Peoples Liberation Army Navy (PLAN)

Integration of Bulbous Bow and SONAR DomeDr DS Cusanellis paper

Presented by S Lt AG Nikhil (43424-R)

ScopeIntroductionAimDevelopmentDrawingsReduction in effective PowerReferences

IntroductionDominic S CusanelliNaval Architect at US Navy (NSWCCD)Specializes in methods of Resistance reduction and stern enhancementsPaperDevelopment of a Bow for a Naval Surface Combatant which Combines a Hydrodynamic Bulb and a Sonar Dome (1994)Published in American Society of Naval Engineers, Technical Innovation Symposium

He has patents for contour stern fla, stern flap corrective motion for fuel saving, hydrodynamic and supportive structure for gated ship stern, combined stern wedge-flap, 3

AimReduce total ship resistance (speeds of 14 31 kn)Improve propeller efficiency Improve cavitation performance due to reduced thrust loading on propeller for ships having SONAR domeIncrease cavitation inception speed for Naval destroyer (10 32 kn)

BackgroundBulbous bows generally developed between BL and DWL reduction in resistanceSONAR dome configurations below BLIncreases drag resistance of ship at low and cruise speeds, decreases resistance at maximum speed by 1-2%SONAR dome has lesser effect on wave-making resistance than bulb near WL

BackgroundNaval Destroyer (DDG-51 Flight I Arleigh Burke Class)L:466 ft (142 m)B:60 ft (18.3 m)T:20.688 ft (6.3 m)D:8500 tSD:4.5 ft fwd of FP (AN/SQS-53 SONAR)

a high-power, long-range system evolved from the AN/SQS-26CX, used actively and passively to detect and localize submarine contactsThe AN/SQS-53C is equipped with high source level, fully stabilized beams, and wide convergence zone annuli coupled with computer-aided detection and automatic contact management6

DevelopmentIntegration of a hydrodynamic bulb into an existing bow which houses a SONAR domeEvaluated many alternative bow design conceptsConducted preliminary model tests to assist in sizing and placement of selected bulbReduction of ship resistance by 3-7% at maximum and cruise speed

DevelopmentTear-drop shaped bulbous bow at stem bow between DWL and Baseline in a spaced relationship with SONAR domeRound end pointing in forward directionForward end of bulbous bow extends forward to a point between FP and 12.7 ft fwd of FPUppermost extending point of bulbous bow is located about 1 ft below DWL

Drawings

Drawings

Body Plan of DDG-51 Flight I with an AN/SQS-53C sonar dome

Drawings

A profile view of scaled model with teardrop shaped bulbous bow at 12.7 ft fwd of FP

Drawings

Side view of bow portion similar to Fig 2 with bulbous bow positioned at FP

Drawings

Body plan view of scaled model of Fig 2

PoweringReduction in time averaged effective power over destroyer Speed-time profile by 4 percentEffective power at 20 kn By 6 percent when bulbous bow located at 12.7 ft fwd of FPBy 2 percent when bulbous bow located at FP

Powering

Graph of effective power ratios of the destroyer with a 26 foot longitudinal length bulbous bow at two distinct locations versus baseline hullform of destroyer without bulbous bow

Powering

Graph of residuary resistance coefficient of destroyer with 26-foot long bulbous bow at two distinct locations versus baseline hullform of destroyer without bulbous bow

Powering

Graph of bow wave profiles of destroyer with 26-foot long bulbous bow located at 12.7 feet fwd of FP

ReferencesCusanelli, D.S. Development of a bow for a naval surface combatant which combines a hydrodynamic bulb and a sonar dome. In American Society of Naval Engineers, Technical Innovation Symposium, 1994. pp. 231-47. Cusanelli, D.S. & Karafiath, G. Combined bulbous bow and sonar dome for a vessel. US Patent No. US 5280761, 1994.Sharma, R. & Sha, O.P. Hydrodynamic Design of Integrated Bulbous Bow/Sonar Dome for Naval Ships. In Defence Science Journal, Vol. 55, No. 1, January 2005. pp. 21-36.