I can anderstand it perfectly! Don't know why but government policy is to decrease the number of places for launching your boat. At every water-side
they dump bricks and rocks to protect the river-shores and I think also to prevent launching.
In Rotterdam for instance there is no slipway at all. Nearest point is Alblasserdam.
Furthermore I don't mind to pay for something where there is a counter effort but prices like 15 or 20 euros in a harbour just for using only ones(!) the slip is a bit too maddening for me!
Launching your rib the way like the picture shows isn't a big problem. That is, as long as your boat is not too heavy, say up to 5m. It just needs some muscles!
..........(\ @ @ /)...........