itma
Queen Bee
I've only just begun and have nationals ... however I have learnt how heavy they can be when loaded with honey/bees. So I am considering poly hives or a weight lifting course!
The weight lifting course would be a better option.
Poly boxes are only a fraction lighter than wood when they are "loaded". The weight is in the load, not the box itself.
There are however plenty of better reasons for going over to poly!
Nationals aren't "big" boxes - comparatively.
But there are hives that use smaller boxes. You could even use 3? national shallows ('supers') as a brood unit ... and "half supers" (taking half the number of frames and stacking 2 to a level) exist giving a lighter lump to shift ...