The Old Ways are Good Ways
I read somewhere that in creating bungs it was not a good idea if you drilled a hole through the axis for the retaining string, as it would leak. Instead drill across the bung. Good idea I thought - never seen it before - but it would have the advantage of stopping them pushing the bung too far in.
Discovered the error of this argument - as the students tore the end off the cork bung leaving the remainder stuck in the hole. Of course drilling in this way had weakened it (not that cork is very strong anyway).
So now I have traditional arrangement with he string down the middle so that which ever way they pull on the string it will get the bung out of the hole, and they won't leak because the hole is not oversize (and besides I coated the string with silicone sealant)
We lost 2 crutches/rowlocks, as the students attempted to practise sculling over the stern. They were tied on but, unlike traditional rowlocks which have a decent collar just below the crutch, so that rope can be tied around them, these were of a 'modern' design with a sloping shoulder design so that the string just slid off.
It used to be that with rudders you engaged the rudder gudgeon on the bottom pintle and could then waggle the rudder around on this pivot to get the top pintle engaged on the top gudgeon. These days the fittings are identical requiring simultaneous lining up of both fittings. Not easy when hanging over the back of a boat with waves knocking the rudder around.
And so it goes on . . .