm seas is not a decisive factor since the emphasis should be on the lifeboat's status as waterborne, regardless of sea conditions.