Following SubMatts' June 14, 2020 article, submarine expert "S" has made some interesting comments regarding the June 12, 2020 14 hour fire on France's Rubis-class SSN Perle (S606).
S comments:
Heating of steel by fire and its cooling by water may result in significant damage of steel [1, 2]. According to submarine design experts, even apparently minor damage to submarine steel by heating and/or cooling might be extremely serious [3,4]. The degree of fire damage to the wiring/electrical system should also be precisely measured and assessed. Perle will be scrapped if damage is as severe as on USS Miami [5].
[1] https://www.steelconstruction.info/Fire_damage_assessment_of_hot_rolled_structural_steelwork
“The assessment of fire damaged hot rolled structural steel is an area in which many engineers and architects have little practical experience. On many occasions fire affected steelwork shows little or no distortion resulting in considerable uncertainty regarding its re-usability. This is particularly true in situations where fire has resulted in some parts of the structure exhibiting little or no damage alongside areas where considerable damage and distortion are clearly visible.”
[2] https://www.jstage.jst.go.jp/article/jssc/21/84/21_84_67/_pdf “Effect of heating and cooling process assuming fire of steel bridged on characteristics of welded joints of structural steel”, Steel Construction Engineering, vol.21, No84, ”Dec/2014, page 67, M. Hirohata, et. al.
“For investigating the effect of heating and cooling process assuming fire of steel bridges on characteristics of welded joints of structural steel members, a series of experiments were carried out. The heating under transformation point did not affect the joint performance regardless of cooling process. The heating over transformation point caused the softening or the hardening according to cooling rate. The degree of them was larger in the base metal rather than in the weld metal because the amount of carbon in the base metal was more than that in the weld metal. Furthermore, the change of microstructure of base metal made by TMC process was more sensitive compared with that of weld metal.”
[3] https://www.jstage.jst.go.jp/article/kyokaisi/460/0/460_KJ00002224747/_pdf “Issues on structural material and construction of submarine”, The Society of Naval Architects of Japan, No 460, Oct/1955, page 429, T. Sugimura et.al. (Technical Research and Development Institute, the Japan Defense Agency).
“USS Thresher sinking in 1963 was caused by fracture of welded parts of pipe of 10cm diameter. Risk of facture must be understood.”
- Also see https://en.wikipedia.org/wiki/USS_Thresher_(SSN-593)#Disaster_sequence_of_10_April_1963
[4] ibid, page 429
“There are two requirements in steel materials for submarine including welded parts: Standard Charpy strength at -70C and -2.2 C shall be more than 2.2kgm and 7kgm, respectively.”
[5] A USS Miami (SSN-755) was a Los Angeles-class SSN which suffering a shipyard maintenance fire in 2013, assessed as intentional sabotage. Inspectors assessed it would cost up to US$700 million to repair. Hence it was decommissioned in 2014.
S
S comments:
Heating of steel by fire and its cooling by water may result in significant damage of steel [1, 2]. According to submarine design experts, even apparently minor damage to submarine steel by heating and/or cooling might be extremely serious [3,4]. The degree of fire damage to the wiring/electrical system should also be precisely measured and assessed. Perle will be scrapped if damage is as severe as on USS Miami [5].
[1] https://www.steelconstruction.info/Fire_damage_assessment_of_hot_rolled_structural_steelwork
“The assessment of fire damaged hot rolled structural steel is an area in which many engineers and architects have little practical experience. On many occasions fire affected steelwork shows little or no distortion resulting in considerable uncertainty regarding its re-usability. This is particularly true in situations where fire has resulted in some parts of the structure exhibiting little or no damage alongside areas where considerable damage and distortion are clearly visible.”
[2] https://www.jstage.jst.go.jp/article/jssc/21/84/21_84_67/_pdf “Effect of heating and cooling process assuming fire of steel bridged on characteristics of welded joints of structural steel”, Steel Construction Engineering, vol.21, No84, ”Dec/2014, page 67, M. Hirohata, et. al.
“For investigating the effect of heating and cooling process assuming fire of steel bridges on characteristics of welded joints of structural steel members, a series of experiments were carried out. The heating under transformation point did not affect the joint performance regardless of cooling process. The heating over transformation point caused the softening or the hardening according to cooling rate. The degree of them was larger in the base metal rather than in the weld metal because the amount of carbon in the base metal was more than that in the weld metal. Furthermore, the change of microstructure of base metal made by TMC process was more sensitive compared with that of weld metal.”
[3] https://www.jstage.jst.go.jp/article/kyokaisi/460/0/460_KJ00002224747/_pdf “Issues on structural material and construction of submarine”, The Society of Naval Architects of Japan, No 460, Oct/1955, page 429, T. Sugimura et.al. (Technical Research and Development Institute, the Japan Defense Agency).
“USS Thresher sinking in 1963 was caused by fracture of welded parts of pipe of 10cm diameter. Risk of facture must be understood.”
- Also see https://en.wikipedia.org/wiki/USS_Thresher_(SSN-593)#Disaster_sequence_of_10_April_1963
[4] ibid, page 429
“There are two requirements in steel materials for submarine including welded parts: Standard Charpy strength at -70C and -2.2 C shall be more than 2.2kgm and 7kgm, respectively.”
[5] A USS Miami (SSN-755) was a Los Angeles-class SSN which suffering a shipyard maintenance fire in 2013, assessed as intentional sabotage. Inspectors assessed it would cost up to US$700 million to repair. Hence it was decommissioned in 2014.
S
5 comments:
No need to procrastinate on this decision. No one will want to go dive in a sub after a fire.
Perle is good for the trash can, the French State can seriously save some renovation money.
KQN
Hi Pete
Some damages such as change in metallographic structure under high temperature and microcrack initiated by heat shock at water cooling cannot be visually measured and non-distractive evaluation of likely damaged hull area seems to be difficult. If hull is exposed to elevated temperature, hull cut/replacement may be carried out from a safety point of view. As ship age of Perle is 27, it might be scrapped instead of repair.
Damage of Perle might result in delay of submarine delivery schedule or tender of Naval Group because of shortage of resource including manpower [1].
[1]https://www.forbes.com/sites/sebastienroblin/2020/06/12/a-french-submarine-caught-fire-in-drydock-it-could-lead-paris-to-rethink-its-nuclear-deterrence-strategy/#2067254c3d05
“If the damage to the Perle is significant enough that repairs are impossible or excessively expensive, the French Navy may have to keep its other Rubis vessels in service longer and/or accelerate construction of the Suffren class.”
Regards
S
Hi pete,
It seems that the U.S. does have problems with steel to its submarines Contractor Accused of Providing Faulty Steel for Navy Submarines to Pay $10.9M Settlement
"The U.S. Justice Department has reached a $10.9 million settlement with a defense contractor accused of producing substandard castings for Navy submarines at a Tacoma foundry and falsifying test results to cover it up, according to settlement documents filed Monday in U.S. District Court of Western Washington.
The settlement is being paid by Bradken Inc, a subsidiary of Hitachi Construction Machinery, that is the U.S. Navy's leading supplier of high-yield steel designed to be tough enough to withstand extreme circumstances such as a submarine collision.
The U.S. Justice Department has filed a criminal complaint charging Elaine Thomas, Bradken's former director of metallurgy, with fraud over three decades, from 1985 to 2017."
/Kjell
Hi KQN and S
Thanks for your comments. I'll use them in a new article on the Perle fire to be published tomorrow.
Meanwhile it is curious that the fire was said to start "at the FRONT of the Perle" https://en.wikipedia.org/wiki/French_submarine_Perle_(S606)#2020_fire and then:
BUT then "Finally at 9:36 p.m local time the Mediterranean Maritime Prefecture reported that the fire had been brought under control by completely flooding the REAR COMPARTMENTS of the boat with foam, further noting that the “reactor rooms remains untouched.” see https://www.forbes.com/sites/sebastienroblin/2020/06/12/a-french-submarine-caught-fire-in-drydock-it-could-lead-paris-to-rethink-its-nuclear-deterrence-strategy/#d43c5693d056
LOOKS LIKE THE FIRE BURNT, OR THREATENED TO BURN, ALONG PERLE'S WHOLE LENGTH!
Note the color of the smoke 10 seconds into this video https://youtu.be/zpPMdgOqLtA
Note "There was no nuclear fuel on board , this having been removed as part of the technical shutdown. There were no weapons (missiles, torpedoes, ammunition) or BATTERIES on board either." https://www.navalnews.com/naval-news/2020/06/firefighters-battled-the-french-ssn-perle-blaze-for-14-hours/
and "The Rubis-class SSN Saphir (second boat of the class) was decommissioned in July 2019. The next class of SSN, the first ship-in-class Suffren , which started sea trials recently, won’t be fully operational until 2021." https://www.navalnews.com/naval-news/2020/06/firefighters-battled-the-french-ssn-perle-blaze-for-14-hours/
THE SUB "RUBIS" ITSELF IS 41 YEARS OLD SINCE ITS LAUNCH IN 1979 - OLD ENOUGH FOR DECOMMISSIONING NOW. https://en.wikipedia.org/wiki/French_submarine_Rubis_(S601)#Construction
Perle could be considered older than 27 as "Construction began on March 27, 1987 [33 years ago] Perle was launched on September 22, 1990 [approx 30 years ago]" https://en.wikipedia.org/wiki/French_submarine_Perle_(S606)
As no Batteries aboard guess how this fire likely started and what really got burning first?
Pete
Thanks /Kjell [at June 17, 2020 at 1:05 PM]
For your info on a slightly different matter regarding a US "Contractor Accused of Providing Faulty Steel for Navy Submarines to Pay $10.9M Settlement" https://www.military.com/daily-news/2020/06/16/contractor-accused-of-providing-faulty-steel-navy-submarines-pay-109m-settlement.html
As well as your quotes interesting "The castings are considered to be critical components of submarines. If they fail, catastrophic damage and possible loss of lives would result, according to the complaint filed in U.S. District Court against Thomas, who is an Auburn resident."
Am I right to assume the "castings" are not ROLLED outer and pressure hull steel sheets themselves but are likely the supporting steel frameworks that reinforce the rolled steel sheets?
Cheers
Pete
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