Posted by Maciek on July 12, 2002 at 09:02:29:
In Reply to: Re: Not really. posted by lance on July 12, 2002 at 07:59:20:
Diver 1: 200 lbs of beef + 100 lbs of gear + 14 lbs of lead - neutral in salt water
Diver 2: 190 lbs of fat + 100 lbs of gear, do you think 14 lbs is what is needed to keep it neutral in salt water? Let's say he needs 24lbs for salt water
Diver 1 displaces V1 gallons of water
Diver 2 displaces V2 gallons of water
V1 < V2.
Salt water weight diver 1 displaced (SWWD1D) = V1 * density of salt water
Salt water weight diver 2 displaced (SWWD2D) = V2 * density of salt water.
As you can see SWWD1D < SWWD2D even though Diver1 total weight is same as diver 2 total weight.
Now let's throw them both in fresh water. Let's say FWWD1D is 95% of SWWD1D and FWWD1D is 95% of SWWD1D. Amount of weight to drop for each of divers is 5% of their SWWD.
5%* SWWD1D < 5%* SWWD2D
What's wrong with TDI_2 calcs? He assumes every 217lbs + 100lbs gear + 14lbs diver will displace same amount of water and that's not true.
Archimedes guy discovered that law long time ago...