that brings the nose to its destination (or actually brings the destination to the nose). now we instantly stop the nose, which springs l back to its original length, bringing the tail to its final destination. we're done. the time it takes to do that is the same as the amount the clocks get out of sync between the nose and the tail.
so if i have a ship that is a light-month in length and i want to get the nose of the ship to a planet that is a light-year away from the tail, l is one light year. i need to compress l to a 12th its size 