U.S. CitiesCity-Data Forum Index
Covid-19 Information Page
Go Back   City-Data Forum > General Forums > Science and Technology
 [Register]
Please register to participate in our discussions with 2 million other members - it's free and quick! Some forums can only be seen by registered members. After you create your account, you'll be able to customize options and access all our 15,000 new posts/day with fewer ads.
View detailed profile (Advanced) or search
site with Google Custom Search

Search Forums  (Advanced)
Reply Start New Thread
 
Old 06-01-2020, 05:56 PM
 
9,068 posts, read 5,173,291 times
Reputation: 13698

Advertisements

The book "Sea Kayaker's Deep Trouble" (recommended above; I read the preview) advises adequate floatation in both ends of the kayak occupying most of the space not being occupied by your body. They don't elaborate as to what that should be...
Reply With Quote Quick reply to this message

 
Old 06-01-2020, 06:08 PM
 
Location: Boydton, VA
2,913 posts, read 3,575,900 times
Reputation: 5607
"(I didn't take physics.)"....neither did I....but common sense overcomes a lack of book learnin' of physics. Like Harry I have resisted chiming in with my 2 cents.....but...

Take an empty glass bowl (your kayak), and float it in a sink full of water. Mark the flotation level. Now blow up a balloon (or cut up a pool noodle)...place inside the bowl, and try the flotation test again....did anything change ? Now, translate the results to your kayak question.

So, you say use helium...after all, helium is lighter than air and helium can lift things...why wouldn't that work.....?

How much helium does it take to lift 100 pounds?

The difference in the up and down force is 0.069 pounds. Therefore each cubic foot of helium could lift 0.069 pounds. In order to lift 100 pounds (which would include the weight of your load, the balloon, and the helium) you would need 1449 cubic feet of helium.

Good luck finding a kayak that large...

Regards
Gemstone1
Reply With Quote Quick reply to this message
 
Old 06-02-2020, 08:56 AM
 
7,950 posts, read 4,473,407 times
Reputation: 21361
Quote:
Originally Posted by otterhere View Post
The book "Sea Kayaker's Deep Trouble" (recommended above; I read the preview) advises adequate floatation in both ends of the kayak occupying most of the space not being occupied by your body. They don't elaborate as to what that should be...
Like has been said several times, that's the keep the kayak itself from sinking when it gets swamped. It's not going to make the kayak hold more weight than it's size can carry. Is your real sticking point here the "sunk" cost you've already spent on the kayak?
Reply With Quote Quick reply to this message
 
Old 06-02-2020, 11:46 AM
 
Location: Raleigh
9,691 posts, read 7,300,912 times
Reputation: 13668
Quote:
Originally Posted by otterhere View Post
You CAN buy "balloon buddies" helium tanks cheaply; would it help to fill beach balls stuffed in the stern and bow? If not, I'll concede defeat.
If a beach ball filled with helium floats away, yes. If the rubber in the beach ball is enough that it falls to the ground, no.
Quote:
Originally Posted by otterhere View Post
So what is the purpose of float bags?

(I didn't take physics.)

Thanks for the goodreads recommendation!

I love disasters as long as they're not happening to me.
Quote:
Originally Posted by otterhere View Post
The book "Sea Kayaker's Deep Trouble" (recommended above; I read the preview) advises adequate floatation in both ends of the kayak occupying most of the space not being occupied by your body. They don't elaborate as to what that should be...
Right. The idea is that space cannot be filled with water. Think of an empty coca cola bottle, with the cap screwed on. It floats, quite well, and since it can't be filled with water, will continue to float. Fill it halfway with water, it doesn't float as high. Fill it all the way and screw the cap on; it sinks. Your kayak is like that coke bottle. By adding flotation bags, you've "Screwed the cap" onto an empty coke bottle.

If you took your 2 liter bottle, and filled it with flotation foam, it wouldn't float any higher in the water, and wouldn't require any more weight to sink it. It would just have less space that water could occupy to weigh it down.
Reply With Quote Quick reply to this message
 
Old 06-03-2020, 02:16 AM
 
Location: Eugene, Oregon
10,614 posts, read 3,764,310 times
Reputation: 15885
Here's a cheap, but effective substitute for expensive flotation bags specifically intended for kayaks. Get a couple of the type of five-gallon water bags that are made of clear, soft plastic and have fold-out nozzles. The plastic is very tough and dependable. After screwing the cap tightly, open the nozzle and use it to blow up the bag. Then close the nozzle and it will be watertight. Put them back under the bow and stern decks and wedge them in tight.
Reply With Quote Quick reply to this message
 
Old 06-03-2020, 06:27 AM
 
9,068 posts, read 5,173,291 times
Reputation: 13698
Quote:
Originally Posted by Steve McDonald View Post
Here's a cheap, but effective substitute for expensive flotation bags specifically intended for kayaks. Get a couple of the type of five-gallon water bags that are made of clear, soft plastic and have fold-out nozzles. The plastic is very tough and dependable. After screwing the cap tightly, open the nozzle and use it to blow up the bag. Then close the nozzle and it will be watertight. Put them back under the bow and stern decks and wedge them in tight.
Sounds good; thank you! (And I DO understand that this won't lift the boater higher out of the water, but will hopefully keep the boat at water level for bailing.)
Reply With Quote Quick reply to this message
 
Old 06-03-2020, 02:49 PM
 
41,727 posts, read 43,564,675 times
Reputation: 17638
Quote:
Originally Posted by otterhere View Post
It was sufficient to "float" dirigibles, and THEY had to weight a lot (at least the gondola and passengers it carried), or is hydrogen more powerful? Yes, I know the Hindenburg exploded, but that's another issue...

The volume of the gas in a blimp or whatever you want to refer to it is huge compared to the other structures. As I recall Mythbusters did episode on this nd they needed thousands of balloons, with the volume you'd be able to store inside the kayak you would be lucky to offset one pound...Just guessing but that is in the ball park. Instead take a dump before you get in the kayak.


As far as your question about Hydrogen look up specific gravity. "Air" which is mixture of gases is 1, it will neither sink or rise. Note the weight of the balloon causes it to fall and if you really wanted to get technical if you blew it up there is more carbon dioxide making the gas mixture heavier than air. Common example that may be of interest is carbon monoxide which is nearly the same density as air so it can easily travel along air currents in your house. Carbon dioxide is about 50% more so it will sink into pools, if you ever heard of someone dying in tank or deep hole this is usually why. Helium is 0.18 and Hydrogen is 0.09 so both are significantly less than "air".
Reply With Quote Quick reply to this message
Please register to post and access all features of our very popular forum. It is free and quick. Over $68,000 in prizes has already been given out to active posters on our forum. Additional giveaways are planned.

Detailed information about all U.S. cities, counties, and zip codes on our site: City-data.com.


Reply

Quick Reply
Message:

Over $104,000 in prizes was already given out to active posters on our forum and additional giveaways are planned!

Go Back   City-Data Forum > General Forums > Science and Technology
Follow City-Data.com founder on our Forum or

All times are GMT -6.

© 2005-2020, Advameg, Inc. · Please obey Forum Rules · Terms of Use and Privacy Policy · Bug Bounty

City-Data.com - Contact Us - Archive 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37 - Top