VTS Meteorology and Environmental Factors 2

Question 1

What hydrodynamic phenomenon causes a vessel to sink deeper into the water when transiting shallow channels at speed, reducing available under-keel clearance?

Accepted Answer

Squat

Answer

Heel

Answer

List

Answer

Trim

Question 2

A temperature inversion exists over the harbor. How does this atmospheric condition most likely affect VHF radio communications used by VTS?

Accepted Answer

It can cause ducting, extending VHF range well beyond normal line-of-sight limits

Answer

It reduces VHF range due to increased atmospheric absorption

Answer

It has no measurable effect on VHF radio propagation

Answer

It causes selective interference only on DSC channel 70

Question 3

What is 'significant wave height' as reported in marine weather forecasts provided to VTS operators?

Accepted Answer

The average height of the highest one-third of all waves in a given period

Answer

The maximum wave height recorded in a 24-hour observation period

Answer

The height of the single largest wave observed during the period

Answer

The wave height exceeded by exactly 50 percent of all waves

Question 4

When tidal current through a harbor entrance exceeds 4 knots, what action would a VTS operator typically recommend or require for a large inbound vessel?

Accepted Answer

Delaying vessel transit until the current decreases to a manageable level

Answer

Immediate anchoring in the fairway to await calmer conditions

Answer

Increasing vessel speed to overcome the adverse current

Answer

Switching to hand steering and reducing radar range

Question 5

What is a 'storm surge' and why must VTS operators account for it in their traffic management decisions?

Accepted Answer

A wind-driven and low-pressure-induced rise in sea level that affects actual water depths and port flooding risk

Answer

A sudden increase in vessel traffic attempting to reach port before a storm arrives

Answer

The turbulent wake generated by large vessels departing during a storm

Answer

A rapid intensification of wind speed during the passage of a squall line

Question 6

How should a VTS operator adjust traffic management when a dense fog advisory is in effect across the port service area?

Accepted Answer

Implement reduced speed advisories and increase minimum separation distances between vessels

Answer

Increase vessel speed requirements to clear the port approach faster

Answer

Suspend all VHF communications until visibility improves above 2 miles

Answer

Transfer all navigational responsibility solely to individual vessel masters

Question 7

What is 'ice accretion' and what specific navigation hazard does it present to vessels monitored by VTS in winter conditions?

Accepted Answer

Build-up of ice on the vessel's superstructure causing stability loss due to increased topside weight

Answer

Formation of ice crystals in fuel lines reducing available engine power

Answer

Ice deposits on VHF antennas causing communications to fail

Answer

Gradual freezing of the harbor approach channel reducing available depth