What human and natural variables could prolong the Middle Passage across the Atlantic?

Human variables:

1...Navigational accuracy or error.

2...(related to 1) Good or poor judgment of where the best slant of wind was to be found

Natural variables:

1...Normal variation in weather. Although the trade wind is normally steady and strong, there are sometimes periods of light airs and even calm.

2...Catastrophic weather. Storms might interrupt the voyage, forcing the ship to heave-to for days.

a) the colonists began to see themselves as different from people in britain.

is there answer chooses?