How does a boat float?

[redduffer999]

Just been asked that question by my 6 year old god son.

How does a 100 tonne steel boat (or is that a ship?) float? Anyone? In 6 year old speak please.

I cant explain it either way so you'll be doing us both a favour by keeping it simple:confused:

Thanks

[jabarnutcase]

HOW (http://merlin.alfred.edu/Muller/PhysWorld/Project4/how_does_a_boat_float.html) does a
BOAT (http://www.boatsafe.com/kids/021598kidsques.htm)
FLOAT? (http://www.howstuffworks.com/question254.htm)
:confused: :)

[Fruss Tray Ted]

JBNCOTN (jabarnutcase'o'thenorth)
NICE.

http://www.usack.org/leith_slworlds_paddle.jpg

[steveo]

I'm still wondering how come I can toss 4 pair of socks in the dryer and 1hr later have only 3.5 pairs. Where are these socks going? What are they doing and who is controlling it?

[Paul Komski]

"They" must be a one-legged race for sure!! :D Beware of people on crutches I say.

[Eutychus]

When I was in the Navy, I was stationed aboard an 11,000 ton nuclear powered cruiser for 4 years. During that time, the ship spent a couple of months in a dry dock. We went into the dry dock, tied up, and all of the water was pumped out. Afterwards, I went down into the dry dock and, to my surprise, the ship was resting on huge wooden blocks. It was then that I realized how those heavy ships kept from sinking.

You see, ships really are too heavy to float on the water. They have these huge wooden blocks stacked all the way from the bottom (keel) of the ship to the ocean floor. I have surmised that every ship has a group of guardian dolphins that move the blocks in front of the ship as it goes through the water. That's why those powerful ships never go more than 30-40 knots; because guardian dolphins can only swim and carry all those blocks just so fast. If the ships went any faster they would fall off those blocks and sink like rocks.

Planes, on the other hand, connect to sky-hooks and swing from one place to the next, not needing to wait for any blocks to be moved.

*Man, you have way too much time on your hands!* :rolleyes:

[jabarnutcase]

Now that makes sense Eutychus! Always wondered what those Dolphins were doing hanging around the ship...:D


FTT - Sure glad he didn't ask how a Kayak floats....Sure seems like some excess water displacement there! :confused: :D

[Pianorak]

Hmmm, now all we need to know is who or what interfers with the efficient working of those blocks and sky-hooks in the Bermuda Triangle. :confused:

[kenz]

That is an easy question - a harder one is how does a heat sink ??

[Eutychus]

If you get caught up on your projects, you can browse through How Stuff Works:
http://www.howstuffworks.com/

It's a real treasure trove for people like me with an insatiable drive to accumulate information that only Cliff on the old Cheers sitcom would appreciate. :rolleyes:

[Gallaeglagh]

It's simply a matter of physics. The boat is drawn downwards by gravity. Counteracting that force is the water. As the water is displaced by the part of the boat under the water line the water will exert an upward force upon the boat.

[jabarnutcase]

Hmmmm- Haven't seen redduffer999 since he posted the "boat float" question.
:confused:

He's probably preoccupied trying to explain where all the wierd people in this thread came from! :D

[Eutychus]

Gallaeglagh, I'm thinking that it has more to do with the air that the ship's superstructure displaces. That air displacement causes a vacuum and the atmosphere essentially holds the ship out of the water by the resulting suction. The water having a flat surface produces less suction than the ship. The taller a ship, the more suction is produced to hold it up. Evidence to support this theory can be seen with submarines, which have very little superstructure and are constantly sinking & rising below the surface. Also, if you toss a steel sheet into the water it sinks because it displaces virtually no air to produce suction. :rolleyes:

Here's another interesting site,
James S. Huggins' Refrigerator Door:
http://www.jamesshuggins.com/

[jabarnutcase]

I think THIS (http://www.pcguide.com/vb/showthread.php?s=&threadid=16800) thread should help clear up any questions.....

Sorry, I'm really losing it now. :eek: :D :rolleyes:

[redduffer999]

Hi - I'm back.

I went for Eutychus wooden block theory in the end. We both seemed happy with that one!!!!!!!

I come from a fish port town so I should really know stuff about boats or are they ships? Anyway I'm just glad there's enough wooden blocks to go around.

Thankyou all - you are truely strange;)

[Eutychus]

redduffer999, you raised the question twice about the difference between a boat & a ship. (I'm putting on my serious, used-to-be-a-sailor face now.) The rule of thumb (an interesting story behind that phrase) is that if it is large enough and carries rigid-body boats then it is a ship. After being keel-hauled a couple of times, most sailors quickly learn never to refer to their ship as a boat. Boats don't carry ships. Ships carry boats. Even if the ship has inflatable lifeboats, it will most likely have launches for normal transportation when at anchor.

While some submarines are as large as a battle cruiser, they are always called boats. I guess that still follows the rule of thumb because, for obvious reasons, they have only have inflatable lifeboats on board.

*Removes serious, used-to-be-a-sailor face.*

[Eutychus]

Before I get flailed, no, I don't believe the myth that rule of thumb has to do with the inexcusable practice of wife beating. One of the briefest articles on the subject:
http://dynamic.uoregon.edu/~jjf/essays/ruleofthumb.html

[Pianorak]

Fascinating link, Eutychus. But what about this (more probable?) etymology?

"There was an old tailors' axiom that "twice around the thumb is once around the wrist", which turns up in Gulliver's Travels. It's most likely that the saying comes from the length of the first joint of the thumb, which is about an inch (I remember once seeing a carpenter actually make a rough measurement this way). So the phrase rule of thumb uses the word rule in the sense of ruler, not regulation, and directly refers to this method of measurement."

[Eutychus]

I read the same thing about the thumb measurement on UrbanLegends.com:

(From Part 1, Ch VI:) "The seamstresses took my measure as I lay on the ground, one standing at my neck, and another at my mid-leg, with a strong cord extended, that each held by the end, while the third measured the length of the cored with a rule an inch long. Then they measured my right thumb, and desired no more; for by a mathematical computation, that twice round the thumb is once round the wrist, and so on to the neck and the waist..."


Full article:
http://www.urbanlegends.com/language/etymology/rule_of_thumb.html

[Paul Komski]

Gulliver's Travels raises the spectre of Politics. I'm definitely a little-endian - always was - always will be. :D

[CLTEK]

Hey there Red...

My daughter's just rolled over the 'six' on her sixth year and she asked me this question a few months ago while we were sailing my Dad's 'boat' across Lake Tahoe. And she asked this (no s*&t) not more than ten minustes after she asked me, "Daddy... Why is the sky blue?" Oy! :::rolling my eyes::: :)

Mind you, my friends and family often accuse me of talking WAY above her head. My arguement in support? Maybe that's why she's so darn smart! Anyway... I found myself at a loss. So I pulled down the main sail leaving only the jib and made a straight tack across the lake. That gave me some time to 'break out' (yet another nautical term) a pad and pencil (for a drawing) and a bucket. I drew for her a cross section of the hull in the water and explained to her that the weight of the boat was less than the weight of the water that took up the space (the space in the cross section of the boat that was beneath the waterline) the boat took. Then, to demonstrate how heavy the water was, I threw the bucket attached to a line over the side and hauled it aboard. I let her see just how heavy the half-filled 5 gallon bucket was. Then I told her that the boat weighed less than 200 (random number) of these things filled with water (the volume of water that would fill the aforementioned cross section). LOL I know, I know, I know... It's pretty complex.

What did she get out of this? After a few months of not bringning it up... As in... Just now... I just asked her, "Jessi... How does a boat float?" She said, "The boat weighs less than the water." LMAO! 20 Minutes of explanation, demonstration and example and that's all she got! LOL I think it's pretty good for a little kid. LOL :)

Now... If I could just explain to her why I can't make it 'stop raining' and why the 'sun won't go down when it's too hot'(read: At Daddy's will). Oy! :)

Respectfully, Cory

Will parents ever get used to these questions? My favorites that Jessi has asked me... "Why is the grass green?... Why does 'poop' smell so bad?..." And my *ALL TIME FAVORITE*... "Daddy?... How come Mommy didn't marry you?" ROTFLMAO Answer: "Sweetheart... You're going to have to ask your Mom abut that one." LMAO!

[redduffer999]

Hi Cory.

I find that kids of about 8 & under ask the most impossible questions. The day to day questions from most people can be answered or evaded. Kids just need to know stuff right now. If truth were told, I think the levels of understanding between us & kids isn't that far apart. Its just we bluff alot better!

Take care