I was sailing in ss Monark August 1958 - until about March 1959.
Monark , built in Oskarshamn 1917 as Masilia for Svenska Lloyd, was for its time a modern ship with Schmidt superheater, forced blast, Howden air pre heater, pneumatic (Vacuum) ash lift and two stage feed water heater but was still coal fired. She became Sweden's last coal-fired steam boat.

Wow !

I haven't a clue all i know is it's a classic picture love the old stuff thank's herringbone 10/10

Now only the location remains, Grangemouth ?

I have put in the Miramar sourced IMO number, but it could be incorrect. However it is more likely that the GT database in use here, that is triggered by the IMO number, will have no reference to this ship.

Thanks for your early response Pieter and Manfred
I have amended the original photo details I posted

Manfred, I had not found that picture, but further searching seems to be unnecessary. We can now be certain which MONARK is depicted above.

This is the one you mean Pieter:
https://digitaltmuseum.se/021018572622/fo161471dia

There was a MONARK operating in Sweden from 1956 to 1964. She was built in 1917 as Massilia by the Oskarshamn Varft, and measured about 2200 GRT. In 1964 she was converted to a barge. Her IMO number seems to be 5239254.

The picture the CASTORP that I have, meets your description found in Ships in Focus and is definitely not the ship in the picture.