What was most shocking about life on board a slave ship during the middle passage?

Many slaves were packed onto ships in dangerous numbers. They were so close that the slaves often had to sit in their own sick. The number of slaves on a ship were determined by the captain, and were known as "tight packers" or "lose packers" depending on the number of slaves they would pack on a ship. 
Some slaves tried to jump off of the ship and simply drown themselves, and others would stop eating. The captains forced the slaves to eat. Slaves were only allowed 30 minutes of deck access every day, in a journey that could last from weeks to months.