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6inch Crack appear on the First LCS

Discussion in 'YachtForums Yacht Club' started by colintraveller, Mar 20, 2011.

  1. colintraveller, Mar 20, 2011
    #1
    colintraveller

    colintraveller Senior Member

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    http://www.defensenews.com/story.php?i=5999454&c=AME&s=SEA


    If this crack has gone un-noticed the outcome would have been very bad especially the Money that's been spent on that line of vessels



    ................

    A 6-inch crack in the hull of the littoral combat ship USS Freedom caused the ship to abort sea-keeping trials on Feb. 12 and return to its homeport of San Diego for repairs, the U.S. Navy confirmed March 18.

    The crack, about three and a half feet below the waterline in a weld seam between two steel plates in the hull, allowed water to enter a void space in the ship, according to Naval Sea Systems Command (NAVSEA). Flooding was contained, however, and, at a speed of about 8 knots, the vessel sailed about 600 miles to San Diego to begin repairs.
  2. Laurence, Mar 20, 2011
    #2
    Laurence

    Laurence Senior Member

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    Perhaps the Navy should not have split the contract between the two designs:

    "In October 2005, Austal/General Dynamics was awarded a contract to build the first of their design for a Littoral Combat Ship. The keel of the future USS Independence (LCS-2) was laid on 19 January 2006 at Austal USA's yard in Mobile, Alabama, and the naming ceremony was held on 4 October 2008. It is now operating with the fleet at its current location in Norfolk, Virginia."

    Superior built in Alabama.

    Attached Files:

  3. Grecko, Mar 23, 2011
    #3
    Grecko

    Grecko New Member

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    Lots of "issues" with that ship...

    I understand that it's also seriously overweight. As a result she sits lower in the water than it should, and the mission equipment bay that houses the small craft that they launch to perform various missions is very "wet" with several inches of water sloshing around in what was supposed to be a dry work area... :eek:
  4. Laurence, Mar 24, 2011
    #4
    Laurence

    Laurence Senior Member

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    Wet Feet

    Would that be with the USS Freedom or the USS Independence?
  5. Grecko, Mar 24, 2011
    #5
    Grecko

    Grecko New Member

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    Lockheeds finest, the USS Freedom...
  6. Kevin, Mar 24, 2011
    #6
    Kevin

    Kevin YF Moderator

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    Honestly, given that computer design systems can predict the weight of each and every individual component to the fraction of a pound... how does that happen? :confused:
  7. Grecko, Mar 24, 2011
    #7
    Grecko

    Grecko New Member

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    From Wiki...

    One of the issues with the ship is that it is six percent overweight and therefore more likely to sink if damaged. This seems to have been caused by design changes during construction. The Navy says that the ship will require special operating procedures until this is corrected. The workaround selected will be to install external tanks for additional buoyancy. And the Navy states that LCS 1 now meets the damage stability requirement with the addition of the external tanks and that the design of USS Fort Worth (LCS-3) includes additional stability improvements.

    Six percent is 180 tons... That's a bunch. It likely comes from "optimistic engineering" in the planning stages and not keeping some margin in the design, because now we are so smart, since we can keep track of all this stuff on spreadsheets and CAD that we don't need as big a margin.... Or at least they probably didn't think they did Also, the cost versus weight problems that arise when you make something that bit.. Finally, the Military has a bad habit of adding stuff to the progam that adds weight and cost and you have to keep the design frozen when you lock in your dimensions, lest the growth eats you out of house and home...

    As Don Gartlits used to say, "It gets hard to add in any more lightness"...
  8. Kevin, Apr 14, 2011
    #8
    Kevin

    Kevin YF Moderator

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    Welding Flaw Led To Crack in LCS-1 Hull

    LINK

  9. chuckb, Apr 14, 2011
    #9
    chuckb

    chuckb Senior Member

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    My understanding is that the Navy changed many requirements after the initial award. So to win the award, the companies optimize the design to the original requirements and specification issued by NAVSEA. Then after the contract is awarded, NAVSEA introduces new requirements... with delays, cost overruns, and basic performance degradation the result. This happened with both builders... Freedom was the first launch and has more sea time. The new requirements may very well be needed, but its not the way to manage a complex build process.

    Building ships for the US Navy is not something I'd want to do!