🔍 Key Concepts

• The difference between indicated horsepower, brake horsepower, and shaft horsepower in marine engines • Where along the power train (inside cylinders, at crankshaft, at propeller shaft) each type of horsepower is measured • Which term is commonly used for power that is actually delivered to the propeller shaft

💭 Think About

• Think about where "available at the shaft" is measured in relation to the engine cylinders and crankshaft—before or after internal engine losses? • Which of these horsepower terms represents power inside the cylinders, and which represents power after friction and mechanical losses have been subtracted? • On a tug, when you care about how much power actually reaches the propeller, which of these standard horsepower terms would you be interested in?

✅ Before You Answer

• Be clear on the definition of indicated horsepower (where and how it is measured) • Be clear on the definition of brake horsepower (what component it is measured at) • Identify which term corresponds to power actually transmitted along the propeller shaft