Hey,

My son who is 12 sails with me and he is small, was quite a challenge to sort a trap harness.

I made one from my old adjustable sailboard seat style harness with a webbing strap like a seatbelt strap to go up over shoulders. The harness has enough adjustemnt to downsize it to close to his size...only just though... he needs to grow some.

I sewed a loop at the back on the seat harness and run the strap through the loop up over his shoulders down to the hook / bar at the front - if that makes sense.

Have one of those plastic strap click together adjusters to make it tighten up.

The seat harness takes all his weight, the shoulder strap just stops it from falling down.

Maybe this helps and cost me nothing excpet some time.

Cheers, Drew