Resistance, running attitude, wave pattern, propeller and stability of the hull you are drawing, across the whole speed range, in seconds.
Select the hull, give the loading and the speeds, and run. Every speed is solved for its own trim and sinkage.
QuickWake against the towing tank (Begović & Bertorello, 2012), at its free running attitude.
| V (m/s) | Fn | QuickWake (N) | Tank (N) |
|---|---|---|---|
| 1.15 | 0.27 | 7.8 | 6.9 |
| 1.72 | 0.40 | 14.9 | 18.3 |
| 2.30 | 0.53 | 30.3 | 31.3 |
| 2.80 | 0.65 | 35.3 | 34.9 |
| 3.40 | 0.79 | 40.2 | 38.8 |
| 4.00 | 0.93 | 45.5 | 42.7 |
| 4.60 | 1.07 | 48.8 | 46.5 |
| 5.10 | 1.18 | 49.7 | 48.3 |
| 5.75 | 1.33 | 50.8 | 52.0 |
| 6.32 | 1.46 | 52.5 | 56.2 |
| 6.89 | 1.60 | 55.4 | 61.3 |
| 7.46 | 1.73 | 59.4 | 65.6 |
Total resistance at every speed, divided into friction, wave and the smaller terms, with the effective power. Displacement and planing hulls, and the transition between them, are handled by one method.
Load your own towing-tank results and they are drawn on every plot beside the prediction.
Fig. 2. A planing hull from 2 to 6 m/s and back: running trim and sinkage against the calm waterline, with the centres of gravity and buoyancy.
QuickWake balances the weight between buoyancy and dynamic lift at each speed and finds the trim and sinkage the hull settles at. Select a speed and the hull is shown in the viewport as it runs.
Fig. 3. The Kelvin wave pattern of the KCS model in plan over the same speeds, recoloured by wave height on one scale as in Plate I: the waves lengthen with speed, the wedge keeps its angle.
The free surface around the hull at the selected speed, coloured by wave height and meeting the hull along its own wave profile. Draw the waves at true scale or exaggerated; add the surface to the document as geometry.
Fig. 4. A catamaran of two NPL 4a demihulls 0.4 L apart, centre to centre, from a Froude number of 0.30 to 0.70 and back: the two demihulls' waves added, recoloured on one scale for this page.
Give one demihull and the spacing, or model both hulls. QuickWake adds the two demihulls' wave systems, so the viewport shows the waves between the hulls and their interference behind the boat, with the streamlines and the pressure coefficient on both sides of each hull.
The two fields are added without reflection between the hulls, and the running attitude is one demihull's: treat the inner side as indicative.
Fig. 5. The flow along the wetted hull of the KCS. Above, marks animated for this page run along QuickWake's streamlines at the local flow speed: rust where the water moves faster than the ship, blue where it moves slower. Below, QuickWake's pressure coefficient of the same flow: blue where the flow is faster and the pressure falls, red where it is slower. The colours end at ±0.25; on the hull Cp runs from −0.17 to +1.00.
Streamlines traced over the wetted surface show where the flow speeds up and slows down along the body, bilge and stern, and the pressure coefficient Cp of the same flow colours the wetted hull. Both come from the linear model and illustrate it; they are not a measured flow or pressure field.
The pressure coefficient is provisional while one term of the solver is under review: faces that point forward or aft, such as a bulb, read the oncoming stream itself and show red whatever the flow, and at the waterline the colours understate the wave pressure.
Fig. 6. The planing hull of Fig. 2 heeled from upright and back, and its Stability tab in the panel: the curve at rest in grey, the curve at the selected speed in blue. The model is small and the code criteria are absolute, written for full-size craft, so some read as not met; QuickWake shows them for reference.
The GZ curve at rest, and at any solved speed with the running trim and the share of the weight the dynamic lift carries. At rest, the hull as modelled floats freely at each heel, with the downflooding angle from the openings you pick, and the curve is set against selected GZ criteria of the IMO Intact Stability Code or the HSC Code for monohulls or multihulls, or your own limits: a reference check, not a complete stability assessment. Hover over the curve to see the hull heeled.
At speed, the hull is held at its running trim and floats on the part of its weight the water still carries; the dynamic lift carries the rest. On a planing hull this shows how the stability falls away as the lift takes over. The lift's own rolling moment is not modelled, so the curve is hydrostatic, not a dynamic roll-stability assessment.
Fig. 7. The KCS at full scale and 24 knots, at a shaft speed of 104 rpm: one B-series design per blade count, and the recommended propeller with its hull–propeller factors, powers and cavitation check. The full-scale resistance comes from the same method, beyond the model-test range it has been compared with.
For the selected speed, QuickWake recommends a Wageningen B-series propeller. Fix the shaft rpm and it finds the diameter; give the largest diameter the aperture takes and it finds the rpm; or enter a propeller you already have and it checks it.
Each blade count gets its own design, with pitch, the blade area cavitation calls for, open-water efficiency and the delivered and brake power. Run the chosen propeller over the whole sweep to see its rpm and power at every speed.
Each hull of the library at full scale, free to trim and sink at its speed, with the B-series propeller QuickWake recommends for it, turning at a tenth of its shaft speed.
KCS container ship
LWL 232 m · 24 kn · single screw
Diameter at the limit given: a larger propeller would need less power.
| Hull | LWL m | V kn | Fn | RT kN | Screws | Z | D m | P/D | AE/A0 | Keller min | rpm | J | η₀ | w | t | ηR | w, t, ηR from | PD kW | PB kW | σ at 0.7 R | Rn at 0.75 R, millions | Flags |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| KCS container ship | 232.5 | 24.0 | 0.259 | 1559.6 | 1 | 4 | 7.90 | 0.966 | 0.66 | 0.66 | 104 | 0.709 | 0.705 | 0.214 | 0.181 | 1.008 | Holtrop (1984), single screw | 25 992 | 26 522 | 0.32 | 76.5 | at the diameter limit |
| DTMB 5415 combatant | 141.5 | 30.0 | 0.414 | 1951.9 | 2 | 5 | 5.20 | 1.105 | 0.87 | 0.87 | 187 | 0.895 | 0.759 | 0.058 | 0.075 | 0.975 | Holtrop & Mennen (1982), twin screw | 41 457 | 42 740 | 0.19 | 64.6 | cavitation number at 0.7 R below 0.25: cavitation is likely to cut the thrust, so the non-cavitating series data are optimistic (a cavitating or surface-piercing propeller may suit better); at the diameter limit |
| Tanker | 329.5 | 16.5 | 0.149 | 1794.7 | 1 | 3 * | 9.90 | 0.697 | 0.42 | 0.42 | 76 | 0.419 | 0.591 | 0.381 | 0.216 | 1.018 | Holtrop (1984), single screw | 20 009 | 20 628 | 0.57 | 73.3 | No wave resistance from the solver at this Froude number: the propeller is sized on friction and form drag; at the diameter limit |
| Series 60 CB 0.60 cargo ship | 122.2 | 18.0 | 0.268 | 319.4 | 1 | 4 | 4.90 | 1.125 | 0.49 | 0.49 | 110 | 0.807 | 0.695 | 0.217 | 0.171 | 1.010 | Holtrop (1984), single screw | 3 983 | 4 106 | 0.61 | 23.5 | at the diameter limit |
| Begović fast boat | 12.0 | 35.0 | 1.660 | 14.6 | 2 | 4 | 0.48 | 1.114 | 1.00 | 1.00 | 2 300 | 0.942 | 0.697 | 0.028 | 0.080 | 1.000 | Blount & Fox (1976), planing craft (twin-screw data) | 438 | 452 | 0.10 | 10.0 | cavitation number at 0.7 R below 0.25: cavitation is likely to cut the thrust, so the non-cavitating series data are optimistic (a cavitating or surface-piercing propeller may suit better); blade area at the series' largest for this blade count: cavitation (Keller), not efficiency, sets the diameter; speed outside Blount & Fox's Fr∇ 1-4: their end values are used |
| Sysser 62 yacht, auxiliary | 10.0 | 6.5 | 0.338 | 0.6 | 1 | 2 * | 0.32 | 0.648 | 0.31 | 0.31 | 1 400 | 0.435 | 0.649 | 0.029 | 0.100 | 0.980 | Holtrop & Mennen (1982), open stern | 3 | 3 | 0.73 | 1.5 | blade Reynolds number below 2·10⁶: model-scale open-water data, uncorrected |
* B4–B7 outline: the series' two- and three-blade outlines are not reproduced here, so these are drawn with the four- to seven-blade one. Hull–propeller factors w, t and ηR are statistical estimates; every hull is a full-scale extrapolation of a model-scale comparison.
Boat speed against true wind angle as the wind rises from 6 to 20 knots and eases again.
| TWA | 6 kn | 8 kn | 10 kn | 12 kn | 14 kn | 16 kn | 20 kn |
|---|---|---|---|---|---|---|---|
| 30° | 3.31 | 4.22 | 4.89 | 5.23 | 5.37 | 5.39 | 5.02 |
| 35° | 4.00 | 5.00 | 5.68 | 6.06 | 6.25 | 6.33 | 6.22 |
| 40° | 4.51 | 5.54 | 6.28 | 6.68 | 6.86 | 6.95 | 6.94 |
| 45° | 4.91 | 5.96 | 6.71 | 7.09 | 7.27 | 7.37 | 7.41 |
| 50° | 5.21 | 6.30 | 7.00 | 7.38 | 7.58 | 7.70 | 7.77 |
| 52° | 5.31 | 6.41 | 7.09 | 7.48 | 7.69 | 7.80 | 7.89 |
| 55° | 5.43 | 6.54 | 7.20 | 7.60 | 7.83 | 7.94 | 8.04 |
| 60° | 5.58 | 6.70 | 7.33 | 7.75 | 8.00 | 8.13 | 8.26 |
| 65° | 5.69 | 6.79 | 7.42 | 7.85 | 8.12 | 8.29 | 8.47 |
| 70° | 5.74 | 6.84 | 7.47 | 7.92 | 8.22 | 8.44 | 8.70 |
| 75° | 5.75 | 6.85 | 7.50 | 7.97 | 8.31 | 8.59 | 8.93 |
| 80° | 5.72 | 6.85 | 7.52 | 8.02 | 8.40 | 8.73 | 9.18 |
| 85° | 5.67 | 6.82 | 7.53 | 8.05 | 8.46 | 8.83 | 9.39 |
| 90° | 5.60 | 6.78 | 7.52 | 8.04 | 8.45 | 8.85 | 9.53 |
| 95° | 5.53 | 6.73 | 7.44 | 8.00 s | 8.45 s | 8.84 s | 9.60 |
| 100° | 5.43 | 6.60 | 7.44 s | 8.06 s | 8.54 s | 8.99 s | 9.73 s |
| 105° | 5.27 s | 6.57 s | 7.44 s | 8.07 s | 8.59 s | 9.08 s | 9.98 s |
| 110° | 5.24 s | 6.52 s | 7.40 s | 8.05 s | 8.58 s | 9.12 s | 10.18 s |
| 115° | 5.16 s | 6.43 s | 7.33 s | 7.99 s | 8.54 s | 9.11 s | 10.31 s |
| 120° | 5.04 s | 6.28 s | 7.21 s | 7.90 s | 8.46 s | 9.04 s | 10.33 s |
| 125° | 4.88 s | 6.10 s | 7.08 s | 7.78 s | 8.35 s | 8.93 s | 10.25 s |
| 130° | 4.69 s | 5.90 s | 6.92 s | 7.63 s | 8.21 s | 8.78 s | 10.07 s |
| 135° | 4.48 s | 5.67 s | 6.72 s | 7.46 s | 8.06 s | 8.60 s | 9.84 s |
| 140° | 4.26 s | 5.44 s | 6.49 s | 7.27 s | 7.90 s | 8.42 s | 9.57 s |
| 145° | 4.03 s | 5.20 s | 6.22 s | 7.06 s | 7.71 s | 8.24 s | 9.32 s |
| 150° | 3.81 s | 4.95 s | 5.95 s | 6.84 s | 7.49 s | 8.05 s | 9.08 s |
| 155° | 3.60 s | 4.71 s | 5.68 s | 6.58 s | 7.28 s | 7.86 s | 8.85 s |
| 160° | 3.41 s | 4.48 s | 5.44 s | 6.33 s | 7.07 s | 7.66 s | 8.65 s |
| 165° | 3.25 s | 4.29 s | 5.23 s | 6.10 s | 6.88 s | 7.48 s | 8.46 s |
| 170° | 3.13 s | 4.13 s | 5.06 s | 5.90 s | 6.69 s | 7.32 s | 8.31 s |
| 175° | 3.04 s | 4.01 s | 4.93 s | 5.77 s | 6.56 s | 7.20 s | 8.21 s |
| 180° | 3.00 s | 3.97 s | 4.88 s | 5.71 s | 6.50 s | 7.15 s | 8.16 s |
Fig. 9. The sail VPP for a yacht with a 10 m waterline (the Delft series' Sysser 62 canoe body), with the Delft series hull resistance. The polar follows the true wind between the solved wind speeds, drawn faint; the rings mark the best upwind and downwind angles.
Give a heel angle and QuickWake floats the hull at it, free to sink and trim, and predicts its heeled resistance; the viewport shows the hull heeled at its running attitude, with the waves of its equivalent symmetric hull around it. For yacht canoe bodies inside the range of the Delft Systematic Yacht Hull Series, the series' heel regression is shown alongside.
The Sailing tab turns this into a speed polar: an ORC-style rig with main, jib, spinnaker or gennaker, the keel and rudder, crew on the rail and the hull's own righting moment, with the sails flattened and reefed as the wind rises. Hull resistance comes from QuickWake or from the Delft series. The heel method and the sail polar are new, and are not yet validated against tank data.
Fig. 10. The results panel. The header names the hull and its run; the note at the top right is QuickWake's own mesh check, which warns when a hull mesh does not close into one piece. The speed table stays in view above the selected speed, its stability, its propeller and the viewport display.
A panel beside the viewport: polysurface, SubD or mesh, full hull or one half. Choose the hull and QuickWake checks it at once, with its hydrostatics and any mesh notes on the Setup tab, before a single speed is run.
Results appear speed by speed as they are solved, in a table or a plot that stays in view while you look through the selected speed, its stability, its propeller and the viewport display; the header keeps the hull, its notes and whether the results still match the inputs. Everything exports to CSV.
| Platform | Rhino 8.20 or later on Windows |
|---|---|
| Hull input | Polysurface, surface, SubD or mesh; full hull (symmetric port and starboard) or one half; catamarans as one demihull or both |
| Hull types | Displacement and planing monohulls; catamarans, with indicative results (less validated; the two hulls' waves added, no hull interaction in the attitude); sailing yachts |
| Results per speed | Total resistance and its parts, effective power, running trim and sinkage (the heave of the centre of gravity), buoyancy and dynamic lift |
| In the viewport | Running attitude, centres of gravity and buoyancy, dynamic lift; the free surface, streamlines and the pressure coefficient on the wetted hull (provisional), for monohulls and catamarans; at a heel, the free surface of the equivalent symmetric hull |
| Propeller | Wageningen B-series design for a fixed rpm or a diameter limit, or a given propeller checked over the sweep; estimated hull–propeller factors; Keller's blade-area criterion for cavitation |
| Heel | Imposed heel up to 45° on displacement monohulls, free sinkage and trim, by an equivalent symmetric hull; the Delft series heel regression alongside for yacht canoe bodies |
| Sailing | Speed polar of a displacement monohull against true wind angle for several wind speeds: ORC sail coefficients, main and jib, symmetric spinnaker and gennaker, flattening and reefing, Delft series keel and rudder, crew righting moment, best upwind and downwind angles; CSV export |
| Stability | GZ curve at rest with free sinkage and trim, and at any solved speed with its running trim and the dynamic lift's share of the weight (hydrostatic); downflooding angle; selected GZ criteria of the IMO IS Code 2008 or the HSC Code 2000, or custom criteria, for reference at rest |
| Output | CSV of every speed; flow geometry added to the document |
| Method | Michell thin-ship theory with closures for friction, form, transom flow, planing lift and spray |
QuickWake predicts the bare hull in calm water and has been compared with model-scale towing-tank tests. It is a tool for the design stage, not a substitute for model tests or CFD for final figures.
QuickWake comes out of ship-hydrodynamics research at the University of Split. The method is set out in these papers.
The thin-ship wave-resistance method QuickWake builds on, with corrections for the boundary layer and the far-field waves.
A study of where linear thin-ship theory holds for slender hulls and where fuller forms need more than it can give.
The method QuickWake uses to carry one prediction of resistance, trim and sinkage from displacement speeds through the hump into planing.
Write to us with a line about your work, and we will reply with the licence options and a demonstration.
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