Almost dropped mine in the deep end on my first time out. Didn't like how close it was to the outboard prop, so kept it in the cabin till we got away from the ramp... Went to put it on & lining up the pintles & gudgeons at that angle while keeping the latch clear was very awkward. Throw in its weight, and not too hard to imagine shedding a tear as it vanishes into the abyss.
Have since kept a line connected to a stern cleat, just in case. And a "cajun tiller tamer" keeps the rudder clear of propeller.
There's some diagrams
on the S16 Association site. I'm sure they'd give you more specifics, and maybe a lead on a spare.
If it's a man made lake that gets drained in the Fall, you could end up with a spare for next year.