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Old 02-18-2011   #11
Idaho, Wyoming
Join Date: Nov 2009
Posts: 147
Originally Posted by billfish View Post
i believe most rescue vests are type lll. type v is for commercial use with a collar designed to keep an unconsious person face up in the water. there are probably others who can clarify this better.
to correct my self, after some quick research, type v floatation devices are designed for specific uses of which rescue and commercial whitewater rafting are two. in addition to higher floation, commercial rafting vests have a collar to keep an unconsious person face up in the water.

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Old 02-18-2011   #12
Droboat's Avatar
Wild Wild West, Colorado
Join Date: May 2008
Posts: 214
Have a 27lb Hi Float (has held up well) and a 15lb-ish drinking jacket.

In a swiftwater course, I wore both and definitely noticed the difference. The added lbs of float provided much more access to air. With Hi Float, I felt like my head was more often at/above the surface rather than bouncing in and out of the slick.

Pretty small sample size of swims, but both did the job and I keep both on my boat depending on the task at hand. When I replace my Hi Float, I'll pay the extra $30-60 to get features of a 25+lb rescue vest.

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Old 02-18-2011   #13
KSC's Avatar
Boulder, Colorado
Paddling Since: 2003
Join Date: Oct 2003
Posts: 2,031
What does the metric "N lbs of float" mean? Is it some factor of weight that the vest will keep buoyant?
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Old 02-18-2011   #14
Droboat's Avatar
Wild Wild West, Colorado
Join Date: May 2008
Posts: 214

What Does 'Pounds of Buoyancy' Mean?
Jeremy wants to know:
"In your course you say that different PFDs have different pounds of buoyancy. What does that mean?"
A buoyant apparatus is anything that can float and hold up weight. For instance, if you had a Type I PFD that is required to have 22 pounds of buoyancy, it would be capable of supporting 22 pounds of dense material such as lead, iron, gold, granite, etc. It would not let the material sink to the bottom. If we tied a 20 pound anchor to this PFD, what do you suppose would happen? If you guessed that it would hold the anchor off the bottom you would be correct.

How can this PFD with 22 pounds of buoyancy hold up a two hundred pound person in the water?
You have to do the math! Let's take the example of a 200 pound person. Approximately 80% of the body is water. Water in the body has no weight in water. So now we are down to having to support only 40 pounds.
200 lbs. X 80% = 160 lbs.
200 lbs. - 160 lbs. = 40 lbs.
But the PFD only has a buoyancy rating of 22 lbs. How can it hold up 40 lbs?
On average our bodies also have 15% fat and fat is lighter than water.
200 lbs. X 15% = 30 lbs.
40 lbs. - 30 lbs. = 10 lbs.
Now you can see that the average 200 pound person only weighs about 10 pounds in water. The 22 lbs of buoyancy in your PFD is more than enough to keep the person afloat.
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Old 02-18-2011   #15
Golden, Colorado
Join Date: Apr 2004
Posts: 831
I am floating the GC this summer in my raft and I'm not even considering taking my "regular" kayaking PFD. It is a high quality rescue PFD that I paddle V- creeks in but it just doesn't have the floatation for big water. As a matter of fact, it is not even that great in medium volume water.

Kayaking PFDs that people use around here seem to run in the mid to high teens for floatation (15-17 lbs). I had a swim at Pine Creek on the Ark once that pretty much showed me how crappy that much float is.

For the Grand Canyon I'm getting a new PFD. Minimum 22 lbs float.

On Westwater on a big day I've been sucked down, down, down, while I was still in my kayak (I'd guess about about 250-300 lbs of float for me sitting in a playboat wearing a PFD). I was down so deep and so long... and it was pitch black. It wasn't even a hole, it was a whirlpool spinning off of a monster eddy line. One of the scariest things I've done in a kayak. I am not a fan of big water.

22 lbs of float will be better than 15-17 lbs but I know for a fact that it will not be much while I am "swimming" in the middle of a huge rapid... I know I am going to be holding my breath for most of the time and when I get out I am going to make my wife oar the next big one.
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Old 02-18-2011   #16
Buena Vista, Colorado
Paddling Since: 1985
Join Date: Jun 2006
Posts: 88
PFD Ratings and Use

The Coast Guard ratings are as follows (floation is not the deciding factor which is why you can have a Type V PFD with 15.5 lbs of floatation):

TYPE III PFDS / FLOTATION AIDS: For general boating or the specialized activity that is marked on the device such as water skiing, hunting, fishing, canoeing, kayaking and others. Good for calm, inland waters, or where there is a good chance for fast rescue. Designed so that wearing it will complement your boating activities:
· Inherently Buoyant Type III PFDs
· Inflatable Type III PFDs
· Hybrid Type III PFDs

TYPE V PFDS / SPECIAL USE DEVICES: Only for special uses or conditions.
· Hybrid Inflatable PFDs
· Canoe/Kayak Vest
· Boardsailing Vests
· Deck Suits
· Work Vests for Commercial Vessels
· Commercial Whitewater Vests
· Man-Overboard Rescue Devices
· Law Enforcement Flotation Device

USCG Type III requires 15.5 lbs. of flotation or greater

USCG Type V is approved for the activity in which the boat is being used and typically range from 15.5 lbs. and up.

Buoyancy - The tendancy of a body to float or sink in water or any other fluid. Most people will naturally float in water, especially if they fill their lungs with air. Most require only about 11 pounds (50 Newtons) of extra buoyancy to keep their head out of water. That is why a PFD with just 15.5 pounds (70 Newtons) of buoyancy can provide adequate flotation for an adult -- even a very large person. PFDs with 22 to 34 pounds (100 to 155 Newtons) can provide superior performance.

In technical terms, buoyancy is determined by Archimedes' Principle:
Any body partially or completely submerged in a fluid is buoyed up by a force equal to the weight of the fluid displaced by the body.

That means someone immersed in water is "buoyed" upward by a force equal to the weight of the volume of water that their body takes up (displaces). Gravity pulls a person's body downward by a force equal to their weight. The difference between these forces is a person's net buoyancy. A PFD is very light weight, but displaces enough water to make the PFD and the person wearing it very buoyant.

It also follows that the people hardest to float are those with compact, dense bodies. These tend to be people with athletic body builds, with a lot of bone and muscle mass, and not much fat. Fat is not as dense as muscle and bone, so people who are overweight can actually be easier to float than someone who is much smaller and leaner. Heavy people do not need a higher buoyancy PFD because of their weight.

Most adults only need an extra seven to twelve pounds of buoyancy to keep their heads above water. A PFD can give that "extra lift," and it's made to keep you floating until help comes. But a PFD is a personal flotation device and it's important to get the right one for you.

Your weight isn't the only factor in finding out how much "extra lift" you need in water. Body fat, lung size, clothing, and whether the water is rough or calm, all play a part.
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Old 02-18-2011   #17
4Corners Riversports
Durango, Colorado
Paddling Since: 4Eva
Join Date: Apr 2010
Posts: 170
Another good option if you want a lower profile rescue vest AND higher buoyancy in one jacket is the Stohlquist Descent with the removable Add-A-Buoy bladder, which puts it at right around 22lbs.
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Old 02-18-2011   #18
Join Date: Sep 2006
Posts: 1,131
Anyone try the NRS Anti Gravity Shirt which adds 10 lbs of buoyance?
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Old 02-18-2011   #19
Boise, Idaho
Join Date: Aug 2010
Posts: 505
Maybe I'm missing something obvious, but why would you want overkill with a Pfds?

It seems like most Pfds flirt with that line between adequate buoyancy and fit/comfort; but I can't think of a reason you wouldn't want double, triple, or more buoyancy.

Again, unless I'm missing something completely obvious...
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Old 02-18-2011   #20
pocatello, Idaho
Paddling Since: 1991
Join Date: Feb 2010
Posts: 471
triple the bouyance = triple the volume of foam = I can't even clap my hands anymore = sumo suit.

You can't have a lot of float under your arms, over your shoulder or below the belly button so the only place to add float is on the chest or back. If it is all on the back it would tend to roll you onto your face. If it is all on the chest- sumo suit.

How about a PFD that has a bladder that you can inflate temporarily for a big rapid and deflate for comfort in between?

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