Dart 15 Trampoline track rivets , Price each.Large penny Aluminium rivet helps spread the load on splitting tracks..
On the Dart 15 tracks with the smaller bolt rope , metal fatigue can cause the track to split. This is partly because the age of the rivet and as it loosens slight movement will eventually spit the track (see picture) or brake the top off causing the track to bend, This will be an expensive job to replace the track.
If your boat is 20 years old then it is likely the rivets are too.
Steve`s Tricks of the trade
using a 5mm drill bit carefully drill off the top of the rivet only, do this on every other rivet then nail punch the remains of the rivet into the boat.
put in the new rivets and pop with gun, if using a hand gun wrap the handles with a towel,there are a lot of rivets to do. ( sealant can be used but not necessary unless you plan to go around the world on it)Then you can do the same with the other rivets. I always put in an extra rivet to double up at the ends of the track.
The standard rivets for newer boats with the dart 18 type track are SSM Medium in Marine fixings