I'm not familiar with the device, can you post a pic. It may just jog this old memory

If this is a Mistral Maui with a sliding track as far I recall it looks like this:



This is the same as the 1988 Mistral Equipe mast track red slider car- you just twist the red latch underneath the universal joint 90 degrees and it comes out of the mast track.








Watch this video of the Mistral Competition SST (which also has the same system) to ensure you understand this.



I hope this helps.