Simplified Scantling Formula

I usually try to do scantlings this way,first Gerr method, than Iso 12215, 12215 sometimes does give very low results and I think this has something to do with some max values they give you for certain parameters.
I also chek with Rina (italy).
Usually find the 3 to be quite close.

 

Raggi,
When I first questioned the gerr mcnaughton issue it was because mcnaughton explicitly tells his readers or students to not buy Gerrs book. I find it strange for an educator to denounce any literature. Shouldn't a student be allowed to make his or her own conclusions?
I have read elements of boat strength, however I have nothing to compare it with. I intend to buy Toms strip plank scantling book or essay or whatever it is if I can ever stop spending all my money on heating oil!

 

Yes, it's a bit strange. He also says "Do not buy or principles of yacht design" if that's the name of Eliasson's and Larsson/?)'s book. I have the impression that he thinks these books get into to much calculations where the input is not documented. If you don't know the forces you will meet, then there is no use in detailed calculations?

 

Just the idea of an educator telling his students to avoid a publication is contrary to my beliefs as to what education should be. I'm not a kid Raggi, I'm 48 . I certainly don't need some someone censoring what I need or don't need to read.
It makes me wonder what Tom's motives are?

 

I don't know Chandler, and I agree with you. I am only guessing that Tom has had some students that wasted too much energy on those books, or who didn't want to read the other stuff or something like that. I also know that Tom thinks that many soft cored sandwich constructions are dangerous. They look great on paper (or in the spreadsheet) but the outer skin is to weak if you meat a hard spot. And of course you have some stories about delamination.

 

I think that the fact that the book is so widely accepted - it's in it's 9th printing - and the fact that (amongst other institutions) the ABYC has endorsed the book as one of Westlawns official texts, might suggest that there may be something more to the story.... proffessional jealousy perhaps? I don't know....
Prior to the ABYC 'takeover', Westlawn (somewhat strangely I thought) suggested that its' students should refer only to the text material provided in the course.... maybe McNaughton holds the same view....

 

Willallison,
Isn't Gerr the director of westlawn? Maybe that have something to do with it?

 

See this thread on use of the Gerr book.

http://boatdesign.net/forums/showthread.php?t=7881&page=3


Tad