Specialist stacking

A pirate sub's speed is 2x to a target and 4x back home.
If the pirate sails with a smuggler and a helmsman does that sub travel at
2x3x2 = 12x to target and 4x3x2 = 24x home
OR
2+3+2 = 7x to target and 4+3+2 =9 home?
Thanks!!
If the pirate sails with a smuggler and a helmsman does that sub travel at
2x3x2 = 12x to target and 4x3x2 = 24x home
OR
2+3+2 = 7x to target and 4+3+2 =9 home?
Thanks!!