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Air Bags

Posted: Sun Nov 20, 2016 12:21 pm
by blueythe
I've seen reference in my reading that some of the more experienced sea kayakers use air bags between the foot pegs and front bulkhead. I presume this is the reduce the volume of water that can flood a kayak in a wet exit, improve overall buoyancy and also speed up the emptying of a flooded boat during re entry or rescue. Is there a real benefit here and what are peoples experience using them? secondly, what airbags do you use as most of the one's I.ve seen are tapered for use in WW boats. thanks

Re: Air Bags

Posted: Sun Nov 20, 2016 3:16 pm
by pathbrae
Not sure about air bags - but I've put in closed cell foam to fill the empty space in front of the footrests.
I don't know how robust an airbag would be or how easy it would be to hold it in place?

Re: Air Bags

Posted: Sun Nov 20, 2016 6:22 pm
by Joe S
As posted above; I use a close cell foam to fill any gap between bulkhead and footrest.

Additional I have air bags in both front and rear hatches to fill any space, especially when playing near rocks!

Re: Air Bags

Posted: Mon Nov 21, 2016 8:21 am
by Mark Gawler
I would avoid anything that could potentially cause an entrapment hazard. Air bags are notoriously difficult to secure. If anything a block of close cell foam glued in.

Re: Air Bags

Posted: Mon Nov 21, 2016 8:47 am
by Chris Bolton
If you're using your own boat and are planning to keep it for a while, it's worth considering moving the front bulkhead. That's more reliable, and has the bonus of additional gear space if you're touring.

Re: Air Bags

Posted: Mon Nov 21, 2016 10:39 am
by robhorton
To be honest I'd be surprised if you can displace enough water to make it worthwhile - if the front and rear compartments are intact it's fairly easy to get the water out and it's possible (but not particularly pleasant) to paddle with a cockpit of water if necessary. If the front or rear compartments are flooded you've got problems which I don't think a small airbag / foam block will help much with.

I have seen people put airbags in the front and rear compartments which is probably a good idea although I've not done it myself thus far.

Re: Air Bags

Posted: Tue Nov 22, 2016 12:27 am
by TechnoEngineer
Yup, I've used an aig bag behind a footplate. Large quantities of CC foam can weigh quite a bit. When a kayak is already above 20kg, you notice every extra 500g. I also use float tubes to provide "internal sponsons" to which I can mount pipe lagging foam.

e.g.
https://www.dropbox.com/sh/5iylrpcx3vx2 ... G_0407.JPG

Re: Air Bags

Posted: Tue Nov 22, 2016 9:24 am
by twopigs
TechnoEngineer wrote:Yup, I've used an aig bag behind a footplate. Large quantities of CC foam can weigh quite a bit. When a kayak is already above 20kg, you notice every extra 500g. I also use float tubes to provide "internal sponsons" to which I can mount pipe lagging foam.

e.g.
https://www.dropbox.com/sh/5iylrpcx3vx2 ... G_0407.JPG
According to Weber & Feckner https://en.wikipedia.org/wiki/Weber%E2%80%93Fechner_law noticing 500g in 20 kg might not be possible! But you do get to the point where you just can't lift the boat on your own!

Re: Air Bags

Posted: Wed Nov 23, 2016 8:02 pm
by blueythe
Hmm! I like the idea of airbags in the hatches if you are rock hopping at the extreme edge of the sport-I'm not. Moving the bulkhead would also be great if I could do this and maintain the strength and integrity-not sure I can. Probably only leaves me with the CCF to fill the space. Sponsons, footplate and airbag looks interesting but don't quite understand the sponsons and presumably the footplate has to fixed to the hull. Has left me wondering whether there is any advantage in any of the modifications.

Many thanks for all your comments, has given me more food for thought

Re: Air Bags

Posted: Wed Nov 23, 2016 8:17 pm
by Phizz4
My first aid kit and bothy bag (well wrapped in dry bag and polythene), live in the space between the bulkhead and the foot brace (I have a Rockpool so it is a large, full-width foot brace). This fills some otherwise dead space and reduces the volume a bit and also makes them very accessible.

Re: Air Bags

Posted: Wed Nov 23, 2016 10:34 pm
by TechnoEngineer
When you start practising Re-entry and roll, you will appreciate the benefit from reducing cockpit volume, and particularly how fitting internal sponsons makes a kayak far more easily paddleable when full of water sloshing around. Without the sponsons a flooded kayak loses its form stability and effectively becomes a log.
http://nordkyndesign.com/transverse-sta ... damentals/

Re: Air Bags

Posted: Fri Nov 25, 2016 6:51 am
by Mark Gawler
TechnoEngineer wrote: sponsons
Sponsons is a banned word on these forums, people have been banned for less :-)

Re: Air Bags

Posted: Fri Nov 25, 2016 10:44 am
by jet
Some air bags are definitely worthwhile :-)

https://www.amazon.co.uk/Kmise-Inflatab ... +protector