I am so frustrated!!! I've played this part for so long without a solution that it's no longer fun.

Following the walkthrough I jump off the Top Bridge (Q), the walkthrough then says "let the current slowly drag you along and watch for the wall of the waterfall." It says if you miss the Stony Bridge you need to "drift up the river, land at the Eastern Cove." That makes it sound like I should be in the main river channel.

When I jump off the bridge I drift about 20 feet and up against the cave wall. Circling the wall it appears I'm in an enclosed hole with no exit except to dive down underwater. On the map it only shows a short portion of blue on each side of the top bridge with my red arrow under the bridge or just barely to either side.

Swimming down into the tube has proven to be suicide as I can't regain the surface, the current seems to be way too strong and I can't get out, everyone drowns. I've drowned something like 28 times and am no closer to getting out.

Please, what's the secret???

You do have to go through that hole. Choose your smallest character and wiggle through. (A pixie, dwarf, gnome, or ratling is best). The others will follow through.

Sometimes if you time it just right, you'll end up on the same side of the boulder as the treasure chest.

Also: if you plunge to the bottom of the waterfall, look for a hidden chest down there in the water...

Cheers,
-Sazerac

You can keep trying to land on the stony bridge! I was able to do it after a few practice runs. Good Luck!