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Stability Findings; Northern Marine

Discussion in 'Northern Marine Yacht' started by olderboater, May 13, 2016.

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  1. olderboater

    olderboater Senior Member

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    The posts in this thread have been split from another discussion...

    Well, we do know of 80'+ boats that have been launched and had no stability.
  2. Norseman

    Norseman Senior Member

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  3. olderboater

    olderboater Senior Member

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    That was the 80'+ I was referring to. Makes me think if I was purchasing an 80' Northern, such as the 2002 model for sale in FLL, I'd be cautious and want the testing, even though there was no known issue before the one you site and the particular boat was built long before by essentially another company.
  4. Norseman

    Norseman Senior Member

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    What was conclusion, or verdict on the 90 Northern Marine that turned turtle?
    They had forgotten to add ballast rocks in the bilge, or a dolly-tires blew and caused the initial list?
  5. unsinker

    unsinker Member

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    Probable Cause The National Transportation Safety Board determines that the probable cause of the capsizing of the yacht Baaden during its initial launch was the vessel’s low margin of stability due to the combined effects of a recording error during the final vessel weigh, which resulted in an incorrect assessment of the vessel’s center of gravity, and an overestimation of the weight of installed ballast.
  6. olderboater

    olderboater Senior Member

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    Basic incompetency, rushing, desperation. 3rd grade math. No one checking the work.
  7. unsinker

    unsinker Member

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    Part of The National Transportation Safety Board Report:

    Vessel Weight, Ballasting, and Stability To determine the displacement (weight) and overall center of gravity of a vessel in the design and building stage, designers total the estimated weight and center of gravity of individual hull components and equipment. This was done during construction of the Baaden. Additionally, at two points during construction, the yacht was actually weighed to verify the accuracy of the ongoing estimates by placing several load cells (weight scales) under the vessel and summing the individual cell readings. Five cells were used―three beneath the bow on the centerline and two beneath the aft cradle, one on each side. Each load cell was photographed, and these recorded weights were supplied to an offsite naval architect, Roddan Engineering, contracted by New World to determine stability. This stability naval architect had previous experience working with New World and Northern Marine but was not the vessel’s hull or overall designer. He stated that he reviewed only vessel speed, powering, weight, and stability.
    The first load cell weight test in July 2013 showed the vessel’s actual weight to be 76.9 LT, which was 5 percent less than the weight estimate. Using the results, the stability naval architect estimated that the vessel’s final weight would be 130 LT at a 6'5" draft, and with 25.93 LT of installed ballast, it would meet Coast Guard stability criteria.
    As the vessel neared completion, a second load cell weigh in March 2014 showed a vessel weight of 124.1 LT, which was over the estimate for the corresponding level of vessel completion. This weight was supplied to the stability naval architect, who revised his projected final weight up to 154.1 LT at a corresponding draft of 7'2". The naval architect said he understood from New World that 23 LT of ballast was already on board during this load cell weighing, and with suggested ballast the yacht was again projected to meet Coast Guard stability criteria.
    Investigators reviewed photographs of the load cells from the second weight test. The photograph of the aft starboard load cell showed a value of 60,550 pounds. Additionally, the investigation determined the load cell values were written in grease pencil on the cradle above the cell from which they were taken. An aft starboard pencil value of 60,350, nearly similar to the value shown in the cell photograph, was found written on the cradle. However, the investigation determined that New World supplied the stability naval architect a value of 68,500 pounds for this cell―indicating a transcription error at New World―and the naval architect used this incorrect weight in his spreadsheet to determine total vessel weight and estimate launch stability. As the aft port load cell reading was 68,700 pounds, an actual aft starboard side reading of 60,550 was more than 8,000 pounds less than the aft port side. The stability naval architect said this 8,000-pound difference indicated a transverse weight differential and would produce a heeling moment to the heavier port side. This meant the vessel’s center of gravity was further to port than had been estimated.
    Launch Capsizing of the Yacht Baaden
    NTSB/MAB-15/14 13
    Left, aft starboard load cell reading of 60,550 pounds taken in March 2015. (Photo by New World) Right, aft starboard cradle grease pencil marks indicating 60,350 pounds 2 days after the accident. (Photo by Coast Guard)
    In addition, the vessel’s installed ballast weight had been overstated. New World had indicated that 23 LT of ballast was installed, and the stability naval architect used this figure in analyzing launch stability. After the accident, however, New World supplied a ballast diagram showing only 16.61 LT of ballast was in the vessel at launching, so the architect’s analysis overestimated vessel stability. The Baaden’s stability naval architect performed a postaccident stability analysis of four different launch conditions―for both the 16.61 and 23 LT ballast scenarios, with and without the port heeling moment created by the 8,000-pound transverse weight differential―all with zero trim (even keel) in calm water. The report calculated the port heeling moment to be 19 LT and concluded that when this moment is applied to the 16 LT ballast condition (as seen during the actual launching and indicated by the purple curve below), “there is very little righting available” to return the vessel to an upright position over a range of heel angles and “if the righting arm is negative, the vessel is unstable.”
  8. Norseman

    Norseman Senior Member

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    Too bad. What happened to attention to details?
    The video of the boat tipping over could have been from some 3rd world country in Africa or on the sub-continent. (Or Haiti)
    Rather embarrassing that it happened in the USA, the land of the Nuclear Subs, the iPhone and the Space Shuttle.
    Let's try harder, this was embarrassing.
  9. olderboater

    olderboater Senior Member

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    When companies are busy falsifying invoices to stay alive, operating without an engineer to save money, not paying their vendors, destroying any employee morale, and not able to pay attention to their boat building, in litigation regarding the other unfinished boat on their lot, in litigation on other matters, plus must launch a boat to meet next weeks payroll, that's the type work they do. Oh, and ad to it the captain supposed to watch the construction was fired and the broker assuming his duties, so basically trusting New World to do it right. Stability was a regular concern on the boat during the build. Rodden suggested they needed to do more work, but the builder didn't hire them to do so.

    Land of the iPhone? Surely you know the iPhone is not manufactured in the US?
  10. Norseman

    Norseman Senior Member

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    Of course.
    But designed, marketed and very successful as a US product.
    (Made in China like most electronics in my house)
  11. JWY

    JWY Senior Member

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    Thanks to those who responded to the original question. The NM posts should be moved over to revive the previous thread about the debacle. Updates should be forthcoming.
  12. olderboater

    olderboater Senior Member

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    What a tease you are....
  13. YachtForums

    YachtForums Publisher/Admin

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    Per Judy's suggestion, posts related to Northern Marine's findings have been split from another discussion. The new thread is in the NM forum, titled "Stability Findings"
  14. Capt J

    Capt J Senior Member

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    I ran a 2003 76' Northern Marine, for the factory (it was used, previously owned, not new) and for the subsequent owners. I had the boat out in 10-12' seas and it was completely stable. The subsequent owners went on to do a transatlantic with that boat, as well as taking it from Florida to South America. I would trust myself in this boat in a heavy sea state. Not sure I would with ones built by New World. This one was built or owned by I believe Ashton Marine if I remember correctly.