Sorry I've tried to get my head around this question but failed particularly with the Alicante address. The nearest I can get is that RCI cruises give you a card to use for everthing you spend on board and that is in US dollars. They will convert that into any currency you wish at the end and charge it to your card however most cards will accept a charge in dollars and convert it at their rate sometimes plus a commission. The Nationwide will not charge a commission and will give you a very good rate of exchange. Not knowing your exact circumstances I can't be more specific but whatever you do should you need to know more do not include any personal details on this or any other open site as it is free to view...not that you would, would you...regards...Nei.
Is it a VISA debit card? If so then often the staff do not know the difference between that and a creditcard - so you can use it!