Possible Clues:

• Water vessel
• Time to tie up outside club, securing old vessel
• Vessel robot manoeuvred in defensive, water-filled ditch
• Moment to abort abnormal launch?
• Books, or book dropped into surrounding water — from this?
• Bottom oar disintegrated in seagoing craft
• Recreational craft produces material for robot in water around castle
• Lake transport
• In second wrongful act, stole powered vessel
• Craft to moor at front of barge at sea