# Design and Construction of a Modular Pump-Jet Thruster for Autonomous Surface Vehicle Operations in Extremely Shallow Water

^{1}

^{2}

^{*}

## Abstract

**:**

## 1. Introduction

## 2. PJM Application

#### The Pump-Jet

## 3. PJM Design

#### 3.1. Pump Design

#### 3.1.1. Geometric Data

#### 3.1.2. Propulsion Data

#### 3.1.3. Pump Head

#### 3.1.4. Impeller Design

- Meridian velocities at inlet and outlet
- Impeller outside diameters
- Impeller vane inlet and outlet angles
- Velocity triangles to be drawn for several streamlines (minimum of three streamlines)

- Selection of the inlet and outlet diameter of the pump impeller and the various geometric data
- Meridian flow analysis resulting in the surface of revolution
- Calculation of blade angles from hub to tip based on free vortex theory
- Geometrical transformation of each surface of revolution into a plane with flow angles
- Reverse transformation of cascade geometry and flow data to the back-to-back intersections on the surfaces of revolution

- The vane discharge angle ${\beta}_{2}$ was the most important design element since all theoretical characteristics were determined by the vane angle alone. All design constants depended on ${\beta}_{2}$. This value was fundamental for determining pump design since normal head and capacity increase when ${\beta}_{2}$ increases. This angle should be between 15° and 35° in order not to affect efficiency appreciably.
- ${K}_{u}={u}_{2}/\sqrt{2\phantom{\rule{0.166667em}{0ex}}g\phantom{\rule{0.166667em}{0ex}}{H}_{p}}$ is a speed constant used for calculating impeller diameters when RPM and pump head ${H}_{p}$ are defined as in our case. Smaller pumps require a higher value of ${K}_{u}$ to compensate losses.
- ${D}_{m}^{2}=({D}_{2o}^{2}+{D}_{2i}^{2})/2$ is the mean effective diameter, which, for mixed flow pumps, divides the flow throughout the impeller into two equal parts.
- The capacity constant ${K}_{m2}={c}_{m2}/\sqrt{2\phantom{\rule{0.166667em}{0ex}}g\phantom{\rule{0.166667em}{0ex}}H}$ value is important since it is obtained from experimental data. Differences from these data may lead to leakages and losses.
- Entrance velocity ${c}_{m1}=Q/A1$ is supposed to be the velocity just ahead of the vanes. This depends on ${K}_{m1}={c}_{m1}/\sqrt{2\phantom{\rule{0.166667em}{0ex}}g\phantom{\rule{0.166667em}{0ex}}H}$. Usually, depending on the impeller approach, ${c}_{m1}$ is equal to the velocity through the impeller eye or slightly lower.
- The minimum number of vanes ${z}_{blades}$ required is six for low ${\beta}_{2}$ and large pumps. Smaller impellers and impellers with smaller head require fewer vanes, but for our experiment, we chose three different numbers of vanes: 8, 9, and 10, to lower the slip factor. The number of vanes depends on ${\beta}_{2}$. The lower ${\beta}_{2}$, the lower the number of vanes.

#### 3.1.5. Pump Geometric Parameters

#### 3.1.6. Velocity Triangles

#### 3.1.7. Pump 3D Drawing

#### 3.1.8. Casing Design and Drawing

#### 3.2. Motors’ Layout and Choice

#### 3.3. Hardware Control System and Power Supply

## 4. PJM Construction and 3D Printing

## 5. Experimental Tests and Calibration

#### 5.1. Test Results

#### 5.2. Bollard Pull Tests

#### 5.3. Bollard Pull Tests at Different Steering Angles

## 6. Conclusions and Future Developments

## Author Contributions

## Acknowledgments

## Conflicts of Interest

## Nomenclature

L | Vehicle length (m) |

B | Vehicle breadth (m) |

d | Vehicle draft (m) |

T | Vehicle immersion (m) |

h | Water depth (m) |

$Cb$ | Block coefficient: $\frac{\nabla}{L\ast B\ast d}$ |

g | Gravity acceleration: 9.81 [m/s${}^{2}$] |

${\rho}_{w}$ | Water density: 1025 [kg/m${}^{3}$] |

${\rho}_{air}$ | Air density: 1.226 [kg/m${}^{3}$] |

${D}_{p}$ | Diameter of the PJM (m) |

${D}_{o}$ | Outlet diameter of the impeller (m) |

${h}_{o}$ | Height of the impeller outlet (m) |

${D}_{i}$ | Inlet diameter of the impeller (m) |

${A}_{i}$ | Impeller inlet area (m${}^{2}$) |

${A}_{o}$ | Impeller outlet area (m${}^{2}$) |

${A}_{d}$ | Nozzle discharge area (m${}^{2}$) |

${r}_{i}$ | Impeller radius (m) |

n | Main motor speed (RPM) |

T | pump-jet thrust (N) |

${T}_{\alpha}$ | pump-jet thrust at $\alpha $ angle (N) |

U | ASV speed (m/s) |

${V}_{o}$ | pump-jet jet outlet speed (m/s) |

${V}_{i}$ | pump-jet jet inlet speed (m/s) |

${\alpha}_{out}$ | Outlet angle with respect to the bottom (deg) |

${m}_{f}$ | Mass flow rate of the jet (kg/s) |

${Q}_{o}$ | Volumetric flow rate of the jet (kg/s) |

${h}_{loss}$ | Losses of pump head (m) |

${h}_{man}$ | Losses due to manufacturing imprecision (m) |

${h}_{n}$ | Losses due to nozzle (m) |

${h}_{i}$ | Losses due to intake (m) |

${p}_{i}$ | Inlet pressure (Pa) |

${p}_{o}$ | Outlet pressure (Pa) |

${H}_{p}$ | Pump head (m) |

${N}_{s}$ | Specific pump speed |

${z}_{blades}$ | Number of vanes |

${\beta}_{2}$ | Vane discharge angle (deg) |

${D}_{m}$ | $\sqrt{{D}_{2o}^{2}+{D}_{2i}^{2}}/2$ is the mean effective diameter (m) |

${c}_{m1}$ | Entrance velocity (m/s) |

${D}_{1t}$ | Tip diameter of impeller (m) |

${R}_{1t}$ | Tip radius of impeller (m) |

${D}_{1m}$ | Mean diameter of the blade (m) |

${R}_{1m}$ | Mean radius of the blade (m) |

${D}_{1r}$ | Root diameter (m) |

${D}_{1r}$ | Root radius (m) |

${D}_{2t}$ | Tip diameter at outlet (m) |

${R}_{2t}$ | Tip radius at outlet (m) |

${D}_{2m}$ | Mean diameter at outlet (m) |

${R}_{2m}$ | Mean radius at outlet (m) |

${D}_{2r}$ | Root diameter at outlet (m) |

${D}_{2r}$ | Root radius at outlet(m) |

${l}_{i}$ | Blade height at inlet (m) |

${l}_{o}$ | Blade height at outlet (m) |

${A}_{1m}$ | Inlet area (m${}^{2}$) |

${c}_{m1}$ | Inlet area (m${}^{2}$) |

${w}_{u1m}$ | Tangential resulting velocity at inlet (m/s) |

${c}_{u1}$ | Axial component ad inlet (m/s) |

${u}_{1m}$ | Radial velocity at inlet (m/s) |

${w}_{1m}$ | Resulting velocity at inlet (m/s) |

${A}_{2m}$ | Outlet area (m${}^{2}$) |

${c}_{m2}$ | Meridian velocity at outlet (m/s) |

${u}_{2m}$ | Radial velocity (m/s) |

${c}_{u2m}$ | Tangential component of velocity at outlet (m/s) |

${w}_{u2m}$ | Tangential resulting velocity at outlet (m/s) |

${c}_{2m}$ | Axial component ad outlet (m/s) |

${w}_{2m}$ | Resulting velocity at outlet (m/s) |

${\beta}_{1m}$ | Vane entrance angle (deg) |

${\beta}_{2m}$ | Vane outlet angle (deg) |

${P}_{Pump}$ | Pump power (W) |

$\alpha $ | pump-jet steering actuation angle (deg) |

${\alpha}_{0}$ | pump-jet steering actuation initial angle (deg) |

${\alpha}_{0}^{\prime}$ | pump-jet actual steering actuation initial angle (deg) |

${k}_{u}$ | Speed constant |

${\psi}_{p}$ | $1/2\phantom{\rule{0.166667em}{0ex}}K{u}^{2}$ head coefficient speed constant |

$\sigma $ | Slip factor |

## References

- Mitsch, W.; Gosselink, J. Wetlands; John Wiley & Sons: Hoboken, NJ, USA, 2007. [Google Scholar]
- Janse, J.H.; van Dam, A.A.; Hes, E.M.; de Klein, J.J.; Finlayson, C.M.; Janssen, A.B.; van Wijk, D.; Mooij, W.M.; Verhoeven, J.T. Towards a global model for wetlands ecosystem services. Curr. Opin. Environ. Sustain.
**2019**, 36, 11–19. [Google Scholar] [CrossRef] - Mogstad, A.A.; Johnsen, G.; Ludvigsen, M. Shallow-Water Habitat Mapping using Underwater Hyperspectral Imaging from an Unmanned Surface Vehicle: A Pilot Study. Remote Sens.
**2019**, 11, 685. [Google Scholar] [CrossRef] - Giordano, F.; Mattei, G.; Parente, C.; Peluso, F.; Santamaria, R. Integrating sensors into a marine drone for bathymetric 3D surveys in shallow waters. Sensors
**2016**, 16, 41. [Google Scholar] [CrossRef] [PubMed] - Gawałkiewicz, R.; Madusiok, D. The Bagry Reservoir–part 3. The application of hydro-drone smart-sonar-boat in bathymetric measurements of inaccessible water areas. Geoinformat. Pol.
**2018**, 2018, 17–30. [Google Scholar] [CrossRef] - Bertram, V. Unmanned surface vehicles—A survey. Skibsteknisk Selskab Cph. Den.
**2008**, 1, 1–14. [Google Scholar] - Schiaretti, M.; Chen, L.; Negenborn, R.R. Survey on autonomous surface vessels: Part I-a new detailed definition of autonomy levels. In International Conference on Computational Logistics; Springer: Berlin, Germany, 2017; pp. 219–233. [Google Scholar]
- Schiaretti, M.; Chen, L.; Negenborn, R.R. Survey on autonomous surface vessels: Part II-categorization of 60 prototypes and future applications. In International Conference on Computational Logistics; Springer: Berlin, Germany, 2017; pp. 234–252. [Google Scholar]
- Odetti, A.; Altosole, M.; Caccia, M.; Viviani, M.; Bruzzone, G. Wetlands Monitoring: Hints for Innovative Autonomous Surface Vehicles Design. Technol. Sci. Ships Future
**2018**, 1, 1014–1021. [Google Scholar] - WAM-V Advanced Marine Robotics. 2019. Available online: http://www.wam-v.com/wam-v-technology/ (accessed on 12 July 2019).
- Mu, D.; Wang, G.; Fan, Y.; Zhao, Y. Modeling and identification of podded propulsion unmanned surface vehicle and its course control research. Math. Probl. Eng.
**2017**, 2017. [Google Scholar] [CrossRef] - Martins, A.; Ferreira, H.; Almeida, C.; Silva, H.; Almeida, J.M.; Silva, E. Roaz and roaz ii autonomous surface vehicle design and implementation. In Proceedings of the International Lifesaving Congress 2007, La Coruna, Spain, 30 November–2 December 2007. [Google Scholar]
- Wang, J.; Gu, W.; Zhu, J. Design of an autonomous surface vehicle used for marine environment monitoring. In Proceedings of the 2009 International Conference on Advanced Computer Control, Singapore, 22–24 January 2009; pp. 405–409. [Google Scholar]
- Mariner, The coastal USV System 2016. Available online: https://www.maritimerobotics.com/mariner (accessed on 12 July 2019).
- Frank, D.; Gray, A.; Schwartz, E. Propagator 2: A planing autonomous surface vehicle with azimuth rimdriven thrusters. In Proceedings of the 14th Annual Early Career Technical Conference, Birmingham, AL, USA, 1–2 November 2014; pp. 1–6. [Google Scholar]
- Caccia, M.; Bibuli, M.; Bono, R.; Bruzzone, G.; Bruzzone, G.; Spirandelli, E. Unmanned surface vehicle for coastal and protected waters applications: The Charlie project. Mar. Technol. Soc. J.
**2007**, 41, 62–71. [Google Scholar] [CrossRef] - Duranti, P. CatOne, multitask unmanned surface vessel for hydro-geological and environment surveys. In Engineering Geology for Society and Territory-Volume 3; Springer: Berlin, Germany, 2015; pp. 647–652. [Google Scholar]
- Kebkal, K.; Glushko, I.; Tietz, T.; Bannasch, R.; Kebkal, O.; Komar, M.; Yakovlev, S. Sonobot—Autonomous unmanned surface vehicle for hydrographic surveys with hydroacoustic communication and positioning for underwater acoustic surveillance and monitoring. In Proceedings of the 2nd International Conference and Exhibition on Underwater Acoustics, Rhodes, Greece, 22–27 June 2014. [Google Scholar]
- Zakeri, E.; Farahat, S.; Moezi, S.A.; Zare, A. Robust sliding mode control of a mini unmanned underwater vehicle equipped with a new arrangement of water jet propulsions: Simulation and experimental study. Appl. Ocean Res.
**2016**, 59, 521–542. [Google Scholar] [CrossRef] - Peng, Y.; Yang, Y.; Cui, J.; Li, X.; Pu, H.; Gu, J.; Xie, S.; Luo, J. Development of the USV ‘JingHai-I’and sea trials in the Southern Yellow Sea. Ocean Eng.
**2017**, 131, 186–196. [Google Scholar] [CrossRef] - Machado, D.; Martins, A.; Almeida, J.M.; Ferreira, H.; Amaral, G.; Ferreira, B.; Matos, A.; Silva, E. Water jet based autonomous surface vehicle for coastal waters operations. In Proceedings of the 2014 Oceans, St. John’s, NL, Canada, 14–19 September 2014; pp. 1–8. [Google Scholar] [CrossRef]
- Li, M.; Guo, S.; Hirata, H.; Ishihara, H. Design and performance evaluation of an amphibious spherical robot. Robot. Auton. Syst.
**2015**, 64, 21–34. [Google Scholar] [CrossRef] - Allotta, B.; Costanzi, R.; Ridolfi, A.; Colombo, C.; Bellavia, F.; Fanfani, M.; Pazzaglia, F.; Salvetti, O.; Moroni, D.; Pascali, M.A.; et al. The ARROWS project: Adapting and developing robotics technologies for underwater archaeology. IFAC-PapersOnLine
**2015**, 48, 194–199. [Google Scholar] [CrossRef] - Salumäe, T.; Raag, R.; Rebane, J.; Ernits, A.; Toming, G.; Ratas, M.; Kruusmaa, M. Design principle of a biomimetic underwater robot u-cat. In Proceedings of the 2014 Oceans, St. John’s, NL, Canada, 14–19 September 2014; pp. 1–5. [Google Scholar]
- Eldred, R.A. Autonomous Underwater Vehicle Architecture Synthesis for Shipwreck Interior Exploration; Technical Report; Naval Postgraduate School: Monterey, CA, USA, 2015. [Google Scholar]
- Gill, J.H.W. Maneuvering or Steering of Ships and Other Vessels. U.S. Patent 1,519,580, 16 December 1924. [Google Scholar]
- Veth Propulsion B.V. 2019. Available online: www.vethpropulsion.com/products/bow-thrusters/ (accessed on 12 July 2019).
- Schottel GmbH—SPJ. 2019. Available online: www.schottel.de/marine-propulsion/spj-pump-jet/ (accessed on 12 July 2019).
- Jastram GmbH & Co. KG. 2019. Available online: www.jastram.net/products/azimuth-grid-thrusters.html (accessed on 12 July 2019).
- Tees White Gill. 2019. Available online: www.teesgillthrusters.com/products/vertical-shaft-units (accessed on 12 July 2019).
- Manaois, J. Pumpjets in de Binnenvaart. Master’s Thesis, TU Delft, Civil Engineering and Geosciences, Delft, The Netherlands, 2011. [Google Scholar]
- Wikeckiewicz, W. Hull impact on the performance of the thruster with bottom-mounted outlet nozzle. 14 Sci. J. Marit. Univ. Szczec.
**2008**, 1, 48–52. [Google Scholar] - Kaul, S.; Huth, S. Hydrojet. US Patent 5,520,557, 28 May 1996. [Google Scholar]
- Altosole, M.; Benvenuto, G.; Figari, M.; Campora, U. Dimensionless numerical approaches for the performance prediction of marine water jet propulsion units. Int. J. Rotat. Mach.
**2012**, 2012. [Google Scholar] [CrossRef] - Schottel GmbH—SPJ. Schottel SPJ15RD Technical Data; Schottel GmbH: Spay, France, 2019. [Google Scholar]
- Stepanoff, A. Centrifugal and Axial Flow Pumps: Theory, Design, and Application; Wiley: New York, NY, USA, 1957. [Google Scholar]
- Srivastava, S.; Roy, A.K.; Kumar, K. Design of a mixed flow pump impeller blade and its validation using stress analysis. Procedia Mater. Sci.
**2014**, 6, 417–424. [Google Scholar] [CrossRef] - Srivastava, S.; Roy, A.K.; Kumar, K. Design of a mixed flow pump impeller and its validation using FEM analysis. Procedia Technol.
**2014**, 14, 181–187. [Google Scholar] [CrossRef] - Wiesner, F. A review of slip factors for centrifugal impellers. J. Eng. Power
**1967**, 89, 558–566. [Google Scholar] [CrossRef] - Scibilia, F.; Skjetne, R. Constrained control allocation for vessels with azimuth thrusters. IFAC Proc. Vol.
**2012**, 45, 7–12. [Google Scholar] [CrossRef]

**Figure 12.**Inlet, outlet, and intermediate section meridian triangles for the design of the impeller.

Thrust T | 12.25 | (N) |

Pump Nominal Speed n | 1185 | (RPM) |

Pump Head ${H}_{p}$ | 1.70 | (m) |

Number of Impeller Blades ${z}_{blades}$ | 9 | |

Metric Specific Speed ${N}_{s}$ | 47 | |

US Units Specific Speed ${N}_{{s}_{gpm}}$ | 2430 | |

Speed Constant ${K}_{u}$ | 0.88 | |

Head Coefficient ${\psi}_{p}$ | 0.39 | |

Diameters Ratio $Di/Dm$ | 0.65 | |

Capacity Constant 1 ${K}_{m1}\phantom{\rule{0.166667em}{0ex}}10$ | 3.02 | |

Capacity Constant 2 ${K}_{m2}\phantom{\rule{0.166667em}{0ex}}10$ | 1.22 | |

Vane Entrance Angle ${\beta}_{1m}$ | 39.5 | (deg) |

Vane Outlet Angle ${\beta}_{2m}$ | 21.3 | (deg) |

Parameters | Pump Motor | Azimuth Motor | |
---|---|---|---|

Type | Maxon Ec-4Pole | Faulhaber 2232-BX4 | |

Nominal power | 123 | 13 | (W) |

Nominal voltage | 36 | 24 | (V) |

Nominal speed | 16,700 | 4840 | (RPM) |

Nominal torque (max. cont) | 63.1 | 14.6 | (mNm) |

Nominal current (max. cont) | 3.43 | 0.54 | (mNm) |

Stall torque | 1130 | 61.7 | (mNm) |

Max. efficiency | 89 | 74 | [%] |

Reduction Ratio | 14 | 59 | : 1 |

Max. continuous torque | 2.4 | 9 | (Nm) |

Max. efficiency | 89 | 74 | % |

Total weight | 239 | 140 | (g) |

Nominal reduced speed | 1193 | 82 | (RPM) |

Nominal reduced torque | 883 | 861 | (mNm) |

${\mathit{D}}_{\mathit{p}}$ | ${\mathit{D}}_{\mathit{o}}$ | Configuration | Nozzle Configuration |
---|---|---|---|

110 | 65 | ${z}_{blades=8}$ Small Nozzle Opening | Symmetrical Outlet |

110 | 77 | ${z}_{blades=8}$ Large Nozzle Opening | Symmetrical Outlet |

120 | 77 | ${z}_{blades=8}$ Small Nozzle Opening | Symmetrical Outlet |

120 | 77 | ${z}_{blades=8}$ Large Nozzle Opening | Symmetrical Outlet |

120 | 77 | ${z}_{blades=8}$ Varying Lateral Outlet Opening | Asymmetrical Outlet |

120 | 77 | ${z}_{blades=8}$ Varying Central Outlet Opening | Asymmetrical Outlet |

120 | 77 | ${z}_{blades=8}$ Varying Lateral Outlet Opening | Asymmetrical Outlet |

120 | 77 | ${z}_{blades=8}$ Varying Central Outlet Opening | Asymmetrical Outlet |

120 | 77 | ${z}_{blades=8}$ Varying Central Outlet Opening | Asymmetrical Outlet |

120 | 77 | ${z}_{blades=8}$ with Flow Straightener | Asymmetrical Outlet |

120 | 77 | Varying ${z}_{blades}:8\phantom{\rule{0.166667em}{0ex}},9\phantom{\rule{0.166667em}{0ex}},10$ | Asymmetrical Outlet |

120 | 80 | ${z}_{blades=9}$ | Asymmetrical Outlet |

120 | 80 | ${z}_{blades=9}$ at Various Angles | Asymmetrical Outlet |

Nominal Thrust | (N) | 12.3 |

Nominal Power Consumption | (W) | 95 |

Maximum Thrust | (N) | 14.5 |

Maximum Power Consumption | (W) | 125 |

Steerable Angle | (deg) | 360 Continuous Rotation |

Absolute Position Precision | (deg) | ≤0.01 |

Nominal Draft | (mm) | 100 |

Minimum Draft | (mm) | 35 |

Operating speed | (m/s) | 1.5 |

Diameter | (mm) | 120 |

Height | (mm) | 300 |

Weight | (kg) | 1.9 |

Operating Voltage | (V) | 36–24 |

© 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

## Share and Cite

**MDPI and ACS Style**

Odetti, A.; Altosole, M.; Bruzzone, G.; Caccia, M.; Viviani, M.
Design and Construction of a Modular Pump-Jet Thruster for Autonomous Surface Vehicle Operations in Extremely Shallow Water. *J. Mar. Sci. Eng.* **2019**, *7*, 222.
https://doi.org/10.3390/jmse7070222

**AMA Style**

Odetti A, Altosole M, Bruzzone G, Caccia M, Viviani M.
Design and Construction of a Modular Pump-Jet Thruster for Autonomous Surface Vehicle Operations in Extremely Shallow Water. *Journal of Marine Science and Engineering*. 2019; 7(7):222.
https://doi.org/10.3390/jmse7070222

**Chicago/Turabian Style**

Odetti, Angelo, Marco Altosole, Gabriele Bruzzone, Massimo Caccia, and Michele Viviani.
2019. "Design and Construction of a Modular Pump-Jet Thruster for Autonomous Surface Vehicle Operations in Extremely Shallow Water" *Journal of Marine Science and Engineering* 7, no. 7: 222.
https://doi.org/10.3390/jmse7070222