The drum must be turned.  The easiest way to accomplish this with the current design is to rest the drum atop axles which turn in unison.  The axles are joined with a roller chain and matching sprockets.  The sprockets are capable of being rotationally fixed to the axle via set screws or a key and in our case, set screws were utilized.  The axle was marked and small flats were drilled into it for the set screws to seat in.

This mess of metal and grease is not going to last years outside without some protection so a housing was made to protect from the elements.  It's well in the category of "can be mocked up in situ" rather than well thought out in advance.  Left brain or right brain, whatever gets the job done around here is good enough!  You can see it sits flush with the frame on the sides but atop the axles.  I will be notching out the space for the axles to pass next time I'm working on it.

The next concern of note will be connecting the gearbox to the axles.  I have the first one I got still.  It's an old winch from Harbor Freight.  I still have the old pulley attached and I think we'll defo want to update that bad boy.  However the belt and pulley is a promising start for this as it has been planned all along to incorporate a clutch mechanism to disconnect the drum from the turbine.  The easiest way to accomplish this will be to use an idler pulley on a beltway to disengage the belt when necessary.

The winch fits well enough on this frame but may be too close to be functional, considering more components are to be added to attach it.

It's time to discuss the math going on here so we can determine where improvements will be made later on.  This drum is 48 inches in diameter, resting atop two axles of a 1 inch diameter.  Our current gearbox is a 40:1 ratio per the manufacturer's specifications.  So our current ratio is as follows.

Axle to Drum
Driving - 1" D x pi = 3.14" circumference
Driven - 48"D x pi = 150.8 circumference
150.8 / 3.14 = 48.02 so 48:1 gear ratio, eyeballed.

Gearbox
40:1 (trust the spec sheet)

Above math subject to criticism.  If we consider then that for the drum to rotate one time, the axles must rotate forty-eight times.  Assume a 1:1 ratio from the gearbox to the axles.  And calculate the 40:1 ratio of the gearbox, we will conclude that for the drum to rotate once, the turbine will have to make 1921 revolutions.  Almost a 2000:1 ratio.  We'll see if that's enough torque once we've got a load in this thing!