Crew transfer vessels (CTVs) are typically aluminium catamarans for 12 passengers, although they can also be larger and this is becoming increasingly common as wind farms are located further from the coast. Approximately 25% of CTVs use waterjets, 25% fixed pitch propellers, and the remainder use controllable pitch propellers as their main form of propulsion. Engines are highly loaded most of the time as vessels run at 15–20 knt transit speed or higher, taking crew where they need to go as quickly and efficiently as possible.
