Mixed Deck — All OBS Topics Flashcards

What is cavitation in the context of boat propellers?

Answer: Formation of vapor bubbles around the propeller that reduce thrust and cause damage

Cavitation occurs when low pressure causes water to vaporize around propeller blades, reducing efficiency and eroding the metal over time.

Which statement about wildlife watching from a boat is correct?

Answer: Maintaining a safe distance and avoiding sudden movements minimizes stress to marine wildlife

Keeping respectful distances, moving slowly, and avoiding loud noises prevents stress responses, disruption of feeding, and separation of mothers from young.

How is a 'nautical mile' different from a 'statute mile'?

Answer: A nautical mile is longer, equal to approximately 6,076 feet

One nautical mile equals approximately 6,076 feet (1,852 meters), making it about 15% longer than a statute mile of 5,280 feet.

What does a red buoy with an even number indicate in the US Aids to Navigation system?

Answer: Leave it to your starboard (right) side when returning from sea

Red even-numbered buoys mark the right side of a channel when returning from sea — remember 'Red Right Returning.'

What is the purpose of a 'float plan' in defensive boating?

Answer: To inform someone ashore of your trip details so they can alert rescuers if you're overdue

A float plan left with a responsible person ashore ensures that rescuers know where to search if you don't return on time.

A passenger on a boat is seriously injured in an accident. Under federal law, within how many hours must the operator report this to the state reporting authority?

Answer: 72 hours

When a boating accident results in a person requiring medical treatment beyond first aid, a report must be filed within 48 hours (not 24) — death or disappearance requires a report within 24 hours.

How does collaboration enhance Vehicle Inspection & Maintenance in Online Boating Safety Certification?

Answer: It brings diverse perspectives and improves outcomes

Collaboration brings together different viewpoints and expertise, leading to better decision-making and outcomes.

Which situation requires an operator to immediately reduce speed to minimize risk to passengers?

Answer: Approaching a congested area, dock, or swimmers in the water

Slowing down near docks, congested areas, and swimmers protects both passengers aboard and people in the water from wake and collision hazards.

Which of the following is a key principle of workplace safety in Online Boating Safety Certification?

Answer: Reporting all near-misses and incidents

Reporting near-misses helps organizations identify potential hazards before they cause serious injuries, creating a culture of safety.

What is the primary reason to avoid operating a boat while fatigued?

Answer: Fatigue impairs judgment, reaction time, and situational awareness

Fatigue degrades the mental and physical abilities needed for safe boat operation, similar to alcohol impairment.

A boat's propeller has a small nick or ding on one blade. Why is it important to have this repaired before operating the vessel?

Answer: Even minor propeller damage can cause vibration that damages the engine's shaft seal and bearings

An out-of-balance propeller creates vibration that can damage the shaft, bearings, seals, and transom over time, leading to more costly repairs.

Which type of current hazard is most dangerous because it is invisible from the surface and can trap swimmers near a boat?

Answer: Hydraulic current near a dam

Hydraulic currents below low-head dams recirculate continuously, trapping people underwater in a deadly cycle called a 'drowning machine.'

A boater notices that the engine is consuming significantly more fuel than usual for the same speed and conditions. Which maintenance issue could MOST directly explain this?

Answer: A fouled or damaged propeller that reduces thrust efficiency and forces the engine to work harder

A fouled hull, damaged propeller, or worn propeller with incorrect pitch forces the engine to burn more fuel to overcome reduced efficiency and maintain speed.

What is the safest way to check for a fuel leak in the engine compartment before starting the engine?

Answer: Open the engine hatch and use your nose to detect fuel vapors before attempting to start

Opening the engine hatch and sniffing for fuel vapors — and running the blower for at least four minutes on gasoline engines — is the correct pre-start safety check for fuel leaks.

When backing a single-engine outboard boat, the stern tends to swing in which direction first?

Answer: In the direction the propeller rotates (typically to port for standard rotation)

Propeller torque and paddle-wheel effect cause the stern to kick in the direction of propeller rotation when backing, usually to port on standard right-hand props.

A passenger falls overboard in cold water. What is the FIRST action you should take?

Answer: Throw a life ring or throwable PFD toward the victim

Throwing a flotation device to the victim is the safest first step while keeping them in sight.

How should passengers be seated to maintain proper boat stability?

Answer: Low and centered, with weight distributed evenly

Keeping passengers seated low and with weight distributed evenly prevents the boat from listing or capsizing.

What should you do if you discover water in the bilge while underway?

Answer: Immediately run the bilge pump and identify the source of ingress

Finding water in the bilge requires immediately activating the bilge pump and locating the source of the leak before it worsens and threatens the vessel's safety.

A boat owner transfers ownership of a vessel. Who is responsible for notifying the state titling authority?

Answer: Either the buyer or seller, but typically the new owner completes the transfer

In most states, the new owner (buyer) is responsible for completing the title transfer with the state authority, though the seller must also sign the title.

What do five or more short blasts on a horn or whistle mean?

Answer: Danger or doubt about the other vessel's intentions

Five or more short blasts is the danger or doubt signal indicating the operator is uncertain of the other vessel's intentions.