Chris_Robb
Well-known member
But jimmie - try it in your bath, then see....
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At work and bored
- Thread starter thewetone
- Start date
BlueSkyNick
Active member
This might be difficult for Jimi at the current time. I'm not sure if he's allowed home, until he remembers where he has left his boat, and gets it back again.
<hr width=100% size=1>People who think they know it all are very annoying to those of us that do.
<hr width=100% size=1>People who think they know it all are very annoying to those of us that do.
Jean
New member
Anchor may not just sit on bottom but actually “compress” bottom material under it (perhaps even releasing some air from “compressed” bottom material in the process). Hence I’m suggesting that it’s also not necessarily as simple as the anchor “just” displacing the water.
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Chris_Robb
Well-known member
I offered to tow him home
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BrendanS
Well-known member
It doesn't matter. If it's not in the boat, it's not floating, and therefore simply displaces it's own volume of water. It's simple physics.
If you want to complicate matters with ideas like displacing air from bottom material then what about atmospheric pressure, gravitational pull from the moon etc etc. It was a simple question, so most have approached it from the simple answer perspective
<hr width=100% size=1>It's this or Xmas posts!
If you want to complicate matters with ideas like displacing air from bottom material then what about atmospheric pressure, gravitational pull from the moon etc etc. It was a simple question, so most have approached it from the simple answer perspective
<hr width=100% size=1>It's this or Xmas posts!
jimi
Well-known member
Aye but what about the submarine, Brendan, answer that one smartie pants!
<hr width=100% size=1>O wad some Power the giftie gie us
To see oursels as ithers see us!
<hr width=100% size=1>O wad some Power the giftie gie us
To see oursels as ithers see us!
dragoon
Well-known member
The answer lies in density (i.e. weight/volume relationship). A boat only floats since it's density is less than that of the water is displaces;
Hence, when the anchor is on the boat, provided that the overall density (boat + anchor / volume) is less than that of the water it attempts to displace, the additional amount displaced is equal to the equivalent volume of water.
i.e. with the boat floating, 1 ton of water is displaced by the boat (imagine how much this is...it's more than a bath full)
Now, when the density is greater than the water, the object will sink. This is the case with the anchor being thrown into the water. In this case, the anchor displaces it's volume and not it's equivalent weight in water. Hence, the anchor in the water displaces less than the anchor in the boat, so the water level in the lake will fall once thrown in.
Don't believe me - imagine this;
- an emtpy oil tanker containing a brick that is so dense it weighs 10,000 tonnes. From the outside, no one is aware of what the tanker is containing, but it will settle at a lower level in the water (as though full of oil).
- now take this heavy brick and throw it into the water. The tanker will rise back to it's empty state, but the brick in the water will just displace it's volume, which is virtually nothing.
Now, which is heavier, a ton of feathers or a ton of bricks? ;o)
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Hence, when the anchor is on the boat, provided that the overall density (boat + anchor / volume) is less than that of the water it attempts to displace, the additional amount displaced is equal to the equivalent volume of water.
i.e. with the boat floating, 1 ton of water is displaced by the boat (imagine how much this is...it's more than a bath full)
Now, when the density is greater than the water, the object will sink. This is the case with the anchor being thrown into the water. In this case, the anchor displaces it's volume and not it's equivalent weight in water. Hence, the anchor in the water displaces less than the anchor in the boat, so the water level in the lake will fall once thrown in.
Don't believe me - imagine this;
- an emtpy oil tanker containing a brick that is so dense it weighs 10,000 tonnes. From the outside, no one is aware of what the tanker is containing, but it will settle at a lower level in the water (as though full of oil).
- now take this heavy brick and throw it into the water. The tanker will rise back to it's empty state, but the brick in the water will just displace it's volume, which is virtually nothing.
Now, which is heavier, a ton of feathers or a ton of bricks? ;o)
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BrendanS
Well-known member
If the submarine's submerged, it'll displace it's own volume 
<hr width=100% size=1>It's this or Xmas posts!
<hr width=100% size=1>It's this or Xmas posts!
Seafort
New member
Yea but its volume will change depending on depth (pressure).
I explained the anchor in boat/on the bottom earlier (Not very well it seems).
What are the forums thoughts on a descending anchor, temp' gradients and inversion layers may come into this one.../forums/images/icons/wink.gif.
Dave.
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I explained the anchor in boat/on the bottom earlier (Not very well it seems).
What are the forums thoughts on a descending anchor, temp' gradients and inversion layers may come into this one.../forums/images/icons/wink.gif.
Dave.
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Seafort
New member
WL will drop more then? nm
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thewetone
New member
Re: Bored and at work
The correct answer is the level of water will go down. And the replies have been very interesting. Thank you.
If you hang a Jacobs ladder over the side of your boat at high tide and the rungs are 1 foot apart, and there are 12 rungs and 3 rungs show. If the range of the tide is 6.7 metres How many rungs will show after 3 hours!!
<hr width=100% size=1>Randy
Once the avalanche has started, it's too late for the pebbles to vote
The correct answer is the level of water will go down. And the replies have been very interesting. Thank you.
If you hang a Jacobs ladder over the side of your boat at high tide and the rungs are 1 foot apart, and there are 12 rungs and 3 rungs show. If the range of the tide is 6.7 metres How many rungs will show after 3 hours!!
<hr width=100% size=1>Randy
Once the avalanche has started, it's too late for the pebbles to vote
BrendanS
Well-known member
Re: Bored and at work
It'll still be 3 rungs, unless you've got a bleedin big keel and have dried out, cos the boat is going to float at exactly the same level no matter the state of tied.
<hr width=100% size=1>Dad, why won't this magnet pick up this floppy disk?
It'll still be 3 rungs, unless you've got a bleedin big keel and have dried out, cos the boat is going to float at exactly the same level no matter the state of tied.
<hr width=100% size=1>Dad, why won't this magnet pick up this floppy disk?
thewetone
New member
Re: Bored and at work
As the title suggests.. I am at work and bored.
I'll try to find some more interesting!! ones
<hr width=100% size=1>Randy
Once the avalanche has started, it's too late for the pebbles to vote
As the title suggests.. I am at work and bored.
I'll try to find some more interesting!! ones
<hr width=100% size=1>Randy
Once the avalanche has started, it's too late for the pebbles to vote
BrendanS
Well-known member
Re: Bored and at work
Ooh! Good. Like these.
<hr width=100% size=1>Dad, why won't this magnet pick up this floppy disk?
Ooh! Good. Like these.
<hr width=100% size=1>Dad, why won't this magnet pick up this floppy disk?
Jean
New member
Re: Bored and at work
Depends on how well Jacob fitted the rungs to the ladder, perhaps some may fall off!
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Depends on how well Jacob fitted the rungs to the ladder, perhaps some may fall off!
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Jean
New member
Atmospheric pressure and gravity pull are not directly affected by the act off tossing the anchor over the side (or are they?) but bottom disturbance is (at least in the short term) and number of replies already suggest even the simplest of questions do not necessarily have the simplest of solutions!
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MainlySteam
New member
Gravity (and hence also atmospheric pressure) will be affected by the act of tossing the anchor over the side. However, much more worrying is that when one does so the earth's rotation will speed up. That is because conservation of energy tells us that the the angular momentum of the earth must be preserved, hence when the mass of anchor moves closer to the centre of the earth, the earth must rotate faster (just the same effect as ice skaters in a pirouette - arms out spin slower, arms in spin faster).
So, the result will be that the days and nights will become shorter, offset only by the smaller influence of the greater mass of the boat moving a much lesser distance away from the centre of the earth as it is relieved of the weight of the anchor (an hydrostatics analysis will show that that can never offset the effect from the anchor). The real problem is that boaters actually throw more anchors over the side than they haul up (because anchors periodically are lost) so an overall effect of boating on the environment is that the rotational speed of the earth is speeding up as more and more anchors move closer to the centre of the earth and there are great concerns as to the effect of this on animal life and indeed the rest of our environment.
There is actually a significant experiment taking place in Brendan's back yard monitoring the oestral cycle of cats, a method known to be a sure indicator of the rotational speed of the earth and the accelerating phases of the moon. The unfortunate side effect of this experiment though is that the offspring of the experiments get bagged and dumped in a nearby river (mentioned by him in a recent thread). I am sure our learned friend Brendan can update us on the latest results from these experiments monitoring the shortening of the days and nights and its effects on the life about us.
John
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So, the result will be that the days and nights will become shorter, offset only by the smaller influence of the greater mass of the boat moving a much lesser distance away from the centre of the earth as it is relieved of the weight of the anchor (an hydrostatics analysis will show that that can never offset the effect from the anchor). The real problem is that boaters actually throw more anchors over the side than they haul up (because anchors periodically are lost) so an overall effect of boating on the environment is that the rotational speed of the earth is speeding up as more and more anchors move closer to the centre of the earth and there are great concerns as to the effect of this on animal life and indeed the rest of our environment.
There is actually a significant experiment taking place in Brendan's back yard monitoring the oestral cycle of cats, a method known to be a sure indicator of the rotational speed of the earth and the accelerating phases of the moon. The unfortunate side effect of this experiment though is that the offspring of the experiments get bagged and dumped in a nearby river (mentioned by him in a recent thread). I am sure our learned friend Brendan can update us on the latest results from these experiments monitoring the shortening of the days and nights and its effects on the life about us.
John
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BrendanS
Well-known member
Very, very good!
Once I've drowned the next batch of kittens, I'll let you know how the experiment is going. The local werewolf population is spending far more time in open, so something is happening.
In the meantime I'll leave you with a joke:
When Albert Einstein died, he met three New Zealanders in the queue outside the Pearly Gates. To pass the time, he asked what were their IQs. The first replied 190. "Wonderful," exclaimed Einstein. "We can discuss the contribution made by Ernest Rutherford to atomic physics and my theory of general relativity". The second answered 150. "Good," said Einstein. "I look forward to discussing the role of New Zealand's nuclear-free legislation in the quest for world peace". The third New Zealander mumbled 50. Einstein paused, and then asked, "So what is your forecast for the budget deficit next year?"
<hr width=100% size=1>Dad, why won't this magnet pick up this floppy disk?
Once I've drowned the next batch of kittens, I'll let you know how the experiment is going. The local werewolf population is spending far more time in open, so something is happening.
In the meantime I'll leave you with a joke:
When Albert Einstein died, he met three New Zealanders in the queue outside the Pearly Gates. To pass the time, he asked what were their IQs. The first replied 190. "Wonderful," exclaimed Einstein. "We can discuss the contribution made by Ernest Rutherford to atomic physics and my theory of general relativity". The second answered 150. "Good," said Einstein. "I look forward to discussing the role of New Zealand's nuclear-free legislation in the quest for world peace". The third New Zealander mumbled 50. Einstein paused, and then asked, "So what is your forecast for the budget deficit next year?"
<hr width=100% size=1>Dad, why won't this magnet pick up this floppy disk?
MainlySteam
New member
Explains why there are no NZ'ers with IQ's greater than 50 left - the last 3 are in heaven.
John
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John
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BrendanS
Well-known member
I'd love to see the submarine that varies it's volume! Perhaps the same technology could be put to work to reduce the length of boats when in marinas, thereby reducing marina costs, but expands when out at sea to provide more room.
Submarines take on and blow ballast water to increase and decrease their density, and some even have weights they can drop, but they dont' typically change their basic volume
<hr width=100% size=1> I asked an economist for her phone number....and she gave me an estimate
Submarines take on and blow ballast water to increase and decrease their density, and some even have weights they can drop, but they dont' typically change their basic volume
<hr width=100% size=1> I asked an economist for her phone number....and she gave me an estimate