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October 2005 37 effectively utsing both ALS and SWEEP technology at all speeds. There is great advantage to discharg- ing the SWEEP's propulsor water jet into an air cavity rather than underwater. This approach avoids turbulent mixing losses that would occur if the discharge jet(s) was underwater. Yet another advantage of discharging a SWEEP's waterjet propulsor into an air layer is that a steering and reversing system can be positioned at the jet dis- charge that is forward in the hull there- by giving unequaled steering and reversing abilities. This is done with no increase in high-speed drag since the steering and reversing systems do not make water contact during forward high speed operation. What are the potential efficiencies to be gained by a SWEEP? Making a comparison of several 450 ft. (137 m) high-speed ships having Waterline Lengths (LWL) of 400 ft. (122 m) - conventional hulls vis-à-vis SWEEP hulls - indicates significant reductions in powering requirements for the SWEEP hull. These comparisons of 450 ft. (137 m) ships were made based on potential applications of SWEEP to fill high-speed needs Presenting these in terms of propul- sive power required in KW (HP), we have: 137 M 2,500 Ton LCS Vknots 35 Conv. 29,800(40,000) SWEEP 19,090(25,600) 137 M 2,500 Ton LCS Vknots 45 Conv. 49,200(66,000) SWEEP 29,530(39,600) 137 M 3,200 Ton Ferry Vknots 35 Conv. 38,030(51,000) SWEEP 24,300(32,600) 137 M 3,200 Ton Ferry Vknots 45 Conv. 62,640(84,000) SWEEP 37,660(50,500) 137 M 12,000 Ton Freighter Vknots 35 Conv. 141,700(190,000) SWEEP 89,500(120,000) 137 M 12,000 Ton Freighter Vknots 45 Conv. 220,700(296,000) SWEEP 132,700(178,000) The blower power required to main- tain the SWEEP's pressurized air layer is only a few percent of its propulsive power. Adding that blower power to the SWEEP's propulsive power require- ments still shows that the SWEEP has considerable advantage. Studies show that the 122 M (400 Ft.) LWL SWEEP hull, including its air layer blower power, requires only about 63 percent of the power of a similar conventional hull at 35 knots and 60 percent at 45 knots. Artist's renderings of a high speed SWEEP Freighter are presented on the previous page, and the design is consid- ered flexible enough for military opera- tions, such as that of a Military Combatant, such as a DD(X). Note that either forward or aft sloping bows can be utilized and that trimaran arrange- ments, while preferred, are also option- al. The SWEEP technology has been studied and found technologically feasi- ble. Further analysis and model testing is planned as the next step in development. Tests and demonstrations of high speed SWEEP freighters, vehicle ferries, and/or military combatants will then fol- low. About the Author Don Burg is the inventor of the SWEEP technology. In addition to aerospace engineering it includes design and development of the SeaCoaster SECAT (Surface Effect CATamaran) and advanced technology waterjet and ventilated enclosed rotor propulsors. For more information on SWEEP, Circle 4 on Reader Service Card Ü Ü Ü ° ? > V } À i } ? À ? } À ? Õ « ° V ? ? # 8 + ' 5 & ' 2 ' 0 & 1 0 % 4 + 6 + % # . ' 3 7 + 2 / ' 0 6 # 8 # + . # $ + . + 6 ; ' P S P W F S Z F B S T O B W B M O F X C V J M E J O H T D P O W F S T J P O T B O E N P E F S O J [ B U J P O T I B W F S F M J F E P O . B D ( 3 & ( 0 3 µ T F Y Q F S J F O D F J O Q S P W J E J O H S F M J B C M F D B S H P N P W J O H T Z T U F N T % F Q F O E B C M F D B S H P G M P X J T D S J U J D B M U P B M P H J T U J D T T I J Q µ T N J T T J P O . B D ( 3 & ( 0 3 I B T E F M J W F S F E Q S P K F D U T G P S O B W J F T J O D M V E J O H U I F 6 4 / B W Z . 4 $ B O E . " 3 " % B O E J T I F M Q J O H E F W F M P Q T P M V U J P O T U P U I F 4 F B # B T J O H K P J O U T U S J L F G P S D F / F X G P S O B W B M B O E D P N N F S D J B M T I J Q T J T U I F H M P C B M . B D ( 3 & ( 0 3 0 O C P B S E $ B S F . 0 $ Q S P H S B N N F X I J D I N B Y J N J [ F T D B S H P T Z T U F N S F M J B C J M J U Z 1 M F B T F W J T J U V T B U U I F 4 / " . & " O O V B M . F F U J O H & Y Q P T J U J P O # P P U I P O 0 D U P C F S > V , " , Ê ? > ? i Ã Ê ? Ì Ê « ? à à ? L i Circle 252 on Reader Service Card Marine Design MR OCTOBER 2005 #5 (33-40).qxd 9/29/2005 5:20 PM Page 37
