We’ve received this very interesting content from Graham Snape relating to his University research.
For my major project at the University of Nottingham I investigated whitewater Personal Floatation Devices (PFDs) and the level of buoyancy they provide. The aim of the project was to increase the total buoyancy available to the user in emergency situations.
The first problem I encountered: increasing the total buoyancy using just foam would significantly reduce manoeuvrability whilst paddling. The amount of foam that could be added without reducing manoeuvrability was negligible, so the route of inflated buoyancy was taken.
To test the idea of using inflated buoyancy, I made standalone inflation chambers. These helped trial different locations for the chambers on the PFD and the adjust the total volume of the inflated buoyancy – giving significant additional support whilst ensuring the user would still be in control when swimming in the water. The additional inflated buoyancy was kept as close to the body as possible to avoid obstructing movement.
Once the best volumes and locations for the inflation chambers were found it was time to design the buoyancy aid and the containment system. This was designed to be as low profile as possible but also include all the necessary features to allow the PFD to be used in extreme environments. A large amount of storage for safety equipment and personal items was featured in the design, including a quick access slot. Other features included: knife tab; rescue harness (with triple looping system); and safety loop (abseiling).
The foam provides 65N of buoyancy for everyday use. This can be increased by 110N (to give 175N) in emergencies. The extra buoyancy helps you resurface quickly and keep your head above the water. When the chamber is inflated the PFD still acts like a normal buoyancy aid but keeps you higher out of the water – you’re still able to swim and turn as usual. The inflation chamber at the bottom helps to keep your hips up when you’re on your back, stopping your legs dropping down and potentially getting stuck.
Super simple inflation method giving you an extra 110N of buoyancy in a matter of seconds.
Different rescue harness positions for different uses:
Standard – so you’re ready for any circumstance
Live-Bait – raises the anchor point to ensure the force of the water doesn’t fold your body keeping your head at the surface
Boat Rescue/Cowstail – lowers the anchor point so the force on you when towing a boat is grounded to your boat and you aren’t pulled back (so not leaning backwards and out of control)
The inflation chambers would always be ready for the day you really need that extra bit of help, making those swims a little more comfortable and keeping you safe when you are most vulnerable to the power of the river.
This was a conceptual project specifically aimed at being used by extreme whitewater paddlers. It was great fun designing and testing the prototype (although limited to testing at Holme Pierrepont by the University). If you’d like to know anymore about the project, feel free to contact me or come down to my Uni degree show for a chat.
grahamcsnape@gmail.com
Design Exhibition 2018
15th, 16th, 18th and 19th June 2018 (09:30-16:00)
Engineering Science Learning Centre (ESLC), Design Studio, Nottingham NG7 2TQ
I like to concept of multiple positions for the chest harness and the idea of extra uplift on request is comforting
Did you consider a dump valve?
I did consider it but decided against it, because if used the entire chamber would fill up with water making you much heavier in the water and on the end of a throwline.
Would this be more applicable to sea kayaking (something I don’t do)?
Interesting. Why sea and not ww?
It definitely could be, but I would redesign the location of the inflation chamber to promote a stronger face up body position.
Was there a specific reason to put the inflation valve on the back. Seems like it’s possible to drop the pull lanyard and loose the capability to inflate.
It was positioned on the back due to its size. If it were on the shoulder straps it would be very bulky. It was left off of the front as it would reduce the capacity of storage that is accessible when worn. As the actual CO2 canister any deployment device don’t need to be on the front it made sense to utilise the back panel for storage. The pull cord is contained and would be fixed to the front panel using Velcro to ensure it doesn’t come loose but can still be pulled when needed.
Valley Canoe products did a buoyancy aid & inflatable lifejacket combo back in the 70s. Either could be worn separately. The inflatable lifejacket could be worn over the BA. BA was foam strips. LJ was mouth inflation only with Buoyancy on front & round neck. Unique V wing shape on the neck to give self righting capability whilst wearing the BA and or wetsuit. Brilliant design by the Goodman brothers. Wore it for many years sea canoeing. Not gas, but still excellent. Worth researching. Let me know if you want more info.