Origami Metal Boat Construction

[SaltyMonkey]

Thanks Gordie!

[Brent Swain]

The joint between the hull and the tank top is a hard spot , as hard as the centreline , probably stronger, as it involves the tank top, the hull ,and the inside of the keel, all comming together , each curved in one direction or another.

[dskira]

Brent, what you say here means nothing, try to rethink how you explain your engenering.
Curved direction is not a proof of any strength, it is just a shape.
if you say "hard spot" it is a red flag. You should never have a hard spot on a steel boat. All the strength has to be diffused to avoid hard and soft spot.
Daniel

[SabreKai]

From what I know of monocoque structures, Brent is correct when he says that the curved hull bottom is adding a lot of strength to the design. A sideways force on one of the keels is not just acting on a single plane fulcrum as Dskira states but it comes close. The fulcrum is curved upwards at both ends making it harder to fold sideways. However, what is shown in the first picture of the cross section drawing does have a weakness if you discount the curved hull bottom. If that tank top were dead flat along its length with the keel joint, it would act as a fulcrum and could potentially fold from a side force. Such being the case, I agree that the frames need to be tied in at the bottom but the way they are terminated at the tank top allows nothing to tie them together below the tank top so they must be connected across the top of the tank top. IF the frames went all the way to the center line, then web floors would greatly increase the resistance to a sideways bending moment but as designed that's not posssible. The frames terminate above the tank top.

Salty Monkey, the photos you posted of the interior structure of that twin keel show a major difference between them and the drawing that Brent posted originally. They have the frames going all the way to the center line and joining. They resist any side forces by doing that because of the way they are all tied together, keel sides to frames to hull skin.

Sabre

[SaltyMonkey]

Maybe so, but I believe that "rough sketch" was drawn by someone else and doesn't come from an original drawing

[Laidback]

Originally Posted by dskira

Brent, what you say here means nothing, try to rethink how you explain your engenering.
Daniel

Dskira, while it is obvious that English may not be your mother tongue, it is no excuse for rudeness.

[dskira]

Originally Posted by Laidback

Dskira, while it is obvious that English may not be your mother tongue, it is no excuse for rudeness.

Rude to ask a designer to be more precise?
If he say something which do not make sence, what is wrong to tell him that?
He is the designer, somone will built the boat, he has the responsability to be accurate.
If you don't like it, its too bad, but don't patronize me.
When you are on the bottom the ocean, ask yourself who is rude.

Daniel

PS. This is the first forum ever where members are picking on my english.
Must be something on the air.

[David M]

We mean it when we request that the nastiness and petty bickering come to a halt. I'm sorry I have to close this thread as I was enjoying the information being presented.

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