Carry on size duffel bag containing:

Sunblock and sunglasses
Cap or broad brimmed hat
Light weight windbreaker (summer)
Foul weather gear (winter)
Deck or tennis shoes (no black sole shoes please)
Camera
Motion sickness medicine

Cooler items:

Drinking water
Food (please wrap and prepare food before boarding)
Alcoholic beverages permitted in moderation
No glass bottles please