Accuracy is irrelevant in a realistic battle except with unavoidable attacks. In comparison to Iron Clash, and assuming that we're using how a battle would actually be (not just two Pokemon standing still across from each other)...
Iron Clash is a physical move that is used to slam into the opposing Pokemon and Hydrojolt is a breath attack (with a limited duration) from a large creature. Even if Hydrojolt had 100% accuracy, in a text based RP it will be terrifyingly easy to dodge unless you're a. Incredibly slow (speed-wise, not headsmarts) or b. strategically outmatched. Iron Clash, on the other hand, is a slamming move that has a status effect, a defensive function, and is much, much more accurate, just based on physics.
I agree that Hydrovolt would be OP in a turn based game but in a realistic situation... Not so much. The only reason I included power is to give an idea of power relative to other moves.