Swedish engine flaws restricting Australian submarines
Posted: Tue Oct 20, 2009 5:40 pm
http://www.theaustralian.news.com.au/st ... 71,00.html
Engine problems cripple Collins-class submarines EXCLUSIVE: Patrick Walters, National security editor | October 21, 2009
Article from: The Australian
THE navy's $6 billion Collins-class submarines face serious operational restrictions after being hit by a run of crippling mechanical problems and troubling maintenance issues.
Some senior engineering experts now contend that the Swedish-supplied Hedemora diesel engines may have to be replaced - a major design and engineering job that could cost hundreds of millions of dollars and take years to complete.
The Australian understands that in recent times only a single Collins-class boat has been available for operational duties but it is unclear whether this involves more than extended training missions.
One senior Defence source characterises the level of concern in senior government ranks about the availability of the Collins submarines as "extreme".
"We spend a lot of money on this core defence capability and they aren't working properly."
Defence Minister John Faulkner and Defence Materiel Minister Greg Combet have now demanded monthly updates from the navy and Defence about the operational state of the Collins-class vessels.
ASC, the Adelaide-based builder and maintainer of the Collins class, is now working through a range of mechanical issues affecting the performance of the six submarines with the state of the diesel engines a fundamental concern.
The trouble-plagued diesel engines are expected to last at least another 15 to 20 years before they are progressively replaced by the planned next-generation submarine from 2025.
While ASC believes they can still last the expected life-of-type and has called in a Swiss consultant to advise on a long-term remediation plan, other external experts believe there may be no option but to start planning for their eventual replacement.
The Hedemora diesel engines have never functioned well from the start and there are now real doubts that they are robust enough to see out the life of the Collins boats.
Other mechanical issues include the performance of the electric motors, batteries and generators but ASC sources are confident that these glitches are being satisfactorily resolved.
HMAS Collins is undergoing repairs on its diesel engines and there are temporary restrictions on two other boats while the bands on their electric motors are fixed.
Ever since they were launched, the Collins boats have been plagued by mechanical problems.
As early as June 1999, a report to the Howard government found a range of serious technical defects in the Collins boats, three of which had been delivered to the navy by that time. These included problems with the diesel engines as well as noise propagation and the performance of propellers, periscopes, masts and the combat system. By far the most expensive fix was the the combat system. The original system never worked and was eventually replaced at a cost of close to $1 billion.
http://en.wikipedia.org/wiki/Collins_class_submarine
Propulsion
Each submarine is equipped with three Garden Island-Hedemora HV V18b/15Ub (VB210) 18-cylinder diesel engines, which are each connected to a 1,400 kW, 440-volt DC Jeumont Schneider generator.[55][63] The combined electrical generation capability of each submarine is 4.2 megawatts.[142] The Hedemora diesels were chosen because of modular construction, which made servicing easier; they could be installed three across in the available space, while other contenders required at least two banks of two; and they ran with turbochargers driven by the exhaust gas.[143] Fifteen diesel fuel tanks are located throughout the submarine: they must be used in specific sequences to preserve the submarine's buoyancy and trim.[144]
Electricity is stored in four 400-tonne lead-acid batteries assembled by Pacific Marine Batteries, a joint venture between VARTA of Germany and Pacific Dunlop of Australia.[23][35] These supply a single Jeumont Schneider DC motor, which provides 7,200 shaft horsepower to a single, seven-bladed, 4.22-metre (13.8 ft) diameter skewback propeller.[23][63]
Diesel engines and propulsion
During trials of the first submarines, the engines were found to be prone to failure for a variety of reasons.[93] Most of these failures were attributed to the fifteen-tank diesel fuel system: the tanks were designed to fill with salt water as they were emptied to maintain neutral buoyancy, but water would regularly enter the engines due to a combination of poor design of the fuel system, gravity separation being insufficient to keep the water and fuel from mixing, and operator error resulting from poor training.[93] Problems were also caused by bacterial contamination of the diesel, which, along with the salt water, would cause the fuel pumps to rust and other components to seize.[94] The fuel-related issues were solved by installing coalescers in the submarines, improving training and operational procedures, and adding biocides to the fuel.[94]
Propeller shaft seals were a significant problem on Collins and Farncomb.[95] Although designed to allow for a leak of 10 litres (2.2 imp gal; 2.6 US gal) per hour, during trials it was found that the seals would regularly misalign and allow hundreds of litres per hour into the boat—on one occasion during a deep diving test the flow rate was measured at approximately 1,000 litres (220 imp gal; 260 US gal) a minute.[95] ASC claimed that solving these problems could be done by manually adjusting the seals as the submarine dove and rose, but this would have required a sailor dedicated solely to that task, affecting efforts to minimise the required number of personnel.[95] It was found that the problem could be temporarily alleviated by running the propeller in reverse for 100 revolutions, pulling the seal back into alignment, although a permanent solution could initially not be found, as ASC refused to accept responsibility for the problem, and the original manufacturer of the seals had closed down.[95] New suppliers were found, with modified seals fitted to the first two submarines in late 1996, before completely re-designed seals were fitted to the boats in late 1997, solving the problem.[96]
Other engine problems included excessive vibrations at certain speeds which damaged various components (which was attributed to the removal of a flywheel and to corrosion caused by the fuel problems), and excessive fuel consumption in Collins at high speed (found to be caused by manufacturing problems with the turbines and turbochargers).[97] The propulsion system was also found to be a secondary source of noise: poor design of the exhaust mufflers, weight-saving measures in the generator mountings, and an incorrect voltage supply to the battery compartment exhaust fans were noise-creating factors found and eliminated during studies by the Defence Science and Technology Organisation.[98]
Engine problems cripple Collins-class submarines EXCLUSIVE: Patrick Walters, National security editor | October 21, 2009
Article from: The Australian
THE navy's $6 billion Collins-class submarines face serious operational restrictions after being hit by a run of crippling mechanical problems and troubling maintenance issues.
Some senior engineering experts now contend that the Swedish-supplied Hedemora diesel engines may have to be replaced - a major design and engineering job that could cost hundreds of millions of dollars and take years to complete.
The Australian understands that in recent times only a single Collins-class boat has been available for operational duties but it is unclear whether this involves more than extended training missions.
One senior Defence source characterises the level of concern in senior government ranks about the availability of the Collins submarines as "extreme".
"We spend a lot of money on this core defence capability and they aren't working properly."
Defence Minister John Faulkner and Defence Materiel Minister Greg Combet have now demanded monthly updates from the navy and Defence about the operational state of the Collins-class vessels.
ASC, the Adelaide-based builder and maintainer of the Collins class, is now working through a range of mechanical issues affecting the performance of the six submarines with the state of the diesel engines a fundamental concern.
The trouble-plagued diesel engines are expected to last at least another 15 to 20 years before they are progressively replaced by the planned next-generation submarine from 2025.
While ASC believes they can still last the expected life-of-type and has called in a Swiss consultant to advise on a long-term remediation plan, other external experts believe there may be no option but to start planning for their eventual replacement.
The Hedemora diesel engines have never functioned well from the start and there are now real doubts that they are robust enough to see out the life of the Collins boats.
Other mechanical issues include the performance of the electric motors, batteries and generators but ASC sources are confident that these glitches are being satisfactorily resolved.
HMAS Collins is undergoing repairs on its diesel engines and there are temporary restrictions on two other boats while the bands on their electric motors are fixed.
Ever since they were launched, the Collins boats have been plagued by mechanical problems.
As early as June 1999, a report to the Howard government found a range of serious technical defects in the Collins boats, three of which had been delivered to the navy by that time. These included problems with the diesel engines as well as noise propagation and the performance of propellers, periscopes, masts and the combat system. By far the most expensive fix was the the combat system. The original system never worked and was eventually replaced at a cost of close to $1 billion.
http://en.wikipedia.org/wiki/Collins_class_submarine
Propulsion
Each submarine is equipped with three Garden Island-Hedemora HV V18b/15Ub (VB210) 18-cylinder diesel engines, which are each connected to a 1,400 kW, 440-volt DC Jeumont Schneider generator.[55][63] The combined electrical generation capability of each submarine is 4.2 megawatts.[142] The Hedemora diesels were chosen because of modular construction, which made servicing easier; they could be installed three across in the available space, while other contenders required at least two banks of two; and they ran with turbochargers driven by the exhaust gas.[143] Fifteen diesel fuel tanks are located throughout the submarine: they must be used in specific sequences to preserve the submarine's buoyancy and trim.[144]
Electricity is stored in four 400-tonne lead-acid batteries assembled by Pacific Marine Batteries, a joint venture between VARTA of Germany and Pacific Dunlop of Australia.[23][35] These supply a single Jeumont Schneider DC motor, which provides 7,200 shaft horsepower to a single, seven-bladed, 4.22-metre (13.8 ft) diameter skewback propeller.[23][63]
Diesel engines and propulsion
During trials of the first submarines, the engines were found to be prone to failure for a variety of reasons.[93] Most of these failures were attributed to the fifteen-tank diesel fuel system: the tanks were designed to fill with salt water as they were emptied to maintain neutral buoyancy, but water would regularly enter the engines due to a combination of poor design of the fuel system, gravity separation being insufficient to keep the water and fuel from mixing, and operator error resulting from poor training.[93] Problems were also caused by bacterial contamination of the diesel, which, along with the salt water, would cause the fuel pumps to rust and other components to seize.[94] The fuel-related issues were solved by installing coalescers in the submarines, improving training and operational procedures, and adding biocides to the fuel.[94]
Propeller shaft seals were a significant problem on Collins and Farncomb.[95] Although designed to allow for a leak of 10 litres (2.2 imp gal; 2.6 US gal) per hour, during trials it was found that the seals would regularly misalign and allow hundreds of litres per hour into the boat—on one occasion during a deep diving test the flow rate was measured at approximately 1,000 litres (220 imp gal; 260 US gal) a minute.[95] ASC claimed that solving these problems could be done by manually adjusting the seals as the submarine dove and rose, but this would have required a sailor dedicated solely to that task, affecting efforts to minimise the required number of personnel.[95] It was found that the problem could be temporarily alleviated by running the propeller in reverse for 100 revolutions, pulling the seal back into alignment, although a permanent solution could initially not be found, as ASC refused to accept responsibility for the problem, and the original manufacturer of the seals had closed down.[95] New suppliers were found, with modified seals fitted to the first two submarines in late 1996, before completely re-designed seals were fitted to the boats in late 1997, solving the problem.[96]
Other engine problems included excessive vibrations at certain speeds which damaged various components (which was attributed to the removal of a flywheel and to corrosion caused by the fuel problems), and excessive fuel consumption in Collins at high speed (found to be caused by manufacturing problems with the turbines and turbochargers).[97] The propulsion system was also found to be a secondary source of noise: poor design of the exhaust mufflers, weight-saving measures in the generator mountings, and an incorrect voltage supply to the battery compartment exhaust fans were noise-creating factors found and eliminated during studies by the Defence Science and Technology Organisation.[98]
