The largest helicopter in production by the western world is the Sea Stallion. It employes the typical configuration of having a single main rotor with a tail rotor for counter torque.
The next biggest is the Chinook. It uses the tandem configuration. Due to this, it does not need a tail rotor for counter torque. A key advantage of this configuration is that all of its power can be used to generate lift and forward thrust.
My question, why was the larger helicopter like the Sea Stallion not based on the tandem configuration? Would it not be a relatively simple up scaling of Chinook to achieve the dimensions and lifeting capacity (or in fact more, due to the savings from not requiring the tail rotor) provided by the Sea Stallion?
Thanking you in advance for all your expert input.