I recently used this website to complete a car rental using a debit card.  The verbiage on the site as I started to book the car under the heading "KNOW BEFORE YOU GO" was as follows:

The rental agency will require a credit card or debit card in the primary driver's name. Sufficient credit must be available for a deposit. Funds used for debit/check card deposits cannot be accessed until the car is returned. Amount of available credit required depends on car type, rental period, and optional items. If using a debit card for your deposit, contact the rental agency for its policy.

After...