I'm generally a cautious guy, but...
Given the right wind, at slack tide, yes you can do it. I did it once in a Seafarer Ranger, and once in a Cape Dory 27, without using the engine.
You need a reaching or a following breeze of at least 10-15 knots, and SLACK (I mean it, slack, or slightly starting in your favor) tide in the Hole. If you don't have the patience to wait at Quisset or Falmouth for those conditions, then by all means get an engine, or just don't go.
Without an engine, you have no redundancy if the wind and current don't play out as you had hoped.
Given the right wind, at slack tide, yes you can do it. I did it once in a Seafarer Ranger, and once in a Cape Dory 27, without using the engine.
You need a reaching or a following breeze of at least 10-15 knots, and SLACK (I mean it, slack, or slightly starting in your favor) tide in the Hole. If you don't have the patience to wait at Quisset or Falmouth for those conditions, then by all means get an engine, or just don't go.
Without an engine, you have no redundancy if the wind and current don't play out as you had hoped.