Re cap of a very sad day

[Top-Water]

Originally Posted by shore things

Top-Water, I didn't see any information pertaining to the shortcomings of CO2 inflated vests in coldwater conditions in the two links you posted. Did I overlook that information or is there another place that you would recommend I go to for info?

Thanks.

I seen the information about the cold water inflation problems at a couple of different places. One that stuck out was this kayaking forum in PA.

http://www.kayak-anglers.com/forum/t...d-cold-weather

Also mentioned here with little more science in the answer. A little ways down the page. I was not aware that the cold (could/would) affect the inflation that much.

http://www.boatsafe.com/nauticalknowhow/082000c.htm

So What's the Catch?
3) Cold weather adversely affects the operation of these PFDs. While the CO2 cartridge will fully inflate the vest most of the year, in extremely cold temperatures the same amount of gas will not expand to the same volume, reducing the vest’s buoyancy.

Sorry should have maybe included these links in the earlier post.

[fatlazyless]

For $18.96, marked down from 28.00, the swimoutlet.com has an adult USCG pfd, made by Sporti, in orange/yellow, that has extra large arm-shoulder cut-outs for active use. Also has two similar smaller pfd's for kids, $16.55, and youth, $18.55.

These look like some good quality, usable pfd's, at a LOW price. Closes with a zipper, plus three strap clips.

Seems like these could be good for snowmobiling, sailing small sailboats, canoes, and maybe kayaks.

https://www.swimoutlet.com/p/sporti-...9/?color=11950


.....hmmmm....does it really have a zipper in the front?


For just $12.99, amazon.com has a somewhat similar Onyx pfd in orange/black for adults, but with smaller arm cut-outs, so probably not as useful for easy arm movement.

[Onshore]

Originally Posted by Top-Water

I seen the information about the cold water inflation problems at a couple of different places. One that stuck out was this kayaking forum in PA.

http://www.kayak-anglers.com/forum/t...d-cold-weather

Also mentioned here with little more science in the answer. A little ways down the page. I was not aware that the cold (could/would) affect the inflation that much.

http://www.boatsafe.com/nauticalknowhow/082000c.htm

So What's the Catch?
3) Cold weather adversely affects the operation of these PFDs. While the CO2 cartridge will fully inflate the vest most of the year, in extremely cold temperatures the same amount of gas will not expand to the same volume, reducing the vest’s buoyancy.

Sorry should have maybe included these links in the earlier post.

Oh that's right, the ideal gas law... I will refrain from getting all geeky and wondering about the corresponding difference in the density of the colder water and whether that is enough to maintain equivalent buoyancy...

Thanks for the info. Putting some serious thought into whether or not the safety gear we assign folks here is what it should be...

[Woodsy]

Shore Things... Don't go all "Deflategate" on us!

Woodsy

[robmac]

Now that's a good one Woodsy!

[DickR]

Originally Posted by shore things

Oh that's right, the ideal gas law... I will refrain from getting all geeky and wondering about the corresponding difference in the density of the colder water and whether that is enough to maintain equivalent buoyancy...

But geeks don't mind getting geeky. The icy water will be more dense at 32 F than at, say, 70 F, so that cold water would impart more buoyancy. It's like being more able to float in salt water. But for fresh water, the density is greater at 32 F vs 70 F, but only by 1/4 of 1%, of no real consequence.

But for a gas inflating a vest, the gas law does make a difference in volume of the vest and thus of buoyant force provided. At low pressure, the volume is about proportional to absolute temperature. For temps in Fahrenheit, add 459.67 to get Rankine, and take the ratio of absolute temperatures. So the gas volume at 32 F is only 87% that at 70 F (winter vs summer temps, approx.). However, CO2 is a bit weird, so an equation of state is more appropriate. Here is a calculator for density of CO2: http://www.energy.psu.edu/tools/CO2-EOS/, from which the density ratio, winter vs summer, is 0.927.

But with a CO2 cartridge, things get more geeky. Under pressure, there is liquid CO2 in the cartridge, with a gaseous CO2 vapor space. When released, the gas expands into the vest, but the pressure in the cartridge drops, causing vaporization of liquid CO2. The heat of vaporization comes largely from the CO2 itself, resulting in a large drop in temperature, and perhaps in some solid CO2 (dry ice) flakes. Eventually, the cold CO2 gas that has expanded into the vest will pick up heat from the cold water and expand more, but initially the inflation will be substantially less than at thermal equilibrium.

[Onshore]

Originally Posted by DickR

But geeks don't mind getting geeky. The icy water will be more dense at 32 F than at, say, 70 F, so that cold water would impart more buoyancy. It's like being more able to float in salt water. But for fresh water, the density is greater at 32 F vs 70 F, but only by 1/4 of 1%, of no real consequence.

But for a gas inflating a vest, the gas law does make a difference in volume of the vest and thus of buoyant force provided. At low pressure, the volume is about proportional to absolute temperature. For temps in Fahrenheit, add 459.67 to get Rankine, and take the ratio of absolute temperatures. So the gas volume at 32 F is only 87% that at 70 F (winter vs summer temps, approx.). However, CO2 is a bit weird, so an equation of state is more appropriate. Here is a calculator for density of CO2: http://www.energy.psu.edu/tools/CO2-EOS/, from which the density ratio, winter vs summer, is 0.927.

But with a CO2 cartridge, things get more geeky. Under pressure, there is liquid CO2 in the cartridge, with a gaseous CO2 vapor space. When released, the gas expands into the vest, but the pressure in the cartridge drops, causing vaporization of liquid CO2. The heat of vaporization comes largely from the CO2 itself, resulting in a large drop in temperature, and perhaps in some solid CO2 (dry ice) flakes. Eventually, the cold CO2 gas that has expanded into the vest will pick up heat from the cold water and expand more, but initially the inflation will be substantially less than at thermal equilibrium.

While water at 32 F may be more dense than water at 70 F it is actually less dense than water at 39 F (a critically important property of water). Also you want to factor in the temperature of the cartridge at time of discharge and ambient air pressure.

[Onshore]

Pulling this thread back to its original purpose, my condolences to all of those who lost someone. I would also like to thank Almostthere for posting the link to the BG article. I have forwarded it to all of our field staff and several friends who are still too young to have a sense of their own mortality in hopes that in the future they might remember what happened and perhaps take an extra precaution or two that could save their life.

[wifi]

Originally Posted by shore things

Pulling this thread back to its original purpose, my condolences to all of those who lost someone. I would also like to thank Almostthere for posting the link to the BG article. I have forwarded it to all of our field staff and several friends who are still too young to have a sense of their own mortality in hopes that in the future they might remember what happened and perhaps take an extra precaution or two that could save their life.

Thanks Shore, too many distractions from the OPs meaning of this thread, to try to make others feel good about themselves and their transgressions.

[fatlazyless]

"An ounce of prevention, is worth a pound of cure": attributed to Benjamin Franklin, February 4, 1735, in The Pennsylvania Gazette. He was talking about fire prevention with regard to a fireplace fire in one's home.

So, the proverbial 'elephant in the room' here is that none of the three February 11-Derby Day drowning victims, three males, ages 15-62-67 was wearing flotation while snowmobiling on the frozen lake, neither a 5" diameter noodle float belt, or a pfd.

Wal-Mart has 5"-diameter x 44" long noodles in green, red and blue, sold in the summer, for 5.29, and all year around, has USCG-approved, standard pfd's in red or blue in three distinct sizes; child-youth-adult, for 9.94-each.

Do the NH F&G officers wear kevlar, bullet stopping vests? Could be that wearing a kevlar vest and a pfd at the same time is not very doable? But, wearing a kevlar vest and a 5" diameter noodle, float belt, is very doable when riding a snowmobile...... and it would set a good example for others out on the ice, when they saw the F&G officers wearing noodle float belts for ice flotation safety. Cheap to make, about six dollars for the noodle and a length of line to thread through the center hole; easy to wear over your coat; easy to put on, easy to take off, and can be used as a flotation rescue tool to be tossed to a victim, or to retrieve a victim with a line, or by hand, or to do a self-rescue for yourself. While not all noodles are particularly sturdy, these 5" diameter noodles are dense foam flotation, sturdy, and bendable into a circle float belt with a sturdy line threaded down through the center hole, and tied off with a knot, making a good fit for you.....not too tight....not too loose....but, just right.

Two 5" or 6" steel nails, or thin, aluminum, designer tent stakes (Wal-Mart), can be inserted directly into the foam belt to be used as ice rescue picks.....at the ready ..... at the time ...... worn like a belt ..... or, tossed 20' like a Frisbee.....as needed!

[Puck]

FLL, Unfortunately no one will appreciate your brilliance until you have field tested your invention under a variety of realistic conditions and published your findings here with your usual eloquence. Please remember when setting up your test scenarios that rescue response times are frequently measured in hours...no cheating. I look forward to reading about how this works out.

[wifi]

I'll only believe it if he tests it on himself

[fatlazyless]

....thanks for your support ..... and probably, I should mention that one has to trim down the 44" long x 5" diameter noodle to a length like 36", so it can be worn like a belt on the outside of your winter coat .... maybe that was obvious.

...for something like 76-cents each, Wal-Mart has these aluminum 6" tent stakes which are pretty interesting for using as ice self-rescue picks, ...

Come the summer, and one can always use the noodle and tent stakes for the lake, and the tent ...... like no kidding!

[robmac]

FLL, please I think you've taken this thread down the wrong path long enough as there is nothing funny about the loss of life!