Unbuilt Austrian 1235 ton Monitor Project, 1916

The part of this design which fascinates me is the swing-down funnel.  I wonder if this was intended to reduce its profile to counterfire?  For a monitor, I'll opine that this is an attractive aesthetic design, and symmetrical.  Few monitors had such qualities.

Peter Klein writes to say:

By all sources I own, this should have been one of the many unimplemented projects of the Austrian Navy in the time of WW-I. There were no capacities for such efforts. At least the guns would have been a not resolvable problem. My first intention was, that they should have taken from a Pre-Dreadnought battleship, but those were 42cal. If they did not intend to shorten the barrels, the weapon must have been a new design. In the books I check, there was no new monitor built in WW-I in Austria.

Pavel Simacek writes to amend:

I just read a four year old contribution by Erwin Sieche about Austro-Hungarian Danube fleet at WWI archive. The contribution is in turn excerpted from "Austro-Hungarian Warships In Photographs, Vol. 2. 1896-1918" by Baumgartner & Sieche, so you may check the volume - I am no expert. However, the following matches your ships too well to be an accident. Quoting:

There were plans to replace the 46 year old veterans Maros and Leitha by two 1.240-t displacement monitors in 1916. They were to be armed with 7.5in (19-cm) and 3.5in (9-cm) guns. The new ships, monitor No XI and No XII were planned for construction from 1917-18, but were never completed by the Linz shipyard.

In October 2006, Jaroslav Tvrdy wrote to offer:

The drawing is most probably one of the alternative projects which led to final technical documentation drawn for Monitors XI and XII. The final plans of these monitors were discovered in Linz years ago and a big model (scale 1 : 25) was built and displayed in Vienna Military Museum.

The main difference between the project in your collection and final drawings is the absence of additional turret for single 9 cm/ L45 gun, which was mounted in the centerline on a superstructure in the after part of the monitor.

In July of 2017, Bill Saalbach emailed the following astute observation regarding my musing about the swing-down funnel:

I believe the folding funnel was to allow passage beneath low fixed bridges. The Danube would certainly have a number of those. Since commercial river traffic was typically low barges or small passenger launches, drawbridges or high bridges were typically built only where preexisting large vessel traffic forced the issue.

Folding funnels were fairly common on coal-fired tugs, which often had to move lighters up industrial waterways which were not fully fitted with drawbridges. An picture of a historic tugboat with a folding funnel can be seen here. Similar folding funnels are apparent on earlier Austro-Hungarian monitors such as these.

The monitor's radio masts appear to have provisions for swinging down, leaving only the searchlights to be unshipped to provide a uniformly low profile.