Beam Winds Combined With Rolling in HSNC 2015

[Diego San]

Dear all,

Recently, I was reviewing the rules for building and classing High Speed Naval Craft 2015 from ABS, regarding the intact stability criteria on it. I stopped on this point (part 3, chapter 3 appendix 1 Alternative Requirements for the Subdivision and Stability of High-Speed Naval Craft) and more exactly at

1.3.4(b) Area A1 is not less than 1.4 A2, where Area A2 extends either 25 degrees or R (if roll angle determined from model tests) to windward from Point C:

1.40*A2 >= A1

----

Reading the text it said A1 is not less than 1.4 A2, but to my understanding, the inequality does not represent the same.

Going further, The inequality does not make any sense because (to me) it will represent a worse stability condition than the opposite.

Can you please tell me whether I am wrong or not?

 

[NavalSArtichoke]

Dear all,

Recently, I was reviewing the rules for building and classing High Speed Naval Craft 2015 from ABS, regarding the intact stability criteria on it. I stopped on this point (part 3, chapter 3 appendix 1 Alternative Requirements for the Subdivision and Stability of High-Speed Naval Craft) and more exactly at

1.3.4(b) Area A1 is not less than 1.4 A2, where Area A2 extends either 25 degrees or R (if roll angle determined from model tests) to windward from Point C:

1.40*A2 >= A1

----

Reading the text it said A1 is not less than 1.4 A2, but to my understanding, the inequality does not represent the same.

Going further, The inequality does not make any sense because (to me) it will represent a worse stability condition than the opposite.

Can you please tell me whether I am wrong or not?

Reading the text, it appears that ABS has flipped the inequality in the formula so that it is the opposite of what is intended. The ABS issues Corrigenda at irregular intervals, and this might be a candidate for correction in the next one.

You may contact your local ABS office and ask for clarification on this rule.

 

[Diego San]

Reading the text, it appears that ABS has flipped the inequality in the formula so that it is the opposite of what is intended. The ABS issues Corrigenda at irregular intervals, and this might be a candidate for correction in the next one.

You may contact your local ABS office and ask for clarification on this rule.

Thank you for your reply.

That was what I tought, but I had to ask to be sure. Thank you again.