Crow's nest declared useless

you are so far out of touch with reality that it really isn't possible to have an intelligent debate with you

I don't know why you even try anymore, surely you've known this for years now.

You are getting your reflectors and refractors mixed up.  Reflectors use mirrors not lenses.  Reflector mirror technology didn't really come of age until after the 19th century.

Refractor telescopes on the other hand, did go through a major advance in the mid 1800's.  That's not to say that there wasn't even more advance during the 20th century, especially in portability and cost.    The point is, Rowbotham wasn't going to be dragging about a large astronomical telescope. 

Regardless of the magnification of the telescope (resolution is a more relevant specification), if one already has a clear view of the subject in the viewfinder, a more powerful telescope is not going to reveal any more detail.

Are you a historian? Have you cited any sources for your claims? No, you are not and have not.

It is so funny that a supposed owner of two state of the art telescopes, who has done observations that are not humanly possible, does not understand the difference between magnification (ex. 300x or 500x) and definition.

For those who have not had the good fortune of having telescopes, let me explain: ever since the basics of telescopes were discovered, around the 1700's or so, it has been possible to make 300x telescopes, or even 5000x telescopes. You just put one additional lens to the eyepiece. Making high magnification telescopes with good resolution is a whole different story. With the highest magnifications you just see blurry images, so you normally use a middle magnification that gives you good definition.

Tom Bishop's position is so unsustainable that he has to mix reflector telescopes with refractor telescopes. For one thing, in the 1800's the only way to get decent images was with cumbersome reflector telescopes, but now refractor telescopes are good enough and have replaced  reflectors for almost every application except astronomy.

Just to show how Tom Bishop is too lazy to do some googling, look at http://www.antiquetelescopes.org/20thc.html, the last paragraph, about Zeiss. Optics have improved a lot since Rowbotham's time, and explanations of these accomplishments are everywhere.

Are you a historian? Who are you to say to what degree telescopes have advanced since the 1800's? Glass making hasn't advanced to any significant degree since the 1800's. Lens making has not advanced to any significant degree. Neither have telescopes.

The paragraph you cited says nothing about how much telescopes have advanced since the 1800's.

Zeiss Telescopes.

Carl Zeiss had originally limited his company to the production of microscopes and accessories. When he died in 1888, Ernst Abbe, his partner, took over and began to diversity the product line. His main interest was prism binoculars, measuring devices, and photographic lenses. Max Pauly joined the firm with experience in telescope construction, especially observatory instruments. The firm of Zeiss began developing large telescopes for commercial use. They were manufactured in the plant at Jena, taken apart, and reconstructed in the customer's observatory. In the 1930's Zeiss was manufacturing refractors of extremely high quality with both achromatic (partially color-corrected) and apochromatic (more fully color-corrected) triplets. In 1935 Zeis developed and patented an anti-reflection coating which remained a military secret until about 1940. In 1948, after the liberation of Germany by the allies, Carl Zeis Jena was reorganized under the direction of the East German government and produced microscopes, measuring instruments, and astronomical telescopes. Zeiss telescopes are difficult to catalogue. A particular 80mm telescope with an alt-azimuth stand, fitted wood storage case, and accessories might carry the name "Asestaron", while the same telescope on another mount would carry another name. Nonetheless, any small or large telescope bearing the name Zeiss is extremely collectable today. For a more complete history of the Zeiss firm see Zeiss telescope history and Zeiss history.

Where does it say that telescopes have advanced to any significant degree?

Perhaps the basic concepts of telescopes haven't changed over the years, but if you seriously believe that the quality of optical glass has not improved in the last 150 years, then you are so far out of touch with reality that it really isn't possible to have an intelligent debate with you.  Even today's optical plastic is far superior to the optical glass of the 1850s.

Are you a historian? Have you cited you claims? No and no.

Quote from: markjo on September 02, 2011, 06:14:54 AM

Perhaps the basic concepts of telescopes haven't changed over the years, but if you seriously believe that the quality of optical glass has not improved in the last 150 years, then you are so far out of touch with reality that it really isn't possible to have an intelligent debate with you.  Even today's optical plastic is far superior to the optical glass of the 1850s.

Are you a historian? Have you cited you claims? No and no.

*sigh*
http://amazing-space.stsci.edu/resources/explorations/groundup/
http://en.wikipedia.org/wiki/History_of_the_telescope
http://www.applet-magic.com/opticalglass.htm

Quote from: pitdroidtech on September 02, 2011, 02:51:48 AM

You are getting your reflectors and refractors mixed up.  Reflectors use mirrors not lenses.  Reflector mirror technology didn't really come of age until after the 19th century.

Refractor telescopes on the other hand, did go through a major advance in the mid 1800's.  That's not to say that there wasn't even more advance during the 20th century, especially in portability and cost.    The point is, Rowbotham wasn't going to be dragging about a large astronomical telescope. 

Regardless of the magnification of the telescope (resolution is a more relevant specification), if one already has a clear view of the subject in the viewfinder, a more powerful telescope is not going to reveal any more detail.

Are you a historian? Have you cited any sources for your claims? No, you are not and have not.

If you can't get the difference between a refractor and a reflector what's the point in even discussing the topic?  It's not relevant anyway.  It doesn't matter one iota, the horizon is close enough for even a 10x lense on an SLR camera to resolve an image of a ship quite clearly.

but anyway, to play the game:

Apochromatic, invented after Rowbotham's death: http://geogdata.csun.edu/~voltaire/tmb/definition.html
Superachromatic, 1963: Max Herzberger and Nancy R. McClure, "The design of superachromatic lenses," Applied Optics 2, 553-560 (1963).

Indeed, it seems improvements are still being made.  Just one of many recent design tweeks you can find by googling: http://www.opticsinfobase.org/abstract.cfm?URI=ao-43-30-5618

*sigh*
http://amazing-space.stsci.edu/resources/explorations/groundup/

That's one of the links which I usually link to show that telescopes hit their peak in the 1800's. The Era of Reflectors and Refractors ends in the 1800's. The technology hits its peak.

The 1900's-2000's are eras of radio, solar, and space telescopes, none of which pertain to this discussion.

http://en.wikipedia.org/wiki/History_of_the_telescope

Nothing on this page says that reflectors or refractors advanced significantly between the mid 1800's and now.

http://www.applet-magic.com/opticalglass.htm

Nothing on this page says that reflectors or refractors advanced significantly between the mid 1800's and now.

If you can't get the difference between a refractor and a reflector what's the point in even discussing the topic?

I know the difference between a refactor and a reflector. I know what I said.

It's not relevant anyway.  It doesn't matter one iota, the horizon is close enough for even a 10x lense on an SLR camera to resolve an image of a ship quite clearly.

but anyway, to play the game:

Apochromatic, invented after Rowbotham's death: http://geogdata.csun.edu/~voltaire/tmb/definition.html
Superachromatic, 1963: Max Herzberger and Nancy R. McClure, "The design of superachromatic lenses," Applied Optics 2, 553-560 (1963).

Indeed, it seems improvements are still being made.  Just one of many recent design tweeks you can find by googling: http://www.opticsinfobase.org/abstract.cfm?URI=ao-43-30-5618

I have not claimed that small improvements have not been made to glare and color of lenses. Those improvements are irrelevant to the discussion.

No significant improvements have been made to magnification or resolution of a telescope since the 1800's.

Quote from: markjo on September 02, 2011, 10:02:14 AM

*sigh*
http://amazing-space.stsci.edu/resources/explorations/groundup/

That's one of the links which I usually link to show that telescopes hit their peak in the 1800's. The Era of Reflectors and Refractors ends in the 1800's. The technology hits its peak.

Just because the most basic design elements of refracting and reflecting telescopes have not changed over the years does not mean that the quality of the optics has not improved with modern material sciences.

The 1900's-2000's are eras of radio, solar, and space telescopes, none of which pertain to this discussion.

Are you saying that radio, solar and space telescopes are not advances in telescope design? 

Quote

http://en.wikipedia.org/wiki/History_of_the_telescope

Nothing on this page says that reflectors or refractors advanced significantly between the mid 1800's and now.

Are you suggesting that refracting and reflecting telescopes are technological dead ends? 

Quote

http://www.applet-magic.com/opticalglass.htm

Nothing on this page says that reflectors or refractors advanced significantly between the mid 1800's and now.

Are you suggesting that improvements in optical glass does not improve the quality of a telescope? 

Tom, I forgot to mention that Rowbotham's claim of perspective is based on the fact that the eye cannot make out anything less than an arc-minute across (2.909*10^-4 radians).

Thus, for a ship at 25 km, which is the distance that pitdroidtech's pictures were taken at, the smallest resolvable detail would be:
25 km *(2.909*10^-4) = 7.27 meters.

with 10x zoom, the smallest detail visible to the human eye would be .727 meters.
A stable camera can make out more detail than the human eye, so the camera should be able to see anything greater than a meter in size.

The amount of hull that is missing is much more than a meter, many meters in fact. Thus, the missing hull is not a matter of not enough restoration due to magnification.

The lines of perspective for the hull and mast do not converge at the same rate. Would you read the chapter in ENaG for heavens sake?

The lines of perspective for the hull and mast do not converge at the same rate. Would you read the chapter in ENaG for heavens sake?

A claim with absolutely nothing to support it other than the belief that the Earth is flat and therefore perspective must behave in that manner.....

It's a self referencing proof: I  postulate A.  For A to exist, B must exist.  Therefore B exists.

Make any sense to you?

The lines of perspective for the hull and mast do not converge at the same rate. Would you read the chapter in ENaG for heavens sake?

Sure thing, Ski, I'll even quote the man:
"The above may be called the law of perspective. It may be given in more formal language, as the following:. when any object or any part thereof is so far removed that its greatest diameter subtends at the eye of the observer, an angle of one minute or less of a degree, it is no longer visible."

Now, I'll quote myself:

Rowbotham's claim of perspective is based on the fact that the eye cannot make out anything less than an arc-minute across (2.909*10^-4 radians).

Thus, for a ship at 25 km, which is the distance that pitdroidtech's pictures were taken at, the smallest resolvable detail would be:
25 km *(2.909*10^-4) = 7.27 meters.

with 10x zoom, the smallest detail visible to the human eye would be .727 meters.
A stable camera can make out more detail than the human eye, so the camera should be able to see anything greater than a meter in size.

The amount of hull that is missing is much more than a meter, many meters in fact. Thus, the missing hull is not a matter of not enough restoration due to magnification.

Quote from: Ski on September 02, 2011, 03:16:21 PM

The lines of perspective for the hull and mast do not converge at the same rate. Would you read the chapter in ENaG for heavens sake?

Sure thing, Ski, I'll even quote the man:
"The above may be called the law of perspective. It may be given in more formal language, as the following:. when any object or any part thereof is so far removed that its greatest diameter subtends at the eye of the observer, an angle of one minute or less of a degree, it is no longer visible."

Now, I'll quote myself:

Quote from: momentia on September 02, 2011, 02:12:42 PM

Rowbotham's claim of perspective is based on the fact that the eye cannot make out anything less than an arc-minute across (2.909*10^-4 radians).

Thus, for a ship at 25 km, which is the distance that pitdroidtech's pictures were taken at, the smallest resolvable detail would be:
25 km *(2.909*10^-4) = 7.27 meters.

with 10x zoom, the smallest detail visible to the human eye would be .727 meters.
A stable camera can make out more detail than the human eye, so the camera should be able to see anything greater than a meter in size.

The amount of hull that is missing is much more than a meter, many meters in fact. Thus, the missing hull is not a matter of not enough restoration due to magnification.

Thank you momentia, there is no good argument to refute your points.  But I'm sure they will try.

Quote from: Ski on September 02, 2011, 03:16:21 PM

The lines of perspective for the hull and mast do not converge at the same rate. Would you read the chapter in ENaG for heavens sake?

Sure thing, Ski, I'll even quote the man:
"The part that has nothing to do with what Ski is talking about."

Now, I'll quote myself:

Quote from: momentia on September 02, 2011, 02:12:42 PM

The part I am understanding, but misapplying to the conversation.

The error in perspective, which is almost universally committed, consists in causing lines dissimilarly distant from the eye-line to converge to one and the same vanishing point. Whereas it is demonstrable that lines most distant from an eye-line must of necessity converge less rapidly, and must be carried further over the eye-line before they meet it at the angle one minute, which constitutes the vanishing point.

Did you read or comprehend this part, I wonder?

Quote from: Dr. Samuel Birley Rowbotham

The error in perspective, which is almost universally committed, consists in causing lines dissimilarly distant from the eye-line to converge to one and the same vanishing point. Whereas it is demonstrable that lines most distant from an eye-line must of necessity converge less rapidly, and must be carried further over the eye-line before they meet it at the angle one minute, which constitutes the vanishing point.

Did you read or comprehend this part, I wonder?

Vanishing point has nothing to do with the size of an object.  Rowbotham is referring to the limit of angular resolution which is a different concept entierly.

Quote from: Dr. Samuel Birley Rowbotham

The error in perspective, which is almost universally committed, consists in causing lines dissimilarly distant from the eye-line to converge to one and the same vanishing point. Whereas it is demonstrable that lines most distant from an eye-line must of necessity converge less rapidly, and must be carried further over the eye-line before they meet it at the angle one minute, which constitutes the vanishing point.

Did you read or comprehend this part, I wonder?

The ship on the horizon isn't at the vanishing point, so this convulated malarky doesn't apply.   The ship would be at the vanishing point if the vanishing point was the same as the horizon, which it would be on a flat earth.  But it isn't on a curved earth.  Further, if the ship was at the vanishing point (to be clear, we are talking about vanishing point of of human eyesight in these discussions), all the points that mark out it's shape would effectively be equi-distant from the eye and the ship would appear as a single dot.  At that distance, the resolving error of the human eye negates the small differences in distances between the mast or the hull and the viewers eye. If a telescope is brought into play, it simply (optically) brings the object back from the vanishing point.  It restores the whole image, not just the hull.  Of course the Hull is never restored because the vanishing point of the human eye, for something the size of a ship, is beyond the horizon.

Rowbotham is using his misunderstanding of perspective to prove a Flat Earth.  In other words, he is saying "this is how perspective would have to work to explain this sinking ship phenomena, so I am going to bloody-mindedly insist that perspective does work this way, and therefore prove the Earth is flat".
 
ie: "I  postulate A.  For A to exist, B must exist.  Therefore B exists."  B is Rowbotham's twisted law of perspective.

His problem comes from having a biased towards the Flat Earth Theory.  His view of perspective is predicated on the vanishing point of the human eye being synonomous with the Horizon, and then heattempts to force the experience of reality to fit this model

Quote from: momentia on September 02, 2011, 07:41:15 PM

Quote from: Ski on September 02, 2011, 03:16:21 PM

The lines of perspective for the hull and mast do not converge at the same rate. Would you read the chapter in ENaG for heavens sake?

Sure thing, Ski, I'll even quote the man:
"The above may be called the law of perspective. It may be given in more formal language, as the following:. when any object or any part thereof is so far removed that its greatest diameter subtends at the eye of the observer, an angle of one minute or less of a degree, it is no longer visible."

Now, I'll quote myself:

Quote from: momentia on September 02, 2011, 02:12:42 PM

Rowbotham's claim of perspective is based on the fact that the eye cannot make out anything less than an arc-minute across (2.909*10^-4 radians).

Thus, for a ship at 25 km, which is the distance that pitdroidtech's pictures were taken at, the smallest resolvable detail would be:
25 km *(2.909*10^-4) = 7.27 meters.

with 10x zoom, the smallest detail visible to the human eye would be .727 meters.
A stable camera can make out more detail than the human eye, so the camera should be able to see anything greater than a meter in size.

The amount of hull that is missing is much more than a meter, many meters in fact. Thus, the missing hull is not a matter of not enough restoration due to magnification.

Quote from: Dr. Samuel Birley Rowbotham

The error in perspective, which is almost universally committed, consists in causing lines dissimilarly distant from the eye-line to converge to one and the same vanishing point. Whereas it is demonstrable that lines most distant from an eye-line must of necessity converge less rapidly, and must be carried further over the eye-line before they meet it at the angle one minute, which constitutes the vanishing point.

Did you read or comprehend this part, I wonder?

I quoted the most formal axiom in Rowbotham's perspective. Everything he says from there on in is supposed to rely on that one fact, and you cannot deny that. So, yes, it is very relevant, and I can use it in calculations.

Hey, even look at your own quote, the part I bolded says that only things that are less than an arc-minute are invisible to the eye. I do not deny this, but I have shown that the hidden part of the hull is much LARGER than one arc-minute under 10x magnification, and thus should not be invisible on a flat earth. Since it is invisible, the earth demonstrates curvature.

It is the reason that both parts

Quote from: Ski on September 03, 2011, 12:23:46 PM

Quote from: Dr. Samuel Birley Rowbotham

The error in perspective, which is almost universally committed, consists in causing lines dissimilarly distant from the eye-line to converge to one and the same vanishing point. Whereas it is demonstrable that lines most distant from an eye-line must of necessity converge less rapidly, and must be carried further over the eye-line before they meet it at the angle one minute, which constitutes the vanishing point.

Did you read or comprehend this part, I wonder?

Vanishing point has nothing to do with the size of an object.  Rowbotham is referring to the limit of angular resolution which is a different concept entierly.

So you read it but did not comprehend it. Noted.

It is the reason that both parts

Quote from: markjo on September 03, 2011, 12:41:47 PM

Quote from: Ski on September 03, 2011, 12:23:46 PM

Quote from: Dr. Samuel Birley Rowbotham

The error in perspective, which is almost universally committed, consists in causing lines dissimilarly distant from the eye-line to converge to one and the same vanishing point. Whereas it is demonstrable that lines most distant from an eye-line must of necessity converge less rapidly, and must be carried further over the eye-line before they meet it at the angle one minute, which constitutes the vanishing point.

Did you read or comprehend this part, I wonder?

Vanishing point has nothing to do with the size of an object.  Rowbotham is referring to the limit of angular resolution which is a different concept entierly.

So you read it but did not comprehend it. Noted.

If you don't see the error of Rowbotham's version of perspective, then perhaps my comprehension is better than yours.

Refusal to rebut a follow on argument, and relying instead on reference back to the original argument which is under question, demonstrates either or several of the following:

1. A dogmatic faith in the original argument, but no logical grasp of the meaning of the argument (and therefore an inability to argue in favour of it)
2. An unwillingness to accept that the argument has been effectively refuted
3. Troll

It is not my fault that you cannot understand that the angular size of the hull and mast decrease at a disparate rate because they converge at different rates.

It is not my fault that you cannot understand that the angular size of the hull and mast decrease at a disparate rate because they converge at different rates.

And so, a whole new law of optics has been born, complete with magical features and unexplainable characteristics.

The masts are made of something special which makes them harder to sink into the vanishing point, the hull vanishes into different vanishing points horizontally and vertically. And all those magical vanishing points are amazingly placed in just the right place to give the appearance of a whole ship hiding progressively behind the curvature of a non-existent round planet. Good to know.

This kind of physical laws is in fact quite common. The planets hover over the Earth, but the real physical laws of their movement are magically twisted so we see them like they orbit the Sun. The Sun is changing its distance from any observer on Earth by a factor of at least 3 during any given day, but the laws of physics (FE physics) are magically making it brighter and bigger as the afternoon progresses, so the observer is fooled into believing in a Sun that is always at about the same distance.

And every single new law of physics that is discovered in this flat Earth is magically made (by a god?) to fool us. No single new law is better than the plain old physics in the text books. No single new law makes predictions that were impossible with the laws on the text books. The success in fooling us is complete.

Now, lets be serious. There are no vanishing points explained in physics books because there are no physics laws relevant to vanishing points. Objects are simply half the apparent size when they are at twice the distance. The vanishing point for an object at 100 meters is right behind the object, at 200 meters. The vanishing point for an object 1000 meters away is also right behind the object, and 2000 meters away. This is not what you are taught in technical drawing class because they want the appearance of three dimensions, not the exact image that a photo, for example, would show.

It is not my fault that you cannot understand that the angular size of the hull and mast decrease at a disparate rate because they converge at different rates.

Looking at the stern of a boat as it recedes, and perpendicular to the stern of the boat, you have an effective square (close enough for the example).  I fix my focus on the centre of that square.

According to FET, the square will gradually get smaller on all dimensions, since the lines of sight converge at an equal rate.  If instead of focusing on the middle of the square, I instead focus on the bottom of the square (also the horizon), the lines of sight are a different distance from the top of the square compared to the bottom of the square, therefore the bottom of the square loses it's angular vertical dimension faste than the horizontal dimension, and the ship disappears hull first. 

So the conclusion from this is that the hull will disappear hull first if I fix my vision on the horizon, but if I fix my vision a fraction of a degree higher, on the centre of the stern, the hull will disappear equally on all dimensions.

This still doesn't make any sense whatsoever.  And I still don't need a telescope, I can simply adjust my point of focus to restore the hull.

It is not my fault that you cannot understand that the angular size of the hull and mast decrease at a disparate rate because they converge at different rates.

I have already shown that the angular diameter of the hull is larger than is necessary for visibility under the given magnification, and you ignored these calculations.
Again-

If:

T1) If [there is nothing obscuring an object from view] then:
[Iff the angular diameter of an object is less than 1 arc second (2.909*10^-4 radians), that object is invisible.]
(This is Rowbotham's theorem.)

T2) The angular diameter of an object is about the object's height in radians divided by the distance to the object times the magnification of the lens used. (AD = (height)*(magnification)/(distance) )

Then:

L1) Let: the distance to the ship be 25 km.
h be the height of the part of the hull that is invisible (call this invisible object "IH")
magnification of the lens =10.

L2) By T2, an object viewed through a 10x lens at 25 km will have an angular diameter of 1 arc second or greater iff the object's height, y satisfies y ≥ (distance)*(AD)/(magnification) = 25000*2.909*10^-4 / 10 = 0.727 m.

L3) h ≥ .727 m by inspection of the photo taken from a high position. By L2, IH has an angular diameter of 1 arc second or greater.

L4) By L3 and T1, since IH is invisible and IH has an angular diameter of 1 arc second or greater, IH must be obscured by something. This is zetetically observed to be water.

L5) By L4, the water demonstrates curvature, which is indicative of an RE.


That is all. If you wish to argue, please point to the line you believe is in error.

It is not my fault that you cannot understand that the angular size of the hull and mast decrease at a disparate rate because they converge at different rates.

Even it that were true (which it isn't), it's completely irrelevant.  When you consider the ship as a whole, the ratio of its height to width changes as it "sinks" behind the horizon.  Perspective will always cause the ratio between an object's height and width to decrease uniformly.

In all honesty, the sinking ship is not really proof of anything. Water height changes with salinity (which cause ships to sit lower in the water). This, especially in the saltier equatorial climes can lead to the illusion of a sinking ship when combined with perspective and waves.

In all honesty, the sinking ship is not really proof of anything. Water height changes with salinity (which cause ships to sit lower in the water). This, especially in the saltier equatorial climes can lead to the illusion of a sinking ship when combined with perspective and waves.

This would be relevant if you could have highly saturated salt water on the edge of the coast and rapidly decreasing salinity as you go away from the coast. This is totally irrelevant in real life, since we do not have big differences in salinity right by the side of our coasts.

And, by the way, this would have to happen by the side of oil exploration rigs, since the photos we are commenting now were taken from one.

In real life the salinity of sea water varies very slightly, not from almost saturation to totally fresh water in 20 or so kilometers of sea, and not even this amount would be enough to hide a ship. In fact, if this were true, ships would not be seen as sinking from the coasts, they would be really sinking.

In all honesty, the sinking ship is not really proof of anything. Water height changes with salinity (which cause ships to sit lower in the water). This, especially in the saltier equatorial climes can lead to the illusion of a sinking ship when combined with perspective and waves.

Increased salinity equals increased bouyancy, so if anything saltier water leads to a craft floating higher inthe water not lower.  In anycase, as Trig says, the differences in salinity in the ocean has a neglible affect on something like a cargo ship. 

Also, the salinity of the ocean doesn't change with respect to an observer changing altitude.  Now if you think that the ocean gets saltier as the observer climbs a cliff face, thereby allowing the observer to see the hull once he reaches the top of the cliff, then gets less salty as the observer climbs back down again, hiding the hull, well I think most of us here even the most dogmatic of FE'ers would accept that that scenario is not likely.

It is not my fault that you cannot understand that the angular size of the hull and mast decrease at a disparate rate because they converge at different rates.

"You don't understand" is not a legitimate answer to a rebuttal.

We fully understand what rowbotham's saying.  We simply don't accept it.  I wonder if it is you who does not understand.

In all honesty, the sinking ship is not really proof of anything. Water height changes with salinity (which cause ships to sit lower in the water). This, especially in the saltier equatorial climes can lead to the illusion of a sinking ship when combined with perspective and waves.

Unless the waves rise above the elevation of the viewer, they can't block the view.  I doubt also, that salinity causes the entire hull to submerge.