Page 61: of Maritime Reporter Magazine (February 1999)

MARINE ENGINEERING

Left:

Dominic Cusanelli led the Stern Flap

R&D team.

Bottom:

The David Taylor

Model Basin is the home for some of the world's most advanced maritime model testing. meters, which are optimized through model testing, greatly influence the performance potential. Compromises must be reached between high speed and low speed stern flap performance, the relative importance of which is indicated by the particular ship's speed/time/operations profile.

In terms of propulsion interaction, in gener- al, delivered power reductions averaged a few percent greater than resistance reductions dur- ing all model tests with stern flaps. An exami- nation of model data from the CG 47 and DD 963 experiments showed an improvement in propulsive efficiency on average between 2 to 2.5 percent, and a reduction in wake factor of as much as 1.5 percent at certain speeds.

The increased pressure under the hull, due to the stern flap, can also serve to suppress pro- peller cavitation and reduce thrust breakdown losses at higher speeds.

The stern flap effect, combined with the reduced propeller loading, can provide addition- al powered improvement by way of increased propeller efficiency.

Stern flaps have been retrofit to two O.H.

Perry (FFG 7) class frigates; two Cyclone (PC 1) class patrol coastals; as well as the A.W.

Radford. All ships have experienced improved powering performance and fuel savings, and have reported not adverse impacts due to the stern flaps.

EPA presented the award during the Earth

Technologies Forum in Washington, D.C.

Winners came from eight countries and one international environmental leadership part- nership.

The Carderock Team was headed by

Dominic Cusanelli (pictured) of the

Hydromechanics Directorate, and included

Lowry Hundley, who was in charge of the ship performance trials; Gabor Karafiath, who provided technical direction; and Steven

Chun, who provided technical support. The

Carderock Division provides research, develop- ment, test and evaluation for U.S. Navy ships and submarines. With its unique facilities and advanced computer design, it has become known as the place "Where the Fleet Begins."

W & O SUPPLY INC

BROWNSVILLE • CHARLESTON • FORT LAUDERDALE I MIAMI • HOUSTON • JACKSONVILLE

LONG BEACH • MOBILE • NEW ORLEANS • NEW YORK/LINDEN • NORFOLK

PORTLAND • SAN DIEGO • SAN FRANCISCO • SEATTLE • TAMPA

ANTWERP-VANCOUVER

Serving The

SPECIALIZING IN M

W&O Supply, Inc.

Stocking branches to mei

DIN, & JIS Stani

Valves, Fittinj alloys includi

Blucher-Jaso: steel system pipe hangei^tal approved ir installation systems try Since 1975

NEERED PRODUCTS

Irvice throughout 17

Material to ANSI, stMpeiMKtwntary includes :d PVC in all lete stainless ings, drains,

W&O Supply, Inc. 3485 Evergreen Ave. • Jacksonville, FL 904-355-5604 • Fax 904-355-5542 1-800-962-9696 email: [email protected] -Josam ront Street

Philadelphia, PA 19148

Phone: 215-339-5370

Fax: 800-962-3312 58 Circle 301 on Reader Service Card

Circle 314 on Reader Service Card

LIFE-SAVING EQUIPMENT

VIKING Davit-Lauched Liferaft

Available in 12,16, 20,25 & 35 person capacities

Automatically self-righting liferafts in 25 & 37/39 person capacities

VIKING Marine Evacuation System

Dual track slide features the evacuation of 500 persons in 30 minutes • Most liferafts are U.S.C.G. approved • SOLAS '96 amendments to SOLAS '74 regulations • LSA Code

LVI ICING]

VIKING LIFE-SAVING EQUIPMENT (America) Inc. 1625 N Miami Avenue • Miami FL 33136 Tel (305) 374-5115 Fax (305) 374-1535 http://www.viking-life.com • e-mail: [email protected]