Here is the full list of all 26 Overboard! achievements.
Everything ship-shape in 4 hours or less
All of Malcolm's possessions, into the sea
Clean someone out at cards
Money, man and murderer in 2 hours or less
Discuss literature with the highest authority
Seven down
Six down
Everything ship-shape in 5 hours or less
Everything ship-shape and Bristol fashion
Talk someone down
Five down
Four down
Put an old lady to sleep
Get your way the hard way
Earn a small fortune for your efforts
Money, man and murderer in 5 hours or less
Get off in 3 hours or less
Get off in 5 hours or less
Reunite with Malcolm
Establish relations with an officer
Steer the ship
Three down
Two down
Allow the killer to escape from justice!
Get yourself a nice man
Get the killer sent to prison