Surfing Waves

I need help with a few aspects of duck diving. I get the technique, but when should I start to sink the board? And how big of waves can you duck? I was watching this vid http://www.youtube.com/watch?v=7BOhDaJH0m4 and around 37 seconds, I was wondering...if someone duck dived right after the wave crashed, would it be possible to get deep enough to where they wouldn't get wrecked by the power of the wave? And even if they did, wouldn't they pop up in the middle of the tube and shoot the falls or something? I feel like they would have to do an EXTREMELY deep and long duck dive. Help?

Hi prdk21, welcome to Surfing Waves.

There's obviously a limit to the size of wave you can duckdive. If the wave is really big and breaking right in front of you, you wouldn't duck dive. You'd leave your board and swim down.
The more experienced you get at duckdiving, the larger the wave you can get under. When you duckdive, try to keep forward motion, the wave should pass over the top of you as you go under it, and you won't come up in the middle of it.

Surfers will try not to put themselves in a position where they would need to duckdive a wave like that.

sweet thanks so much for the tips!

no probs, there's a whole host of other advice about duck diving throughout the forum, and on the main site if you need it.