Question about older H16

A friend of mine was recently given what appears by the VIN to be a 1973 H16. On the aft beam there are two small jam cleats set at angles. Any idea what these are for? Also, the boat has the old style jib cars with the built in cam cleats but the cars won't lock in the front tracks. Normally there is a spring loaded pin with a knurled knob but these have a strange looking metal disc with a pie wedge cut in them. Any clues? Sorry I didn't have my camera or I would have snapped a pic.

Well, the two jam cleats on either side are for the main traveler.simply tie two pieces of line to either side of the traveler and into the Jam cleats. I would recommend buying an accecory mountin plate and a swivel cleat and upgrading to the new style of traveler.

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'72 Hobie 16
with
#56 Gonzo Nationals