![]() ![]() ![]() Have the OOD cycle the rudder, from right full to left full or vice versa. The ship must be making way, approximately 8-10 knots on a relatively calm day. Should you desire an estimate of your Metacentric Height, the following method works well when underway. The ship's roll period is directly related to the Metacentric Height of your vessel. If GM is negative, the ship will capsize when inclined. If GM is slightly negative, the ship will loll (stay heeled at the angle of inclination where righting and upsetting forces are equal) and flop from side to side. If GM is very small, the ship is apt to hang at the end of each roll before starting upright. If GM is small, the ship has small righting arms and will have tender, slow rolls. If GM is large, the ship has large righting arms and will have stiff, fast rolls. Therefore, GM can be used as a representation of initial righting arms. For small angles of heel (0°-7/10°) GZ is proportional to GM. In lesson 4.01 the relationship between Metacentric Height (GM) and righting arms (GZ) was discussed. Fire: Extreme thermal effects on structural members. Violent longitudinal whipping (ex: grounding at high speed, underwater detonation.)Ĭ. Excessive stresses from hull damage or improper distribution of liquid (failure to follow the ship’s Liquid Loading Instructions (LLI).ī. Breaking Up - Caused by strength member failureĪ. Plunging - Loss of longitudinal stability: the trimming moment exceeds the longitudinal righting moment (TM > RM) and the ship sinks by the bow or stern.Ģ. Capsizing - Loss of transverse stability: the inclining moment exceeds the righting moment (IM > RM) and the ship rolls over.Ĭ. Bodily Sinkage - The addition of weight (flooding water) has caused the force of gravity to exceed the force of buoyancy.ī. The ship stops heeling, changing trim, and settling shortly after initial damage.Įxperience has shown that the loss of ships lasting several hours after damage and then sinking is directly traceable to progressive flooding.Ī. Two possible situations exist following the infliction of damage:ĭamage is so extensive that the ship never stops listing, trimming, or settling, and goes down within minutes (JTI 3.2.1, 6.0, 6.1, 6.2)Ħ.33 DESCRIBE the relationship between metacentric height and roll period.Ħ.34 DEFINE floodable length, angle of maximum roll, angle of semi-permanent heel, and reserve dynamic stability.Ħ.35 DESCRIBE the three possible causes for list after damage and the indicators for each.Ħ.36 Given a DC book section II(a), CALCULATE danger angle.Ħ.37 DESCRIBE the survivability design considerations outlined in NAVSEA DDS-079-1 and NAVSEAINST 9096.3(series) which enable the ship to withstand external, dynamic forces and damage.Ħ.38 Given a written summary of damage, a description of the ships behavior and list, EXPLAIN the cause of the list and the procedures necessary to eliminate or reduce the list.Ħ.39 DESCRIBE the intended method of disabling a ship as it applies to: homing influence torpedoes, impact (WWII) torpedoes, anti-ship missiles, influence and contact mines.Ħ.40 Given a ship's beam and average roll period in calm water, use the Roll period equation to CALCULATE the ship's metacentric height.Ħ.41 DRAW a righting moment curve with a heeling moment curve that identifies angle of maximum roll, angle of semi-permanent heel, and reserve dynamic stability remaining. MEDIA:Ĝlassroom lecture with visual mediaĦ.0 EVALUATE shipboard stability by analyzing weight and moment considerations. LESSON TOPIC:Ĕ.6 TITLE: HULL DAMAGE ASSESSMENT/ LIST IN STABILITYĬontact periods allotted this LESSON TOPIC: ![]()
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