ask for some help

Stuhl · Oct 10, 2010

Petros said: ↑

IF this is a collage engineering exercise or contest I would not get too elaborate on the actual hull shape. My own school participated in a similar project 30 years ago. I have since built over 12 kayaks and canoes and learned about hull design.

The most important design element is that your final hull weight and your crew weight is below the displacement capacity of your design. Make it as light as possible (very thin skin with wire mesh reinforcement), and your design will be fastest. Our school's entry was way too heavy, the hull failed under its own weight and never made it to the water. The lightest boat will be fastest.

Canoe and kayak shapes in general have less drag than most other shapes because of their fineness ratio (length to width). A round bottom will have less surface area but will not be stable, so make it with a fairly flat bottom. Find a canoe about the size you want and just copy the hull lines. Since even a thin walled canoe of concrete will weight a lot, you must make sure you have enough free-board to float the weight of the canoe and crew without taking on water over the sides. That is your most important design consideration.

Make it long and slim, make it as light as possible (thin walled yet still water tight), and make it so it can float itself and crew, and you will have the best one.

Good luck.
Click to expand...

you mean the most important thing we need to consider is to make the canoe lighter but stable? if i don't understand wrong
our team ,discussed yesterday we want to make the canoe 1.0cm to 1.2cm thick ,and a kind of glass fibre to strength it ,but if the thick will increase the difficulties to ensure the shape and uniformity? this time we want make the canoe all by hand ,not rely on any factory or machine ,so how to keep the accuracy is a big problem.
thank you for your suggestion!

Martijn_vE · Oct 10, 2010

John Winters has done a lot of research on this subject.
You'll find a lot of useful information and theoretical background on his website

pavel915 · Oct 10, 2010

Stuhl said: ↑

Is 'Basic Ship Theory' the book writen in english? it's a little difficult for me now , or i can find some books in similar
oh~~it's much more complex than i expected,also more interesting
Click to expand...

Yes, it is in English. What is your language? Chinese? there is a lot of naval architects in china and many of them are in this forum. They may refer you any good book which is in chinese.

yipster · Oct 10, 2010

Martijn_vE said: ↑

John Winters has done a lot of research on this subject.
You'll find a lot of useful information and theoretical background on his website
Click to expand...

mis Kaper but together with Michlet it's in delftship
yet instead of starting a NA study for this short term project
it may be wise (for me as well) reading up on the competition
http://www.google.nl/search?hl=en&source=hp&q=concrete canoe&aq=f&aqi=g6g-s1g3&aql=&oq=&gs_rfai=
http://www.google.nl/images?hl=en&q=concrete canoe&um=1&ie=UTF-8&source=og&sa=N&tab=wi

Stuhl · Oct 10, 2010

Petros said: ↑

IF this is a collage engineering exercise or contest I would not get too elaborate on the actual hull shape. My own school participated in a similar project 30 years ago. I have since built over 12 kayaks and canoes and learned about hull design.

The most important design element is that your final hull weight and your crew weight is below the displacement capacity of your design. Make it as light as possible (very thin skin with wire mesh reinforcement), and your design will be fastest. Our school's entry was way too heavy, the hull failed under its own weight and never made it to the water. The lightest boat will be fastest.

Canoe and kayak shapes in general have less drag than most other shapes because of their fineness ratio (length to width). A round bottom will have less surface area but will not be stable, so make it with a fairly flat bottom. Find a canoe about the size you want and just copy the hull lines. Since even a thin walled canoe of concrete will weight a lot, you must make sure you have enough free-board to float the weight of the canoe and crew without taking on water over the sides. That is your most important design consideration.

Make it long and slim, make it as light as possible (thin walled yet still water tight), and make it so it can float itself and crew, and you will have the best one.

Good luck.
Click to expand...

you mean the most important thing is the weight and stablity ,right?
this time our team intend to make the canoe 1.0 to 1.2 thick, and we do it all by hand ,so whether it will be more difficult to make sure the shape and uniformity ?
this work seems much more complex than i expected when we really begin to do it ,more and more problems come out and wait us to consider.thank you for all your help!

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