To have the wind free
"The trip from St Martin to Antigua has the wind free but the Equatorial Current forces you stay close hauled".
I am not sure about the meaning of that sentence.
Does it mean that the wind is running free but, because of the current, I must stay close hauled? Would I need to tack?
The definition of a 'reach' on Encyclopedia.com is: "As a verb, the act of sailing a vessel with the sails full and the wind free".
So I believe that if there was no equatorial current, the boat would be reaching. However the current is pushing you in another direction.
This vector means that you have to sail a different course to get to the same place. Instead of reaching (which would mean you would end up lower - in the wind - as the current would push you down), the boat must close haul, which would allow the boat to reach its actual destination (Antigua).
I think you will better understand this concept if you read about Vectors
Thank you for your interestingly mathematical question!