# water displacement **URL:** \ **Category:** Factual Questions\ **Created:** [September 30, 2000, 7:43pm UTC](https://boards.straightdope.com/t/water-displacement/35174 "2000-09-30T19:43:36Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![brook](https://avatars.discourse-cdn.com/v4/letter/b/41988e/32.png) [@brook](https://boards.straightdope.com/u/brook)\ **Post date:** [September 30, 2000, 7:43pm UTC](https://boards.straightdope.com/t/water-displacement/35174/1 "2000-09-30T19:43:36Z")
IF ALL THE VESSELS WERE TAKEN OUT OF ALL OF THE OCEANS,(SUBMARINES,FRIGATES,AIRCRAFT CARRIERS ETC,BY HOW MUCH WOULD THE WATER LEVELS FALL. ALSO WITH ALL CESSELS IN THE WATER WHAT WOULD THE TOTAL WATER DISPLACEMENT IN TONNES. ---
**Author:** ![AWB](https://avatars.discourse-cdn.com/v4/letter/a/bb73d2/32.png) [@AWB](https://boards.straightdope.com/u/AWB)\ **Post date:** [September 30, 2000, 8:35pm UTC](https://boards.straightdope.com/t/water-displacement/35174/2 "2000-09-30T20:35:24Z")
[sub]I don’t know the total tonnage displacement of the worlds ships. But I’d wager that they displace less than an inch worldwide. And to offset your yelling, I’m whispering. 😃 ---
**Author:** ![sailor](https://avatars.discourse-cdn.com/v4/letter/s/a587f6/32.png) [@sailor](https://boards.straightdope.com/u/sailor)\ **Post date:** [September 30, 2000, 8:44pm UTC](https://boards.straightdope.com/t/water-displacement/35174/3 "2000-09-30T20:44:18Z")
AWB, an inch??!! Come on! They couldn’t raise the water level of lake Superior by an inch, much less the entire whole wide world! Look, I just did some math in another thread. Someone do the math on this one. Why does it always have to be me? I did the dishes yesterday. It’s just not fair. ---
**Author:** ![brad\_d](https://avatars.discourse-cdn.com/v4/letter/b/50afbb/32.png) [@brad\_d](https://boards.straightdope.com/u/brad_d)\ **Post date:** [September 30, 2000, 9:44pm UTC](https://boards.straightdope.com/t/water-displacement/35174/4 "2000-09-30T21:44:18Z")
The [radius of the earth](http://search.eb.com/bol/topic?eu=108974&sctn=1#s_top) is about 6378 km, and oceans cover [71%](http://search.eb.com/bol/topic?eu=115011&sctn=1#s_top) of it. I calculate that this means the surface area of the earth’s oceans is roughly 3.63x10[sup]14[/sup] m[sup]2[/sup]. For the purposes of this, assume that the ocean shores are vertical walls - the ocean need not expand in area as it rises. I know this is is not accurate - we can worry about how bad it is later. I’m no mariner, so there are some serious guesses here. Let’s go with 100,000 ships (probably way high?) displacing an average of 10,000 tons (again, probably extremely high?). 10,000 tons = 9.072x10[sup]6[/sup] kg, so the total displacement of all ships is 9.072x10[sup]11[/sup] kg. This has a volume (using 1000 kg/m[sup]3[/sup] as the density) of 9.07x10[sup]9[/sup] m[sup]3[/sup]. That volume distributed over that area would give a drop in ocean levels of 2.5x10[sup]-5[/sup] m, or about 25 microns. That ain’t much. 🙂 ---
**Author:** ![brad\_d](https://avatars.discourse-cdn.com/v4/letter/b/50afbb/32.png) [@brad\_d](https://boards.straightdope.com/u/brad_d)\ **Post date:** [September 30, 2000, 9:49pm UTC](https://boards.straightdope.com/t/water-displacement/35174/5 "2000-09-30T21:49:58Z")
Ach! I already found a mistake. Total displaced volume is 9.07x10[sup]8[/sup] m[sup]3[/sup]. Which makes the answer even smaller. 2.5x10[sup]-6[/sup] meters, or 2.5 microns. Lemme know if you find any other math errors… ---
**Author:** ![Skelji](https://avatars.discourse-cdn.com/v4/letter/s/b38774/32.png) [@Skelji](https://boards.straightdope.com/u/Skelji)\ **Post date:** [October 1, 2000, 12:39am UTC](https://boards.straightdope.com/t/water-displacement/35174/6 "2000-10-01T00:39:57Z")
Hmmm, if all the Chinese people stood on chairs, and… :: d & r :: ---
**Author:** ![sailor](https://avatars.discourse-cdn.com/v4/letter/s/a587f6/32.png) [@sailor](https://boards.straightdope.com/u/sailor)\ **Post date:** [October 1, 2000, 12:54am UTC](https://boards.straightdope.com/t/water-displacement/35174/7 "2000-10-01T00:54:22Z")
The Chinese people are so poor there are not enough chairs in China for them to use at once and they have to take turns so your point is moot. 🙂 ---
**Author:** ![Smeghead](https://avatars.discourse-cdn.com/v4/letter/s/f1d935/32.png) [@Smeghead](https://boards.straightdope.com/u/Smeghead)\ **Post date:** [October 3, 2000, 12:37am UTC](https://boards.straightdope.com/t/water-displacement/35174/8 "2000-10-03T00:37:44Z")
Of course, if all those sponges weren’t living in the ocean, it’d be much deeper, too…