Gwen the Pirate

The seafarer’s Sheltie, climbed onto the Oyster Star
To be taken to a far away land;
Her rider, the captain, maiden Gwen’s bars
Would let aught know she was not a man.

I tried my best, but I don’t know if this is going to be a good one or not. I think the terminology I used was too obscure. It was a Prompt on Quora. Lol.