[Classic30]

The rig is a version of an Alden Jib Top Schooner:

Actually... no, it isn't. To start with, given that the after-most mast is lower than the forward mast, that makes it a Ketch.. meaning the rig is called a Staysail Ketch and the sail in question a "Fisherman".

Here's a pic of a bigger one:

IIRC the rig was devised before the era of powerful winches and meant that the "main sails" were of a size more easily handled by a small crew.

Whilst the rig is out-dated now, it's not at all uncommon.