Larian Studios Forums Divinity: Original Sin 2 Divinity - Original Sin 2 - General managed to get on Lady Vengeance , the big ship.

My guess with teleport:
http://steamcommunity.com/sharedfiles/filedetails/?id=850215857

There is a really little part where you can get too, but not with for example Tactical Retreat:
http://steamcommunity.com/sharedfiles/filedetails/?id=850217617


Not sure how tough, the distance is over 18 m and it works if target even stands beside caster.