I have a fear of being on boats and on the water, how can I get over this?

Hypnosis? As I have personally used hypnosis to treat patients with phobias, and have seen how successful it can be, I would recommend it as one solution to your problem. There are numerous approaches to your phobia using the tool of hypnosis.
Several options. Psychologists treat phobias by several different methods. If medications are needed, psychiatrists can help. Behavioral therapists also treat phobias. Hypnotherapists can be very helpful. Do your research before seeing anyone as you want someone who treats phobias specifically, not a general psychoanalyst, therapist, etc. Also, have a realistic idea of the cost.