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Finding Ship's New Draft

A vessel enters port with an arrival draft of 11 meters at sea water density. If her FWA is 254, what will be her draft in dock water with relative density of 1.009?



ANALYSIS OF THE PROBLEM:

The vessel is from the sea going to a brackish water. Since there is a change in water density, so what will happen to its draft? In the case of a ship from the sea to a brackish water, the draft will increase.
Therefore, we can expect that the answer of this problem is more than 11 meters.

SOLUTION:
We can use the formula in getting allowable increase (AI)


Step 1. We have to get the difference of density by subtracting sea water density by dock water density.  

            1.025 - 1.009 = 0.016

Step 2. Multiply the answer of step 1 by the fresh water allowance (FWA).
             0.016 x 254 = 4.064

Step 3. Divide the answer of step 2 by 25.
              4.016 ÷ 25 = 0.16256 meters

Step 4. We have to add the answer of step 3 to our original draft.
             11 m + 0.16256 m = 11.16 meters is our final answer.

Note: We add the answer of step 3 to our original draft because the ship is coming from the sea to a brackish water.

Do you have another way of solving this problem? Why not comment and share it to us.



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8 comments:

  1. Hello ,

    Why did you divide by 25 in step 3 ?
    Thanks

    ReplyDelete
    Replies
    1. Isn't it because he used the formula of allowable increase? AI=FWA(SW-DW)/25

      Delete
    2. The formula says you have to divide it by 25

      Delete
    3. its the conversion from meters to millimeters

      Delete
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    Replies
    1. kindly share the solution sir

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    2. Same problem. You have the solution?

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