Fair enough, but you will be questioned upon it when you return. Kindly don't forget, or evade the questioning.
Any provision of a contract that entails accepting greater risk in order to maintain production parameters obviously equates to endangering life. If the maintenance of schedule is paramount and enshrined in contractual obligation, such a contract could be considered unconscionable.
However, there is considerable informal pressure to maintain production parameters, and this is evident in the shipping industry. In his book Normal Accidents, Charles Perrow points out that there have been several significant advances in technology designed to improve the safety of shipping. However the accident rate has remained flat; it has not decreased. He finds that this is because shipping companies use the additional safety margins to increase production. This understanding has had profound effects in the engineering industry, where we discover that there is a normalization of risk that can lead to complacency.
It's plausible to believe that the captain of MS Estonia felt pressure to maintain his schedule. But to say that he was contractually obligated to do so smells very fishy.
If the shipping company owns or operates the docking facilities, it literally doesn't matter when the ship arrives.