The Hobie 16 forestay/shroud/jib arrangement is unique and somewhat non-intuitive. The rig will be very sloppy and loose until the jib is raised. THIS IS THE WAY IT'S SUPPOSED TO BE. Do not try to tension the rig by dropping the forestay down in the adjuster.
There is a stainless steel wire that is sewn inside the jib luff. This wire becomes the forestay once the jib is hoisted and tensioned and the actual forestay wire will be totally slack. Use the 3:1 purchase on the jib halyard line to set your rig tension. Most likely the original owner had two adjusters attached to the bridle so that the forestay can be attached to the top of the upper adjuster and the jib tack gets attached to the lower adjuster. Once the jib is hoisted, a bungee cord can be hooked onto the upper adjuster to hold it forward and out of the way so the forestay doesn't flop around.
This page should have plenty of info to get you up to speed.
https://www.hobie.com/support/hobie-16/ sm