Maxprop doesn't have springs - at least mine doesn't. Its the centrifugal force that turns the blades from zero pitch (feathered) to maximum pitch (preset), when the forward or reverse gear
When motoring forward and killing the engine
its sometimes necessary to put the gear in reverse to get the prop to feather while sailing.
This is a feathering propellor. The pitch is only adjustable by taking the prop apart and resetting the internal gears.
A folding, or yacht propellor has its blades thrown out by centrifugal force when the shaft turns and the blades just fold aft when the shaft stops turning. The pitch like a fixed propellor is a function of the shape of the blades and you can't change it yourself
There are other props called Autoprop, Gori et al which are fully pitch-self adjusting props according to direction, load, engine
Variable pitch prop systems, like Hundestat, are complicated and expensive, but allow the control, as said by a lever at the helm
so the pitch can be fine tuned for the conditions you are encountering. These are not common in small yachts as the mechanism is quite big and heavy. Steve Dashew used one on his 78ft Beowulf
You always need a gearbox
of some sort...even with a variable pitch prop you need some method of disconnecting the engine from the shaft.