A report says medical staff should be on duty overnight at HMP The Verne in Portland, Dorset.
The attraction, in vast disused stone mines, would create about 100 year-round jobs.
The Bibby Stockholm barge was moored at Portland Port for 18 months before it was shut down.
Temporary traffic lights are being manned to minimise tailbacks while urgent repairs take place.
Flooding and disruption are expected during high tides, along with further heavy rain.
Flood warnings are in place and disruption is expected as Storm Ingrid arrives in south-west England
The Jailhouse Cafe at Verne Prison in Portland is unable to secure its future at the site.
The work to Ferry Bridge is due to start on Monday and continue until early March.
Campaigners protest against a planned waste incinerator at Portland Port, in Dorset.
