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!
For those confused: To calculate our ships squat we must ( Multiply Block coefficient by speed relative to water in square) divided by 100 This is for deep seas Example: (0.835 x 12²) ÷ 100 = 1.2024 m For shallow waters we multiply answer by 2 so it would be 1.2024 x 2 = 2.4048 meter According to this reducing our speed by 50% gives us only 25% of the original squat Example: (0.835 x 6²) ÷ 100 = 0.3006 m But since we are in motion our squat may not drop from 1.2024 to 0.3006 Thus its safer to expect our squat to be reduced only by 25 % of the original squat (Basically there is a chance the ship won't float all the way up since we are traveling so it's better to be safe then sorry)
Static draft is the draft of the vessel when she is stationary, and you can find this value by checking the ship's draft marks. The dynamic draft accounts for the vessel's motion and includes factors like squat, trim, and wave action. It’s the draft when the ship is moving through the water. To calculate this, you’ll need to know the speed of the ship and apply the squat formula for your vessel type. Kindly check some videos for the detailed explanation about dynamic draft.
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.
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 YOU SO MUCH FOR THE VERY DETAILED AND CLEAR LESSON !
You're very welcome!
For those confused:
To calculate our ships squat we must
( Multiply Block coefficient by speed relative to water in square) divided by 100
This is for deep seas
Example: (0.835 x 12²) ÷ 100 = 1.2024 m
For shallow waters we multiply answer by 2 so it would be
1.2024 x 2 = 2.4048 meter
According to this reducing our speed by 50% gives us only 25% of the original squat
Example: (0.835 x 6²) ÷ 100 = 0.3006 m
But since we are in motion our squat may not drop from 1.2024 to 0.3006
Thus its safer to expect our squat to be reduced only by 25 % of the original squat
(Basically there is a chance the ship won't float all the way up since we are traveling so it's better to be safe then sorry)
Thank you very much for the additional info.
Good information sir thank you
Welcome.
Thank u for good informatio.
Welcome.
very well explained thanks for the effort!
You are welcome!
thanks. it's a comrehensive guide
You're welcome! I'm glad it was helpful.
very informative, tyvm sir
Welcome.
Very helpfull, thanks alot
Welcome.
Thank you sir
Welcome.
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.
thank you for good video.
Welcome.
Please do a vdo on canda grain calculation and NCB
I will try, thank you for the comment.
How will i get static and dynamic draft?
Static draft is the draft of the vessel when she is stationary, and you can find this value by checking the ship's draft marks. The dynamic draft accounts for the vessel's motion and includes factors like squat, trim, and wave action. It’s the draft when the ship is moving through the water. To calculate this, you’ll need to know the speed of the ship and apply the squat formula for your vessel type. Kindly check some videos for the detailed explanation about dynamic draft.
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.