Anything moving on water leaves behind a trail that displaces water from rest of the water.
Let's assume a normal ship speed is 500 mpm with sails in full wind. Now with "water trail" that ship will go little bit faster as long as it stays in the trail. So if the trail is 50m long, chasing ship will get slightly faster as it gets closer to the ship thats being chased.
Speeds below are in full wind and chasing smaller ships is hard because trail isn't as big as it is for big ships.
Waves outside of the trail and wind can push a ship off the trail so someone has to be on the wheel.
Galleon speed: 600 mpm.
If the trail is 50m long, divide in an increment of 5.
Chasing a galleon, chasing galleon will gain 13 mpm per increment (665 mpm overall)
Chasing a brig, galleon will get faster at 10 mpm per increment. (650 mpm overall)
Chasing a sloop, galleon will get faster at 7 mpm per increment. (635 mpm overall)
Brigantine: Speed 450 mpm.
Chasing a galleon, brig gains 12 mpm per increment. (510 mpm overall)
Chasing a brig, chasing brig gains 9 mpm per increment. (495 mpm overall)
Chasing a sloop, bring gains 8 mpm per increment. (490 mpm overall)
Sloop: Speed 350 mpm.
Chasing a galleon, 13 mpm per increment. (420 mpm overall)
Chasing a brigantine, 10 mpm per increment. (400 mpm overall)
Chasing a sloop, chasing sloop gain 8 mpm per increment. (390 mpm overall)
Note: mpm = meters per minute.
This feature isn't meant to let slower ships catch up to faster ships or anyway around. It's just a feature.
Let me know what you think about it or how it could be improved. Thanks!