USCG Stability Test for Power Trimaran

Discussion in 'Stability' started by mike w. schultz, Feb 10, 2020.

  1. Mr Efficiency
    Joined: Oct 2010
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    Mr Efficiency Senior Member

    The existing cruise ships are visually disturbing in ways I can't explain, it seems to be a case of continually upping the ante, I guess boredom can set in on those cruises without more novelties.
     
  2. samana
    Joined: Apr 2013
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    Location: usa

    samana New Member

    Like others have said, you'll probably have a very hard time getting your stability approved through MSC. There are limits on passenger crowding heel angle, immersed freeboard, etc. Plus you'd need to provide a lines plan and your own analysis, preferably with a computer model.

    However, your local office can supervise a simplified stability test (SST) as you'd likely be classified as a monohull and you'd meet the other criteria. This is effectively a simple form of inclining experiment where you use actual weights of all gear and passengers. Your route (rivers, etc) would dictate the criteria that need to be met.
     
  3. boatgm2
    Joined: Nov 2011
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    Location: guam

    boatgm2 Junior Member

    If there a site were I can get more info on this power tri?
     
  4. bajansailor
    Joined: Oct 2007
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    Location: Barbados

    bajansailor Marine Surveyor

    I think that this trimaran was designed by the Builder Mike - and the Forum has not seen him since the 25th May, so I hope that he has not abandoned us totally.

    Mike, if you do read this, can you give us an update re your progress please?
     
  5. BlueBell
    Joined: May 2017
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    Location: Victoria BC Canada

    BlueBell . . . _ _ _ . . . _ _ _

    Sounds like Builder Mike may be Jon's side-kick, helper, gofer, grinder, hand-holder, assistant, buddy, co-builder/designer.
     
    Last edited: Aug 30, 2020
    bajansailor likes this.
  6. BlueBell
    Joined: May 2017
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    Location: Victoria BC Canada

    BlueBell . . . _ _ _ . . . _ _ _

    This is all I was able to find on Jon Coats.
    I hope he's a better boat builder than videographer!
    Cheers
     
  7. mike w. schultz
    Joined: Dec 2018
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    Location: South Mississippi

    mike w. schultz Junior Member

    Sorry for my absence... Boat is progressing slowly... She fell off the blocks in the yard due to Hurricane that hit us last week of October, slid 5 feet and is fine, a few scratches. Got her blacked in sole completed, flybridge structure including roof done, Hope to install Outboards this spring and go for sea trail. will post new photos shortly
     

  8. zstine
    Joined: Sep 2013
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    zstine Senior Member

    I don't think he needs any fancy computer tools if he doesn't have access to them. If the amas are submerged 10" at design waterline, then he can just use his 'fill with water' method to measure the change at +/- 1 inch, +/- 2 inch, etc. The distance from the boat's center to the ama's center, times the change in weight of water should give him a good estimate to calculate heeling moment / resistance. I'm sure the USCG has an approved method that is required for inspected vessels if the SST is not accepted..( Is a calc always required??), but this method should give him a good idea of roll angle if 12 people (160lb per person?) stood at the gunwale without fancy software. I think under 10deg is generally allowed?? he may need to extrapolate his water measurements to 10deg as filling amas that high is a lot of water! the allowable heel angle is addressed on page 1-9, row (N) of form SST JOB AID-EX CG-4006
     
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