If you have received care at Nantucket Cottage Hospital in the past you are already registered, however, it is a good idea to confirm and update your information by calling the number above. Hours of operation to call and register: 7:30 a.m. - 6 p.m. Mon-Thurs; and 7:30 a.m. - 5 p.m. on Fridays. Must sign-up for the Patient Gateway..