Tropical Revolving Storms which forms in Tropical regions. Northern hemisphere it moves towards north and vice versa in Southern hemisphere.
if the cpa matters , and collision cant be avoided by the give way vsl alone then i will alter other wise , maintain co and speed.
take the series of brg if risk of collision does not exist the maintain co and speed if roc exist the i will give five sort and rapid blast, check nav lights, inform master,inform engine room,put helms men and still she is not taking an action then one short blasta/co to stbd if depth available or reduce speed
in addition there are some non-adjustable erroes
graduation error,shade error,optical error, prismatic error,telescopic error
Sextant Errors are of 2 Types:
1) Adjustable error,
2) Non Adjustable errors
1)Adjustable errors:
a)error of perpendicularity,
b)Index error,
c)Side error,
d)Error of collimination
2)Non adjustable Errors:
a)Graduation Error,
b)Shade Error,
c)Optical Error,
d)convex Error..
velocity of propagation in water, stylus speed error, pythagoras error, multiple echoes, thermal and density layers, zero line adjustment error, cross noise, Aeration.
