Ok. Waves move at different speeds. The bigger they are, the faster they travel. Swell size is determined by wave height, and duration: Open ocean wave height is monitored by NOAA weather buoys all over the world.
http://www.ndbc.noaa.gov/station_page.php?station=51001
By listening to the weather buoy, on the North Shore of Oahu, we could estimate when swells would hit the islands. I spent ten years chasing the biggest waves I could find, as you said, on THE place in the world known for giant waves. We got very good at predicting when big swells would arrive. A 20 second duration swell meant very big waves, for the height.
Longer the duration, the bigger the wave becomes when it hits the reef, in addition to it's height.
David's post got me thinking, so I checked the wave height and speed that night. Wasn't super big, so the wave speed, and duration, indicated his boat, while hauling tail, wasn't moving in the 20 mile an hour range, because the swell duration, and size, indicated a speed more like 10-15 miles an hour. David's bought is designed to sit up and hydroplane, going down wind. In other words, the boat actually DOES surf, if the conditions are right.
Mark Foo and Ken Bradshaw are two of the most famous big wave riders of all time. I surfed with Ken a LOT. Mainly because he would ALWAYS go out with me, unless he had something else he had to do, which was very rare. We LIVED for giant waves, and arranged our schedules that way. Foo and I were cordial, but, mainly because we surfed Wiamea when we could. This was just prior to the insanity that was caused by the Eddie Aikau contest, and, the Bilabong 50k for biggest wave contests. The Bay is pretty much unrideable, now due to wannabe big wave guys, and pros, trying to get giant waves for cash.
Just for reference: Big wave riding, without towing in, using an artifical
speed source, is very difficult. The waves are moving towards the beach at 25 miles an hour. You have to use your arms to paddle near that fast, on a giant board, and as the wave hits the reef, it easily doubles in size.
So, you have a 4-5 story building, moving at 25 miles an hour, that you are trying to catch, by running on your hands. When you catch it, you have to jump up, get your balance, usually blind, because for it to be good, the wind is blowing in your face, blinding you with spray. If you do all this, you drop about 40-50 feet, pretty much straight down, and hope there isn't a bigger one behind the one you caught.
For Wiamea to close out, the wave faces are in the 40-80 foot range. A closeout means a wave so big, it breaks outside the bay, peaking in the middle of the bay, and crashing over at once, in one giant wall of 30-40 foot white water.
Closeouts are about as big as this wave Ken towed into, on an outer reef.
Towin surfing is really waterskiing, on surfboards, into waves. We did it in Santa Cruz, but using a boat, on a lake, in the early 70's.
The wave below is from a day like I was talking about, but, bigger. Ken road a giant wave that day, considered by many the biggest of all time, and no one got a real good shot of it. Weird, but, that's his kind of luck.
The irony of this, for me, is this day just happens to have fallen on my birthday, and, I wasn't there, having moved back to the mainland to go to law school.
http://www.kenbradshaw.com/order2/
:x
Greg