Well, let's look at this thing subjectively...
OP sez it is 7' x 10', I take that to mean it is 10' long and 7' wide at its widest end..but it is not in a V-shape...the far end, appears to be about 3' wide. In other words it has a trapezoidal shape.
The 10' lenght....plus the trapezoidal shape ....to me..means it is too short and the wrong shape for a dink.
Moving on. It has a large symmetrical hole in the middle, that appears to be about 9" in diameter. This hole has reinforced edges. The shape and size is wrong for any kind of mast. But this hole does not have a zipper or anything, so it is designed to "go over something " short and round", another clue it is not for a mast of kind.
It has another hole on the wide 7' end, near the edge....but that hole has a zippered opening on the wide end. That particular hole...to my eye has more of an oblong shape....it has a zippered entry, in other words, it is designed to push over something and then zippered up.
A similar hole appears to be on the narrow 3' side.. also with a zippered entry.
Both holes have a "cuff"
Then you have those short sections of rope
with a wood handle on one end, and a clip on the other. The wood handles appear to be meant to be used as a tightening device, as one side of the rope
is knotted and the other side simple goes thru' the hole on the wood. I think the clip is attached to something, and then the rope handle is used to tension the rope.
On the starboard side of the fabric
, are two more holes. These holes appear to "half-holes" with a leather reinforced edge. They both have an opening, meaning it pushed over an object and then closed up.
Only the starboard side appears to have these holes. The port side has none.
I think we can eliminate that is a dink cover. I also think we can eliminate that is an awning of any kind.
I have googled Gemini
cats and have seen nothing that would suggest it fits on a Gemini.
It could have come off another boat. It does not appear to have seen any use. My 2c....at this point....is that it does not belong to this boat.