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Propellor drop

Procedure: Turn the engine to coincide the mark on the propeller with stem boss (for reference with previous measurements) or keep cyl 1 in TDC or methods followed on vessel or blades are numbered and designated blade is kept above. (A hole is made on the stern-frame boss,stern tube and bush during building of vessel.upper end of the hole is drilled to larger diameter and tapped out & closed using a screw plug) The
screw plug is removed and another plug with a central hole is inserted, the top of this plug is the datum form which all measurements are made, a depth micrometer( poker gauge ) is used to measure distance from the top of the datum and and top of the screw shaft.

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