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Re: Lee
By:Ian Johnston
Date: 4/21/2000, 3:16 am
In Response To: Re: Bryan (lee)

: Bryan, Please do this for all of us and "end the Madness!" Make
: some test panels, use two layers of woven smooth 3oz glass on 3mm ply. One
: layer on each side. Make another panel with 6oz glass on either side.
: Break them. Which one's lighter ? which one's stronger? ok, ok, ok, well
: then how about two layers of woven smooth 3oz on either side of the 3mm,
: which one's lighter? which one's stronger? hmmmmm

Of the three the 3oz/ply/3oz would be lighter. The 3oz/30z/ply/3oz/3oz would weigh the same as the 6oz/ply/6oz, but would be stronger and markedly so. 2 layers are not twice as strong they are sometimes up to 3 times stronger so for arguments sake, if the 3 oz failed at 100 lbs. and the 6 oz at 200 the double 3 oz would be in the neighbourhood of 250 lbs. A laminate is stronger than the sum of its parts.
:
: What I'm getting at is lighter is not stronger, they are two different
: things. But good building practices can make something stronger per unit
: of material, and that is different from lighter and stronger. Just to be
: cantankerous about the whole issue there's no way that a 30lb strip built
: kayak is going to be stronger than a 45 lb kayak built of the same
: materials, make the boat and test it. All I can tell you in my experience
: is that when lightness is the goal then strength and durability are
: compromised. That's true whether the forces are between a well built Honda
: and a chevy suburban or kit kayak and a boutique ultralight. We all live
: in the same reality.

By changing from a single 6 oz layup to a double 3 oz layup, we have not lightened the boat we have engineered in a higher strength to weight ratio. George saves the weight by using 1/8 inch stips instead of the standard 1/4 inch. On a 17 foot kayak I think he would save roughly 9-10 lbs.

The 1/8 inch strips are a benefit because they flex 7-8 times as much as a 1/4 inch strip before breaking which brings all the factors in the composite closer together. The strips do not break before the layup nor does the layup fail before the strips. They fail at roughly the same time.

What George has done is eliminate a variable that adds weight but not strength. The bonus is that the extra flex from these thinner strips actually makes the composite stronger because it eliminates early strip failure.

If I use your automobile analogy; a 2500 lb Honda built 15 years ago is not nearly as safe as a 2500 lb Honda built this year. Both cars weigh the same but the new one has engineering improvements that make it safer. Many of these improvements are actually a weakening of the structure to allow it to perform in a desirable manner.

Ian

Messages In This Thread

Safety, two points
Nolan -- 4/20/2000, 9:32 am
Re: Safety, two points
Rehd -- 4/22/2000, 3:59 am
Re: Safety, two points
Erez -- 4/22/2000, 10:16 pm
Re: What information do you want?
Nick Schade - Guillemot Kayaks -- 4/21/2000, 11:49 am
Re: What information do you want?
Nolan -- 4/21/2000, 12:33 pm
Re: P.S.
Nolan -- 4/21/2000, 12:36 pm
Re: Seat of the pants tests
Nick Schade - Guillemot Kayaks -- 4/21/2000, 2:10 pm
Re: Seat of the pants tests
Don Beale -- 4/21/2000, 9:09 pm
Re: Seat of the pants tests
Nolan -- 4/21/2000, 2:46 pm
Re: Seat of the pants tests
Nick Schade - Guillemot Kayaks -- 4/21/2000, 4:19 pm
Re: Seat of the pants tests
Ross Leidy -- 4/21/2000, 4:43 pm
Re: Seat of the pants tests
simon king -- 4/21/2000, 5:07 pm
I do agree
Marcelo -- 4/21/2000, 5:58 pm
Re: I do agree
Ian Johnston -- 4/22/2000, 2:18 am
Re: I do agree
Dean Trexel -- 4/23/2000, 1:29 pm
Off topic: Banana Republic Citizen
Marcelo -- 4/22/2000, 3:16 pm
Re: Off topic: Banana Republic Citizen
Ian Johnston -- 4/22/2000, 7:02 pm
Re: Diesels for marine use ...
John B. -- 4/22/2000, 6:47 pm
Re: Avoidance/responsibility
Ian Johnston -- 4/21/2000, 3:37 pm
Re: P.S.
Ian Johnston -- 4/21/2000, 1:22 pm
Re: martial soap operas
lee -- 4/21/2000, 7:54 pm
Re: Well Put
Mike Hanks -- 4/21/2000, 2:05 pm
Re: Well Put
Dean Trexel -- 4/21/2000, 2:23 pm
Re: What information do you want?
Dean Trexel -- 4/21/2000, 12:22 pm
Re: What information do you want?
Bill Heuser -- 4/22/2000, 6:07 am
Time to step back and take a deep breath
Brian Nystrom -- 4/22/2000, 9:36 am
Re: Your Flame Sucks
Spidey -- 4/23/2000, 1:27 am
A little testy, are we?
Brian Nystrom -- 4/23/2000, 7:18 am
Re: Time to step back and take a deep breath
Bill Heuser -- 4/22/2000, 5:17 pm
Re: What information do you want?
Richard -- 4/22/2000, 7:54 am
Re: What information do you want?
Don Beale -- 4/21/2000, 12:19 pm
Re: What information do you want?
Nick Schade - Guillemot Kayaks -- 4/21/2000, 12:33 pm
Re: What information do you want?
Don Beale -- 4/21/2000, 8:58 pm
Re: There are no standards
Nick Schade - Guillemot Kayaks -- 4/22/2000, 9:53 am
Re: Propriatary data
Don Beale -- 4/23/2000, 11:55 pm
Re: safety,reality,and b.s.
lee -- 4/21/2000, 12:54 am
Well put Lee (nt) *NM*
Doug Keaster -- 4/21/2000, 9:05 am
Re: safety,reality,and b.s.
Nolan -- 4/21/2000, 8:03 am
Re: Good morning
lee -- 4/21/2000, 9:24 am
Re: safety,reality,and b.s.
Brian G. -- 4/21/2000, 9:10 am
Re: safety,reality,and b.s.
Brian G. -- 4/21/2000, 1:55 am
The right to make unsupported statements.....
Bruce -- 4/20/2000, 4:03 pm
Re: oops!
Dean Trexel -- 4/20/2000, 9:47 pm
Re: oops!
Bruce -- 4/20/2000, 10:12 pm
Re: oops!
Brian Nystrom -- 4/20/2000, 10:58 pm
Re: oops!
Brian G. -- 4/21/2000, 12:37 am
Re: The right to make unsupported statements.....
Dean Trexel -- 4/20/2000, 5:31 pm
Safety priorities....
Will Brockman -- 4/20/2000, 8:49 pm
Now THIS I agree with!!!
Doug Keaster -- 4/20/2000, 4:48 pm
Well written points by Nolan.
Allen R. -- 4/20/2000, 2:19 pm
Re: Well written points by Nolan.
Nolan -- 4/21/2000, 7:44 am
Re: Safety, two points
Dean Trexel -- 4/20/2000, 12:24 pm
Re: Safety, two points
Chicken Little -- 4/21/2000, 10:39 am
Re: Safety, two points
Ken Finger -- 4/20/2000, 11:38 am
Re: Safety, two points
Nolan -- 4/21/2000, 7:50 am
Re: Safety, two points
Derek -- 4/20/2000, 11:37 am
An outsider's perspective
Brian Nystrom -- 4/20/2000, 1:30 pm
Re: An outsider's perspective
Dean Trexel -- 4/20/2000, 2:05 pm
Not true, from what I've seen
Brian Nystrom -- 4/20/2000, 2:48 pm
Re: Not true, from what I've seen
Dean Trexel -- 4/20/2000, 5:13 pm
Re: Not true, from what I've seen
Brian Nystrom -- 4/20/2000, 10:41 pm
Re: Bryan
lee -- 4/21/2000, 1:39 am
Here you go.
Brian Nystrom -- 4/21/2000, 8:02 am
Re: Strength Data Graphs *Pic*
Nick Schade - Guillemot Kayaks -- 4/21/2000, 12:28 pm
Re: Strength Data Graphs
Brian Nystrom -- 4/21/2000, 12:51 pm
Re: Strength Data Graphs
Shawn B -- 4/21/2000, 4:04 pm
Re: wood density
Nick Schade - Guillemot Kayaks -- 4/21/2000, 4:25 pm
Re: wood density
Bill Heuser -- 4/22/2000, 4:38 pm
Re: Optimized Boats
Nick Schade - Guillemot Kayaks -- 4/21/2000, 3:01 pm
Agreed
Brian Nystrom -- 4/21/2000, 5:08 pm
Re: Agreed
Ian Johnston -- 4/21/2000, 5:45 pm
Re: Well Said, Nick!! *NM*
Ian Johnston -- 4/21/2000, 3:42 pm
Re: Here you go.
lee -- 4/21/2000, 8:59 am
Fair enough, but...
Brian Nystrom -- 4/21/2000, 10:19 am
Re: p.s. guys in a snit
lee -- 4/21/2000, 9:17 am
Off topic, but since you went there...
Brian Nystrom -- 4/21/2000, 10:56 am
Re: Off topic, but since you went there...
lee -- 4/21/2000, 7:36 pm
Re: Lee
Ian Johnston -- 4/21/2000, 3:16 am
Re: Lee
lee -- 4/21/2000, 9:07 am
Re: Hondas and Suburban/Guillemot and Roberts
Ian Johnston -- 4/21/2000, 12:54 pm
Re: Lee
Bill Heuser -- 4/21/2000, 6:03 am
Re: Lee
James Neely -- 4/21/2000, 7:32 am
Madness continues
Dale Frolander -- 4/21/2000, 3:10 am
A nibble of crow.
Dale Frolander -- 4/22/2000, 3:38 am
Good points, Dale.
Brian Nystrom -- 4/21/2000, 10:34 am
Re: Good points, Dale.
Dale Frolander -- 4/21/2000, 11:57 am
Raka
Brian Nystrom -- 4/21/2000, 12:16 pm
Re: Raka
Ross Leidy -- 4/21/2000, 2:18 pm
Raka glass with MAS epoxy
Allen R. -- 4/24/2000, 3:32 pm
Re: Raka glass with MAS epoxy
Dan Lindberg -- 4/24/2000, 5:50 pm
Re: Experience with this layup *Pic*
Mike Hanks -- 4/21/2000, 1:04 pm
Practice makes perfect
Brian Nystrom -- 4/21/2000, 5:02 pm
Re: Raka
Dale Frolander -- 4/21/2000, 12:37 pm
Re: It runs when you leave the room
Shawn B -- 4/21/2000, 3:52 pm
Re: Raka
Dean Trexel -- 4/21/2000, 12:29 pm
Re: Madness continues
lee -- 4/21/2000, 9:29 am
Re: Safety, two points
Ross Leidy -- 4/20/2000, 10:11 am
Re: Safety, two points
Rob Forsell -- 4/20/2000, 9:57 am