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Re: Other: concrete kayak
By:Mike Savage
Date: 3/2/2012, 9:45 am
In Response To: Re: Other: concrete kayak (John Messinger)

: I don't get it. Concrete/aggregate is heavy and weak in tensile
: strength. It requires steel or other fiberous material to give
: it tensile strength. Steel rusts at the water line and causes
: the concrete to explode apart at the waterline. There are so
: many better materials to choose from to make a boat.

: It is not attractive, the only place we use concrete in our living
: spaces is garage floors and basements. Yet for the past 60+
: years civil engineering programs have been giving students the
: busywork of making boats out of cement. Sigh.

: Then there is the old joke about the four engineers discussing what
: kind of engineer God is...

Hi John,
Many fine boats have been built with ferrocement without any rusting. The rust only happens if the cement is porous/broken so that it bares the steel reinforcement.
There's a vast difference between concrete and what is used for boat building, the concrete uses gravel/coarse agregate, ferrocement is a fine sand plaster, basically the same as is put on a concrete block build house. That is what waterproofs the house walls.

Mike Savage
South West Cork

Messages In This Thread

Other: concrete kayak
gilad naor -- 2/21/2012, 10:22 am
Re: Other: concrete kayak
Robert N Pruden -- 2/21/2012, 12:45 pm
Re: Other: concrete kayak
Matthias -- 2/22/2012, 2:25 am
Re: Other: concrete kayak
gilad naor -- 2/22/2012, 3:26 am
Re: Other: concrete kayak
Dan Caouette (CSFW) -- 2/22/2012, 8:26 am
Re: Other: concrete kayak
Bill Hamm -- 2/26/2012, 2:31 am
Re: Other: concrete kayak
Mike Savage -- 2/26/2012, 11:19 am
Re: Other: concrete kayak
ancient kayaker -- 2/26/2012, 12:43 pm
Re: Other: concrete kayak
Bill Hamm -- 2/28/2012, 2:41 am
Re: Other: concrete kayak
Björn Thomasson -- 2/28/2012, 4:01 pm
Re: Other: concrete kayak
Bill Hamm -- 2/29/2012, 1:57 am
Re: Other: concrete kayak
Björn Thomasson -- 2/29/2012, 2:29 am
Re: Other: concrete kayak
Bill Hamm -- 2/29/2012, 1:59 am
Re: Other: concrete kayak *PIC*
Björn Thomasson -- 2/29/2012, 2:51 am
Re: Other: concrete kayak
Etienne Muller -- 2/29/2012, 3:23 am
Re: Other: concrete kayak
Björn Thomasson -- 2/29/2012, 4:03 am
Re: Other: concrete kayak
Bill Hamm -- 3/1/2012, 1:51 am
Re: Other: concrete kayak
Paul G. Jacobson -- 3/7/2012, 6:10 pm
Re: Other: concrete kayak
Rob Macks/Laughing Loon CC&K -- 3/7/2012, 8:57 pm
Re: Other: concrete kayak
Bill Hamm -- 3/8/2012, 2:09 am
Re: concrete or newspaper kayaks
Paul G. Jacobson -- 3/8/2012, 2:53 am
Re: concrete or newspaper kayaks
Jim Ham -- 3/9/2012, 12:13 am
Re: concrete or newspaper kayaks
Ulrik Schou -- 3/9/2012, 1:31 am
Re: concrete or newspaper kayaks
Björn Thomasson -- 3/9/2012, 1:11 pm
Re: Other: concrete kayak
John Messinger -- 3/1/2012, 5:44 pm
Re: Other: concrete kayak
Mike Savage -- 3/2/2012, 9:45 am
Re: Other: concrete kayak
Bill Hamm -- 3/4/2012, 2:01 am
Re: Other: concrete kayak
John Messinger -- 3/4/2012, 7:34 am
Re: Other: concrete kayak
Paul G. Jacobson -- 3/8/2012, 2:40 am
Re: Other: concrete kayak
Kevin McAtee -- 3/8/2012, 3:57 pm
Re: Other: concrete kayak
Mike Savage -- 3/9/2012, 4:49 am
Re: Other: concrete kayak
Robert N Pruden -- 3/13/2012, 6:02 pm
Re: Other: concrete kayak
John Messinger -- 3/14/2012, 9:46 am
Re: Other: concrete kayak
Robert N Pruden -- 3/14/2012, 9:58 am
Re: Other: concrete kayak
Cole -- 3/9/2012, 9:21 am