There used to be a highly unofficial 'how low can you go' competition just off China Beach, between what you'd know as Monkey Mountain and Hoi An. As there are a number of tourist hotels located along this strip, the idea was to show the foreign running dogs how truly amazing we were.
AFAIK, the game is still running, albeit at a scaled down level. If you're interested, you'll need to get up early. Show's normally over by 6:30 am.
Which reminds me... rapidly putting on power close to the ground straight and level seemed to unsettle a '21 awfully, to make it want to tuck its nose. Does any amazingly talented aerodynamicist have any idea why? I alway suspected it was something to do with the CofG, but technical matters were beyond me. I just pressed buttons, moved the stick and stuffed chocolate under my mask.