Welcome to the Glossary.

Please note that definitions are ”plain english” rather than purely technically correct.

• BHP - Brake Horse Power, measurement of a motors power.
• Bollard Thrust - aka Static Thrust, maximum towing ability in lbs pull.
• BWL - Beam (max) at waterline.
• DAR - Disc Area Ratio, apparent area of a propeller viewed end on compared to area of a disc of the same diameter.
• DBA - Developed Blade Area. True area of blades in square inches.
• Displacement - weight of water (in lbs) displaced by vessel.
• Draft - Depth below surface of water.
• Hull Speed - Maximum speed of a displacement hull as defined by SL Ratio.
• Knot - One Nautical Mile Per Hour.
• LWL - Length (max) at waterline.
• MWR - Mean Width Ratio. Ratio of blade width to propeller diameter.
• PBA - Projected Blade Area. Apparent area of blades in square inches when viewed end on.
• PD - Pitch Diameter Ratio or Pitch ratio. Diameter in inches divided by Pitch in inches.
• Pitch - angle at which blades of a propeller are set.
• Required Speed -  full throttle ahead speed desired.
• RPM - Revolutions Per Minute, measurement of how fast a device rotates.
• SL - Speed Length Ratio - relationship between LWL of a displacement hull and max speed.
• Torque - turning force in a shaft, (foot pounds or ft/lb) not to be confused with “power” / BHP.
• Transmission Losses - Power lost (as heat) in devices such as gearboxes and bearings.

That’s the lot.