A bad fear of being in the sea after nearly drowning at age 5 there anyway I can get over my fear of being on boats and out on open water?

Therapy. Behavioral therapy often works to help people overcome phobias. See your physician for a referal to a local psychologist or psychiatrist that does cognitive/behavioral therapy for phobias.
Retraining. Retrain in controlled water. Once your brain adjusts to the water fear should gradually subside. Sometime hypnosis may be helpful.