If that sleeve is cracked and leaking water into your boat you will need to repair it.I like Gluvit Epoxy waterproof sealant for this repair.Before you start epoxying that sleeve, you will want to thoroughly clean out that sleeve with acetone. I built a tool. It's a long plunger with a rubber stopper screwed into a piece of old broom handle..........that way I could pump acetone in and out of any crevice to better clean and increase the bonding of the epoxy.
I made my drum sander with a ceiling fastener (lag style screw in on one side and a 1/4-20 coupling on the other) that screwed into a 24" piece of old broom handle. Than I duct taped long pieces of emery cloth on the other end and built a drum sander the length I needed. Install the hex end of 1/4-20 coupling into my variable speed 1/2" drill and sanded away slowly..... now vacuum and clean again
To get the epoxy into that wing socket, I took a paint roller and straight out the steel rod to form a long Q tip. This way I was able to cover the entire inside surface of that sleeve. I could pump the epoxy in and out of any crack. Apply epoxy in thin layers for less sanding.
Let sit over night and lightly hone out that sleeve again with the drum sander to fit................
That should seal your wing sleeve but may also want to rebuilt that fiberglass sleeve by wrapping the outside of the sleeve with fiberglass and resin. This will require a new access port just to reach it.
The sleeve is fiber glassed into what looks like a cereal bowl upside down and that's fiberglass to the inside of the hull partly of the bottom and partly on the side of the hull. This "horn" is rather thin and a weak link to the whole wing system, In my opinion.
My aft port side horn broke loose once while sailing offshore in high winds on Lake Michigan with my kids. I have a triple trapezes system and we overloaded the wing. Pretty scary situation. We sailed straight to shore..................and so these repairs where needed.
and our sailing vacation was shortened..........
But now my wings sleeve are Bullet Proof...........And I can really drive my boat hard........