You'll have to pardon my ignorance, but can somebody explain what is meant by primary and secondary stability. I've often seen it mentioned, but haven't got my head round it yet. Its probably something really simple and I'm going to look completely daft for asking.
Nige
Ok sticking my head up to get knocked about a bit but my interpretation is:-
Primary:- Get in your canoe and paddle, the wobble you do or do not experience is yer primary stability.
Secondary:- Now this is when you start to move around a bit and lean over edging your canoe. Every canoe has its limit of tilt before it goes from a controlled tilt to uncontrolled and its bite/yank point when your required to
jerk it back to recover or take on water..If your not expecting it, its that that 'whoa!!!' point. This point if done in a controlled manner takes a definate effort to cross.
I think
But i'm just a no nothing poser
Nige Wrote:You'll have to pardon my ignorance, but can somebody explain what is meant by primary and secondary stability. I've often seen it mentioned, but haven't got my head round it yet. Its probably something really simple and I'm going to look completely daft for asking.
Nige
Primary stability defines the steadiness you have when the boat is flat. A flat bottomed wide boat such as a We No Na Prospecter has lots of primary stability.
However, when a boat is heeled over (on edge for the kayakers) some boats tend to just fall over or wobble a lot. This is the secondary stability. Softer chined (the angle of transition between the side and bottom of the boat) or more rounded hulls tend to be more forgiving. Flare in the centre often provdes secondary stability. The Esquif Prospecteur (correct spelling) has a little more seconday stability than the We No Na.
If you take specilist white water canoes as an extreme example, because balance/stability are more of an issue, then the Esquif Zoom has almost zero primary stability, but pretty good secondary stability. The Bell [Dagger] Ocoee has much better primary stability, but its secondary stability is less good, pound for pound, than the Zoom.
As with any craft, it is the time in the boat which provides a sense of balance.
Cheers,
Ken
Primary stability
This is the initial stability in a canoe if you can stick the gunnel on the water it has lots of it.
Secondry stability
Is the when you have gone past the point of Primary stability and your going into a capsize situation through your fault or the action of wind, waves, currents, ect ect.
River boats tend to have more of this.
The amount of stability your canoe give's to you to recover fom that situation without capsizing.
Genraly canoes with big chimes () the bulges under the gunnel in the center of the canoe have great secondry stability but not as much initial stability.
My boat is a prime example of this if you look at the pic you can see the chimes that give it great secondry stability.
The Holy grail is a boat with both. ( which sevral people no mine has'nt
eh Lee and Tubby )
![[Image: SunshineonThirlmere-1.jpg]](http://i170.photobucket.com/albums/u267/retro4848/SunshineonThirlmere-1.jpg)
Thanks chaps for the quick responses. Suitably enlightened now
Nige
Probably refers to the boats position when you've got your gunwhale in, the point it rests at semi swamped before that gives way to it flipping over.
But thats a complete guess
Tertiary is third init?
I don't think this is the right reply
1: Biochemistry. 1995 Jan 10;34(1):172-9.Links
Tertiary stability of native and methionine-80 modified cytochrome c detected by proton-deuterium exchange using on-line Fourier transform infrared spectroscopy.de Jongh HH, Goormaghtigh E, Ruysschaert JM.
Laboratoire de Chimie-Physique des Macromolécules aux Interfaces, Université Libre de Bruxelles, Belgium.
The stability of the tertiary structure of cytochrome c and of a methionine-80 chemically modified form of this protein has been investigated by monitoring on-line the exchange of amide protons with deuterons using infrared spectroscopy. The modified protein has a structural stabilization energy of approximately 50% of that of native cytochrome c, whereas the secondary structure is not affected by the modification. In the modified protein the fraction of slow exchanging amides is smaller compared to that in the native protein, and the exchange rate constants are found to be 2-3 times larger for the slow (half-life of 5.5 h) and intermediate (half-life of 4.1 min) exchanging fraction of amides. The exchange rate of a fast exchanging fraction of amides (half-life smaller than 1 min), most likely surface exposed amides, is not influenced by tertiary destabilization of the protein. The results in aqueous solution agree well with data obtained by monitoring the amide-proton exchange using 1H-nuclear magnetic resonance. In films, using attenuated total reflection infrared techniques, this difference in tertiary stability between modified and native cytochrome c could also be demonstrated. The various advantages and complications of this approach are discussed in detail.
PMID: 7819193 [PubMed - indexed for MEDLINE]
Blame Google
Graeme @ YC Wrote:I don't think this is the right reply
1: Biochemistry. 1995 Jan 10;34(1):172-9.Links
Tertiary stability of native and methionine-80 modified cytochrome c detected by proton-deuterium exchange using on-line Fourier transform infrared spectroscopy.de Jongh HH, Goormaghtigh E, Ruysschaert JM.
Laboratoire de Chimie-Physique des Macromolécules aux Interfaces, Université Libre de Bruxelles, Belgium.
The stability of the tertiary structure of cytochrome c and of a methionine-80 chemically modified form of this protein has been investigated by monitoring on-line the exchange of amide protons with deuterons using infrared spectroscopy. The modified protein has a structural stabilization energy of approximately 50% of that of native cytochrome c, whereas the secondary structure is not affected by the modification. In the modified protein the fraction of slow exchanging amides is smaller compared to that in the native protein, and the exchange rate constants are found to be 2-3 times larger for the slow (half-life of 5.5 h) and intermediate (half-life of 4.1 min) exchanging fraction of amides. The exchange rate of a fast exchanging fraction of amides (half-life smaller than 1 min), most likely surface exposed amides, is not influenced by tertiary destabilization of the protein. The results in aqueous solution agree well with data obtained by monitoring the amide-proton exchange using 1H-nuclear magnetic resonance. In films, using attenuated total reflection infrared techniques, this difference in tertiary stability between modified and native cytochrome c could also be demonstrated. The various advantages and complications of this approach are discussed in detail.
PMID: 7819193 [PubMed - indexed for MEDLINE]
Blame Google
Dang that was my first thought, i knew i should have stuck with it!!!
Maybe Ken can give us a definitive answer
(I hope don't fancy this one at all:exclamation
Graeme
Graeme @ YC Wrote:I don't think this is the right reply
1: Biochemistry. 1995 Jan 10;34(1):172-9.Links
Tertiary stability of native and methionine-80 modified cytochrome c detected by proton-deuterium exchange using on-line Fourier transform infrared spectroscopy.de Jongh HH, Goormaghtigh E, Ruysschaert JM.
Laboratoire de Chimie-Physique des Macromolécules aux Interfaces, Université Libre de Bruxelles, Belgium.
The stability of the tertiary structure of cytochrome c and of a methionine-80 chemically modified form of this protein has been investigated by monitoring on-line the exchange of amide protons with deuterons using infrared spectroscopy. The modified protein has a structural stabilization energy of approximately 50% of that of native cytochrome c, whereas the secondary structure is not affected by the modification. In the modified protein the fraction of slow exchanging amides is smaller compared to that in the native protein, and the exchange rate constants are found to be 2-3 times larger for the slow (half-life of 5.5 h) and intermediate (half-life of 4.1 min) exchanging fraction of amides. The exchange rate of a fast exchanging fraction of amides (half-life smaller than 1 min), most likely surface exposed amides, is not influenced by tertiary destabilization of the protein. The results in aqueous solution agree well with data obtained by monitoring the amide-proton exchange using 1H-nuclear magnetic resonance. In films, using attenuated total reflection infrared techniques, this difference in tertiary stability between modified and native cytochrome c could also be demonstrated. The various advantages and complications of this approach are discussed in detail.
PMID: 7819193 [PubMed - indexed for MEDLINE]
Blame Google
PARDON???: I wasnt realy convinced of your explanation to me of the use of that Sexwax that Jamatrad bought for me.
Why worry about such Technicalities.
Just paddle the bloody thing and if you fall out you fall out.
Ok so thats my technique.
Therefore:
I always carry a bailer, a large sponge and a bottle of.......... shower gell. 
notice the Avatar. It is there for a reason
Sorry Graeme, never heard of it!
