HMS Pelorus

Here's what launched us on our journey to learn as much as possible about her: a watercolor, ca 1830, found in a local fine arts gallery. It measures 8.50 by 12.50".
We can tell by the colours she's flying that the painting dates to before 1842 when her career as a ship of the Royal Navy came to an end.

The painting shows her with three masts, whereas a brig-sloop has two. We discovered that she began, and ended, her days as a brig sloop, but had the third mast between 1825 and 1830. This fact further dates the painting.
There is no indication of the artist, but the ship's name is clearly painted in the lower righthand corner.
For what we know of her story so far, continue here: