SAIL MEETS SPACEFLIGHT
Koru’s classic silhouette. Blue Origin propulsion pods at full thrust. A dramatic rise onto plane, an 85-knot cinematic run, and the physics behind the thought experiment.
Ignition, a visible bow rise, and a sustained 85-knot run. Speed, 3 m hull rise, and roughly 5° running trim are prescribed for this cinematic visualization. They are not calculated from the available thrust. The original 29-knot study remains available above.
Sound on: actual NASA SLS test-fire recording, edited and mixed for the sequence. No music or synthetic engine tone. This is a real rocket recording, not a recording of Blue Origin’s BE-3. Audio source and credit: NASA.
The engine identity and livery reference Blue Origin’s New Shepard. The elongated horizontal fairings, yacht saddles, and installation are artistic adaptations—not stock New Shepard flight hardware or an approved marine design. The cinematic sequence and its speed display are directed animation. The force-model film illustrates the central assumed equilibrium. Neither film solves fluid flow, hull lift, sail loads, or structural feasibility. Analysis controls below recalculate the study without changing the films. Independent concept; no affiliation or endorsement.
THE PROPULSION STUDY
Two engines have a published combined full-power thrust of 980 kN. What that does to a yacht depends on resistance, displacement, and burn duration.
TRANSIENT RESPONSE
Numerical integration of the force balance. The three curves show alternative assumptions—not confidence bounds and not verified attainable speeds.
| Time | Speed | Gain | Propellant used |
|---|
HOW TO READ THE RESULT
Blue Origin lists BE-3PM at 490 kN, burning liquid hydrogen and liquid oxygen. Two engines therefore contribute 980 kN at full throttle—roughly 100 tonnes-force in total. Each mounting system must transfer its own engine’s load into the yacht’s structure.
Mass flow follows thrust divided by specific impulse and standard gravity. The default 360 s is an explicitly assumed sea-level Isp, not a manufacturer specification. At full thrust, 320–400 s implies about 312–250 kg/s of total propellant.
Water resistance grows rapidly. The model assumes a family of resistance curves, holds the original driving force constant, and accounts for propellant mass loss. The central curve is a scenario, not a naval-architecture prediction.
THE PLANING QUESTION
Two BE-3PM engines provide enormous forward thrust. Whether Koru rises onto plane depends on how its underwater hull generates lift and how much resistance accompanies that lift. The speed model above does not solve either one.
A substantial share of the vessel’s weight is carried by dynamic water pressure rather than buoyancy. Bow rise alone is not proof of planing, and exceeding a conventional “hull speed” is not a hard transition into it. Horizontal thrust does not need to exceed the yacht’s weight: the water provides the lift.
Koru’s sailing hull is not established as a prismatic planing hull. Savitsky-style planing calculations need the relevant hull geometry and running trim; applying them directly to this yacht would be unsupported.
As a simple inclined-bottom illustration, pressure drag is Dₚ ≈ L tan(τ). Assume dynamic lift supports 80% of weight at 4° running trim. This is a diagnostic assumption, not a predicted Koru attitude.
Friction, wave-making, and air resistance would consume additional force. Other lift fractions and trim angles change this comparison; passing it would still not prove planing.
The cinematic film now shows the requested rise onto plane and an 85-knot run. Its 18–85 kn progression, 3 m hull rise and roughly 5° trim are prescribed animation curves. The boat really translates through the Blender scene at the displayed visual speed, but those curves are not force- or lift-balanced.
For comparison, select the original full-throttle study: approximately 29 kn under the central assumed resistance curve, with restrained trim. The scientific calculations below retain the same assumptions. Neither view establishes a feasible speed or a planing capability for the real Koru.
REPRODUCIBLE REASONING
T = 2 × 490,000 × (throttle % / 100) N
ṁ = T / (Isp × g₀) kg/s
R(v) = R₀ × (v / v₀)ⁿ N
m(t) = mᵈʳʸ + ṁ(tᵇᵘʳⁿ − t) kg
dv/dt = [T + R₀ − R(v)] / [m(t) + mᵃᵈᵈᵉᵈ] m/s²
The assumed existing sail/propeller driving force equals R₀ and stays constant throughout the burn. Thus it exactly balances drag at the starting speed v₀ = 18 kn. This is a controlled comparison with an unchanged baseline; it is not a sail-performance calculation.
Integration uses fourth-order Runge–Kutta at 0.05 s steps. mᵈʳʸ here means the loaded yacht plus the assumed 20 t dry installation, excluding rocket propellant. Hydrodynamic added mass is assumed to be 10% of that mass. The initial propellant load is exactly what this burn consumes; no reserve or boil-off is modeled.
Friction check, not total drag: with assumed wetted area 1,700 m², waterline 105 m, seawater density 1,025 kg/m³, and kinematic viscosity 1.19 × 10⁻⁶ m²/s, the ITTC-1957 line gives about 117 kN of frictional resistance at 18 kn. The 170 kN default total is an illustrative allowance above that; it is not calibrated against Koru. Wave-making, appendages, air resistance, and hull form remain unmeasured.
Upper-bound check: an ideal rocket-equation estimate, ignoring the extra water resistance and added mass, bounds the speed increase of this particular force-balance model. The calculated trajectories are checked against that bound and the assumed drag-balance equilibrium. Neither bound is an attainable yacht rating.
What the model leaves out: trim and heave, nonlinear wave resistance, sea state, sail loads and apparent-wind changes, structural flexibility, cryogenic tank engineering, changing engine efficiency with throttle, startup/shutdown transients, heat transfer, exhaust impingement on the sea, spray ingestion, and asymmetric engine behavior. Tanks and marine mounts are conceptual. Engine thrust alone does not establish a feasible conversion.
What would establish an actual speed: verified displacement and hull geometry; a measured or validated CFD resistance curve; coupled trim and stability analysis; structural load paths; propulsion integration and plume/water analysis. Without those, a precise top-speed claim would be unsupported.
Blue Origin branding uses the original vector outlines: wordmark artwork and feather artwork. These replace the first film’s recreated lettering and feather.
Sources checked 8 October 2026. All calculated figures are rounded; sensitivity curves are hypothetical scenarios.