View Full Version : Fooling most of the people most of the time!

12th January 2011, 01:11 PM
Much is being made by some parties about the magazine endorsement of the Fastcat technology.

Here is an example of just how lacking in understanding the magazines and other are when reviewing products.
A while back on a TV show in the UK a product called Water Buoy was promoted.
Go to this link and then choose the Dragons Den video on the right and watch how easy it is to fool the panel on how this device can lift the 1kg weight.


Of course given archimedes principle (and that is why boats float) the load being pulled by the balloon is 1 KG less the weight of water displaced which judging by the size of the object must almost be the same - I doubt if the balloon is pulling more than 10o grams. Had the inventor used a steel weight of 1 kg the balloon would never have lifted because the volume of water displaced would have been far less.

Further in practice the ballon takes up to 30 seconds to blow and by that time the object can be deep and hence the water pressure higher and lifting power less - so the lifting power reduces as the object sinks.

So what did the mags say - well the product won gongs on both sides of the Atlantic and reviews even claimed you need never use anything overboard again - that you can save things such as GPS units, binoculars etc. They repeat the claim that the water buoy can lift anything up to 1 kg weight.
Read this review
There are more links to reviews on the site all demonstrating the same total lack of understanding of the simplest of physics - so what hope is there for the same mags including those in the USA like Sail magazine ever getting near to doing a decent review on Green Motion? In my opinion none.

So Eric that is why I really cannot trust the mags who even seem to fail when it comes to really understanding how boats float::)

12th January 2011, 01:38 PM
Iím still convinced that Eric (sigmasailor) is a Trojan horse.:eek:

12th January 2011, 02:29 PM
Iím still convinced that Eric (sigmasailor) is a Trojan horse.:eek:

With the way that their publicity department has been so good at own goals, should that not be Trojan Herse

12th January 2011, 03:27 PM
I think eric is a straight and honest person who simply tries very hard to see the good in bad people. Not a Trojan horse at all.

12th January 2011, 07:53 PM
I think eric is a straight and honest person who simply tries very hard to see the good in bad people. Not a Trojan horse at all.

Paul, thanks for coming to my rescue.

I'm afraid you just demonstrated you don't understand the law of our mutual comrade Archimedes:

Lets assume the balloon displaces a little over a liter in volume, Archimedes dictates that upward force is equal to the volume of he displaced liquid (sweet water is 1 kg/ltr) minus the weight of the balloon, its packing and the weight of air filling it (0,0013 kg/ltr). Making the balloon a little larger than 1000 CC would compensate for its own weight resulting in the claimed upward force of 1 kg net. (as in period).
Now lets assume 1 kg (as in mass) of steel in the weight, at 7.8 kg/dm3 this would be a volume of about 130 cc. That volume is displaced under water reducing the downward force with 130 grams leaving 1000-130= 870 grams to lift. The balloon displaces a little more than 1 liter and can lift 1000 grams so wins and brings the lot to the surface.
If the volume of the weight increases due to lower specific gravity it would make the balloon win even easier.

The only reservation I would have to the system is the speed at which the balloon inflates; if allowed to go too deep the water pressure may get bigger than the pressure blowing up the balloon; if might not reach its maximum volume en hence not be able to lift its rated capacity.

In the way the experiment was demonstrated (balloon cannot go deep) you just have to believe what you see. Use Archimedes properly to proof it scientifically.

Paul, why don't you believe what you see or read (either on BBC or in Magazines)?


12th January 2011, 10:31 PM
A FLOATING body displaces its own WEIGHT of water.

As long as the submerged part of the floating air filled balloon is at least a litre in volume, then it will carry a kilogram (approx) - practically its makes no real difference what size or shape the weight is in the ocean.
A heavier weight will pull the balloon deeper to displace more water until the weight (in kg) is more than the volume (in litres) of the floating object, in which cse it will pull it under. Eg. a 5kg weight will float if attached to a 5.1litre balloon. The shape/size of the weight in not important.

There is another principle which says a SUBMERGED body displaces its own VOLUME of water.

13th January 2011, 12:49 AM
Damn the lack of science in my private school. I shouldn't have skipped to play drums.

I prefer the Letterman -- will it float? principal. I bet that Archamakdj[ was good at that.

I wonder if Archimedes would buy a Fastcat? (He might, but it would weigh 33% more than the ad, deliver half the amps, and you might have to run the generator all day. In addition, I wonder if any greek (?) philosophers get good after-market service.) ::)


13th January 2011, 02:02 AM
I am not misunderstanding it at all.

Wrong assumptions are being made about the size of the baloon.

Did you watch the video? - the 1 kg object was large and of low density needing very little force to lift it. The same balloon could not cope with 1 kg of steel because that would displace so little water and take more force to lift it.

To make it perfectly clear you need more force to lift 1 kg of steel than you require to lift 1 kg of a maerial with an SG of say 1.02.

Before we go any further do you agree or disagree with that?

13th January 2011, 02:53 AM
I just watched the video, the 1kg weight was bigger than the balloon!! Clearly it must have had a very low SG. It is a clever visual trick I agree, esp. with the big '1kg' in black letters making it 'look' v.heavy! haha, did you see how slowly it sank. Nice one.

On a related matter, a 1kg weight would take over an hour to reach the seabed if it fell over the Mariana Trench :)

13th January 2011, 03:21 AM
Exactly - it was a big low density weight that he tried to malke look heavy - if it has been steel it would never have managed it and of course there is the increasing pressure with time hence lower lifting power - yet the mags fell for it.

That is my point and I cannot understand why for the life of me Eric cannot understand that is just what I wrote. I have a Master of Science in water resources and i promise that i do understand Archimedes Eric. The fact that you even take issue with this simply amazes me.:):):):):)

By the way in order to generate a lifting force that lifts a mass the force also has to overcome frictional forces but that only complicates matters.

The consumer is being misled by this product because most really do think it can lift 1 kg of anything like keys, instruments etc and that is simply not the case - the lifting power is only a fraction of that as is evident from the video.

13th January 2011, 12:18 PM
Eric I woke up this morning for the first time understanding that your support for a product that totally flouts some of the basic rules of physics is at last an explanation for your support for the Fastcat and Gideon - it explains it all.::)

13th January 2011, 05:07 PM
Dear Paul,

I guess you slept well and woke up happily. Good for you.

You stated that if the weight was 1 kg in pure steel the balloon would not lift it. I proofed you are wrong on that part, no more, no less. If the balloon displaces more that a liter it will lift (slowly but surely) a kg of steel.

You are right that when the specific gravity decreases it becomes easier for the balloon to win (due to the displaced volume of the weight itself becoming a bigger factor. At lower than 1 it will even float by itself (like most types of wood do).

More of the balloon would stick out of the water at lighter loads; the part under water (displaced volume) is the weight of the load under water (mass minus the weight of its displace volume in water).

Looking at the weight in the movie it must be hollow and water filled to be one kilo since the volume seems to be several liters; agreed, this paints the picture maybe a bit optimistic (but not untrue). I guess the product is intended to protect keys, a GPS, a winch handle etc. weighing less than 1 kg; not for steel or lead weights (would still do it as I demonstrated).

Drag caused by the speed of rising will not decrease the upward force; it merely decreases the speed at which it will (for sure) rise.


13th January 2011, 07:18 PM
You did not prove anything I wrote wrong at all.
You assumed that the balloon was big enough to lift a kilo and then in effect stated because it could lift a kilo I was wrong!!!! You cannot fail if your assumption was that in the first place.

Look at the video. The i kilo weight is very large and hence much lower density than a kilo of steel and that is the limit the balloon could lift so that balloon the one we under discussion is not big enough to lift a kilo of steel and that is evident from the video.

Frictional forced could actually keep the object pinned to the bottom in the smallest amount of mud or sludge, so they have more effect than you assume. I could even expand on that but I want to stick to the main point.

Given that the balloon in the video only managed to just lift the 1 kg weight at the size and hence low density shown - do you think this balloon is capable of lifting a kilo of steel?

Also, as pointed out in my opening post, considering that this demo showed its maximum power and it had not sunk for 10 or 20 seconds do you not accept that this balloon on this device cannot be said to be capable of lifting even the weight shown at the time it actually inflates?

Do you not consider that mags that write that it can lift a kilo of anything are misleading their customers?

I am having trouble thinking you can be serious with your points on this and can only conclude you are now just winding me up because nobody can be that in defence of the undefencable:):):):):)

13th January 2011, 07:30 PM
Perhaps we have Don Quixote as a forum member here.::)

14th January 2011, 04:35 AM
a simple experiment should explain it all to you - take a balloon and fill it with 1 kg of seawater (if you are doing it in seawater) and attach a draw scale to it and then put it in seawater - all being equal it should register very close to 0, so anything that exerts a bit of lifting power will be able to float it.

Now take a 1kg balance weight from a scale and do the same - depending on the material the weight is made of, the reading on the scale will be substantially higher than the previous 0 and so would require a lifting force greater than this.

If still in doubt get hold of 1kg mercury and I promise you will be convinced!

Best in sailing,

PS Just read the following today:

In 4 BC Mo Ching stated: 'The cessation of motion is due to the opposing force ... if there is no opposing force the motion will never stop. This is as true as that an ox is not a horse.'
... and this around 2000 years before Newton! Makes you think.