827,859 .on 21 just aft of the propeller. this;tunnel is opeii a,t the side towards the ivatei@. In any case whether the tunnel aft of the propeller is rectaii,atilar in cross-section, eirculdr, ellipt-ical, entire,ly closed on its sides or open a:t oine side, the fins are to be applied to the diverging walls of the rear end. of the u -he,@' @pelle@. t nnet@aft 6.f t@ In general wherever the Dropeller race fol 0 ows a hull siirface which is at such 6.,@kle to the axis of tl@e -rae-e, @ a.@,i-t -le:ives the -propeller@ t-hat an increase c,f pressure w6tild result.in an iiierease of forw,,ird thrust upon th6 h-dlll the installation of fins will produce an. in_ 15 crease of press-Lire upoti the h-Lil-1, the install,,i@.tion,@ of fins -,to prodiiee, @an increase. Qf pressiire @ upoii @ the t hull stitface by cheekiiao,, the rotation,i,i,i tl,- e@,race will be@,,tdvantage@iis: This loc,,tl@@ip-crease@ Of presstir6 wiII7; also @20 catise,--.tlie race@to h-Lig the@sLIrf,,tce b@-,tter and it @is: this! inclirect, aciion 6f the fins wl-iibh is particularly helpftil tuniiels. beit-the,@ivaterinore@nearly rnail,.itains the -Dref@sLite itblocitv relations Of@,a -fluid, a:nd. ect: the cheekir@ e sternperl @g of:@ th wtrd, vel-ocity@a@@tl-,e tunnel expands res-LtJts in the: 6f@:a useftil,for-ward tlirlist. Lo the fins may be @-of uniform wid @Fins@-in a circ'ular diverging @@@30 tnnnel- ihave,'Iittle to g-,tin,by, va-rying,@width, j@,,@T9. se e,, . ii @ Ly btit@- tho on, ih - sides o,f @ a@. t-Linnel@ @ of app.r oxiniataly:,Ir(,etangular setti6n)@,wayl-be ,wid @to ardtlieir@@afte - d enecl W r en g, with -a:dvan tage. al@,tuiii@el the combination@.with a tiini-iel diverging at its rear end.. andi, a pr@op,eller in th6 tLin@nel,- 6f moans in.,said dii@erging, end fto @ simultaneously - cheok - race, rota40' prci @duce a forwarclly 'propell'i iig ccmpol@ent on tt. w is@zof sai-d te divergingc ql th.e combinationi"W,Ith@a,; 't-Lmnel divergin@, 'it! its,@rear,eT-id,,and,a.ptopeller 3n the @@tlii@nel; @of .,means pr.oje@tito, .froni the@Id@ve@r.-g-i-iig iwalls Of !Sa'ld@%tuu-iiel@,to cheeki@ rqce,@ ratation,@. an-d. simiAlta;ne,Ous.1y, pro,@@du@ce ' a@-forwardly, propejhno-, force. on'@the diverging .,waJIs- of 1 said, rear- ei@d @.qft@. of .@ the @,pro,p.eller., 3.1 In,,4 tlinuel @boat,, th&, comWn,,ttiQia w,,ith tvtn-nel a,,nd-@. a@p.-ro,pol@ler therein,, said tuniiei dive,,ging, . fi:om@ the. p,roppllerposition @to! its reai,- ,&iAd,'of,fins projeeltin-, frorn the@@divor 9- -ing .,w, tlls, @of , sald raee.@ 4. @ 1-n:-.a.- ttinnet boat, the,.,coni@IDination @with and a, p,ro@peller@therein, di-N,erging from the propel lerlposit,ion@t6,,it-S rear E@nd;,of -fius projecting from the --diverginul,wq.@ll@;Of@.-said.race,'inereasim in@wldth t' I 9 f rom.,, ihe, propeller@@ppsi,@icn to. the@ rear. end of the tunnel. a, t-Lu-inel@ rboatz having @a tunnel7 @ubc@oss section.@,aiid de closed@@on its four, si s @@a prc,,p,@ller@@in@ tl@e tunnel, saicl tunnel havin g its tw6 sicles cliverging; of fins on the diverging sides extendin(y from the propeller Dosition aft that increase in width. In testimony that I clalim the fore@yoing as iriy invention, I have signed my name. DAVID@. W. TA-YLOR. 7 @ I @ I

Patented Oct. 20, 1931 : 1 , 8 2 7 , 8 5 9 UNITED STATES PATENT'OFFICE@ DAVID W. TAYLOR, OF WASHINGTON, DISTRICTor@ coLumi3IA TUNNEL 330AT Applicati on filed April 11 1930. Serial No. 443,399. In the screw propulsion of vessels, the wa@- F i 5 is a, l@orizontal section @Of- a tunfiel, te in the propeller race behind the screw lias forni @d - by a depi-e@sion in the @ side:: of a, vesa sternward and a rotary motion. @ For most - sel qnd- open-@'tf th6 @ide of tho tunn' 61.@ vessels the propel a -f ler r ce is C16ar of the hull. Fi(@ 6 is an elev@ci6n.thereo -hero,y that i Fi- 7 - b A-ny sttucture built to regain s g. is A section on iiie of Fig. 5 i,isuallv carried off in the race m-List be fitted F i g s . 8 , 9 a n a l 0 s h 6 w @ s e c t i o n - s 6 f , d i : f f e ' r e n ' t f o r s o f f i n s o r r i s . within the race.', There are ho-,@,ever some m b Roferring vessels which give an opportlinity to utilize to Fia@ire@ 1-3, the stern., over the nlomentiim of the race by striietures han--- oi ti@e hul-I is'@2-m@ dicatpd at 11 and it car-.., 10 around it. This is notably@ the case in tun- ries t@e tiinnel -12 @ubsiaiit.ia@ll@ @-r6@tangular"'160 nel boats. .@incros-s-s6i2tion,,openatits@f@ontend;andhas In mv a plication, Serial No. 364 494 filed -.'prefer@bly a eir6ular porfion 13 in -vvhich the p A,Iay 20, 1929, I have @utilizecl the diverging rear end of the ttinnel of a tunnel boat,.on 15 the (liverging sid6s of -which I d6vellop a forwardly propellin(r force compop-ent by first stoppiilg the rotation of the race in a@ non-, diverging portion thereof, and ther,e developing this component by special means in the 20 diveroing porti6n of the tunnel after the race leaves the n-ieans for stopping the rotation. My pi-esent invention is to deveio-p this for-wardly propelling@ pressure or component froni the race on the diverging surfaces or 25 walls 6f the rear end of the tunnel by iheans wholly within th6 divergeiit portion of the rear end of the tunnel and that simultaneously stops iotation of the@ race and develops the forwardly propelling pressure therefrom. 30 For this pi@rpose I preferably use fins or ribs fitted on the di.verginsurfaces. of the rear ends of the tlinnels afrof the propeller. which stop the rotation of the race in the in-imediate vicinity of the diverging surf ac,6 35 of the tunnel. These fins or ribs chanue the rotary direction of movement of the water of the race and direct it aft to raise the presstire on the divergina walls of the race and thereby obtain a Lise@-Lil forwardly,pro elling p 40 action on the diverginly sides. Referring to the d@awings, in which like parts are similarlv desiznate:d:. 'propeller-14 rotates. Th6 @ropl6ller is driveii -by a; sha.ft 15. @'The@iiiniiel is@elo@6(f,on ail@four@sides has@,@@6,5 -,ide@ wills @16 div@@gin@ at the.r@-"ar end.' 6n!y the @side -v@alls @ cli@erge to: r,educe: the,, draft 6f @l ilie @boat. Th6@6@"S.1de - v@alls 16, -alre profl ' 'b vided -with projecting ns, ri s or plates 17-, preferably but not iiec@ssar,ily projelot'ing be-" @O yorid th@ eirciilfir P'dth;of ti-Ds of th ro elp- p p ler blades. The race:ilea;-Viii6- @the prop6lle@ f4 h@s a vement aiid encount r rot@,ry@ o e s the fin@ 17---, '0@ii the divergink w@,lls of th6 5 rear:en( o @ ihe lt;tnn I el that stop-rbtation'-@of 'the race or, that portion of @ it iii tht, @e,@,ioii o@-the fi ns which ditee@'ihe water a;ft. alon 't,he di@@rg9 ing @-v@ alls of the tiinnel on Nvhich the prossure.., devolbps.' , The pre -Ssutb byrea@on: of , acting' 80 .6n;the@ walls which@ are inclin6d to @ the dir@e-ction in whi@li the i)ressure is developed P)@6pts @ f orwardl 7 driving componeiit us6ful in@ asisting the p@opulsion of the 'v6ssel. -@5 The @fins, ribs or plate@ may have@ various silapes in cross seciion as @shown at. 17, 18@ 19 in Figs. 8, 9:and 10 r6s ecti@ely dnd,are p generally of the'sha e of the.! angles fqstenp e'd to inii6r, divetgi'ng walls -of th6 tunnel @and inav vary @n width esll)ecially in tiiiinels sub- 90 sia"nfi'all'y -r-e6tan6,iilar in cross section. In, Fig. 2 t-hese@ indrease in . dth tow'ard fins.f@ WI Figure I is, a v@rticar section on line 1-1 @heil. aft ends. of Fiu. 3 of a tunnel sliowino- my invention - Iii Fig. 4;1 have also shown' a, t-Llhhel 6los6d 9 5 45 es b Ilipti@al in Fig. 2 is a. horizontal section on line 2-2 on all@ sid biit sii @thntialIV@e of Fig. 1; cross; secti'on@in its' diVerg@Ing portion 16a havFig. 3 is an end elevation; inL), fins l@a directed iadially. Fig. 4 is tn end cleva-tion of a rear-end of 'I'yi-':Fibs. 5'6 7 I hav6 ' wn tunn@l s h o a ; d e p @ e s q i o n , , , 2 0 @ : ' i i , t h e ' s i d , @ - o f a tunnel havin Iliptical sect on and dig,e f6rriie'd @by 50 vergin-- walls.- ve@sof @and radial rib in the ioe s d i v e r , - ' l n g p o r