http://www.defence.gov.au/dmo/news/ontarget/mar06/inn.cfm
In a world first, Neptune Marine has successfully painted sections of a Collins Class Submarine without dry docking the platform, making innovative use of their underwater welding housing to create a dry environment to paint below water.
The contract involved painting the surface areas of a Collins Class Submarine where it had rested on blocks in a ship lift during a prior dry dock painting, hence remaining unpainted.
Environmental constraints ruled out using an underwater paint to coat these unpainted surface areas and dry docking the submarines for a second time was an expensive solution that lead Defence Materiel Organisation (DMO) to brainstorm other innovative alternatives.
DMO Centre for Maritime Engineering, Assistant Director Engineering Hugh Hyland came up with the solution.
Neptune Marine Services Business Development Officer, Grant Mackenzie said Mr Hyland remembered that Neptune Marine had been involved in a previous underwater welding project. He called us to see if our technology could be adapted to paint underwater.
Neptune Marine Services has patented underwater welding technology that applies an approved permanent weld, equal to dry weld standards. Achieving welds to the American Welding Society 3.6 Class A code, previously only possible in a dry welding environment
The Neptune system incorporates a housing that fully encloses and isolates the heat affected zone from the surrounding environment.
Water is purged from the housing before superheated argon gas is delivered into the habitat to provide a completely controllable environment around the immediate weld area.
The Neptune, Collins Class, paint job involved reconfiguring their welding housing equipment to suit a paint applicator.
Mr Mackenzie said adapting the housing enabled Neptune to apply the paint without lifting the vessel and without any risk to marine life through paint spillage.
‘Essentially, our housing was fitted to the area that required painting and the area was flushed of water and dried before a coat of paint was applied by a diver.
‘Once the first coat of paint was applied we left the habitat over the surface for the paint to dry and moved on to clean another surface area that required painting.
‘A second coat was applied to the initial area with the habitat remaining over this surface until it was dry. The divers then removed it and moved on to the next area they had prepared between coats,' he said.
Mr Mackenzie said Neptune did not want to be seen as just an underwater welding company.
‘We wanted to be seen as a solution provider so we decided to take the challenge of adapting our technology for the painting process.
‘The hull painting was completed successfully without the cost of lifting and moving the vessel which proved to be far greater than the cost involved using our system.
‘The project gave our company the opportunity to expand our product. We were in the water for three days painting the designated surface areas. The adaptation was such a success that our divers completed additional paintwork not specified in the contract at no charge to Defence.
‘We plan to explore other potential adaptive uses for our housing. To me fiberglass work would be the next logical step. We also want to explore working deeper and covering larger surface areas with the current welding technology,’ Mr Mackenzie said.