I have visited the monitor SMS Leitha/Lajta last Wednesday. The ship is 'run' by the Institute and Museum of Military History of Hungary, and is free too visit until November. Guided tours are run every half hour until 4pm. She's anchored right before the Parliament building.
The tour begins at the foredeck, in front of the gun turret. I believe you can find most details elsewhere and if you take the tour, you will be told all of it, but in short: after the success(?) of the USS Monitor, European powers began building their own. The KuK Navy had two purpose-built in the 1870s as part of the river flotilla. These have a less deep hull than seafaring monitors because of the shallow Danube riverbed.
The Leitha was in service from 1871 until 1918, refitted multiple times according to the age's requirements. The current state of the ship resembles that of the late 1880 - early 90s. After disarming, she was used for dredging duties until 1994 - certainly a long and eventful career. Restoration had started at the beginning of the new millenium.
The circle shows a dent of a grenade hit on the vaulted steel deck. It must have come in an acute angle so no surprise it bounced off, the guide used this to demonstrate how well-clad the Leitha was.
The tour was, by the way, led by a very nice lady and there were only an elderly couple besides me as visitors so it was cozier than a full tour. There are some very narrow doors inside and the average headspace of the lower deck is somewhere at 1,5 metres, so I felt very uncomfortable at places - luckily enough I'm not claustrophobic and do not have to spend my service as a KuK sailor!
These gentlemen represent the living conditions on board: at the later periods of her service, the Leitha was manned by 57 people - on a 50 by 8 m (357 BRT) area.
Late 19th century carbines, basically the only equipment that are not replicas.
Senior NCO's quarters.
The first version of the turret, weighing multiple tons, was rotated using human power (and this thing above). Later a smaller steam engine was built in for this purpose.
Boiler of the steam engine. The ship could only reach a speed of 8 knots and had to be towed on some parts of the river.
Two models of sister ships for wargamers.
Pistons of the steam engine - these are able to move, but they are replicas.
Stamp of the hull builder, a British company, visible on one of the beams.
The side corridor is about a meter high, it requires some serious crouching.
Commander's quarters with the Kaiser looking right at me.
Coming up at the aft, we inspected the boats, the first water flush toilets implemented in an European navy (the two structures on the left and right side), and the place where, in the later stages of her career, the first aft-mounted gun was placed. Of course the structure on the main deck prevented the turret from shooting backwards, so before adding the secondary armament, the ship's rear was not protected.
Main armament inside the turret.
Secondary armament on the gun deck (as was called by the guide). This is a Nordenfeldt gun (and not a Gardner, I asked and the guide couldn't tell, so I used my google-fu to solve the puzzle). It can be rotated and aimed vertically - at least with greater ease than the main cannons.
The first battle station for the commander was this steel keg (it had an entrance only from below originally). Very comfy if you ask me.
I failed to take a photo of the steering wheel that was also on the gun deck, so here's the last photo, of the secondary armament trailed on the Parliament and the smokestack that can be laid down when moving under bridges. Pretty smart.