Base saills +25% hit points

[Redish]

Can someone please explain what this does. It seems it has nothing to do with increased speed.
Thanking you in advance.

[Most Lee Harmless]

Hit points are the amount of damage a ship can take before it is defeated and sunk. They are divided into two parts : sails and hull. The proportion can vary between ship types. So a boost to sail HP of 25% can increase the amount of damage a ship can survive so it fights longercand thus inflicts more damage itself.
Speed is a seperate issue. It does get confused in the game by the way sails is used to describe both factors. A lvl 1 cutter has the same speed as a lvl 10 but far less sail HP, for example.
Voodoo can also factor into matters as can techs. SPANISH GALLEONS tech can boost both ship speed and hull points (in PVP).
So combining techs, traits and voodoo can turn a ship into a far more effective one but not always in an obvious manner such as adding more attributes.

[Redish]

Thanks