No Ship at Avoca

A further structural assessment has confirmed the helicopter hanger on the port side of the ship has now come loose requiring a temporary closure of access to the site in the interests of public safety.

Parks Victoria website
July 4, 2011
http://www.parkweb.vic.gov.au/1park_display.cfm?park=294

HMAS Canberra was scuttled on October 4, 2009 off the Victorian coast near Geelong and is an identical sister ship to the Ex-HMAS Adelaide.

It is less than two months since the ex-HMAS Adelaide was sunk on April 13 2011 and divers have already reported the hull has cracked. The crack has appeared in the ship’s ‘weak spot’ as outlined by a marine engineer in a $4000 report the No Ship Action Group commissioned in the month before the Adelaide was sunk in a last-minute bid to prove to authorities the ship would break up quickly and pollute the bay.
Read Werner Hoyt’s report online here  http://bit.ly/fLRcqY

The marine engineer predicts the Adelaide will break up faster than the Canberra as the site has less protection from large swell conditions.

Click here http://bit.ly/fwNZFi to read NSAG Media Release April 6, 2011 ‘New report says frigates are wrong ship to scuttle’

The report was the basis of a summons in the Land and Environment Court the day before the scuttling in what was a last-minute bid to stop the dumping. Read the Summons here http://bit.ly/kJi8EB
 
However, Premier Barry O’Farrell and Member for Terrigal Chris Hartcher chose to ignore the report, endangering swimmers and marine life for the next 250 years.

Metal sections of the ex-HMAS Adelaide have been washing up on various parts of North and South Avoca as the ship begins to break up. One piece of aluminium sheet measured two metres by 60cm and hundreds of smaller sections measuring on average about 20cm by 20cm have been found strewn along the beach.

Click here to see photos of the same aluminium sheeting littering the ocean floor around the ex-HMAS Canberra.  Figures 7,8,14,15,16.

The sheet is of sandwich construction with air trapped in a honeycomb of very thin aluminium between two sheets of aluminium. The trapped air gives the sheets enough buoyancy to keep them floating
 
According to expert marine engineer, Werner Hoyt, “The material washing ashore are internal partitioning aluminum wall materials not removed during preparation for reefing.”

In this form with razor sharp edges it could prove deadly in the surf zone. A surfer or child struck by a thin sharp sheet this size could sustain a very serious injury.
 
Local surfers want answers. How many of the deadly sheets are still lurking in the surf area from Avoca Beach to North Avoca? This could be a serious hazard to marine life if ingested such as whales, dolphins, turtles and other marine creatures.

“It appears that the Adelaide is becoming the poster child of why ships should no longer be reefed,” Mr Hoyt said. “Cost of reefing is now at four times the raw cost to recycle with out counting the resource recovery. The planners failed to account for differences in construction technologies and their likely behavior when subjected to a reefing environment.”  

Werner Hoyt, marine engineer and ship breaking expert with over 30 years experience working with naval ships sent the following email to the No Ship Action Group on 9/2/2011: 

“And the Saga of the HMAS Adelaide continues. Estimated costs so far to reef in excess of $3100/ton and she is not yet reefed. 

With the news on problems with the Ex Canberra breaking up the No Ship Action Group (Residents of Avoca Beach NSW) have a good chance of stopping the reefing.

What is happening to HMAS Canberra in an active environment will happen on a similar scale of time for the Adelaide but faster.  

The increased turbulence at Avoca will do several things:

1. As the vessel paint exfoliates due to corrosion propagating between the paint and metal flaking it off, surface area available to drive galvanic corrosion processes increases. 
Essentially the ship has become a giant battery discharging through the water.
A positive feed back loop is in place. Corrosion rates increase, increasing available surface areas to support the galvanic process until the point in time there is no longer contact between the aluminum in the superstructure and the steel of the hull.

2. Result is a faster breakup of the vessel.

3. The good news here is that fibre glass will not be washing up on Avoca’s beaches.As a result of the tribunal’s orders all fibre glass insulating material was to be removed at substantial cost. The effect of this will be to expose surfaces of the ship to the environment sooner, more available oxygen for corrosion.
         
4. The bad news.  The galvanic corrosion process will rapidly corrode away locations where aluminum lockers and electronic cabinets were mounted. This will make these heavy items susceptible to moving/falling over if the ship shifts in it’s reefed position endangering divers. 
Lighter aluminum lockers freed of their attachments will be flushed out of the hull due to the more dynamic (turbulent) environment and soon wash up on Avoca’s beaches. 

Why has this happened?  It is a basic difference in ship construction. 
Ships with aluminum superstructures reefed prior to HMAS Canberra were assembled by inserting a dielectric material between the steel and the aluminum and huck bolted (riveted) together and isolated electrically. 

The HMAS Canberra and HMAS Adelaide were constructed utilizing an explosion bonded steel and aluminum bi-metalic joint. This provides 100% conductivity between the superstructure and the hull driving the galvanic corrosion process.

The ship is a giant galvanic corrosion cell. Essentially once immersed in sea water the ship becomes a giant battery discharging through the sea water. 

This was not seen in earlier reefing sites because the riveted joint provided an extremely high resistance connection comparatively between the hull and superstructure of the ship. 

This difference results in corrosion activity that takes place in 1.5 years versus 20 to 60 years or more previously experienced in earlier reefings. 

Best of luck mates cleaning the mess up if HMAS Adelaide is reefed. Dearly hope that wiser heads ultimately prevail here. 

Sincerely,Werner F. Hoyt, PE
Program Manager
Ship Recycling Programs
Mare Island Shipyard,
Vallejo, CALIFORNIA