Been ill, and at 4am while out of it, had an idea - original idea for the tank meant on materials, that I could do without at the mo. Saved that idea for the next tank.
Cut two 'blades', tack 'em together.
Having worked out holes distance and sizes, mark up and make blades like Swiss Cheese. Separate blades.
Make metal tee from sq tube, clamp in vice. Spend ages lining up the blades either side of the tee horizontal tube - spirit level, eye, inventive swearing (cussing).
Cut lengths of tube in various diameters. Insert and tack round the insides of the blades.
Tack a strip of steel to the top. Cut down to match the taper, and finish weld. Can't see it in the pic, but the thing gradually tapers to a sharp point at the back end, and curves in at the front.
Chop down the protruding tube stubs, finish weld.
Stick to tank, job done, a lightweight holey spiney Thing. Here 'tis with a coat of plod about to get DA'd:
