[blam]

"I am still looking for anyone (other than myself) that has actually dove the mouth of the Columbia River. I fear I am the only one...that has ever been dumb enough and actually survived, and I did it twice."

I did drive a 10,000 ton freighter up there once. The entrance has to be timed to the high tide level.

[TexasTransplant]

Both times I dove it the water was absoutely flat for about 15 minutes, the last dive lasted 16 minutes and I had to be picked up in the middle of 20' swells that were fast becoming 30' with a current that was trying to rip my tanks and flippers off.