So one of my players is considering his new character to be a far strike monk from a dwarven whaling community, and he really likes the idea of grappling with the harpoon. He's been going on about all the things you could theoretically do with a ranged grapple weapon and they are super cool. Unfortunately, as far as I can tell scouring the wiki, the mechanics are not really fleshed out at all because it doesn't seem like paizo really considered grappling with a thrown weapon (I would really like to be proven wrong.) Immediately moving a grappled opponent to an adjacent space might be more viable in some situations, but not all (and it doesn't exactly make sense for someone to pull a creature all the way to them in one turn, especially if they were to throw the harpoon at it's maximum range of 50 feet.)
So, to get to the point, here are an amalgamation of ideas between me and the player that sort of flesh out the idea of grappling with a harpoon. I want the experts (you guys) to really give considerations of balance here. I should add that all these ideas are for grappling outside of the harpoons melee range, and everything would go back to the standard grappling rules should the attacker move into threat range of the defender.
-if the defender of the grapple destroys the rope, the grapple is lost along with the harpoon, however, the escaped defender moves at half movement unless they take a standard action to remove the harpoon from their body first.
-the attacker can only move the grappled target towards their direction. The attacker may choose to stay still or move in the direction they are pulling the defender. If the attacker stays still they can only move the grappled target 5 feet per round plus an additional 5 feet for every 5 points the attacker's CMB to maintain the grapple exceeds the defender's CMD. If the attacker moves away from the defender, the attacker moves both the attacker and defender at half the attacker’s movement speed. If the attacker attempts to move the defender into a hazardous space in this way (let's say off a wall or a cliff), the defender still receives the immediate grapple attempt at a +4 bonus.
-The attacker can attempt to tie someone up by completing a full circle of movement around the defender. This attempt is made at the normal CMB -10 vs. the defender's CMD but is made at a distance, rather than while adjacent to the the grappled defender and is triggered as part of a move action once the circle is completed. If the attacker has the Equipment Trick combat feat ability "Hogtie" this is done at a -5 penalty to CMB instead. Because the bonds of the rope are looser than they would be if the attacker could actually tie up the defender, the DC to escape being tied up is instead 10 + the attacker's CMB unless the attacker moves to be adjacent to the defender and sures up the knots with a standard action, in which case the DC becomes the normal 20 + the attacker's CMB to escape being tied up.
-if any creature moves between the attacker and defender while maintaining a grapple, the attacker may attempt a trip maneuver as an attack of opportunity. This is limited to the number of attacks of opportunity the attacker can do per round (so one, unless they have combat reflexes.)
So, rip me apart forum. How broken is this? All this only happens on critical hits anyway, so my thought is maybe it isn't too broken but I do have a history of giving players more abilities than is maybe good for game balance.
Additionally.. what is the AC of rope? I might need to know this for the first idea and I cant figure out how to determine the size category of a length of 50 feet of rope. Does the AC of objects change if it is attended to?