Question about the anchor

[rwams]

Please some correct me it I am wrong...You have to understand that the buoyancy of water displaces the weight hanging over the side. With the anchor hanging at half staff the ship is still with no list either side. You are not turning a little sailboat. If in an emergency the brake on the chain running around the capstan hopefully would hold the chain then the deck hands can get a chain stopper on it, then the anchor can hold the ship from maneuvering.

[mariner]

Get over your emergency. Bow thrusters turning. A little weight. Got a thurster on a destoyer?

[mariner]

And let go a few feet from the dock.

[3rdGenCunarder]

That TOTALLY makes sense to me.....I see it the same as if i'm carry my purse with all my junk in it. If i carry in my hand with my arm down by my side it will make my body lean to that side, if I carry the same purse close to the center of my body, it will be more balanced an not feel as heavy. See, it's really easy just use one of my favorite thing (a purse) and I get it.:D:D

 

In the case of your purse, you're changing its position relative to your center of gravity. In one case, the purse is farther away from the center of your body than in the other. But in the case of the anchor, it may be higher or lower, but it is the same distance from the center line of the ship whether it's just above the water or snug up against the ship. I'm with jtl513 on this one.

[GarySuzy]

And let go a few feet from the dock.

 

Mariner you just have to keep explaining it until someone listens.:D

[mariner]

Or until the ship hits the dock

[GarySuzy]

Or until the ship hits the dock

 

That's true and I have seen it done, both military and civilian.

[mariner]

So much for the anchor

[bob brown]

Can you explain how it does that? I can see if it was actually in the water producing a little drag, but just hanging in the air ... :confused::confused:

Maybe a minutia bit of 'air drag'??:D

 

I would have to agree that the emergency deployment is a more logical explanation than the aid to turning explanation....:)

 

Edit: On the other hand....doesn't the ship have an anchor on each side? And if so, why not have both sides lowered for quick deployment?.....

 

On the other hand....wait....there is no other hand....:D

[DFD1]

LOL...LOL...I love this! Keep it up!

 

Mariner...I'm hanging on your every word. I just don't understand the physics of it.

 

The purse part is the icing on the cake!

[jtl513]

That piece of metal hanging down adds to the list of the ship. Upright it doesn't.

The anchor adds some weight to the side of the ship that is turning.

Up or down, the weight of the anchor is the same, and there is no leverage applied by lowering it. Furthermore, that anchor really doesn't weigh that much compared to the weight of the ship and cargo, and I believe that any possible list produced would be miniscule, and have a negligible effect on turning.

 

When we watch the portevergladeswebcam Hyatt camera and see ships leaving pier 26 going forward, first they turn to port as if they were going to head up to the Northport piers (where Princess normally docks), or up to 17th street bridge. If your claim is correct, an anchor hanging low on the starboard side would be opposing that first turn.

 

Topsham/Capt Card, can you weigh-in here please? I'll believe whatever you say.

[josie724]

OK, let me start off by saying that my purse comment was in fun, and I don't have ANY idea of the physics or science behind any of this. But now my curiosity has been tweeked, and I too would like to know the real answer.

 

Once again, I have NO CLUE about the physics, but I would think that if the anchor were dropped suddenly to stop the ship wouldn't the back of the ship turn outward? Now if someone could explain it to me using a shoe reference I'm sure I'd understand.....:D:D;)

[BillB48]

Up front I have not read this thread completely... just have been skimming it. I also assume there has been a bit of tongue in cheek as well;), now that all the disclaimers are behind, here's what I know in general terms. When the anchor is dropped out of the pocket as in the early pic, one of the most common reasons is they feel they may need to use it for maneuvering as dropping the anchor (in the water) to use it as a pivot point or to check the swing of the bow if there was too much wind and insufficient power on the bow thrusters for the conditions present. The anchor just hanging above the water does not provide any drag to the ship at all. There could be some other reason as well, like the bozo that let the anchor go not too long ago:eek:, this does not appear to be the case here.

[jtl513]

The anchor just hanging above the water does not provide any drag to the ship at all.

Nor any list either, correct?

[BillB48]

Nothing that would be detectable. I guess it would be conceivable that since the anchor weight was being held slightly further away from the center line of the ship, with fine enough instruments and a long enough decimal point it possibly could be measured.... just speculation on my part. Then again maybe 30 passengers moving to the opposite side of the ship would cancel everything out:D.

[ASIWISH]

That TOTALLY makes sense to me.....I see it the same as if i'm carry my purse with all my junk in it. If i carry in my hand with my arm down by my side it will make my body lean to that side, if I carry the same purse close to the center of my body, it will be more balanced an not feel as heavy. See, it's really easy just use one of my favorite thing (a purse) and I get it.:D:D

 

So, so, so flippin' funny!!!!

 

:D:D

[jtl513]

Nothing that would be detectable. I guess it would be conceivable that since the anchor weight was being held slightly further away from the center line of the ship, with fine enough instruments and a long enough decimal point it possibly could be measured.... just speculation on my part. Then again maybe 30 passengers moving to the opposite side of the ship would cancel everything out:D.

I don't think it's any further from the center line when lowered. Lower relative to the center of gravity, but still the same distance from the longitudinal axis.

 

I thought the weight of the anchor chain when in the lower position may shift some weight that way compared to when it is stored inboard, but that again is pretty negligable.

[3rdGenCunarder]

OK, let me start off by saying that my purse comment was in fun, and I don't have ANY idea of the physics or science behind any of this. But now my curiosity has been tweeked, and I too would like to know the real answer.

 

Once again, I have NO CLUE about the physics, but I would think that if the anchor were dropped suddenly to stop the ship wouldn't the back of the ship turn outward? Now if someone could explain it to me using a shoe reference I'm sure I'd understand.....:D:D;)

 

But your purse example was a good physics experiment. I had my physical science students do all sorts of balance and center of gravity experiments. I'd have used your purse example if I'd thought of it!

[ASIWISH]

Alright.. this is great!

 

I have one question - disclosing that I know NOTHING about anchors!

 

How much faster would an anchor fall, in the event of an emergency, if it was in it's upright position vs it's down position? It seems like at that weight, it would be about 1-second… hardly a relevant difference.

 

I'm sticking with John on this one… he's never wrong!

[BillB48]

Probably a bit too much over thinking as well:):)!

[jtl513]

I'm sticking with John on this one… he's never wrong!

I thought I made a mistake once, but I was wrong. :D

[bob brown]

This debate has got me thinking....just how many anchors does a large cruise or any ship have? Aren't there two on the bow, one on either side? And BillB48 brought up that incident a while back when some drunken passenger released a rear anchor. Are there two in the stern as well?

[BillB48]

Two on the bow and on ships with stern anchors (not all ships have them) there is one. If they were to have more they would be for a unique application. I have seen some war ships with only one anchor on the bow, but this would not be what is a"normal" application.

[josie724]

But your purse example was a good physics experiment. I had my physical science students do all sorts of balance and center of gravity experiments. I'd have used your purse example if I'd thought of it!

 

 

Why thank you, but I'd give up one of my kids, ok maybe both, before I gave you The Gucci. :eek::D:D

[josie724]

So, so, so flippin' funny!!!!

 

:D:D

 

 

Glad I made you :D, I know reading your "Live From" posts has brought many a smile to my face.