Prior to the Zulu War I imagine it was a commercial enterprise, whoever crossed would pay for the pleasure.
At the start of the campaign Mr. A. Daniells was paid for his service. After iSandlwana there was an account ledger maintained by Harford which shows that some of the European N.N.C. non-commissioned officers received extra pay for operating the ferry. Subsequently British troops undertook the task.
The other ferries were on the Thukela River, rather than the Mzinyathi River.