Here in the USA, along the coasts and in the Great Lakes we have Emergency Services related aquatic units. I was thinking that there should be some type of aquatic units to the game to add a larger variety of calls while also improving the game play experience.
Units:
Fire Boats - Respond to fire related calls in large bodies of water or assist to calls located within 500 yards of the coast.
Fire Rescue Boats - To act as some type of aquatic ambulance in large bodies of water or assist to calls located within 500 yards of the coast.
Police Boats - Respond to police related calls in large bodies of water or assist to calls located within 500 yards of the coast.
Ferry - Allows a certain number of land vehicles to be transported over large bodies at a faster rate of time. For example if you are located in a place with a lot of islands it will allow mutual aid to travel faster.
Buildings:
Fire Boat Station - Cost: 150K
Fire Rescue Boat Station - Cost: 250K
Police Boat Station - Cost: 150K
Dock - Cost: 300K