Uganda Journal - Vol 25, p. 43 - CMS Boats in East Africa by H.B. Thomas - ….. The 'Highland Lassie' under her European crew, Captain Canham with Harry Hartnoll as mate, eventually reached Zanzibar on 20 June [1876] "in excellent condition". For some years she acted as CMS despatch boat between Mombasa and Zanzibar. But she gave increasing trouble - she was underpowered for monsoon weather.

By September 1881 she was reported to be unseaworthy and was converted into a coal hulk off Frere Town. Note - Hartnoll accompanied Mackay up-country with the main body of the Victoria Nyanza caravan, leaving the Coast on 30 August 1876. It would be convenient to infer that this was the occasion for James Martin's joining the 'Highland Lassie', of which he is later recorded as mate. This would be in line with Joseph Thomson's remark, when engaging Martin early in 1883, that Martin had been  for over 6 years with CMS.

Hartnoll did not return to the 'Highland Lassie'; after a few months at Mpwapwa he was invalided to England.

Ujiji - Harry Hartnell [sic] came to East Africa to serve as mate of the CMS steamer 'Highland Lassie'. He later went inland to Mpwapwa where his colleague Clark said in praise "as nearly all sailors are he is a unversal genius."  Ill health forced Hartnell to return to Britain in 1877.

1871 Census has Harry Hartnoll [William Henry Hartnoll]

There appear to have been 2 more marriages [but this may not be the right man - he appears to be a printer in censuses].