Even if you are a lady pirate you better wear pants at sea. For example these knee-length blue and white striped pants. If you are not very comfortable at sea, you can also use these pants for a medieval costume.
This underbust corset with a high neck made from russet leatherette with a tear-like structure looks like it withstood some weather fronts. As a steampunk pirate you should be ready for nasty weather on the sea as well as in the air.