Layup schedule help

Design category - Trimaran
Power or Sail - sail
Length of the Hull (LH) m 8.45
Length of the fully loaded waterline at mLDC m 8.45
Beam of the hull (BH) m 4.75
Beam of the fully loaded waterline at mLDC m 5.31
Depth (Dmax) m .56
Draugth at mLDC (TC) m .56
Loaded displacement mass of the craft (mLDC) kg 1474

 

Stiffness is the property that is based on how much a material deflects when a force is applied. It is one of the basic parameters when designing anything, whether it is a hull laminate or the handle for a frying pan.

 

@Scuff, the measures that you give seem incompatible with each other. Could you show a drawing of your boat, with dimensions, in order to obtain the necessary data?

 

He never said it was a trimaran, but nothing I saw seems incompatible with a monohull. The boat gains no length loaded so has sharp bow and transoms. The beam changes under loading, but the draft does not. Is this the part that is impossible? Like a fixed keel boat that sinks lower in the water would have greater keel depth at load? I have a feeling that is a typo and he misread the datasheet. Unless morning cobwebs got me, no way the draft can be the same under load if the beam changes.

 

Just to try to clarify concepts that seem to be very confusing
Stiffness: Ability to resist deformation (not only deflection).
In engineering, deflection is the degree to which a structural element (not a material) is displaced under a load. It may refer to an angle or a distance.
Young's modulus, a coefficient of elasticity of a substance, expressing the ratio between a stress that acts to change the length of a body and the fractional change in length caused by this force. This is the property of the material (although it is not the only one) or of a compound that is used to calculate elements subjected to bending.

 

Design category can be "A", "B" or "C"
Trimaran is the type of hull.
LH and Lwl can not be, or are not usually, the same.
BH is the maximum breadth of the hull and therefore can not be less than the Bwl
Depth can't be the same as the draft, unless we are talking about some kind of submarine.

 

That is incorrect. Young's modulus and stiffness are the same in the elastic region. Any value above that means the material failed, so it is outside the design parameters. These links explain it in detail:
http://web.mit.edu/course/3/3.225/book.pdf
Lesson 14 Mechanical Properties of Materials http://wweb.uta.edu/faculty/ricard/Classes/KINE-3301/Notes/Lesson-14.html

 

There is no point in talking about Young's modulus beyond the proportional (more suitable than "elastic") region.
Gonzo, you can not understand it but, in reality, we are saying practically the same thing. And, please, learn that beyond the elastic limit material does not have to collapse (PRF, that is what we are talking about here, does not). In a certain area, beyond the elastic limit, when the stress ceases, the material recovers almost completely. A little beyond, in the limit of rupture, the material effectively collapses.

That is absolutely incorrect and can lead to catastrophic results. Review, please, all the links you can find with Google and try, as well as reading them, to understand them. The allowable values for the design are much lower than the elastic modulus. This any beginner knows, it is the first thing that a designer asks himself : what are the admissible stresses?

I was right, from what I see, in trying to clarify the concepts. But I will not continue arguing with Gonzo about this, in this thread, so he does not learn too much and because, I think, that does not interest the OP at all.

 

I think this ought to help the op to determine if he made a clerical error. Not sure why LH and LWL can't be the same, but I agree the BH and the BWL seem to be in strange proportion. However, perhaps the BH is not the max, but rather the beam at the deck, so he erred or was given an erroneous measure. And, yes, we agree the depth loaded and the depth unloaded should be different. I find this very interesting, just trying to add the idiot's perspective, which can at times be helpful, believe it or not.

 

LH and Lwl could be the same but it is really strange that this happens.
The maximum breadth, which is considered in these calculations, is normally on the deck but does not have to be that way. Some sailing ships, not the modern ones, and many old ships did not have the maximum beam on deck, but somewhere below it.
For me "depth" is the height of the deck from the keel, measured on the side of the ship. Therefore, it should not be equal to the draft, which is the vertical distance between the waterplane and the keel, usually measured at half the length between perpendiculars.
Many advances of humanity have occurred thanks to the "nonsense" of someone who, in his day, was described as idiot or crazy.

 

Apologies I messed the info up. I'll sort it out and repost.

 

Design category - B
Power or Sail - sail
Length of the Hull (LH) m 8.45
Length of the fully loaded waterline at mLDC m 8.17
Beam of the hull (BH) m
Beam of the fully loaded waterline at mLDC m 5.31
Depth (Dmax) m .56
Draugth at mLDC (TC) m .432
Loaded displacement mass of the craft (mLDC) kg 1474

I can't figure out what mLDC is or stands for. In my documentation I don't see an unloaded waterline value and so I don't know the beam 'dry'. I did ask the designer what was included in the weight listed on the design and he indicated it was a fully equipped vessel with no additional specifics. The beam mldc is the extreme beam. My understanding of draught is the amount of water required to float the vessel .. so that Value is the draft of the main hull.

 

If depth is 0.56 and draugth is 0.432 then freeboard is 0.128 , wey low.
Could we see a drawing of your boat?
What is the composition of the laminate you want to analyze and for what purpose do you want to modify it?

 

Depth and draft are different dimensions measured at different points. The depth of the hull is independent of the keel dimension. A quick google search will illustrate that.

 

It seems a statement somewhat ... exoteric, mysterious ?, but in any case difficult to understand. How could different dimensions be measured at the same points?