INAV FINAL
Types of AIS data - answer static, dynamic, voyage
static - answer unchanging. name, call sign, length. 6 min interval refresh
dynamic – answer changeable. heading, rate of turn, mmsi. refreshes in accordance
with speed
voyage - answer crew size, cargo, destination. 6 min interval refresh
AIS works off of – answer VHF
what vessels must be fitted with AIS? – answer vessels over 300 GT
STW - answer speed relative to the water. water tracking mode
SOG - answer speed in reference to a fixed object (seabed). Bottom tracking mode.
Can track up to 600 ft
janus configuration - answer forward, after, and athwartships transducers. also known
as single axis system.
janus config accuracy is about ____ and can work at a minimum depth of ____ -
answer.5% and 1.5 ft
Basic Principle of SONAR - answerspeed of sound in water will vary with temperature,
salinity, and pressure.
Temperature - answeras temperature decreases, attenuation decreases
Salinity - answerAs salinity increases, velocity increases. Usually 1500 m/s
Pressure - answerspeed decreases with depth. Max error is at 800 feet at 2%
Effects of Gain - answerlower frequency deeper range, narrow beam. Higher frequency,
short range wide beam.
DBK - answerDepth below keel.
DBS - answerdepth below sounder
DBT - answerDepth below transducer. Differs from depth below keel based on trim
, Sinkage - answerbodily increase in draft due to the effects of moving in a shallow
channel
Trim - answerrotation about the transverse axis due to the change in pressure and draft
along the length of the ship with the greatest change at bow or stern
Squat - answercombination of sinkage and trim. Largest change and location of that
change along the ship's hull depending on max change in trim. Ships with a block
coefficient less than .7 squat by the stern and greater than .7 is by the head. Speed^2 x
block coefficient/30
squat equation - answerSpeed^2 x block coefficient/30
A ship's turning circle ____ in shallow water because there is less water running over
the propeller with more force - answerincreases
Bernoulli's principle states that - answeran increase in the speed of a fluid occurs
simultaneously with a decrease in pressure or a decrease in the fluid's potential energy
When the ship is going forward, the pivot point moves to the - answerforward third of the
ship. When moving aft, it moves to the transom.
The bow will seek the wind when moving - answerforward and when moving aft the
stern will seek the wind.
1 knot of current - answer= 30 knots of wind
MOB - answerNotify bridge, throw smoke float, full rudder to MOB side 3 long blasts
(Oscar)
Williamson Turn - answerslow turn; 60 degrees hard over then 120 degrees in the other
direction to get on reciprocal course. Good for night time
Anderson Turn - answerRound Turn; hard rudder to side person fell; fastest
Race Track Turn - answerHard over to direction of reciprocal course then hard over to
direction of original course
Recovery - answerapproach from windward side to create a lee and allow the vessel to
drift toward victim
anchoring step 1 - answerWalk the anchor out to the water's edge while engaged.
anchoring step 2 - answerPut the brake on and disengage the windlass
Types of AIS data - answer static, dynamic, voyage
static - answer unchanging. name, call sign, length. 6 min interval refresh
dynamic – answer changeable. heading, rate of turn, mmsi. refreshes in accordance
with speed
voyage - answer crew size, cargo, destination. 6 min interval refresh
AIS works off of – answer VHF
what vessels must be fitted with AIS? – answer vessels over 300 GT
STW - answer speed relative to the water. water tracking mode
SOG - answer speed in reference to a fixed object (seabed). Bottom tracking mode.
Can track up to 600 ft
janus configuration - answer forward, after, and athwartships transducers. also known
as single axis system.
janus config accuracy is about ____ and can work at a minimum depth of ____ -
answer.5% and 1.5 ft
Basic Principle of SONAR - answerspeed of sound in water will vary with temperature,
salinity, and pressure.
Temperature - answeras temperature decreases, attenuation decreases
Salinity - answerAs salinity increases, velocity increases. Usually 1500 m/s
Pressure - answerspeed decreases with depth. Max error is at 800 feet at 2%
Effects of Gain - answerlower frequency deeper range, narrow beam. Higher frequency,
short range wide beam.
DBK - answerDepth below keel.
DBS - answerdepth below sounder
DBT - answerDepth below transducer. Differs from depth below keel based on trim
, Sinkage - answerbodily increase in draft due to the effects of moving in a shallow
channel
Trim - answerrotation about the transverse axis due to the change in pressure and draft
along the length of the ship with the greatest change at bow or stern
Squat - answercombination of sinkage and trim. Largest change and location of that
change along the ship's hull depending on max change in trim. Ships with a block
coefficient less than .7 squat by the stern and greater than .7 is by the head. Speed^2 x
block coefficient/30
squat equation - answerSpeed^2 x block coefficient/30
A ship's turning circle ____ in shallow water because there is less water running over
the propeller with more force - answerincreases
Bernoulli's principle states that - answeran increase in the speed of a fluid occurs
simultaneously with a decrease in pressure or a decrease in the fluid's potential energy
When the ship is going forward, the pivot point moves to the - answerforward third of the
ship. When moving aft, it moves to the transom.
The bow will seek the wind when moving - answerforward and when moving aft the
stern will seek the wind.
1 knot of current - answer= 30 knots of wind
MOB - answerNotify bridge, throw smoke float, full rudder to MOB side 3 long blasts
(Oscar)
Williamson Turn - answerslow turn; 60 degrees hard over then 120 degrees in the other
direction to get on reciprocal course. Good for night time
Anderson Turn - answerRound Turn; hard rudder to side person fell; fastest
Race Track Turn - answerHard over to direction of reciprocal course then hard over to
direction of original course
Recovery - answerapproach from windward side to create a lee and allow the vessel to
drift toward victim
anchoring step 1 - answerWalk the anchor out to the water's edge while engaged.
anchoring step 2 - answerPut the brake on and disengage the windlass
