## Graphical SolutionThe graphical solution for reverse dial alignment problems is a method that will give you an actual visual indication of the misalignment very much like that used for cross dial alignment. The results will be the same as if they were calculated mathematically. The only difference in this type of alignment is that the MM indicator reading must have its sign changed before plotting.Procedure: Layout a horizontal line at the approximate middle of the graph paper. This is the running alignment line (RAL). Layout a vertical line near the left edge of the graph paper. This represents the SM dial indicator position. Lay out another vertical line scaled from the SM indicator line that represents the MM indicator. If the distance is 6 inches and you are using a 1:1 scale, the line will be 6 blocks from the SM indicator line. Lay out another vertical line scaled from the SM indicator line that represents the MM front foot. Lay out the last vertical line scaled from the SM indicator line that represents the MM rear foot. Determine the SM dial indicator TIR (remembering to account for bar sag) and divide the reading by two. This is your plot point on the SM indicator line. Positive readings are above the RAL, and negative readings are below the RAL. Determine the MM dial indicator TIR (remembering to account for bar sag) and divide the reading by two and then change the sign (positive readings become negative and negative readings become positive). This is your plot point on the MM indicator line. Using a straight edge, extrapolate these plotted points across the vertical lines for the MM front and rear foot. This is the misalignment line. On the vertical lines for the MM feet, count the number of blocks either up or down from the misalignment line to the RAL. If the misalignment line is above the RAL, shims must be removed. If the misalignment line is below the RAL, shims must be added. Assuming a 1:1 scale is being used, each block equals .001 inch.

### Difference Between A, B & C-Class Divisions?

IMO Symbol A Class Division  IMO Symbol B Class Division  SOLAS has tables for structural fire protection requirement of bulkheads and decks. The requirements depend on the spaces in question and are different for passenger ships and cargo ships. The Administration has required a test of a prototype bulkhead or deck in accordance with the Fire Test Procedures Code to ensure that it meets the above requirements for integrity and temperature rise. Types of Divisions: "A" Class "B" Class "C" Class "A" Class: "A" class divisions are those divisions formed by bulkheads and decks which comply with the following criteria: They are constructed of steel or equivalent material They are suitably stiffened They are constructed as to be capable of preventing the passage of smoke and flame to the end of the one-hour standard fire test. they are insulated with approved non-combustible materials such that the average tempera

### Load Line & Why it is Important

Merchant ships have a marking on their hull know as the Plimsoll line or the Plimsoll mark, which indicates the limit until which ships can be loaded with enough cargo, internationally, the Plimsoll line on a ship is officially referred to as the international load line. Every type of ship has a different level of floating and the Plimsoll line on a ship generally varies from one vessel to another.  All vessels of 24 meters and more are required to have this Load line marking at the centre position of the length of summer load water line. There are two types of Load line markings:- Standard Load Line marking – This is applicable to all types of vessels. Timber Load Line Markings – This is applicable to vessels carrying timber cargo. These marks shall be punched on the surface of the hull making it visible even if the ship side paint fades out. The marks shall again be painted with white or yellow colour on a dark background/black on a light background.  The comp

### Bilge Injection Valve

Bilge Injection is a valve that enables the engine room bilges to be pumped out directly overboard in the event of an emergency such as flooding. The valve is normally fitted to the end of a branch connection with the main sea water suction line. This enables large main seawater cooling pumps to be used as a bilge pump in an emergency. Emergencies like fire and flooding involve the use of seawater. If there is a fire, seawater is the biggest resource of water available in the sea. Similarly, if it involves flooding of the engine room, cargo spaces or any other place on the ship for that matter; you would again require pumping the sea water out of the ship. In both these cases, you require pumps.  There are two valves in close proximity namely main injection valve and bilge injection valve. Both of them have their own independent controls. The diameter of the bilge injection valve is kept nearly 66% of the main valve diameter which draws water directly from the sea through the