Possible Clues:

• Paddle in doubt, struggling to find boat's motor
• Motorboat feature
• Sort of motor not allowed to go on
• Old tub moved by means of propulsion attached at the back?
• Sort of engine not popular with directors
• At last, get instruction from airline on holiday to put motor in boat
• Motor variety for a boat
• *Motor variety
• Usual kind of motor for small boats
• Exhausted, get on motor of a sort