Structural Arrangement

Hi,

I am currently designing a 33m sailing yacht. The lines are done and the initial hydrostatics have been calculated. The yacht weights 85 tonnes and is a round hull with a modern keel with 30 % of the overall displacement used as ballast in the bulb.

I am working with lloyds and ABS rules to find out the most suitable structural arrangement i should consider. I have decided to use FRP but is the first time i need to draw a midships structural arrangement using FRP, i ofcourse need to show how i would like my stiffeners, floors, girders,... longitudinally and transversely. This is only a in depth project as part of my degree but i would like to get the drawing as realistic as possible. If anybody can give me a hand i will be very great ful.

Thanks,
Ivan

 

A good guide would be Dave Gerr's "Elements of Boat Strength" this will show you how it all fits together for the requisite strength.

 

Look at "Princples of Yacht Design"
by Larsson and Eliasson
That has a good section on structure.

 

Both elements of boat strength and principles of yacht design are good books as a starting point. however what is the bases of this project? a general preliminary design, detailed structure design etc If you want to look at the structure in detail and it is available a good starting point is the Lloyds SSC program. It cant handle high end materials that well, how ever it will give you a tool to quickly assess if you weight budget for the hull is realistic. It's also worth noting that at this size you shoulod really be looking at the gobal loads.

 

I have both books with me and i have followed both of them and got to an initial estimation for the scantlings in excel, morgig where could i find the lloyds ssc program?, i will post the initial midships structural arrangement onece i have finished, maybe today or tomorrow, so i can get your opinions,
Thanks for your help
Ivan

 

Ivan,

SSC program can be ordered here:

http://www.lr.org/rules_and_standards/Rules_and_regulations/index.htm

Drop them a mail and mention you need the ssc software.

 

I'm not sure if LRS make the software available free to students, if not I would suggest that you ask if your college has a copy. BV also have an interesting bit of software called Marspeed which looks at the loads globally, you then transfer these loads/BM to the local frame/stiffeners. What’s more interesting is that I think they make it available for free.

 

I can be short here: No LRS does not have a free student version.
Accept maybe when arranged between a school and a local office.

 

I have just recieved an email from LRS and yes the copy is available to students as long as a letter from the department which the student is part of is sent for conformation. I will also have a look at the software you have reccomended me, Morgig.

So far i have all the scantlings which i dirived from the Elements of Boat Strength but i will like to compare them with the classification societies.

 

Ivan,

Nice going!! I believe Gerr has used ABS or Lloyd's Rules as the basis of his book (for structural items).
If you have any questions about the program, don't hesitate to contact me. I'll be glad to help.

Good luck,

 

I will try to have the midships section finish by tonight and i will post it so you can have a look, its the first structural arrangement i do for a yacht, it doesnt look anything like a tanker which i did before ,

 

It seems that Marspeed is free indeed, but it's only for high speed craft so it may not be applicable in this case...

 

Look at http://www.veristar.com/
Click on "Downloads" and "Free software"...