Відео

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In the context of ship stability and dynamics, the moments (represented by £ X•Y•Z in your comment) can indeed cause a ship to rotate or revolve around certain angles. Here’s a brief explanation: Moment: A moment is a measure of the force causing an object to rotate. In physics, it’s calculated as the product of the force and the distance from the point of rotation (lever arm). Axes of Rotation (X, Y, Z): These refer to the three principal axes in a 3D coordinate system. X-axis: Typically runs from the bow (front) to the stern (back) of the ship. Y-axis: Typically runs from port (left side) to starboard (right side) of the ship. Z-axis: Typically runs vertically, from the bottom (keel) to the top (deck) of the ship. A ship can rotate around these axes due to the moments acting on them, resulting in different types of movement: Roll: Rotation around the X-axis (side-to-side tilting). Pitch: Rotation around the Y-axis (up-and-down tilting of the bow and stern). Yaw: Rotation around the Z-axis (left-to-right turning of the bow). When a moment acts on a ship, it creates a rotational force that can cause the ship to rotate around one or more of these axes, changing its orientation in the water. For instance, a moment around the Y-axis (X•Y•Z referring to Y) would cause the ship to pitch, while a moment around the X-axis would cause the ship to roll.

Thank you. I just used Microsoft PowerPoint 2021. To animate, I usually apply Morph transition.

As stated in this video, the company policy for the Under keel Clearance (UKC) should be greater than 10% of the ship's static draft. The 10% of 7.50m is 0.75m, so the UKC should be greater than 0.75m. But if the company policy states that the UKC is greater than 10% of the ship's draft or 1m whichever is greater, then the minimum UKC should be 1m. The 1.53m is the new squat when the speed is reduced. In the video, the solution that you have seen is like this: Depth of the water minus ship's draft, minus Squat, minus Swell, minus CATZOC, equals UKC. You can do it using this method: Depth of the water minus (-) the sum of (draft + squat + swell + CATZOC) equals UKC. In calculating the ship's UKC, always refer to the company SMS manual, the procedure may vary between companies.

As stated in this video, the company policy for the Under keel Clearance (UKC) should be greater than 10% of the ship's static draft. The 10% of 7.50m is 0.75m, so the UKC should be greater than 0.75m. But if the company policy states that the UKC is greater than 10% of the ship's draft or 1m whichever is greater, then the minimum UKC should be 1m. The 1.53m is the new squat when the speed is reduced. In the video, the solution that you have seen is like this: Depth of the water minus ship's draft, minus Squat, minus Swell, minus CATZOC, equals UKC. You can do it using this method: Depth of the water minus (-) the sum of (draft + squat + swell + CATZOC) equals UKC. In calculating the ship's UKC, always refer to the company SMS manual, the procedure may vary between companies.

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Kindly review the procedures in the video, maybe you miss something.

Thank you. I'm glad you found my video valuable. Yes, I'm planning to upload a video on celestial navigation calculations soon.

I will make a seperate video on how to construct a gz curve manually.

@@nauticalacademy001 it will be so important and useful information for us, thank you

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Thank you for the comment. Squat calculations typically provide an approximate answer rather than an exact one due to complex interactions between the hull and the water, which are affected by the ship’s speed, hull shape, water depth, and other factors such as water density, wave action, and the specific characteristics of the waterway (e.g., channel shape and seabed composition). As shown in my video, I subtracted 0.51 m from the original squat of 2.04 m. The new squat after reducing a speed of 50% is 1.53 m. This 1.53 m as the new squat should also be subtracted from the given depth of the water to find the UKC. 2.04m x 25% = 0.51m. Then, 2.04m - 0.51m = 1.53m. Then, given depth of water (12.30m) MINUS new squat (1.53m), MINUS ship's draft (7.50m), MINUS swell (1.00m), and MINUS CATZOC (1.25m) = UKC (1.02m). This is the calculations shown in the last part of my video. In the example, the given ship's speed is 11 kts with Cb 0.8450, if we calculate the ship's squat at a speed of 5.5 kts, then the ship's sinkage due to squat in confined water is 0.51 m. But if we consider this "IF THE SHIP'S SPEED IS REDUCED BY ONE-HALF, THE SHIP'S SINKAGE DUE TO SQUAT IS REDUCED TO ONE-FOURTH." I read this from one of the books on ship handling but forgot the author's name. So from the original speed of 11 kts, the ship's approximate squat is 2.04 m. Reducing the ship's speed from 11 kts to 5.5 knots, the sinkage due to squat is reduced by 0.51 m. Considering "SINKAGE DUE TO SQUAT IS REDUCED TO ONE-FOURTH", subtract 0.51 m from the original squat which is 2.04 m. The new approximate squat is 1.53 m. This new squat should be subtracted from the given depth of the water to find the UKC. Given the safety margin of my ship to avoid grounding, I'd rather take the approximate squat of 1.53 m rather than 0.51 m since my original speed was 11 kts, and it was just reduced to 50%. But if my ship's original speed is 5.5 kts, I will take 0.51 m as my approximate squat. Thank you very much for the comment. Have a safe voyage!

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Here is the link for that video. ua-cam.com/video/dGu3m7-xNgg/v-deo.html

Glad it was helpful! Thank you.

I will, thank you for your comment.

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I will mske a seperate video for that. Thank you.

Thank you for your appreciation! It's great to hear that you found the information useful.

FWA is the number of millimeters by which the mean draft changes when a ship passes from saltwater to freshwater, or vice versa, while floating at the loaded draft. This is typically measured when a ship is moving from seawater to freshwater, such as when entering a river or a lake. Dock Water Allowance (DWA): DWA is the number of millimeters by which the mean draft changes when a ship passes from saltwater to dock water, or vice versa, when the ship is loaded to the Summer displacement. Dock water is a type of water with a density between that of seawater and freshwater. DWA is typically measured when a ship is moving from seawater to dock water, or vice versa, while in a dock or a shipyard. FWA is the change in draft when a ship sails from seawater to freshwater or vice versa, while DWA is the change in draft when a ship sails from seawater to dock water or vice versa or from dock water to another dock water with different water densities. The key difference is the type of water involved, with FWA involving a transition between seawater and freshwater or vice versa, and DWA involving a transition between seawater and dock water or vice versa.

@@nauticalacademy001 so we can calculate the change of draft by FWA value and TPC value with the given formula DWA= change in draft= displacement * change in density/ 0,025

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Thank you for your comment and you're most welcome.

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Hi! Thank you for your comment. In my last example, in the final step, I subtracted the dock water allowance from the departure draft to find the arrival draft, since the ship sails from a lower R. density (1.007) to a higher R. density (1.018). The effect on the ship upon reaching higher density, she will rise, and as a result, there will be a decrease in the ship’s draft. That is why DWA should be subtracted from the dep. draft to find the arrival draft as shown in my final step which is also stated in your comment, a decrease in the arrival draft. Maybe you are confused when I take the difference of the departure and arrival relative density because, in my solutions, I have shown (1.018 - 1.007) which is the arrival R.D 1.018 minus the dep. R.D 1.007. What I did is subtract the lesser from the greater R.D. so that I would have a positive DWA, but this procedure does not affect the ship’s draft yet. As you mentioned in your comment the ship will rise in this problem, and there should be a decrease in the ship’s draft “You are right”. That is why in my final step, I have subtracted the DWA from the dep. draft to determine the arrival draft because the effect is a decrease in draft. Now you can also follow this format (1.007 - 1.018) which is departure R.D 1.007 minus arrival R.D 1.018, you will have a negative DWA. A negative DWA should be subtracted from the departure draft, and the result will be a decrease in the arrival draft as shown in my final step. Thank you very much👨

thank you very much for your detailed answer sir, your channel is very helpful and insightful. plus the animation is superb. make it more easy to understand. have a great day.

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There are several formulas to find the scope of the anchor, others use the numerical ratio to find the number of anchor shackles to be dropped depending on the weather conditions. You can use any method that you prefer as long as you comply with the company's Quality Management System (QMS) Manual.

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Thank you for your comment. The magnetic variation should be 6.75 deg. E or 6.8 deg. E, not 4.75 deg. E. Thank you for calling my attention.

Subtracting 2H to ZD 5 is can not be, you need to borrow 1day on the date which is equivalent to 24 hours, then add that 24 hours to 02H, so you have now 26H minus the ZD 5, the answer is 21H.

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I will make a seperate video about the parts of the anchor. Thank you for your comment.

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Thank for the comment. Depth of the water will be applied when you determine the number of anchor shackles to be dropped. Here is the link in my video how to determine the number of shackles in a specific depth of water in different weather conditions: ua-cam.com/video/GCSn4DNmLEk/v-deo.html