The phrase "full sail" means to go forward with great speed and force, like a ship moving at its maximum speed with all its sails unfurled. Full definition
To do this, get in close to the island, keeping the ship straight and at full sail, then hop off as you near a beach or a dock. (digitaltrends.com)
When looking at this photograph, in addition to thinking I look like a ship in full sail, I can't help wishing the dress I was wearing was a little longer. (mumshideout.com)
It gives me some flow, but I don't feel like a ship under full sail! (whenthegirlsrule.com)