Here is the moveset I used for Pokémon Red:
Confusion / Surf (?)
Water Gun / Disable / Surf (?)
Phychic is always awesome to have, as it rarely misses and does 90 base Damage. Headbutt does 70 Damage, Confusion does 50. If this is your primary water type, teach Surf in place of Confusion or Water Gun. Water Gun is learned a bit late at level 33, and does 40 Damage. You can keep disable if you want, it can be a bit of a gamble, but it still hilarious when you are in a battle with a friend and you disable one of their best, most problematic moves! Never gets old!