The Natal Line owned by Bullard & King had been purchased by the Union-Castle Line in 1919.   It then became the practice to put pensioned off Union-Castle ships to Bullard & King giving them Natal Line names prefixed by Um.

The UMKUZI (above), 1903, was built as Union-Castle Line's CLUNY CASTLE  and transferred to Bullard King in 1924.   

In 1920 the 1894 SABINE and the ROSYTH CASTLE became the UMZINTO (II) and UMLAZI (II) respectively.   The latter was a WW1 standard freighter and to the end retained a single pole mast.   

Then again, in 1924, two ageing Union-Castle ships, the "extra" steamers and sister ships CLUNY CASTLE and COMRIE CASTLE were transferred to the B-F flag and became the UMKUZI (II) and UMVOTI (II).   They had been built in 1903 and 1904 and, at 5,100 tons,  were the largest vessels of the B-K fleet.   

Both gave long service,  the UMKUZI being scrapped in 1939.

Both were twin-screw ships and did the UK-Cape passage in a leisurely 25 days.