This is all outside of my pay grade, but here is more:

"Reg. 105, Reg. 106, Reg. 107
SHELLS, ANGLE RINGS, BUTT STRAPS, ETC.


Angle Rings

Angle rings for the attachment of end plates to shell plates and/or flue sections shall be rolled or machined so that they fit closely to the flat and cylindrical surfaces to be connected, and shall be machined or machine gas cut on the caulking edges.


Reg. 106
SHELLS, ANGLE RINGS, BUTT STRAPS, ETC.


Thickness of Shell Angle Rings

Where shell plates and end plate are connected by means of an external angle ring, the angle rings shall be no less in thickness than as follows :-

(1) For shell plates upto and including 5/8 inch in thickness. 10 per cent in excess of the thickness of the shell plate.
(2) For shell plate exceeding 5/8 inch in thickness and upto and including 1 inch in thickness.
90 per cent of the thickness but not less than 11/16 inch.
(3) For shell plates over 1 inch in thickness. Made from angle bar having a section thickness of 1 inch.


Reg. 107
SHELLS, ANGLE RINGS, BUTT STRAPS, ETC.


Welded Shell Plates

The requirements of welded shells shall be covered by the provisions made in the Regulations in Chapter V or Chapter XII, as the case may be.

The working pressure of such shells shall comply with Regulation 176 where J = 100 and C = 2.75.

Reg. 111, Reg. 112
SHELLS, ANGLE RINGS, BUTT STRAPS, ETC.


Alternative Construction

As an alternative to the tucking of butt strap ends under the shell rings, the ends may be terminated at the edge of the shell rings or ends and electrically welded thereto.

Reg. 112
SHELLS, ANGLE RINGS, BUTT STRAPS, ETC.


Local Welding of Butt Seams

(a) The ends of longitudinal butt seams of shell rings may be welded for a length not exceeding three times the overlap at the circumferential seam, provided the butt straps are run as closely as practicable to the circumferential seam.

(b) Only metal arc welding of the butt seams of shell rings shall be permitted.

(c) Where hemispherical shell crowns are pressed from plate they shall be pressed to form by machine in progressive stages without thinning and on completion shall be annealed."

With my HS shop class knowledge of welding I can't say if the above nightmare would meet any of this.

Even by third World standards this is some pretty shady work. I am sure you could probably display this in a military museum and call it a "early improved explosive device".

I believe that is the last remains of the jacket.

Ok, I can see that that one ugly patch at the top of the throat looks like it was cut around....not over top...that (jacket) sheet, so that makes sense... although why any portion of the jacket would survive except to shield the crew from steam leaks in the cab remains a mystery.

Now for pictures of the inside....!