During one adventurous journey outside South America, Trolle's ship encountered four Spanish vessels and fought a four-hour-long battle, which ended with the entire Swedish crew being captured and imprisoned.

In 1766, after years that had seen the Swedish Navy being reduced, he travelled on his own expense to Brest, Flanders and Amsterdam, where he observed shipbuilding and fortress construction techniques.

As a reward for his support in the royal revolution of king Gustav III in 1772, he was given command of the Archipelago fleet and was ennobled, thus being allowed to attach the prefix "af" to his family name.

During the following years, Trolle came into conflict with traditionalist supporters of the blue water navy who were against the very existence of a naval unit under army command.

With the help of powerful allies and support from the court he managed to aide af Chapman become chief naval architect, further developing and renewing the army fleet according to their visions.