Trade fleets, first. If you still win, "it's the Indian not the arrow." Or use some Optional Rules--give him Well Trained Gunners and yourself Gunners Lacking Training. Also, Let The Men Drink gives a first-turn bonus, and maybe have him start with his guns using Double Shot.

Also, each ship log has two sides--flip his cards to the stronger side and yours to the weaker, and consider using Captain/Crew Abilities from here: https://www.aresgames.eu/11116