Discussion in 'Education' started by black_sheep, Sep 18, 2009.

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### black_sheepJunior Member

Hi!

I got some questions that i can't give answers to, so I hope someone here can?

-What determines the value of the minimal freeboard?
-What is the number of bulkheads related to?

Thanks

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### Itchy&ScratchySenior Member

You cant determine any of the above without more information, size of boat?
What is its main purpose -what is the vessel to be used for?
Building method -steel? fibreglass? wood? etc
Sail powered? Motor powered?

etc etc etc
J

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### black_sheepJunior Member

All right.
You see, the questions are repeatquestions from the chapter in the book, and they are not related to any vessel. So that's why I wonder.
link to q's (number 124): http://dokmar.com/vragen.asp?BoekID=9&TaalKeuze=_US&Hoofdstuknummer=19

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### Raggi_ThorNav.arch/Designer/Builder

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### black_sheepJunior Member

Sure. But it is nothing about it..Or, what can you get out of this:
"The plimsoll mark or freeboard mark consist of a circle with diameter of one foot, which through a horizontal line is drawn with as upper edge the centre of the circle. This level indicates the minimum freeboard insalt water summer conditions. Beside the circle is a number of horizontal lines indicating the minimum freeboard as above."

I guess that's the answer for "determines the minimal freeboard" But if you could explane it to me, so i would understand it?

But there's nothing about the other two.

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### jehardimanSenior Member

Either there has to be more information in context or the questons are just poorly worded.

Once at school we were given the question. "The majority of marine boiler tubes are produced by ______?" The obvoius answers were (at the time ) Babcock-Willcox or Foster Wheeler. The answer that was wanted was "Cold drawing".

But in reference to the first two questions, go review your damaged stability notes and the answers should jump right out at you. And no, the Plimsoll Mark does not "determine" the minimum freeboard, it marks it (though if you are a Deck Cadet it is sort of a GOD SAYS answer). As for the other, go review an dimensioned structural midships drawing...again the answer will be obvious.

Last edited: Sep 18, 2009
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### Raggi_ThorNav.arch/Designer/Builder

OK, you can read about plimsoll amrks and the North Atlantic in the Winter etc.
A typical homework asnwer would be "Minimum freebord for a given vessel, as shown by the plimsoll mark, is determined by the season (winter/summer) and the region's climate (North/South Atlantic for example).

Wikipedia tells you:

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### hoytedowFly on the Wall - Miss ddt yet?

So, he would have to answer for each condition, then...?

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### Raggi_ThorNav.arch/Designer/Builder

Well, I don't think so but it's better to ask the teacher if the answer should be detailed or more general. Maybe they just want to know that you have read about the plimsoll mark and know how to us it in practice?

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### hoytedowFly on the Wall - Miss ddt yet?

Thanks.

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### Raggi_ThorNav.arch/Designer/Builder

Maybe in the book they forgot to tell that the plimsol marks are on the hull of the ship?

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### black_sheepJunior Member

Now, i have a new one. And it goes like this:

"Why are there sometimes big local differences in local upward pressure and the weight acting on a section of a ship?"

Is it because of the waves, and where the ship is in the waves? If the aft are at the top of the wave, and fore are in the trough?
...no wait, can it depend on the cargo? Where the cargo is placed? .. I don't know

Thanks again!

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### gonzoSenior Member

Both. However, if this is to answer a test, it doesn't matter whether it makes sense or not. Read the book or ask the professor.

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### black_sheepJunior Member

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### Raggi_ThorNav.arch/Designer/Builder

I have seen some graphics showing distribtion of weight and flotation for a ship.
While the sum of the two are equal, maybe you have seen this too, the wight is not evenly distributed while the pressure from the water is (quite).

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