And they charged the city with being evasive on whether the prison barge would be temporary or permanent.
Under a court ruling last year, a state of emergency allows the city to suspend certain review and permit requirements in placing its prison barges.
First, the prison barge was not ready on time.
Avondale has never built a prison barge before.
It would be the twin of the Bibby Venture, the city's first prison barge, which is now under repair.
On recent issues from homeless shelters to prison barges, the Mayor has proposed undertakings with relatively little diplomacy.
Community groups have maintained that the city's two prison barges are not secure enough and should not be moored close to large residential areas.
With 16 jails and two prison barges, the city already has the largest municipal penal complex in the world.
Those options include the lease of a prison barge from a British company to house 396 inmates.
The city had considered acquiring the site from Britestarr to build a jail and a dock site for a prison barge.