The Manx government says it is ready to sign a deal to take over the Steam Packet Company (IoMSPC) for £124m.
Last year Tynwald rejected the current operator's "best and final offer" to continue running services beyond 2026.
The multimillion-pound buy-out plan was approved by Tynwald on 15 May with only one MHK voting against it.
The Manx Treasury said the deal would bring "operations into public ownership" although government "would not take over the day-to-day running".
Treasury Minister Alfred Cannan said that while the buy-out was "not a proposal to nationalise the company" it would "provide long-term stability to the island's lifeline ferry operations".
The IoMSPC provides freight, passenger and vehicle services between Douglas and five ports in the UK and Ireland.
The Manx government has committed to purchasing 100% of MIOM Ltd, the IoMSPC's parent company, for £48.3m.
It will also lend £76m to the Steam Packet. This loan will be repaid to the government with interest.
"By taking a controlling interest, the Isle of Man Government will ensure stability for our people and businesses," said Mr Cannan.
The latest company accounts, published in 2016, show annual profits of about £9m.
The government said a formal agreement concluding the acquisition would be signed this week.