I got myself singed up for a cardboard boat race this saturday. We
are given two sheets of 5x8 card board, duct tape and plastic
sheeting. I was thinking of building a canoe style, but was worried
about the boat folding in half. I know plywood has alot more
stability than card board, and was wondering if anyone has had
expirence in this area, or could point me to a web site that might
offer help. I don't know how big the plastic sheeting is, which is a
problem. I don't know how long the boat could be. I was thinking
along the lines of a D4, or a 12' canoe, but made a bit wider for
stability.

Playing around in the hulls program (great program!) shows me that for
one person, displacement isn't as much of a concern. My main concern
is of the plywood folding around me when I sit in it.

Any hints?

The race is Saturday.




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"Dave Allyn" wrote in message
...
I got myself singed up for a cardboard boat race this saturday. We

The race is Saturday

The cardboard boats I have seen were usually covered in layer after layer
of spray paint, are you allowed to use any ?

On Fri, 2 Sep 2005 06:43:07 -0500, "Phil" wrote:


"Dave Allyn" wrote in message
.. .
I got myself singed up for a cardboard boat race this saturday. We

The race is Saturday

The cardboard boats I have seen were usually covered in layer after layer
of spray paint, are you allowed to use any ?

No. They have to be built on site, and the only things you can bring
is stuff to decorate your boat, but no spray paint.


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Think triangles. Strips of cardboard folded into three sided tubes are
quite strong. Use for chine logs, sheer clamps, and thwarts.

Get one of the gadgets that put the rubber retaining strips back into a
screen door. You can crease and fold across the corrugations where needed
without cutting the paper.

Duct tape!

Bathing suit.

Roger

http://home.earthlink.net/~derbyrm
"Dave Allyn" wrote in message
...
I got myself singed up for a cardboard boat race this saturday. We
are given two sheets of 5x8 card board, duct tape and plastic
sheeting. I was thinking of building a canoe style, but was worried
about the boat folding in half. I know plywood has alot more
stability than card board, and was wondering if anyone has had
expirence in this area, or could point me to a web site that might
offer help. I don't know how big the plastic sheeting is, which is a
problem. I don't know how long the boat could be. I was thinking
along the lines of a D4, or a 12' canoe, but made a bit wider for
stability.

Playing around in the hulls program (great program!) shows me that for
one person, displacement isn't as much of a concern. My main concern
is of the plywood folding around me when I sit in it.

Any hints?

The race is Saturday.




email: dallyn_spam at yahoo dot com
please respond in this NG so others
can share your wisdom as well!

Yes, yes. Can support with stringers running the lenth of the boat, either
triangular cross section as suggested, or at right angles like an I-beam.
Also frames accross boat to retain shape. But remember, the fewer pieces
there are, the faster and easier it will be to build. For example, if
bottom is V-shaped or W-shaped instead of flat you get quick and easy
support from folds without cutting. Long and narrow is faster than short
and fat. Minimize two kinds of drag: a) amount of surface friction with
water, b) amount of waves made (that's where long and narrow comes in).
Turn boat over, tape plastic to outside to waterproof.

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William R. Watt ) writes:
Yes, yes. Can support with stringers running the lenth of the boat, either
triangular cross section as suggested, or at right angles like an I-beam.

I forgot about gunwales and side decks. Fold over along top of side.
The triangle idea sounds good here.

Be sure to let us know if we win.

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On 2 Sep 2005 14:57:41 GMT, (William R.
Watt) wrote:


Yes, yes. Can support with stringers running the lenth of the boat, either
triangular cross section as suggested, or at right angles like an I-beam.
Also frames accross boat to retain shape. But remember, the fewer pieces
there are, the faster and easier it will be to build. For example, if
bottom is V-shaped or W-shaped instead of flat you get quick and easy
support from folds without cutting. Long and narrow is faster than short
and fat. Minimize two kinds of drag: a) amount of surface friction with
water, b) amount of waves made (that's where long and narrow comes in).
Turn boat over, tape plastic to outside to waterproof.

I'm not as concerned with speed of construction. I have from 9:00am
till about 4:30-5:00 in the afternoon to get done. With no paint or
glue to dry, and no epoxy to cure, 7-8 hours should be enough time.

My other concern is what direction the corrigation goes. If the
cardboard is "strong" on the 5' dimention, It would mean more splices
on the sides, and I would want to plan accordingly.

If it is strong on the 8' dimention, then I basically have two sheets
of plywood, and a pair of pieces that are one foot by 8 feet that can
be cut into strips for the triangle tubes.

I am planning a 12-14 foot canoe, with triangle tubes running down
both the tops of the sides, and three horizontal members holding the
sides where they should go. I kinda like the cinderella canoe
(don't recall where I found it) and the NC14 from banteau.com.

I also considered making a "one sheet boat" and then using the other
sheet of carboard to "double up" the hull. I'm just not sure if that
would be the fastest, or if the canoe would be better. I will be the
only one in the boat, and it has to be paddled. (paddles provided)

This brings up thoughts of seating location. Lower is more stable,
but more power can be gained from kneelling. Of course, kneeling will
also put more stress on the bottom of the boat than sitting will.
Sitting should spread it out more, right?

just some more thoughts....


thanks!

dave


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On Fri, 02 Sep 2005 12:58:13 GMT, "Roger Derby"
wrote:

Think triangles. Strips of cardboard folded into three sided tubes are
quite strong. Use for chine logs, sheer clamps, and thwarts.

I figured a triangle along each of the sides (top and bottom if I have
enough) as well as three horizontal stabilizers should help
considerablly with the over all stability of the boat.

See my other post as well. I ranted there about canoe vs single sheet
etc....




Get one of the gadgets that put the rubber retaining strips back into a
screen door. You can crease and fold across the corrugations where needed
without cutting the paper.

Great Idea. Thanks. I'll stop on the way there and get one!

Duct tape!

Provided, and can be the only type of adhisive etc...

Bathing suit.

but if I build it correctly, I shouldn't get wet right?

Roger

http://home.earthlink.net/~derbyrm
"Dave Allyn" wrote in message
.. .
I got myself singed up for a cardboard boat race this saturday. We
are given two sheets of 5x8 card board, duct tape and plastic
sheeting. I was thinking of building a canoe style, but was worried
about the boat folding in half. I know plywood has alot more
stability than card board, and was wondering if anyone has had
expirence in this area, or could point me to a web site that might
offer help. I don't know how big the plastic sheeting is, which is a
problem. I don't know how long the boat could be. I was thinking
along the lines of a D4, or a 12' canoe, but made a bit wider for
stability.

Playing around in the hulls program (great program!) shows me that for
one person, displacement isn't as much of a concern. My main concern
is of the plywood folding around me when I sit in it.

Any hints?

The race is Saturday.




email: dallyn_spam at yahoo dot com
please respond in this NG so others
can share your wisdom as well!




email: dallyn_spam at yahoo dot com
please respond in this NG so others
can share your wisdom as well!

On 2 Sep 2005 15:15:00 GMT, (William R.
Watt) wrote:


William R. Watt ) writes:
Yes, yes. Can support with stringers running the lenth of the boat, either
triangular cross section as suggested, or at right angles like an I-beam.

I forgot about gunwales and side decks. Fold over along top of side.
The triangle idea sounds good here.

Maybe cut the sides a little thicker and just fold it over so it is
one piece.... hmm... lots to think about.

Be sure to let us know if we win.

Pictures will be posted (somewhere) either way.

Thanks for all the help.

dave



email: dallyn_spam at yahoo dot com
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Ah.. the plot thickens. I asked the lady in charge how long the
plastic is. She then asked me why? how big of a boat are you
biulding? I said "Probably 12-14 feet long" She smirked. "You know
the cardboard is only 8 feet long, right?"

"Sure. Thats bigger than plywood, but I know people that have built
30' boats with 8 foot sheets of plywood. There is even a guy who
made a 19' canoe from only one 4x8 sheet!

"huh. well, you are going to want to triple the cardboard up anyway
to hold your wieght.

"I'm sorry, but the displacement is what will hold up my weight. I
just need to engineer the boat not to colapse. that's why I need to
know how big the plastic is.

"I don't know. I havn't cut it yet. Probably about 10 feet long."


There goes my 14' canoe!!!!


back to the drawing board. I chopped the back 4 feet off the canoe,
made it into a "V-hull" and widened it out a bit. Hulls gives me a
water depth of 5.6" and a swamp depth of 11.2" that gives me a
freeboard of 5.6", and that should be enough.

Cardboard can be doubled up on the floor, and set at an angle against
the V-Hull for added strength.

Thinking this out again now, 10' of plastic won't be able to come up
the sides very well on the ends. let me do some more thinking.

thanks
dave


email: dallyn_spam at yahoo dot com
please respond in this NG so others
can share your wisdom as well!