Boat Building Forum

Find advice on all aspects of building your own kayak, canoe or any lightweight boats

Re: Material: alu-tube rigidity
By:Jeff Buyer
Date: 11/17/2012, 4:07 pm
In Response To: Re: Material: alu-tube rigidity (Bill Hamm)

: It's been suggested to me to be careful using only carbon on the
: tubes, has a nasty habit of failing instantly with little if any
: warning.

: Bill H.

I planned my build based on beam deflection calculations. A 0.5" diameter carbon tube with a 1' span between frames deflects a little less than a 0.75" aluminum tube with a 2' span between frames at identical loading. So I went with 1' frame spacing. Of course, that is not a complete model of stress on a kayak in use. Also, while the pultruded tubes are extremely stiff in compression and extension, and therefore have good resistance to bending, they are prone to catastrophic failure in torsion (i.e. twisting of the tube). I will probably use Kevlar fiber a la Platt Monfort, wrapped around each intersection of tube and frame, to further avoid torsion. The additional frames and the Kevlar may not be necessary, but given the lack of experience with the carbon fiber tubes these seem like reasonable precautions. And we won't try out this kayak until the water warms up in the spring!

Jeff

Messages In This Thread

Material: alu-tube rigidity
CarstenT -- 11/14/2012, 3:26 pm
Re: Material: alu-tube rigidity
Marc Upchurch -- 11/14/2012, 6:55 pm
Re: Material: alu-tube rigidity
ancient kayaker -- 11/15/2012, 12:06 am
Re: Material: alu-tube rigidity
Bill Hamm -- 11/15/2012, 2:03 am
Re: Material: alu-tube rigidity
Brian Nystrom -- 11/15/2012, 7:18 am
Re: Material: alu-tube rigidity
Bill Hamm -- 11/16/2012, 10:22 am
Re: Material: alu-tube rigidity
Brian Nystrom -- 11/16/2012, 12:31 pm
Re: Material: alu-tube rigidity
CarstenT -- 11/16/2012, 5:32 pm
Re: Material: alu-tube rigidity
Marc Upchurch -- 11/16/2012, 9:22 pm
Re: Material: alu-tube rigidity
Bill Hamm -- 11/17/2012, 1:39 pm
Re: Material: alu-tube rigidity
Marc Upchurch -- 11/17/2012, 3:53 pm
Re: Material: alu-tube rigidity
Bill Hamm -- 11/18/2012, 12:35 am
Re: Material: alu-tube rigidity
Marc Upchurch -- 11/18/2012, 9:40 am
Re: Material: alu-tube rigidity
Bill Hamm -- 11/19/2012, 1:16 am
Re: Material: alu-tube rigidity
Mike Savage -- 11/17/2012, 3:54 pm
Re: Material: alu-tube rigidity
Marc Upchurch -- 11/17/2012, 7:07 pm
Re: Material: alu-tube rigidity
Bill Hamm -- 11/18/2012, 12:38 am
Re: Material: alu-tube rigidity
Mike Savage -- 11/18/2012, 12:42 pm
Re: Material: alu-tube rigidity
Yostwerks -- 11/15/2012, 11:06 am
Re: Material: alu-tube rigidity
CarstenT -- 11/15/2012, 12:22 pm
Re: Material: alu-tube rigidity
Yostwerks -- 11/15/2012, 1:42 pm
Re: Material: alu-tube rigidity *PIC*
Yostwerks -- 11/15/2012, 2:02 pm
Re: Material: alu-tube rigidity
CarstenT -- 11/15/2012, 3:04 pm
Re: Material: alu-tube rigidity
Bill Hamm -- 11/16/2012, 10:26 am
Re: Material: alu-tube rigidity
Jeff Buyer -- 11/15/2012, 11:11 am
Re: Material: alu-tube rigidity
CarstenT -- 11/15/2012, 12:51 pm
Re: Material: alu-tube rigidity
Bill Hamm -- 11/16/2012, 10:32 am
Re: Material: alu-tube rigidity
CarstenT -- 11/16/2012, 5:53 pm
Re: Material: alu-tube rigidity
Bill Hamm -- 11/17/2012, 1:42 pm
Re: Material: alu-tube rigidity
Bill Hamm -- 11/16/2012, 10:29 am
Re: Material: alu-tube rigidity
Jeff Buyer -- 11/16/2012, 11:21 am
Re: Material: alu-tube rigidity
Bill Hamm -- 11/17/2012, 1:44 pm
Re: Material: alu-tube rigidity
Jeff Buyer -- 11/17/2012, 3:53 pm
Re: Material: alu-tube rigidity
Bill Hamm -- 11/18/2012, 1:45 am
Re: Material: alu-tube rigidity
Jeff Buyer -- 11/18/2012, 1:56 pm
Re: Material: alu-tube rigidity
Bill Hamm -- 11/19/2012, 1:19 am
Re: Material: alu-tube rigidity
CarstenT -- 11/16/2012, 6:53 pm
Re: Material: alu-tube rigidity
Marc Upchurch -- 11/16/2012, 9:29 pm
Re: Material: alu-tube rigidity
CarstenT -- 11/17/2012, 5:30 am
Re: Material: alu-tube rigidity
Yostwerks -- 11/17/2012, 10:40 am
Re: Material: alu-tube rigidity
Bill Hamm -- 11/17/2012, 1:47 pm
Re: Material: alu-tube rigidity
Jeff Buyer -- 11/17/2012, 4:07 pm
Re: Material: alu-tube rigidity
CarstenT -- 11/17/2012, 4:34 pm
Re: Material: alu-tube rigidity
Jeff Buyer -- 11/17/2012, 5:40 pm
Re: Material: alu-tube rigidity
Bill Hamm -- 11/18/2012, 1:50 am
Re: Material: alu-tube rigidity
Jeff Buyer -- 11/18/2012, 2:10 pm
Re: Material: alu-tube rigidity
Bill Hamm -- 11/19/2012, 1:22 am
Re: Material: alu-tube rigidity
Bill Hamm -- 11/18/2012, 1:51 am
Re: Material: alu-tube rigidity
Jeff Buyer -- 11/18/2012, 2:07 pm
Re: Material: alu-tube rigidity
Bill Hamm -- 11/19/2012, 1:25 am
Re: Material: alu-tube rigidity *PIC*
Yostwerks -- 11/19/2012, 10:14 am
Re: Material: alu-tube rigidity
CarstenT -- 11/18/2012, 4:31 am
Electrolysis
CarstenT -- 6/2/2013, 6:39 am
Re: Electrolysis
Jeff Buyer -- 6/2/2013, 7:39 am
Re: Electrolysis
CarstenT -- 6/2/2013, 9:46 am
Re: Electrolysis
Tom Cooper -- 6/2/2013, 10:35 am
Re: Electrolysis
CarstenT -- 6/2/2013, 12:57 pm
Clogged up hinges. Solution
CarstenT -- 6/26/2013, 4:43 am
Re: Material: alu-tube rigidity
JohnAbercrombie -- 11/18/2012, 3:03 pm
Re: Material: alu-tube rigidity
Bill Hamm -- 11/19/2012, 1:33 am
Re: Material: alu-tube rigidity
Yostwerks -- 11/19/2012, 9:48 am
Re: Material: alu-tube rigidity
CarstenT -- 10/17/2014, 5:31 am
Re: Material: alu-tube rigidity
Bill Hamm -- 10/17/2014, 9:56 am
Re: Material: alu-tube rigidity
CarstenT -- 10/18/2014, 6:00 am