Administrators are being appointed to take over the Ferguson shipyard in Port Glasgow.
It is expected ownership will transfer to the Scottish government, which has said it is “ready and willing” to do a deal to avert the yard’s closure.
Ferguson has been involved in a long-running dispute with the Scottish government over the construction of two ferries for CalMac.
About 300 people work at the Inverclyde shipyard.
The legal negotiations mean the yard will no longer be owned by industrialist Jim McColl, who could not persuade ministers to pay more than the £97m contract price for the disputed ferries.
The GMB union has issued a qualified welcome, saying that nationalisation would secure the immediate future of the yard.
GMB Scotland organiser Gary Cook, said: “Nationalisation secures the immediate future of the yard and that is a very welcome development, particularly after all the recent uncertainty.
“Our members were caught in the middle of a situation that had nothing to do with them and their relief will be palpable. It is five years since the yard went bust and the Scottish government has prevented that from happening again.”
He said nationalisation would not be a quick fix for the yard.
“There will, for example, be limits to the amount of private sector work for which the yard can compete – but the alternative to nationalisation was closure, and that was no choice at all,” he added.
“Our immediate priority is to secure the re-employment of the workers released last weekend because their skills are essential and then we will insist the government works with us to develop a proper industrial plan for the yard because lessons must be learned.”