So I'm running a sort of piratey aquatic homebrew campaign, and I think it's sort of on theme to have pirates riding down on some special ropes from one location to another, but I'm having a little difficulty deciding how that works in the action economy. I'm thinking maybe it's a full round action to take a bent metal bar and hook it around the rope then jump. I'm also considering having a DC 15, acrobatics check, that on any roll below a 5 they fall (into water below), and anything above that they fall prone at the landing site.
I'd do standard action for the bar unless it's particularly large, then move action to jump, including half a round's movement down the line--so, almost exactly the same. Acrobatics check sounds about right too, or maybe a Climb check since the action is similar to hanging onto a ladder on a moving train or something--up to you.
Sounds like a fun game! Though the mood may change for the silly if all the enemy pirates flub their rolls and faceplant into a pile of scalawags.
Shouldn't they move faster then their typical move action allows considering gravity and what not?
Oh, absolutely. I meant however far they could move along the zip line in half a round. That part's up to you and Pythagoras.