Activating this trainer:
If not state otherwise below, press F1 at main menu.
Listen for 'Trainer Activated'.
Press desired hotkey. All hotkeys can be changed on the trainer.

Promo Options:
NumPad2: Unlimited Storage

Trainer Options:
NumPad1: Unlimited Hull
NumPad2: Unlimited Storage
NumPad3: Unlimited Food/Rum/Powder/Gold
NumPad4: Max Morale
NumPad5: Max Sailors
NumPad6: Easy Rank Up

Notes:

Unlimited Hull:
Toggle on for effect.

Unlimited Storage:
Toggle on for effect.

Unlimited Food/Rum/Powder/Gold:
Toggle on for effect.

Max Morale:
Toggle on for effect.

Max Sailors:
Toggle on for effect.

Easy Rank Up:
Toggle on for effect.  Note that this makes it easy for competitor navies to level up so probably best to toggle on only when you are sending Captain to rank up.