Designing a Concrete Canoe

[concretedesign]

I am the captain of a college run concrete canoe team. Every year the American Society of Civil Engineers (ASCE) puts on a national competition. They change the rules from year to year and this year we need to design a new canoe hull. You can check out this website that explains the competition pretty well. www.concretecanoe.com What I need is some solid canoe advice. What we are going with is roughly a 21.5' long canoe, flat bottom, soft chines, 9 degrees of flare, and 28 inches max beam. Our canoe will roughly weigh 175 lbs (this depends on how dense the concrete mix is this year).

All I need is couple of sages to help me out. Advice?

Also, we are using Rhino and MaxSurf to model our canoe. We would like to dynamically and statically model our canoe.

[concretedesign]

also our rocker is about 3.5 @ bow and 1.1 @ stern. we need to determine how long the flat section of the canoe is for better turning.

[gonzo]

The flat bottom will force you to have a much heavier hull

[concretedesign]

we need the stability, turning, and the load carrying capacity. we fit 4 people in these boats.

[gonzo]

For people in a canoe that size is not a heavy load. Some camber in the bottom should not make the stability much less. It will reduce wetted surface too.

[concretedesign]

we aren't going with a complete flat bottom. we are going to have some v shape in order to improve tracking. what would you recomend?

[gonzo]

A vee shape is using flat sections. A cambered section will be stiffer and lighter. About one inch camber should be adequate.

[Wavewacker]

Go flater with a full length keel....good luck

[philSweet]

The 2012 rules are here, all 83 pages.

http://www.asce.org/uploadedFiles/St...egulations.pdf

[philSweet]

The race course is more of a skills challenge than anything else. Get your hands on three or four Oldtown Tripper XLs and chop the thwarts, reinforce the gun'ls, and ballast them and practice those turns. Try having the sternman walk to the bow to fly the stern around the mark, then return to the normal position. Crew pads should be individually made for each crew member so as to ensure trim is as good as it can be on the straight sections. I'd be inclined to regard the one four person event as a survival event and design for the four two person events.

[Petros]

the more flat the bottom the more difficult to turn it will be. more rocker, easier to turn. Less rocker and more length, the slower it will turn.

It is a trade off, either it turns quickly and tight but will not be easy to keep in a straight line, or it is directionally stable (tracks well) and more difficult to turn.

Best thing to do is try out some popular designs at a rental place to get a feel for how they behave, and than choose the rocker and depth of hull based on known behavior of actual boats. There is all kinds of fancy software and calculations you can do a head of time, but without a good feel for how the hull will behave the analysis is meaningless. So pick the design based on what you like out of existing designs, than go back and do the analysis and rationalization for the design presentation.

keep it simple, keep light, make it stout and you should be fine. Good luck.

[rasorinc]

What sadist would require a concrete conoe to have a race with?????????????????????
TRANSFER TO ANOTHER COLLEGE asap. What's next a ballon turned into a submarine?

[philSweet]

Um, what do the UTK engineers compete in thesedays, rasorinc. when I was there we were still trying to build faster punch card readers. I managed to get on a group that looked at Kodak film processing. Both were long outdated processes even then. Concrete is still around, I see.

[Frog4]

Originally Posted by rasorinc

What sadist would require a concrete conoe to have a race with?????????????????????
TRANSFER TO ANOTHER COLLEGE asap. What's next a ballon turned into a submarine?

ROFLMAO

[DennisRB]

A guy on here made something similar to what you describe. The pics are gone though.

Proa-Cement

Ferro-Cement Multihull Scantlings