Free Surface Effect (FSE) ll Ship's Stability ll Calculate Free Surface Correction ll Slack Tank

[@reeve3854]

A ship is at the light displacement of 3000 tonnes and has KG 5.5 m, and KM 7.0 m. The following weights are then loaded: 5000 tonnes of cargo KG 5 m 2000 tonnes of cargo KG 10 m 700 tonnes of fuel oil of relative density 0.96. The fuel oil is taken into Nos. 2, 3 and 5 double bottom tanks, ®lling Nos. 3 and 5, and leaving No. 2 slack. Sir, please explain this problem. I can calculate it. The ship then sails on a 20-day passage consuming 30 tonnes of fuel oil per day. On arrival at her destination Nos. 2 and 3 tanks are empty, and the remaining fuel oil is in No. 5 tank. Find the ship's GM's for the departure and arrival conditions.

[@nauticalacademy001]

This solution serves as a guide only. The KG (center of gravity) for fuel oil tanks No. 2, 3, and 5 at departure, as well as for tank No. 5 at arrival, are not provided in the problem. The KG values used in this solution are based on assumptions. If anyone has a better solution or more accurate data, your input would be greatly appreciated! Step-by-Step Solution: Step 1: Convert Fuel Oil to Weight and Find Volume Relative Density of Fuel Oil = 0.96 Weight of Fuel Oil = 700 tons Volume of Fuel Oil = Weight / Relative Density = 700 / 0.96 ≈ 729.17 m³ Step 2: Calculate Departure Condition Calculate Total Weight and Moments: Light Ship: Weight = 3000 tons Moment = 3000 tons × 5.5 m = 16500 ton-m Cargo: 5000 tons at KG 5 m Moment = 5000 × 5 = 25000 ton-m 2000 tons at KG 10 m Moment = 2000 × 10 = 20000 ton-m Fuel Oil: Total Weight = 700 tons Assuming even distribution in Nos. 3 and 5 double-bottom tanks: Moment = 700 × 0.5 = 350 ton-m Calculate Total Displacement and KG for Departure: Total Weight (Displacement) = 3000 + 5000 + 2000 + 700 = 10700 tons Total Moments = 16500 + 25000 + 20000 + 350 = 61850 ton-m KG (Departure) = Total Moments / Total Displacement = 61850 / 10700 = 5.78 m Calculate GM for Departure: KM (Given) = 7.0 m GM (Departure) = KM - KG = 7.0 - 5.78 = 1.22 m Step 3: Calculate Arrival Condition Calculate Remaining Fuel Oil: Fuel Oil Consumption = 30 tons/day × 20 days = 600 tons Remaining Fuel Oil = 700 - 600 = 100 tons Update Moments After Fuel Oil Consumption: No. 2 and No. 3 tanks are empty, No. 5 tank contains remaining fuel. No. 5 Tank KG (Assumed) = 0.5 m Moment from Fuel Oil in No. 5 Tank = 100 × 0.5 = 50 tone-m Calculate Updated Displacement and KG for Arrival: Total Weight (Arrival Displacement) = 10700 - 600 = 10100 tons New Moments (After Fuel Oil Consumption) = 61850 - (600 × 0.5) = 61850 - 300 = 61550 tone-m KG (Arrival) = 61550 / 10100 = 6.09 m Calculate GM for Arrival: GM (Arrival) = KM - KG = 7.0 - 6.09 = 0.91 m Summary of Results: GM (Departure): 1.22 m GM (Arrival): 0.91 m These calculations show that the ship's metacentric height (GM) decreases from departure to arrival due to fuel oil consumption. As fuel oil, which is stored below the ship's center of gravity (G) is consumed, the center of gravity (G) rises, resulting in a decrease of GM upon arrival.

[@reeve3854]

@@nauticalacademy001 thanks a lot Sir ♥️ from Myanmar

[@MaungMaung-b4o]

I was confusing about this topic for long time and now I got a clear concept and thanks from the bottom of my heart for informative video .

[@nauticalacademy001]

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

[@raymondallenjhangiani7670]

Great explanation 🙏 every video by NAUTICAL ACADEMY is awesome 👍 thank you very much sir 🙏 much appreciated 🙏

[@nauticalacademy001]

Thank you.

[@mahendraniwas2505]

Nice video... explained it well

[@nauticalacademy001]

Thank you.

[@MissPiggyM976]

Very good, thanks!

[@nauticalacademy001]

Welcome.