How to Calculate Under Keel Clearance ll Determine Ship's UKC ll CATZOC ll Squat ll Passage Planning
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- เผยแพร่เมื่อ 17 ม.ค. 2024
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This video provides a step-by-step guide on calculating a ship's Underkeel Clearance (UKC) in accordance with the company's procedures. It's important to note that procedures may vary among different companies, and this tutorial is intended solely as a reference. The process involves assessing depth accuracy through the use of a Category of Zone of Confidence (CATZOC).
The Ship's UKC stands for "Ship's Under Keel Clearance." It refers to the vertical distance between the lowest part of a ship's hull, usually the keel, and the seabed beneath it. UKC is a critical parameter in maritime navigation as it determines the minimum depth of water required for a ship to safely navigate without grounding.
The Electronic Navigational Chart (ENC) within the Traffic Separation Scheme (TSS) is deliberately scaled down, making the depth-sounding appear shallower in the Northbound lane. However, adjusting it to a larger scale reveals ample navigable water within the traffic lane.
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#shiphandlingsimulator
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When we reduce the ship speed 50% it will be affected by the squat effect only 25% of the original speed ? Am I right… so we will sub 0.51 m not 1.53m ?
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!
I'm preparing for my interview and this explains everthing in detail. Please make more tutorial videos. Thanks
Welcome & thank you.
Thank u for good informatio.
Welcome.
Very helpfull, thanks alot
Welcome.
Good information sir thank you
Welcome.
thank you for good video.
Welcome.
Thank you sir
Welcome.
Please do a vdo on canda grain calculation and NCB
I will try, thank you for the comment.
Shallow contour, Safety depth, Safety contour, Deep contour settings please for ecdis. Thank you.
Thank you for your comment! I will try to make this in my next video covering these topics. Stay tuned for the upcoming video.
th-cam.com/video/JKExTQXFSk8/w-d-xo.html this is the link to your requested video which is Safety Parameters.
Why we a calculate 10% at 7.5 m ,but our present draft for this leg 7.5+ 1.53 m?
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.
Why we a calculate 10% at 7.5 m ,but our present draft for this leg 7.5+ 1.53 m?
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.