Atheists believe the size of the ark would have caused it to break apart in the stormy seas, but the Bible never says the waves were raging or even that the water was choppy. The Bible simply says it rained until nobody had a ladder tall enough and they all drowned. The sea upon which the ark floated was as calm as your grandmother on valium. Aside from this, ship building experts (see web site below.) have determined that a craft the size of the ark could have easily made the voyage described in the Bible.

www.worldwideflood.com/ark/safety_aig/safety_aig.htm

Rebuttal?

From:

http://www.freeratio.org/thearchives/showpost.php?p=985297&postcount=6Analysis by George W. Herbert, moderator of sci.space.tech and holder of a degree in naval architechture:

Quote:

>

http://www.answersingenesis.org/home..._arksafety.aspSure...

On first inspection:

0. Editorial comment

This paper was written by people who looked at a naval

architecture text book and did not understand what they

were seeing; it uses terminology from the profession

but not correctly, and does not use the right analysies.

Either the translation was grossly incorrect or the

paper was the work of not particularly attentive undergrad

students, given that the authors were supposedly at the

Korea Research Institute for Ships and Engineering.

1. "Draft and center of gravity" section

Displacement is given as:

(delta) = 1.025 L B d

That is the correct formula, for a brick.

Perhaps a bad sign of things to come.

Real ships are not perfect rectangular prisms;

they have rounded shapes, and the actual

displacement is some fraction depending on

the curvature of the ship, keel deadrise,

and numerous detail factors. These combine

to give a 'block coeficient' Cb which is simply

the actual volume divided by the volume of

the rectangular shape of the same length,

breadth, and depth. Cb varies from about 0.9

(really blocky huge oil tangers) to 0.55

(light destroyers) but is not 1.0 even for

rectangular barges, which have *some* rounded

off parts...

2. also in "draft and center of gravity" section

These guys calculate the height of the center of

gravity... which is good, and they don't seem to

have completely blown it, but the simplicity of the

analysis jumps out.

*No* mention is made of the height of the center

of buoyancy (the geometric centroid of the displaced

volume).

*No* mention is made of the equally important

Metacentric Height. The metacenter (M) is the imaginary

point around which the geometric center of the

waterplane area rotates as the ship rolls and

pitches. As that area shifts, the actual dynamic

stability of a ship depends on how far above

the center of gravity the metacenter is found.

The metacenter is some distance above the center

of buoyancy, and has to be calculated.

No real ship other than a submarine has its

center of gravity under its center of buoyancy.

The actual moment arm for stability calculations

is the height from the center of gravity G to

the metacenter M (GM).

3. "Comparative hull forms" section

Huh?

Comparative hull dimentions table, maybe.

"Hull Form" implies looking at the curvature,

block coeficient, etc.

4. "Method of Evaluation" subsection in "Seakeeping Performance" section

"A widely used strip method"...

These guys have not even determined KB, BM, or GM, and they

are performing computational motions analysis?

Er.

Ok. This fails the scratch and sniff test, but the method used

is not grossly inappropriate.

5. "General" subsection of "Structural Safety" section

These people do not understand wooden shipbuilding.

Using the terms associated with steel ships is

a gross mistake.

6. "Structural analysis of Ark" subsection of "Structural Safety" section

This fails the scratch and sniff test.

They plug the numbers in to a FEA rather than presenting the basic

by hand back of the envelope calculation. Bzzt.

They assume that they could rigidly attach a 2 dimentional girder

structure to a wooden "shell" ... no mention of how this is made

strong in shear, which is why thick hulled wooden ships are not

made that way.

They do not list the scantlings (thickness and dimentions of

the hull, longitudional and transverse frames, etc).

Without knowing what the actual dimentions are nobody

can crosscheck their numbers. Showing computer program

output without scantlings is the equivalent of lying

with graphics.

"Structural Safety Index" is introduced without any

foundation for what it is supposed to represent

in the analysis and optimization.

7. "Righting Arm" calculations in "Overturning Stability" section

Ah, now we get the metacenter. Except they're calling it Z,

instead of M, and they *integrate* to find the height rather

than simply pulling "Principles of Naval Architecture" off the

shelf and plugging the one line formula in... D'oh.

8. "Overturning stability Index" in "Overturning Stability"

What is this 'overturning stability index' and where is it

coming from? The term is not defined, referenced, etc.

It is not a term of the art in the field.

9. "Voyage Limit of the Arc"

Calculated for rolling motion. Never calculate in roll;

always calculate in pitch and sagging/hogging moment.

"Thickness of wood..." thickness *where*?

10. conclusions

Yet more of these imaginary safety indexes, which are not defined.

Yet more graphs without any supporting explanation of what the

axies mean.

11. my conclusion

This paper fails to show its work.

Almost none of its stated conclusions are supported

with enough documentation to review and evaluate for

technical correctness. Were this a student paper

it would fail on that basis, and it would never

be published in a naval architecture journal for

the same reason.

This paper fails to show basic familiarity with the

standard terminology, rules of thumb, and standards

of practicing naval architects, much less student

naval architects.

This paper fails to reference any of the standard

textbooks in ship design (Such as, Principles of

Naval Architecture 1990 ed). While papers have

certainly been written without reference to PNA,

the inclusion of a bunch of more specific references

without any reference to or use of the basic methods

and overview survey in PNA is bizarre.