Quiet Auxiliary Propulsion Unit for Combatant Craft

Navy SBIR 22.2 - Topic N222-115
ONR - Office of Naval Research
Opens: May 18, 2022 - Closes: June 15, 2022 (12:00pm est)    [ View Q&A ]

N222-115 TITLE: Quiet Auxiliary Propulsion Unit for Combatant Craft

OUSD (R&E) MODERNIZATION PRIORITY: General Warfighting Requirements (GWR)

TECHNOLOGY AREA(S): Ground / Sea Vehicles

The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), 22 CFR Parts 120-130, which controls the export and import of defense-related material and services, including export of sensitive technical data, or the Export Administration Regulation (EAR), 15 CFR Parts 730-774, which controls dual use items. Offerors must disclose any proposed use of foreign nationals (FNs), their country(ies) of origin, the type of visa or work permit possessed, and the statement of work (SOW) tasks intended for accomplishment by the FN(s) in accordance with the Announcement. Offerors are advised foreign nationals proposed to perform on this topic may be restricted due to the technical data under US Export Control Laws.

OBJECTIVE: Develop a rugged, quiet, transom-mounted, retractable electric propulsion system for high-speed planing craft such as the 11m Rigid Hull Inflatable Boat (RHIB) or Special Operations Craft Riverine (SOCR).

DESCRIPTION: Recent design studies provide operational and technical justification for the performance parameters listed in this Description for the quiet APU. Proposers will be expected to minimize the vibro-acoustic source level of all components of the propulsion system; however, specific (classified) performance parameters will not be provided. ONR will support acoustic testing of an outfitted SOCR under a separate R&D program. The test platform SOCR will be provided by the Government.

The APU system shall provide a minimum thrust at varying speeds as indicated below:

Speed (kts) 3.5 4.0 4.5 5.0 5.5

Thrust (lb) 113 338 553 725 890

The propeller/impeller shall be designed to minimize underwater acoustic noise and eliminate cavitation.

The thruster system must be able to provide reverse thrust (or rotate) sufficiently to provide 2 kts reverse speed.

Thruster, transom mounted with a quiet, automated deployment/retraction mechanism

Steering controls will be provided by the proposer (e.g. via joystick)

Drive motor and controller with drive frequency and primary harmonics greater than 50 kHz.

A portable electrical storage system (ESS) will be provided by the proposer for temporary installation on the target platform for the purpose of all performance trials and should have the capacity to propel the platform at 5.5 kts for approximately 4 hours on a single charge.

The system shall be acceptable for use in various harsh marine environments, and be capable of continuous operation in 0-45C seawater.

The system (retracted) will be capable of handling dynamic shock loads frequently experienced by small craft during operation (6.0-7.0 Gs depending on vessel operation parameters).

The system shall be constructed from materials acceptable and proven for use in marine/offshore applications using galvanically compatible materials to minimize corrosion to ABS standards.

The APU system must be designed to minimize weight and space because deck and transom space as well as weight margins on target platforms are extremely limited.

All seals and bearings will be capable of operating without deleterious effects in bodies of water with high levels of turbidity, silt, and sand.

Work produced in Phase II may become classified. Note: The prospective contractor(s) must be U.S. owned and operated with no foreign influence as defined by DoD 5220.22-M, National Industrial Security Program Operating Manual, unless acceptable mitigating procedures can and have been implemented and approved by the Defense Counterintelligence Security Agency (DCSA). The selected contractor must be able to acquire and maintain a secret level facility and Personnel Security Clearances, in order to perform on advanced phases of this project as set forth by DCSA and ONR in order to gain access to classified information pertaining to the national defense of the United States and its allies; this will be an inherent requirement. The selected company will be required to safeguard classified material IAW DoD 5220.22-M during the advanced phases of this contract.

PHASE I: Demonstrate the capability to design, build, and assess an advanced propulsion system through a parametric study on propulsion efficiency, cavitation performance, materials/weight, and vibration for every component in the drive train from controller to prop. Employ state-of-the-art design and performance analysis tools such as Computational Fluid Dynamics (CFD) tools, FEM, etc. but may also rely on historical performance databases in conjunction with the computational efforts for all components under consideration by the performers. Demonstrate capability through validation of their computational/empirical design and analyses by comparing with well-documented experimental data.

The cost estimate for travel (as detailed in the Navy Instruction for this BAA in under the Cost Volume heading) will be for the Norfolk, VA area. It is estimated that travel to Norfolk, VA will take place at the start of the Phase I award.

Prepare a Phase II plan.

PHASE II: Revise and refine the system designs. Fabricate a proof-of-concept demonstrator (vendor-designed power and drive train) to be installed and tested on either a SOCR or 11mRHIB (proposer choice). (Note: U.S. Navy personnel will participate in these tests so that multiple Phase II systems can be evaluated.) Test for thrust, speed, endurance vs payload, and acoustic trials in protected (SS0) conditions on a test platform provided by ONR during the demonstration period. Acoustic trial data will be classified as they will be performed on Navy platforms.

It is probable that the work under this effort will be classified under Phase II (see Description section for details).

Commercial Impact: It is highly probable that a rugged deployable electric propulsion system would find a strong market in the commercial and sport fishing sectors where current "trolling motors" are cumbersome to attach and deploy, and are easily damaged in harsh physical environments. In addition, for pleasure craft, the additional sea keeping control achievable with auxiliary electric drive would make harbor navigation and docking much safer, and quieter. Many boat makers are already experimenting with related technologies.

PHASE III DUAL USE APPLICATIONS: Further refine, re-fabricate, and demonstrate the system under conditions exceeding those in Phase II. Phase III testing will include higher sea-state performance, vibro/acoustic measurements, and impact/debris testing. If successful, the technology vendor could add their product to the GSA Federal Supply Schedule as Militarized-Off-The-Shelf (MOTS) technology.


  1. https://www.onr.navy.mil/en/Science-Technology/Departments/Code-33/All-Programs/331-advanced-naval-platforms/unmanned-surface-vehicle
  2. https://www.maritimepropulsion.com/news/propulsion/hybrid-drives
  3. SOCR Transom Sketch https://navysbir.com/n22_2/N222-115_REF_3_SOCR_Transom_sketch_2.pdf

KEYWORDS: Electric propulsion; cavitation; vibration; efficiency; motor; controller; acoustic; Rigid Hull Inflatable Boat; 11m RHIB; Special Operations Craft Riverine; SOC-R


The Navy Topic above is an "unofficial" copy from the overall DoD 22.2 SBIR BAA. Please see the official DoD Topic website at rt.cto.mil/rtl-small-business-resources/sbir-sttr/ for any updates.

The DoD issued its 22.2 SBIR BAA pre-release on April 20, 2022, which opens to receive proposals on May 18, 2022, and closes June 15, 2022 (12:00pm est).

Direct Contact with Topic Authors: During the pre-release period (April 20, 2022 thru May 17, 2022) proposing firms have an opportunity to directly contact the Technical Point of Contact (TPOC) to ask technical questions about the specific BAA topic. Once DoD begins accepting proposals on May 18, 2022 no further direct contact between proposers and topic authors is allowed unless the Topic Author is responding to a question submitted during the Pre-release period.

SITIS Q&A System: After the pre-release period, proposers may submit written questions through SITIS (SBIR/STTR Interactive Topic Information System) at www.dodsbirsttr.mil/topics-app/, login and follow instructions. In SITIS, the questioner and respondent remain anonymous but all questions and answers are posted for general viewing.

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Help: If you have general questions about DoD SBIR program, please contact the DoD SBIR Help Desk via email at DoDSBIRSupport@reisystems.com

** TOPIC Q&A **
Questions answered 05/11/22
Q1. Can you provide details of the transom?
A1. Yes, we have made this available as a reference. For the SOCR Transom Sketch please visit - navysbir.com/n22_2/N222-115_REF_3_SOCR_Transom_sketch_2.pdf
This information will be added as Reference 3 for this topic.
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