Your character will start with a Average Crit due to the duress that months at sea bring and being chained as a slave and underfed. It will not have an ongoing effect. You can creatively think about what exactly the crit is from. Maybe your bare feet have Trench Foot. Maybe it's malnutrition or some sort of mental duress. Maybe it's an infection from the whip cuts.
Also, you will eventually get your starting equipment. Somehow. If/when you escape slavery. For now, you start with rags for clothes. That's it.
The ship you are on is similar to a Longship (https://en.wikipedia.org/wiki/Longship). It has stopped many times anchored out at sea but you have never been allowed off. It is an Orc ship. There are many warriors aboard. Anyone that has exhibited any magic or has even been suspected of having magical capabilities have been killed immediately.
If you want, come up with a secret that your character has. Something that he/she wants to keep from others.
These are some great questions you could answer for your character. More important is getting your Fear/Desire/Strength/Flaw as per Genesys core rules.