Speaking to Forces News at the aircraft's unveiling in May, one new member of the Mk 4 described the new system as a "game changer".
Two of the biggest focuses on making the aircraft suitable for life on HMS Queen Elizabeth is the introduction of a folding tail rotor and a folding motor rotor - designed so the aircraft will take up less space when onboard the aircraft carrier.
Four of the new folded Mk4s can occupy the same hangar space as one Chinook, which is also used for transporting troops. The folding process takes two-and-a-half minutes.
Up to 24 troops can be transported in the back of the Mk4. The cockpit, engine rating and gearbox rating have also been standardised.
The Ministry of Defence (MoD) says it is faster and more powerful aircraft than its predecessor.
In total, 25 Commando Merlin Mk4 helicopters will be delivered to the air wing of the Royal Marines - the Commando Helicopter Force.
The first ten are expected to come into service by the end of the year.
The first Merlin Mk1 helicopter came into service in the late 1990s.
HMS Queen Elizabeth Flight Trials
Three of the Commando Merlin Mark 4 helicopters have started their journey to join up with HMS Queen Elizabeth and begin flight trials in the US.
The trials will see F-35B fighter jets conduct 500 take-offs and landings from her deck during four months.
HMS Queen Elizabeth has a 4.5-acre flight deck where a fleet of Merlin Mk4s and F-35Bs will soon be taking off from.