using 'off' or 'from' in a sentence

The joys of prepositions!

You may jump from a ship, from a train, from a step, from a height. You jumped in a direction whose starting point is defined by "from".

You may also jump off them. You were on; after you jump you are off.

You may do something "at the right time": it is done when the time is right. "at" refers to a particular time (e.g. at ten o'clock, at the beginning of the year, at the dawn of time, at the time I married etc).

You do not do something on the right time even though the expression is confusingly close to expressions such as "The train arrived on time", "the plane left on time", both of which tell you that the time was the same as that predicted "on" a timetable.

So "you jumped off the ship at the right time" is the correct conventional version.