SYH

About to do my first cruise for 8 days with my husband. In my day to day life I carry very little cash anymore thanks to debit cards and forms of payment. We are will be traveling to American islands where I am making the assumption they will take ccs and such. Is that wrong? Will tipping folks on the boat, times we are off the boat-cabs,food,shopping ext- how much money should we bring with us?