They were delayed by lack of volunteers to fill two ships. Then the second ship, the Speedwell, after much delay and expense proved to be unseaworthy. The logistics of getting willing "pilgrims" back from Holland and now onto one ship and problems with the British authorities plagued the entire departure.

Further delays happened when a large portion of the party decided it was too much of a disorganized mess and went back to Holland.

So poor planning, inexperience and the whole thing happening while avoiding the authorities.

A dry read, but full of information.

Fantastic read

Edit: Specifically regarding the cold winter. They were aiming for much further south, present day Virginia. Not Cape Cod which obviously has much harsher winters.