This morning I went kayaking for my exercise. Boats are a very nice way to sit and get upper body exercise. Are there canoe and kayak rental places on the bay? Obviously this isn't a useful daily plan for your geography but it could be a way to get occasional exercise and have fun on a weekend. Gyms also have indoor boat simulators, though usually it's rowing machines, which require feet. I don't know if there are some canoe or kayak simulators that would not require feet.