Propeller Sizing Calculator

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Propeller sizing is a fundamental concept in marine engineering, which involves selecting the appropriate size of the propeller for a boat or ship to achieve optimum performance. This is primarily based on three parameters: boat weight, engine horsepower, and gear ratio. Marine engineers and naval architects typically deal with propeller sizing in the field of marine engineering.

Propeller Sizing Calculator
Propeller Sizing Calculator Results (detailed calculations and formula below)
Propeller Diameter (D) inches
Propeller Pitch (P) inches
Propeller Diameter Formula and Calculations
D = √W × HP × 0.5/GR × 1.5
D = √ × × 0.5/ × 1.5
D = × /
D = ×
D =
Propeller Pitch Formula and Calculations
P = HP/GR × 2
P = / × 2
P = × 2
P =
Propeller Sizing Calculator Input Values
Boat Weight (W) lbs [pounds]
Engine Horsepower (HP) HP [horsepower]
Gear Ratio (GR)

Example Formula

D = √W × (HP × 0.5) / (GR × 1.5)
P = (HP / GR) × 2


  1. D: Propeller Diameter in inches
  2. W: Boat Weight in pounds
  3. HP: Engine Horsepower
  4. GR: Gear Ratio
  5. P: Propeller Pitch in inches

Impact on Society

The concept of propeller sizing is not attributed to a particular individual, but it has greatly impacted maritime industries and societies. Proper propeller sizing ensures that boats and ships operate efficiently, resulting in lower fuel consumption and emissions. This contributes to environmental sustainability. Additionally, propeller sizing is crucial in naval architecture and is also applicable in aerospace engineering for sizing propellers of aircraft.

Real Life Application in Industry

In the maritime industry, propeller sizing is vital for various types of vessels, including cargo ships, fishing boats, and yachts. For instance, a shipping company might save millions of dollars annually in fuel costs by optimizing the propeller size for its fleet. This also allows for faster and more efficient transportation of goods, benefiting the global economy.

Key Individuals in the Discipline

David W. Taylor is one of the pioneers in naval architecture and marine engineering. In the early 20th century, he played a significant role in the design and optimization of ship hulls and propellers, contributing to the advancement of naval shipbuilding.

Interesting Facts

  • During World War II, propeller design and sizing were vital components in the construction of fast and efficient warships.
  • The largest ship propellers in the world can weigh over 100 tons and have a diameter of more than 30 feet.
  • Improvements in propeller sizing techniques have contributed to the significant reduction of underwater noise, which affects marine life.


Propeller sizing is a fundamental concept in marine engineering that involves calculating the optimal size of a propeller basedon boat weight, engine horsepower, and gear ratio. While not attributed to any single individual, the development of propeller sizing techniques has had a profound impact on maritime industries and environmental sustainability. With applications in naval architecture and aerospace engineering, it remains an essential aspect of engineering that continues to evolve with technological advancements.