ship's stability part 23 | GZ Curve & Righting Lever: Everything You Need to Know

This video (Part 23) explains one of the most important theoretical topics in ship stability—the GZ Curve (Curve of Statical Stability). It covers how the curve is developed, how to interpret it, and why it is essential for evaluating a vessel's stability during operation. These concepts are highly important for 2nd Mate (FG) and MMD examinations. Key topics covered in this lecture: (0:00–3:58) Introduction to the GZ Curve Learn what the GZ (Righting Lever) Curve is, how it is derived from Cross Curves (KN Curves) in the ship's Stability Booklet, and why it is fundamental to ship stability. (4:31–5:47) Structure of the GZ Curve Understand how the graph is plotted: ⚓ X-axis – Angle of Heel ⚓ Y-axis – Corrected Righting Lever (GZ) (6:02) Maximum Righting Lever (GZ Max) Explanation of the maximum value of the righting lever and what it indicates about a ship's stability. (6:22) Angle of Heel at GZ Maximum Discussion of the heel angle where maximum righting ability occurs, typically around 45° for many merchant ships. (6:50) Angle of Vanishing Stability (AVS) Learn the point where the righting lever becomes zero again, beyond which the vessel loses positive stability. (7:48) Range of Positive Stability Understand the range between upright condition and the Angle of Vanishing Stability where the vessel maintains positive righting ability. (8:44) Initial GM from the GZ Curve Learn how the initial Metacentric Height (GM) can be estimated using the tangent at the origin and the 57.3° radian relationship. (11:35) Righting Moment Calculation of Righting Moment using: ⚓ Righting Moment = Displacement × GZ (13:04) Area Under the GZ Curve Explanation of the area under the curve and its importance under the IMO Intact Stability Code requirements. (15:24) Dynamical Stability Understand how the area under the GZ curve represents the work required to heel a ship to a particular angle. (18:04–24:06) Is GM the Most Important Stability Factor? A discussion on why GM alone does not determine ship stability. The instructor explains that overall stability depends on multiple factors including: ⚓ GZ Curve ⚓ Righting Energy ⚓ Range of Stability ⚓ Angle of Vanishing Stability ⚓ Maximum Righting Lever ⚓ Dynamical Stability ⚓ Vessel Loading Condition ⚓ Hydrostatic Characteristics Key Learning Points: ⚓ GZ Curve (Curve of Statical Stability) ⚓ KN Curves ⚓ Righting Lever (GZ) ⚓ Righting Moment ⚓ Initial GM ⚓ Angle of Vanishing Stability (AVS) ⚓ Range of Positive Stability ⚓ Dynamical Stability ⚓ IMO Intact Stability Code This lecture is highly recommended for cadets, deck officers, and Second Mate candidates preparing for MMD written and oral examinations. ⚓ Ship Stability | GZ Curve | Righting Lever | Dynamical Stability | MMD Preparation LINK YouTube:    / @sailor_rider   Instagram:   / sailor_rider   Facebook:   / 19imzynlrp   Threads: https://www.threads.com/@sailor_rider TAGS ship stability part 23 gz curve explained curve of statical stability righting lever gz kn curves ship angle of vanishing stability dynamical stability imo intact stability code 2nd mate stability mmd ship stability #MerchantNavy #ShipStability #DeckOfficer #MarineEngineering #Seafarers