The following video shows on a bench demonstration how the blades engage into the reverse position when reverse gear is engaged.

It also shows how from either of the possible starting positions,  the Tri Roller will initially rotate if required to engage a flat on the Tri Roller, and then rotate further as the reverse position is adopted.  The internal dog in the boss of the unit allows rotation of the Blade Carrier Assembly about the Boss by 100º before forcing the entire assembly to now rotate in a reverse direction.

The blades will now under pressure from the water adopt a maximum pitch position independent of the pitch screw setting.

At the end of the reverse engagement the internal torsion spring will return the Blade Assembly to it's feathered positon. This again allows the blades to freely feather from an Ahead position with the pitch screws touching the pitch stop faces on the tripod casting - to a trailing aft position - to an extreme position ~ 25º over centre.

This is designed to allow the  blades to remain feathered by following  the streamlines of the water when the shaft is at an angle to the hull and/or there is leeway from sailing on the wind and again the lfow is at an angle relative  to the  shaft.

Reverse Action Video click to play: