Possible Clues:

• Vessels that make things deeper
• Vessels used to deepen channels
• They get to the bottom of things for sailors and medic from Trim with half the cars
• Doctor with advantages, employing right cleaners of beds
• Flour-sprinkling devices
• They stay right way up to get bottom up
• They profoundly improve channels of communication
• They get bottom up
• Tunnel-building machines
• Sprinklers needed for specialised vessels