I hired a boat in Menorca's cala'n bosch marina, a boat rental is the best way to see the beaches 

Can you hire a self drive boat in Menorca without a license? Yes!!
I found a place in Cala'n bosch marina that did just that, they rented boat that took up to 6 people, you can rent one for 4 hours or 8 hours.
Usually 10am - 2pm or 10am - 6pm.
cost is from around 120 - all the way to 280 euros depending on size and duration of hire.
Cala'n bosch marina is located 5 miles south of Ciutadella on the west side of the island of Menorca, but i believe you can hire boats elsewhere too.