Weather
Which creates steeper seas?
A strong current opposing the wind.
What does VHF stand for?
Very High Frequency
A dewatering pump starts but won't prime.
List 2 possible causes.
Examples:
What does FLIR actually detect?
Infrared (heat), not visible light.
You are overtaking another vessel at night.
Who is the stand-on vessel?
Answer
The vessel being overtaken.
How can mountains make a 15-knot forecast inaccurate?
Funneling winds:
Gap winds
A gap wind occurs when wind is forced through a narrow valley, mountain pass, or fjord, causing it to speed up—similar to putting your thumb over the end of a garden hose.
Williwaws: A williwaw is a sudden, violent downdraft of wind that rushes off steep mountainsides, usually during unstable weather or after heavy rain.
Local acceleration:
Even if there isn't a true gap, the shape of the shoreline or islands can funnel or accelerate wind.
Examples:
Your VHF receives perfectly but nobody can hear your transmissions.
Possible answers:
One battery reads 12.0V.
What does that mean?
12.0V is approximately 25% charged.
You find a lifejacket floating during a search. Do you immediately recover it?
Not necessarily. Mark the position, report it to JRCC, photograph if possible, and recover only if directed or appropriate because it may be an important clue.
A sailboat under sail meets a fishing vessel actively fishing.
Who has right of way?
Fishing vessel.
Why is ebb tide dangerous near river mouths?
Standing waves
Breaking seas
Reduced control
Why are log booms particularly dangerous at night?
Possible answers:
What's the first thing you should check if a pump won't start?
Fuel, battery, or power supply (depending on pump type).
Your search object has a high drift rate.
What information becomes critical?
(3 things)
Wind
Current
Time since last seen
Two power vessels meet head-on.
What should each do?
Alter to starboard.
You're returning home and notice a line of black/dark clouds with virga approaching rapidly.
What weather does this suggest?
Possible squall/downburst with sudden wind shift.
"Virga" is precipitation (rain or snow) that falls from a cloud but evaporates before it reaches the ground or the water.
It often looks like wispy, streaky curtains hanging below a cloud.
When should you use SECURITÉ instead of PAN-PAN?
Safety information affecting navigation but not requiring assistance.
While inspecting an outboard, you notice the tell-tale ("pee stream") is weak. Name three possible causes.
Answers:
You detect a heat source on shore.
What could it be besides a person?
Possible answers:
A vessel is displaying:
🔴⚪🔴
What does it mean?
Restricted in ability to maneuver.
What is the difference between wind waves and swell?
Wind waves are created by local wind and are short and steep.
Swell is generated by distant weather and is longer, smoother, and more regular.
You hear a MAYDAY on Channel 16, but no Coast Guard station responds. What should you do?
Continue listening briefly. If there is still no acknowledgement, relay the MAYDAY to JRCC or the nearest Coast Guard Radio station, while avoiding unnecessary interference.
During a vessel inspection, you notice corrosion on the battery terminals. Why is this a concern?
Answer:
Corrosion increases electrical resistance and can lead to poor engine starting, charging problems, equipment failures, or complete loss of electrical power. The terminals should be cleaned and protected before the vessel is placed in service.
Why should AIS never be used as your only means of collision avoidance?
Answer:
Because:
Why is crossing between a tug and its tow extremely dangerous?
Towline may be submerged and under tremendous tension.