Buddies out mackerel fishing today came upon a giant great white shark like they’ve never seen before “bumping” and “nudging” a dead whale and then circling their boat off Martha’s Vineyard. The line from the seminal shark flick “Jaws” quickly came to mind for the crew –“We’re gonna need a bigger boat.” The monster of the sea was “20 feet” long, said captain Jeff Lynch of Chilmark. “To see something that big was crazy. It was as big as my boat.” The shark had zeroed in on a dead minke whale that was tangled in lobster gear and died. The shark, he said, kept at the whale but never chomped down —possibly sensing it was long dead.