I don't know much about antennas but I zoomed in on the photos to try to see how it's set up.

To me, it looks like the co-axial cable enters the tube at the bottom but then continues up the tube exiting out the top where it is fed down the outside finally terminating in the loading coil.
That suggests it is base loaded but I can't see how it is finally connected to the tube antenna.

Also wouldn't the tube antenna have to be separated in the middle for centre loading to work ? So could that black plastic collar around the tube below the coil be holding the two halves together ? Maybe there isn't enough detail in the images to work it out.

Don't short antennas for MW have to be entirely helically wound to work properly ? I think that's what Radio Caroline tried on the Ross Revenge but it went up in flames.

So can a 15 feet short metal pole put out any kind of decent signal on MW even with a coil ? Unless you ran 100W or even more to get 1W out.

Perhaps the experts could explain please ?