Скачать или смотреть SHIP'S MAGNETISM, PART -04, NAV AIDS, PHASE -II, CHIEF MATE EXAM (MMD), Coefficient A Explained 🧭🧲 🚢

Coefficient A — Constant Magnetic Compass Deviation Explained 🧭 | Ship’s Magnetism | Merchant Navy
This lesson explains Coefficient A, the type of compass deviation that remains constant regardless of the ship’s heading.
Coefficient A represents a fixed error on the magnetic compass and is divided into two important parts: Real A and Apparent A — both essential for compass correction and exam numericals.
🧲 Real A — Constant Deviation from Soft Iron
Real A occurs due to unsymmetrical horizontal soft iron fitted in the ship:
• Unequal longitudinal structures
• Unequal athwartship beams
• Irregular soft-iron distribution in the hull
Because these iron structures are not balanced, the induced magnetism produces the same deviation on every heading.
The video demonstrates this effect on multiple headings including:
• North
• East
• Northeast
However, Real A is rare on most merchant ships, because modern vessels are built with symmetrical soft-iron arrangements.
👉 Therefore, Real A is usually not corrected physically.
Instead, it is applied as an index error on the deviation card.
🧭 Apparent A — Constant Error Not Caused by Magnetism
Apparent A is not due to magnetism at all.
It results from external errors such as:
• Defect in compass card
• Mis-aligned lubber line
• Human error while observing or calculating deviation
These errors also create constant deviation on every heading — so they behave like Real A, but originate from different causes.
📐 How Coefficient A Is Calculated
Coefficient A is obtained by averaging deviations on at least four equally spaced headings.
In practice, navigators normally use eight headings (cardinal + inter-cardinal) to increase accuracy.
When these deviations are averaged, other coefficients cancel out — leaving only Coefficient A.
This method is standard during compass adjustment and deviation card preparation.
🎯 Who Should Watch
✔ Chief Mate / Mate exams
✔ OOW & Cadets
✔ Compass adjustment learners
✔ Anyone studying ship magnetism and deviation
Understanding Coefficient A builds a foundation for solving magnetic compass numerical problems and reading deviation cards correctly.
🔍 SEO TAGS
Coefficient a ship magnetism
constant compass deviation explained
real a compass error
apparent a compass deviation
horizontal soft iron magnetism
index error deviation card
magnetic compass correction tutorial
merchant navy compass deviation
chief mate magnetism lesson
oow compass deviation study
navigation aids compass correction
induced magnetism ships
compass adjustment explanation
deviation coefficients explained
marine navigation magnetic compass
#️⃣
#MagneticCompass
#Navigation
#MerchantNavy
#ChiefMateExam
#NauticalScience