The loan term can run one to seven years. Long term loans may not be a good idea if you plan to trade the car in after three or four years; at that point you may still owe more on the loan than the car is worth.
If you do miss the ship, go into the cruise terminal and talk with the port agents, who are in contact with both shipboard and shoreside personnel. They can help you decide the best way to meet your ship, and start to pave the way for rejoining your cruise, which will be already in progress without you.
Seasickness is especially bad when no one else seems to be afflicted, and it certainly is not limited to only wimps. Knowing that about half the astronauts take motion sickness medication when in space should make you feel a little better! People who are prone to motion sickness in cars, airplanes, or carnival rides may also be more susceptible to seasickness. However, the motion on different ships affects people differently. Just because you get seasick in a small boat does not mean you will have problems on a large cruise ship.