Sailing speed reduced to slowest ship?

[Dusk]

Your sailing speed when not in combat...

is it based on the speed of your slowest ship

or is it based on number of ships?

Because then I might think twice before hauling great galleons with me to carry all the luxuries and stuff...

 

[nem]

Any ship you have in your fleet in addition to your flagship will inevitably trail behind and your flagship will slow down so it/they can catch up. This definitely goes for ships as fast as and slower than your flagship. Haven't tested it with ships faster than the flagship though.