With a direct drive main propulsion...

Question 1 / 2707066636eef28f7522a1c51fa44

Question 1 of 2707066636eef28f7522a1c51fa44

With a direct drive main propulsion arrangement, what statement is true?

Question 1 of 27070

With a direct drive main propulsion arrangement, what statement is true?

🔍 Key Concepts

• Direct drive main propulsion (engine connected to propeller shaft without a reduction gear) • Relationship between engine RPM (revolutions per minute) and propeller shaft RPM in different arrangements • How geared vs direct drives change speed ratios

💭 Think About

• If there is no reduction gear between the engine and the shaft, how many turns does the shaft make for each turn of the engine? • In which type of arrangement (direct drive or geared) would you expect the propeller shaft to turn slower or faster than the engine? • Which answer choice describes a 1:1 speed relationship between engine and shaft?

✅ Before You Answer

• Confirm what direct drive means: is there a speed-changing gear between engine and shaft? • Decide whether a ratio other than 1:1 is possible without gearing in a direct drive system. • Eliminate any choices that require the shaft and engine to turn at different RPMs when they are rigidly connected.

Question 1 of 27070

With a direct drive main propulsion arrangement, what statement is true?

The engine to propeller shaft speed ratio is variable.

The engine speed is greater than the propeller shaft speed.

The engine speed is equal to the propeller shaft speed.

The engine speed is lower than the propeller shaft speed.

Question 1 / 2707066636eef28f7522a1c51fa44

Question 1 of 2707066636eef28f7522a1c51fa44

With a direct drive main propulsion arrangement, what statement is true?

Back

Question 1 of 27070

With a direct drive main propulsion arrangement, what statement is true?