What this category covers
Propulsion terms describe how a tender or chase boat converts fuel (or battery energy) into thrust. That includes the engine itself, the drive train between engine and water, and the design choices that follow from each combination: jet vs sterndrive vs outboard vs surface drive, single vs twin vs triple, diesel vs petrol vs hybrid vs full electric.
Why it matters
The propulsion package decides three of the things owners notice first: top speed, how shallow the boat can run, and how easy it is to come alongside without scarring the mothership. A waterjet tender will tuck into a beach in calf-deep water and idle past divers without a spinning prop in sight; a sterndrive will give a flatter cruise and better economy at twenty-five knots but needs draft. Outboards have eaten into both ends of that range over the last five years as four-stroke power has climbed past 600 hp per leg.
For captains, propulsion choice drives the maintenance calendar. Jets need impeller and wear-ring inspections on a different cadence to sterndrives; outboards have their own oil and gearcase intervals. Get the spares plan wrong and a single failed component can ground a tender for a week in a remote anchorage.
For project managers and build managers, propulsion is where the weight, fuel, and noise budgets are won or lost. The choice ripples through engine room layout, tank positions, exhaust routing, and ultimately the longitudinal centre of gravity that the naval architect has to balance.
Where it shows up
- The jet tenders spoke is the most propulsion-led page in the tender library and references most of these terms directly.
- The chase boat specifications and chase boat range spokes use this vocabulary when comparing driveline options at the 50-knot-plus end of the market.
- The tender specification guide treats propulsion as one of the four pillars of a brief, alongside hull, layout, and equipment.