Chart Work Navigation | Chart plotting 5047, 5048 & 5056 | Blind & Single PL | Mate’s Exam phase -1

Blind Navigation & Single Position Line (PL) — Full Concept Explained | Mate’s Exam Navigation 🚢 This lesson explains two important chart-work topics often asked in Mate’s Examinations: 1️⃣ Solving a Complex Blind Navigation Problem (0:22–16:51) A tricky exam scenario where: • Vessel’s course is unknown • Initial position is unknown • Only bearings to lights and ship’s speed are given The instructor shows how to: • form a position line from reciprocal bearings • construct a geometric triangle using two relative bearings • calculate distance off the light vessel (10.4 miles) • plot a position circle • find the ship’s position by intersecting PL + circle • draw tangent to determine true course steered Pure geometry + logic — no electronics needed. 2️⃣ Single Position Line (PL) / Blind Navigation (17:11–52:00) Used when visibility is poor and only one PL is available. You’ll learn: • what blind navigation means • which PLs are suitable (master’s discretion matters) • what information the question normally provides (PL + DR/EP + speed + current + wind) What we must find: ✔ first Course To Steer (CTS) ✔ alteration time ✔ second CTS Procedure covered step-by-step: • plot PL and transferred PL • choose safe CMG (perpendicular where possible) • draw a safety margin around DR • use vector triangle to calculate CTS • find alteration time from DMG & SMG • calculate second CMG (always along transferred PL) • recompute second CTS considering current and wind Also discussed: 👉 situations where perpendicular CMG is unsafe and how to choose an alternative. 🎯 Best For ✔ Mate’s exam candidates ✔ Chief Mate & Second Mate students ✔ Anyone revising blind navigation & PL concepts Blind navigation Single position line navigation PL navigation method Transferred position line Course to steer calculation Alteration time navigation Vector triangle navigation Dead reckoning vs estimated position Perpendicular CMG method Safe CMG selection Position circle plotting Reciprocal bearings navigation Light vessel distance calculation Navigation exam blind problem Mates exam chart work Chief mate navigation problems Restricted visibility navigation Navigation plotting example Fix from single position line Navigation geometry plotting . #Navigation #MatesExam #MerchantNavy #ChartWork #NauticalScience