By Far took the longest to obtain, You have to let the ship sink.
Sounds Easy, But most crew would use all their wood to fix the boat then freeze to death afterwards, Takes some work.
One guy remaining, hes crawling around, and ship isnt sank yet? Put him in a bed to start healing cause a crew member has to be alive when the ship sinks for this to pop.
Spend the first 2 days making 5-6 barrel bombs, only set down 2 to 3 at once.
Barrels explode causing the max amount of damage to the ship (20-25 holes) people will come back, start to fix them, when they're almost done set off 2 more, rinse repeat until ships sank, for bonus points try also throwing all teh wood you can find into the river so they have a harder time repairing the ship.
It takes Work though, not going to happen on your first try, many crew will sack themselves fixing the boat.
GL!