In the UK we look at the rotation from behind the vessel and the direction of the topmost blade. It goes right for forward, right handed. The continentals look from inside the boat. If buying a prop originating on the continent, remember the difference.
Whichever, it is vital to fix it to the shaft properly. Have a serious read about lock nuts and how to apply them so that they work and are not just an ornament, and a dab of Locktite helps enormously as well. Many a prop that in theory winds itself tighter in normal forward use has unwound itself very rapidly as soon as reverse was applied.
