Heeled into the stiff wind, with the jib straining, the rigging humming, the bow cleaving the waves and spray cascading over the fore-deck, you seem to be making great headway.
But a glance back to the shore confirms the truth.
Something about that island you are trying to leave seems to be holding your ship in its thrall, as if an invisible rope stretches back to the shore.
But it is not the island's gods preventing your escape.
It is nothing more than the tides. You have started your voyage at the wrong time. You must give up this vain attempt, furl your sails, drop your anchor, and go below.
You must sit this out and wait for the tide to turn.