Hello, I'm still working various bits, lines etc on my Cavalier 28.
I'm a little confused. I am trying work out what appears to be a second boom vang on my boat, but I don't thin it is.
Is this a Cunningham or is it be used for reefing?
There is enough line to reach the cockpit, but there also appears to be a reefing at the mast end of the boom.
Pic here shows boom vang with red arrow.

Agree with above blue purchase is Cunningham.

is the lower section removeable? if so it could be a gybe preventer. attaches to rail?

It may be way too close to the front of the boom to use as a preventer. You will have a broken boom if you use it at that spot.
As an absolute minimum it should be at the vang, but at least some where near the middle and preferable at the end of the boom.
I agree that it is more likely a cunningham.

Thanks for your advice EC31, rumblefish, I'll go with the cunningham and upgrade the rope and set up a true preventer separately.
Thanks again all.