What is the difference between a single screw and a twin screw?

What is the difference between a single screw and a twin screw?

• A. One Propeller
• B. Two Propellers
• C. Three Propellers
• D. No Propellers

Answer: (B)

In this context, a “screw” is an old term for a propeller. A single screw means the vessel has one propeller, while a twin screw means it has two propellers, usually on two separate shafts at the stern. Having two propellers gives more thrust and easier maneuverability, since the two shafts can be controlled to assist turning or provide redundancy if one propeller or shaft has an issue. So the difference is simply the number of propellers: one for a single screw, two for a twin screw.

In this context, a “screw” is an old term for a propeller. A single screw means the vessel has one propeller, while a twin screw means it has two propellers, usually on two separate shafts at the stern. Having two propellers gives more thrust and easier maneuverability, since the two shafts can be controlled to assist turning or provide redundancy if one propeller or shaft has an issue. So the difference is simply the number of propellers: one for a single screw, two for a twin screw.