Honestly, I'd use Deepseatooth with Clamperl on an NU Trick Room team. Then just put Surf, Ice Beam, and Aqua Ring. with a max Special Attack stat of 572 after DST, Clamperl will be doing really well under the influence of Trick Room.
So competitively, Clamperl can be used in NU (Wouldn't push it with UU, but it's possible), but needs the right support to be a viable option.
EDIT: Sheesh, I only put THREE moves...-_-
For the fourth move, you want Whirlpool / Clamp. You don't the opponent to switch in a stronger Pokemon. BE a clam, and trap your prey.