You may be looking for the Bodkin Boats League modpack which this mod is used in!
This mod makes it so boats share their velocity and WASD inputs over the network so other client can show the true position of other boats more accurately.
When boats collide custom physics is used from Dyn4j, which factors in the rotation and velocity of each boat.
See licence for lib: https://github.com/dyn4j/dyn4j/blob/master/LICENSE.md
