X-band RADAR
3 cm
S Band RADAR
10 cm
Short Pulse RADAR
Range: 0-3 NM
A object that appears stationary on a relative motion radar
has the same course and speed as your ship
3 cm RADAR is used inshore because
it gives you a more detailed picture
Sea Clutter
sensitivity control
Using a True Motion RADAR in an area with significant set and drift, you are on a constant heading. What will an object stationary object do on your RADAR screen?
It will stay where it is as you move: True Motion RADAR shows what is truly happening.
As you increase range of RADAR
you increase pulse length
On a chart a RADAR range is plotted in an
Arc
Subrefraction
Decreases the normal RADAR range you are able to see
SARTs appear on
X-Band RADAR
Vertical Band Width
The wider it is, the more you can see. It increases the RADAR's range and helps avoid target switching (this is when the RADAR is unable to recognize multiple objects on the same bearing).
Minimum Detection Range
is not influenced by shadowing from the ship's strcture
If the Gyro Compass fails
You can still use the RADAR in Heads Up display
Heads Up display
Unstable
Course Up display
Unstable
North Up display
Stabilized
AIS gives you
target information and can be helpful in target/collision avoidance
Radar Horizon Distance formula
D= 1.22*squrt of the height
Rudder Pitch Formula
(engine speed x 6080)/(RPM x 60)
(I think this is right but I couldn't find it in my notes. If you remember something different, let me know.)
Slip Formula
((Engine Speed - Observed Speed)/(Engine Speed))*100
or
100% - Efficiency
Engine Speed Formula
(RPM x 60 x Pitch)/(6080)
Pivot point
1/3 of the vessel length from the bow
turning diameter
approximately 3 ship's lengths
Shallow water truing
turns are wider so you need more space
things to communicate when being relived at the helm
- Gyro Heading
- Speed
- Course Over Ground
- Weather Conditions
- Traffic Conditions
- How the ship has been steering
Right/Left Rudder
Apply right/left rudder instantly the desired amount requested
Right/Left full rudder
put the rudder over to the right/left very close to the maximum amount. On most ships this is 30 degrees.
Right/left hard rudder
put the rudder over to the maximum angle the rudder can achieve. On most ships this is 35 degrees
Meet Her
Stop the swing of the vessel
Ease rudder to _____
decrease rudder angle to ______
Steady or steady as you go
keep vessel of given course
Rudder amidships
Rudder angle to zero
shift your rudder
move rudder to the opposite direction at the same amount
Mind your Rudder
Warning to helmsman to watch ordered course carefully
Nothing to the right/left of
steer nothing beyond the given course
How does she head?
Helmsman is supposed to state the current heading of vessel
Keep her so
maintain the present course