I had a very similar thing happen to the strake on my Humber but down the side - I wanted to tidy it up and did the following.
bought a tube of bostic inflatable adhesive
and cleaned out the gap as best I could with a piece of cloth.
Forced some glue into the hole and then squidged it all around until all surfaces where covered.
Left it to go tacky then pushed it back together and held for as long as I could - to my surprise it worked and stuck well.
This was strictly an amature repair and it was probably under less load than your example as mine was on a straight rather than a curve. but worth a try for a fiver.
There are probably better glues than this - I have heard people talk of bostik 2402 2 part adhesive which I assume is stronger but not sure if it gives as instant a bond.