The best swells in Hawaii arise in the South Pacific during the Summer in the northern hemisphere, and travel great distances. They smooth out considerably because of their great distance, and you get excellent, very smooth, long rides such as at Panic Point on Oahu. In the Winter in Hawaii there are few swells from the South Pacific (summertime then), and the large waves come from the North Pacific hitting the North Shore (such as Pipeline, Sunset, Waimea Bay, etc.) They tend to be somewhat choppier because the swells have not travelled as far, but they are much larger than the summertime surf on the south shore beaches.
Never seen a large wave in the middle of the ocean? You have to realize there is land on both sides too so it doesnt matter which way it goes.
Sometimes I just wonder why I bother. My explanation in post 2 did not meet those criteria? Please Register or Log in to view the hidden image!
I have been at sea with a swell higher then the mast on a 34foot sail boat. Swells are very powerful and not influenced much by offshore winds.