N112-157 TITLE: Non-Abrasive Propeller Cleaning System (NAPCS)

TECHNOLOGY AREAS: Ground/Sea Vehicles, Materials/Processes

ACQUISITION PROGRAM: NAVSEA 00C

OBJECTIVE: Develop a diver-operated, non-abrasive propeller cleaning system (NAPCS) to remove propeller fouling with improved cleaning effectiveness, blade coverage, through reduced cleaning time, and risk of blade surface and edge damage.

DESCRIPTION: Fouling on the propeller causes a significant increase in fuel consumption, cavitation, and propeller noise. Fouling rates vary depending on the ship�s operational profile, geographical area, and environmental conditions. Current Navy practice prescribes interim inspection and cleaning of the propellers at regular intervals (typically every 3 months). During this period, fouling accumulation can generate a 3-6% increase in power requirements, penalizing fuel consumption. If neglected, the development of hard fouling and calcareous growth can double the required power. Divers currently use a combination of hand pads brushes, scrapers, cleaning discs, and waterjet guns to clean propeller surfaces and restore a smooth blade surface (Rubert Scale B or better). Special care must be taken to select the least abrasive tool for cleaning so as not to damage the underlying surface, coatings, or thinner sections for the propeller. Due to the high risk of potential damage to blade edges, power tool cleaning is restricted. Divers currently have to manually hand clean the outer 3 inch periphery on each side of the propeller blade edges and tips. This can often increase the propeller cleaning labor by 15 to 20 hours per propeller.

This SBIR seeks to develop a non-abrasive, diver operated, propeller cleaning system to improve cleaning efficiency and reduce the risk of damage to the propeller surfaces. The current process can take 2-3 days to clean a submarine propeller. The objective of this SBIR is to shorten this period by 50%. The required capabilities of the NAPCS include:
� Removal of soft fouling, hard fouling, and calcareous deposits from the propeller surface without damaging the underlying nickel-aluminum-bronze (NAB) surface.
� Accommodate complex propeller geometry.
� Preserve surface uniformity and smoothness (Rubert Scale B or better).
� Ergonomic, to minimize diver fatigue due to reaction forces, noise, or vibration.
� Minimize equipment size and weight to facilitate transportability and provide ease of use (not to exceed 60 cu.ft. and 6000 pounds).

PHASE I: Develop an overall NAPCS concept design and evaluate the feasibility of various cleaning technologies. Determine parameters governing the effectiveness of the selected cleaning method without damaging blade surfaces. Demonstrate cleaning effectiveness through analysis, simulation and lab testing as appropriate. Option: subject several NAB (alloy will be specified) test coupons to accelerated fouling growth and deposition for Phase II testing.

PHASE II: Based on the Phase I development, refine the design and fabricate a breadboard NAPCS prototype. Demonstrate effectiveness in removing fouling and quantitatively assess the impact on the substrate through in-water testing on NAB test coupons. Study fouling regrowth characteristics (degree, rate) after cleaning with the NAPCS and compare against the regrowth after employing the conventional methods of machine and hand cleaning. Deliver a handheld prototype to conduct a field trial on a government furnished fouled NAB propeller blade. The emphasis of this demonstration shall be to validate the NAPCS non-destructive capabilities, ergonomics, and maneuverability under operation by divers.

PHASE III: Deliver system prototype NAPCS to pier and satisfactorily perform pier side acceptance testing on a full-scale ship propeller. Develop procedures consistent with the Naval Ships� Technical Manual for NAPCS operations. Develop final NAPCS packaging, manuals, and fabrication drawings to NAVSEA 00C. Transition NAPCS to NAVSEA 00C for incorporating technology into NSTM and contract specification for government contracted cleaning services.

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: Propeller fouling and its penalties to fuel consumption, maintenance, noise, and vibration impact both commercial and Naval ships of all classes. The advantages of this technology would provide equal benefit to divers of commercial ship husbandry operations.

REFERENCES:
1. Naval Sea Systems Command, "Waterborne Underwater Hull Cleaning of Navy Ships," Ch081 of the Naval Ships� Technical Manual, S9086-CQ-STM-010 Rev 5, 01 Oct 2006.

2. Hundley, L. L., "Ship Performance Self-Assessment, a Method to Improve the Cost Effectiveness of the U.S. Navy Hull and Propeller Maintenance Program," CRDKNSWC/HD-1481-01, Sep 1998.

3. Jessup, S. D., "Prediction of Power Losses Due to Propeller Roughness," CRDKNSWC/HD1269-03, Feb 1998.

4. Hundley, L. L. and C. W. Tate Sr. "Hull-fouling studies and ship powering trial results on seven FF 1052 Class Ships," DTNSRDC 80-027, March 1980.

5. Townsin, R. L., Spencer, D. S., Mosaad, M., and G. Patience, "Rough Propeller Penalties," SNAME Transactions, Vol. 93, pp. 165-187, 1985.

6. Grigson, C. W. B, "Propeller Roughness, Its Nature and Its Effect upon the Drag Coefficient of Blades and Ship Power," Transactions of the Royal Institute of Naval Architects, 1982.

7. Mosaad, M., "Marine Propeller Roughness Penalties," PhD Thesis, University of Newcastle upon Tyne, 1986.

8. Preiser H. S., Colger, C. P., and H. E. Achilles, "Energy (Fuel) Conservation through underwater removal and control of fouling on hulls of Navy Ships," NSRDC Report 4543 Dec 1975.

9. Black, S.D. and S. Swithenbank, "Propeller Bio-Fouling and its Effect on Ship Fuel Consumption: A Study of the DDG 51 Class," NSWCCD-50-TR-2010/49, Jul 2010.

10. Naval Sea Systems Command, "PROPELLERS AND PROPULSORS", Ch245, Naval Ships� Technical Manual, S9086-HP-STM-010

KEYWORDS: Propeller Cleaning, Fouling Removal, Ship husbandry

** TOPIC AUTHOR (TPOC) **

DoD Notice:   Between April 26 and May 25, 2011, you may talk directly with the Topic Authors to ask technical questions about the topics. Their contact information is listed above. For reasons of competitive fairness, direct communication between proposers and topic authors is not allowed starting May 26, 2011, when DoD begins accepting proposals for this solicitation.

However, proposers may still submit written questions about solicitation topics through the DoD's SBIR/STTR Interactive Topic Information System (SITIS), in which the questioner and respondent remain anonymous and all questions and answers are posted electronically for general viewing until the solicitation closes. All proposers are advised to monitor SITIS (11.2 Q&A) during the solicitation period for questions and answers, and other significant information, relevant to the SBIR 11.2 topic under which they are proposing.

If you have general questions about DoD SBIR program, please contact the DoD SBIR Help Desk at (866) 724-7457 or email weblink.