▁the ▁sides ▁of ▁the ▁boat . ▁In ▁ 1 8 4 2 , ▁he ▁built ▁the ▁ste amer ▁Nap ol éon ▁in ▁a ▁joint ▁vent ure ▁with ▁ ▁ship builder ▁August in ▁Norm and . ▁However , ▁he ▁was ▁not ▁able ▁to ▁interest ▁the ▁French ▁Navy ▁in ▁his ▁idea ▁and ▁when ▁he ▁tried ▁to ▁develop ▁it ▁commer cially ▁on ▁his ▁own ▁he ▁was ▁not ▁successful , ▁went ▁bank rupt ▁and ▁land ed ▁in ▁deb tor ’ s ▁prison ▁for ▁a ▁time . ▁ ▁Today , ▁the ▁practical ▁development ▁of ▁prop ellers ▁is ▁generally ▁cred ited ▁to ▁Josef ▁Ress el ▁( A ust ria ) ▁who ▁took ▁out ▁pat ents ▁in ▁ 1 8 2 7 , ▁although ▁Sau v age ▁was ▁clearly ▁a ▁pione er . ▁ ▁External ▁links ▁Who ▁invent ed ▁the ▁sc rew ▁prop eller ? ▁▁ 1 8 4 2 . ▁Le ▁Cor se , ▁av iso ▁à ▁hé lice ▁( France ), ▁L ' histoire ▁de ▁la ▁Marine ▁de ▁ 1 7 0 0 ▁à ▁ 1 8 5 0 ▁ ▁Category : 1 7 8 6 ▁birth s ▁Category : 1 8 5 7 ▁death s ▁Category : Pe ople ▁from ▁Bou log ne - sur - Mer ▁Category : F rench ▁engine ers <0x0A> </s> ▁Mer v yn ▁Sh arp ▁is ▁a ▁long ▁distance ▁sw immer ▁from ▁We ym outh , ▁Dor set . ▁His ▁first ▁crossing ▁of ▁the ▁English ▁channel ▁was ▁in ▁ 1 9 6 7 ▁from ▁France - Eng land , ▁he ▁did ▁it