Bowtubes and the USCG

You surely remember the broken lumber A-frame shown recently here on the 42 daycharter cat.  The owner chose to replace and update with a standard alloy tube and wire system.
My worst fears about MSC came true.
I submitted the stock, stamped, original plan sheet to MSC.  I also submitted an 2017 version with the same section properties or better.  Keys Rigging submitted the proposed with extra strength on all items.
It was rejected. They wanted the calculations also.  Done. Those were rejected until I would explain how I did my calculations. They did not have a standard to aim for. In fact I was asked to explain what the relevant factors were.  It has been almost 2 weeks of back and forth now. My fear that nothing that was settled “law” before, is now.
I have probably done a hundred of these, and I bet Keys Rigging has done that many also, or more.
I also get the feeling that they are stressed and angry at MSC. Maybe Trump chaos has hit there also.
This is one part of why no postings last week. Deadlines also. Next week will be better I’m sure.

One thought on “Bowtubes and the USCG”

  1. Wondered why the brief absence. Just now taking interest in multihulls and really appreciate a seasoned and dedicated designers’ perspective on subject. Thank you for educating me what I want when it comes time to get into a multihull.

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