AyeTides XL is designed for the larger screen size of the iPad. With so much more room, more information then in the iPhone version is displayed.
The tide display is self-contained. No internet connection is required to view the tide or current stations. Some features (maps, email, forum browsing) do require an internet connection, but the primary function of displaying tides and currents does not require the net.
The two functions of AyeTides XL are station selection and station viewing. Secondary functions include setting preferences, and getting information about AyeTides XL.