I am just back, and here's my two cents worth.
Don't bother booking ships tours. You spend way too much time waiting for other people, sitting on busses, etc. etc. For example, on our tour to Pearl Harbour, we got on the bus at 8:30. We didn't leave til close to 9:00 a.m. and got there close to 10:00 a.m. - had a two hour wait. When we were done, we were shuttled about 15 feet to another bus to take us to the Mighty Mo. Herding on and off takes about 20 minutes. We go to the Mighty Mo for 45 mins, we wait for another bus to herd us back to another bus (restricted busses) and back to the ship around 3:00.
If we had taken a cab at 7:30 a.m. on arrival to Pearl Harbour, we would have been done before noon and had time for Waikiki Beach.....
We had never been to Hawaii and werent' sure what to expect - save your time - take a cab and go yourselves. Way faster.