Into Clanker's Cavern you will swim. How can you fathom these depths, being you're so dim?
In the room where Treasure Trove Cove's puzzle is, there is a shock pad. Jump up to the ledge using it. Fill in the Clanker's Cavern puzzle. To get to the entrance, go back into the room with the river. Climb into the top pipe. Hit the switch to your right, and jump across the newly raised pipes.
As you swim across this vast, marine expanse, keep in mind that it's here where I wash my ol' underpants!

Moves
WonderwingFind Bottle's molehill inside a chamber branching off the main chamber inside Clanker.Hold Z and press C right
Jiggies
Winding Tunnel - Swim through a long winding tunnel to your right when entering the chamber. The tunnel is far back.
Crabs - go into the glowing green tunnel and kill the crabs.
The Key - Swim straight down below Clanker into the well. Swim through the key hole. Swim back up. Repeat three times
Tales of Old - talon trot up Clanker's tail.
Elevator - Ride the screw Clanker blows out of his blow hole to the platform, then jump off.
Dentist Banjo - From the two platforms near Clanker's mouth, shoot the two golden teeth. Go inside the holes for treasures and a jiggy.
Down She Goes - jump into Clankers blow hole. Hit the witch switch, and run through the blades.
Wonder Wing - where Bottles teaches you the wonderwing, run through the blades with the wonder wing on.
Rings - Swim through the green ring, then through the next ring that turns green. Repeat.
Jinjos - One is in a tunnel off the main chamber. One is in the bottom of the well. One is in a small duct, with an extra life. One is in a gill tunnel inside Clanker. The other is in the entrance room, on a platform.

Notes
4 - left pipe from oil tank
4 - right pipe from oil tank (8)
6 - entrance pipe (14)
10 - on top of Clanker (24) *
10 - pipes above Clanker's tail (34) *
8 - in mutant crab cave (42)
7 - in pipe on floor of cavern (49)
4 - above blow hole (53)
2 - in alcoves above the beehive (55)
4 - on pipe right of jump point (59) *
5 - on pipe left of jump point (64) *
8 - in Clanker's mouth (72)
3 - in left gills passage (75)
12 - in passage with grinders (87)
5 - in right gills passage (92)
8 - at bottom of chain (100)
(* only possible/easier after you have freed Clanker)

Extra lives
One's inside a duct with the orange jinjo
Two're on ledges in the main chamber

Extra Honey comb pieces
#1: At the duct with the extra life and orange jinjo.
#2: Swim up a pipe just to the right of the platform with a shock spring pad.

Witch Switch
Right down Clanker's blowhole in the witch switch. Exit Clanker's Cavern. In the area with Clanker's Cavern's jigsaw puzzle, pound down Grunty's eyes for a jiggy.

Fun Things
Moving Sliding Board - Run up Clanker's tale with the Talon Trot on. Turn off the talon trot, and slide down, trying to not fall off.