Abstract: A method of replacing a component (28b) of an offshore wind turbine (10) includes providing a sea vessel (30) having a transport system (50)) with a base (52), an elongate platform (54) connected to the base (52), and a transport frame (56a, 56b) for receiving a component (28b) of the wind turbine (10). The sea vessel (30) is positioned such that its deck (40) is separated from the wind turbine (10) by more than a maximum working distance (72) of a crane (26) onboard the wind turbine (10), and further positioned such that in an extended position, the transport frame (56a, 56b) is within the maximum working distance (72) of the crane (26), and in a retracted position, the transport frame (56a, 56b) is outside of the maximum working distance (72). The method includes arranging the transport frame (56a, 56b) in the extended position, lowering a component (28b) of the wind turbine (10) using the crane (26), and placing the component (28b) on the transport frame (56a, 56b).