According to wikipedia this is the less likely and imo less interesting explanation. They did find coconuts that are genetically distinct from the ones the Spanish brought over from the Philippines, but those ones are more distantly related to the ones in polynesia so they probably didn't float over. Instead they are more likely evidence of pre-columbian contact of Polynesians with south and central America, along with sweet potatoes originating in South America but being present in polynesia and SEA prior to columbus.

So this would boot Columbus off the podium in people who discovered America.

1. Bering strait people / native American ancestors

2. Polynesian people

3. Vikings, Leif Erickson

4. Columbus