Sept. 18, 1934. 1'. M_ THQRSEN ' '_ . 1,9735783 STREAM LINE STERN POST BLOCK AND ASSEMBLY Filed July so, 1932 2 Sheets-Sheet 1

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A TTORNEY. - ' Sept. 18, 1934. T. M. THORSEN 1,973,783 STREAM LINE‘: STERN POST BLOCK AND RUDDER ASSEMBITIY Filed July so. 1952 2 sheets-sheet . 2

INVENTOR, Theoc‘ZoreM. Thor-sen.‘

A TTORN . ‘ Patented Sept. 18, 1934 1,973,783

UNITED STATES ‘PATENT OFFlCE

1 STREAM LINE STERN-POST BLOCK AND . >RUDDER. ASSEMBLY '7 :Theodore M. Thorsen, Bellingham, Wash. . Application July so, 1932, Serial No. 626,695 1 Claim. _'(01. lug-162) "" My invention‘relates to improvements in con ‘tion of ‘Fig. 1 with the propeller and rudder tra-propeller, stream-line, stern-post block and omitted drawn on a larger scale, Fig. 6 is a rudder assemblies for wooden and has horizontal section of Fig. 5 on theline 6+6, for an object to provide stream-line parts for Fig. 7 is a horizontal section of Fig. 5 on’the, ‘ 5 removable attachment to the stern-post and line 7-7, Fig. 8 is a horizontal section of 'Fig. \ml rudder of such boats to occupy the open space 5 on the line 8—'—8,-‘Fig. 9 is a horizontal section 'usually found between the stern-post and the of Fig. 5 on the line 9-9,>Fig. 10 is a transverse propeller thereof and to buildup the rudder into section of Fig. 1 on the line 10—10, drawn ‘on stream-line shape. ‘ a larger scale, as viewed from above the said . . ' 10 - ‘Another object of my improvement is to pro 'line 10—10, Fig. 11 is a transverse section of 35; ;vide wooden stern-post blocks and ruddercheek the rudder, segregated, on the line 10-10 of Fig. 'pieces in order that they may be easily con 1 ‘as seen from below 'the' said line drawn on a formed to fair stream-line surfaces for [the stern larger scale, Fig. '12 is a transverse section of of each particular . Fig. 1 on the line 12—-12, (drawn on a larger ., ' 15 Other objects of my improvement will appear scale) Fig. 13 is a transverse section of Fig. 19. as the description proceeds. 1 on the line 13-—13 drawn on a larger scale, ‘In the hulls of Wooden boats it is the prac and Fig. 14 is a diagrammatic representation of tice to allow a considerable free space between the fairreverse curve along which the water is the stern post and the propeller blades, and also ~720to use a’ relatively thin metal plate of plane impelledblock and betweenmy stream-line my stern-post rudder above stream-line the pro- ‘75 shape for the rudder. The said free-space pro peller axis by the revolving propeller, and ‘the » vides for the occurrence of local whirls and eddies curved‘surfaces of the said block and rudder in the water at this place which oppose the pass between which the said current of Water passes. , ing flow of water impelled by the propeller rev- ’ Similar characters refer to similar parts ._ . ‘ 25 olutions. Also the plane surfaces of the rudder throughout. encourages the forming of local whirls in the -With more particular reference to the desig water next the surfaces thereof which hinder nated parts: A wooden boat hull 16 has the the rearward ?owof water» thereover, and in ‘ 17, the stern-post 18, the 19 with crease the turning radius of the'boat. rudder bearing 20 thereon, the rudder shaft ., ' 30 - Because of the individual characteristics of the _'21, the rudder shaft bearing 22, the rudder shaft '85 hullsof wooden boats the dimensions and shapes coupling 23, the rudder 24, the rudder of the ‘parts thereof about which this inven 28, the rudder stem shank 01.28, the rudder - tion is concerned vary to a degree making it un gudgeon 29, the propeller shaft 30, the propeller practical to provide metal castings for the pieces shaft 'outbearing 31, the propeller hub 32, the ., > 35 which my improvement‘ require because nearly propeller blades 33 and 1133 and the stream-line ‘90 - each boat would require special patterns for these propeller shaft nut 34. ‘ pieces thus adding considerably to the cost of The rudder 24, which in boats of this char the improvement. . ~ acter usually is a relatively thin plate of iron In practice I have found that suitable pieces vor ‘steel, preferably for my purpose is cleft at "4740 made of wood can be especially shaped for each 26 in its ‘counterbalance edge in line with‘ the "95 ‘boat at ‘a small expense and fastened in place axis‘of the propeller shaft, and the said edge ' in'a manner insuring a reasonable term of serv above the cleft is bent outward as at 25 inv one ice. “ - ~ ~ - > ' direction while the edge 27 below the cleft at - I attain these and other objects of my im 26 is bent outward in the‘ other ‘direction, and. . 45 provement with devicesillustrated in the two theven'ds of the bent over parts at: the cleft “100 ‘ sheets of accompanying drawings in which Fig are bent at a larger angle than the ends thereof ure 1 is a side elevation of a portion of the stern at the and bottom of the rudder as shown of a wooden‘ boat hull,‘ the remainder thereof in Figs. 2‘ and 4. _ ' being broken‘ away, showing my stream-line - > '50 blocks in place thereon and also the cheek pieces the'It'is stern-post, the custom'to of those make boats the with ’ which surface this"1°5 of for the rudder thereof in place thereon, Fig. 2 invention is concerned, straight transversely; . is a top-plan view of the rudder before my cheek thus failing to complete the stream-line shape pieces are attached thereto, Fig. 3 isa side eleva Yof the hull at the stern thereof, and providing tion of Fig.2, Fig. 41s an elevation view of the "a place into which the water may not quickly , . I‘ ~55 forward end of the rudden'Fig- 5 iSa real‘ eleva ‘enter as the boat moves forward, thus com- "110 1,973,788 pelling a quantity of water to- follow along with vertical opposite the propeller but follows the the boat aft of the stern-post while it is being shape of the hull and curves rearward above revolved by the main body of the water past the same, and my stern-post block follows the which it is being carried and more especially direction of the aft surface of the stern post 18 by those parts of the main body of the water and consists of the part 935 below the shaft out 80 which are deflected to pass between the stern bearing 31, the hub part 36 around the said out post and the rudder as impelled by the revolv bearing, the central part 35 above the hub part

ing propeller blades. _ _ n . I . and the top part 3'7 above the propeller. For Thestern-post?“stream-line‘block 3'5, Q35 and. ‘(convenience of construetion the top part 3'7 is 10 the stream-line'rudder 40, i140, H40 and'b40, f40 made separately from the other parts to which 85 provide stream-line surfaces between which the“ ‘it is‘joined opposite the top of the propeller. said de?ected currents of water may ?ow in ‘fair,’ _ The peak a3’? of the top part of the block is curves unhindered by the eddying waters being nearly medial thereof and this part of my block carried along with the aftgpartsiofithesaid is relatively. .thin making the fastening thereof 15 boats when built as usual. 1 - tov the stern post easily attained by the nails The diagrammatic drawingshown in Fig. 14 .39 driven through the‘ block and into the stern will aid in explaining the" way in’which the" ‘post against which it is placed. The lower parts desired stream-line surfaces are-Tdet'ermined. ‘In of. the block which are opposite the propeller are Fig. 14 o—o is the center line of the boat being thicker and are fastened to the stern-post by 20 improved by the addition of my devices." The the'staples 38 alone. 95 ,line :c—-a: ,is_,drawn_through. the center of the The peak 035 of the-part 35at the top there propeller blades at‘right angles with 0-0. , The of is near the center but it curves toward the "line 'y—y is'drawn through the rudder axis at right hand,“ as’. onev faces forward, and vjoins ‘right angles with the line o_—o. Two positions the hub part 36 near the right-hand side of of ajpropeller 'blade'above the axisthereof are the block. . The peak ‘e35 ofi the partvd35 at the 100 ‘given the one in solid lines at, 33 is,_in rotation, lower end of the block is, near the middle of the "in front, of the propeller. axis and the one in block aty-its bottom and curves toward the left dotted lines’ at 33'_ is,’ in rotation, behind the to join with the hub part 36 near the'left side ‘said axis. I " ' g of the block. Thus at the hub the ends of the The fair curved'line' B—7-A is drawn from curved peak lines, are spaced apart. The con-;_ 105 the‘ intersection of the line 0—_o with the aft tours. of the. slanting sides of’ the , block :are "surface of, the'sternfpost '18, to intersect the indicated in the selected cross-sections thereof intersection ‘of a'r-i-zr with ‘the propeller blade shown in Figs. 6-¢9‘taken on lines of like number '33 and to be atright angles with the propeller in Fig. 5. I - , blade. The_ fair curve D—Ct is drawn from the in As stated above. the rudder 24 has the cleft 110 ' tersectioi‘i' of the line 0+0 and the line y-y to 26 made in the forward edge‘ thereof in_ line intersect the intersection of the line m-—.f1: with with the axis of the propeller and the parts the propeller blade position at 33’ and be at 25 and 27 respectivelyabove and belowthe cleft ' right angles with the said-propeller blade posi are bent outwardly oppositely,._-the bending-being tion. at a greater angle at the cleft ‘than at the top. ".115 Ifv the boat being considered were a and bottom of the rudder. The forward edges vessel'the peak 1‘035 ‘of the block 35 would be of the parts >25~and 27 areethe peaks e40 and "on the‘linefo—bo. “But because of the diagonal e40, respectively, of the stream-line rudder which ' direction of the current forced by. the revolving .I make from the metal plate rudder 24 by fas propeller blades the peak 035 interseetsoris tening wiomien~ cheek pieces thereon. It may‘. onv the curve B—.A and the sides of the block be noted that atthe cleft 26 the peak line '35 ‘are in the curyes'a35: and D35. The shape 040 is at the left of the propeller axis while the ‘ofthe curved sides e35 and Z235 depend on the block peak line e35‘ isat the right thereof at its fair curve B—A. I ~ _ I t ' bottom end,landv thatat the.cleft;26 the peak 'The'peak cLlO .of the forward rudder edge line e40 is at the right‘ of thevpropeller axis-.125 ‘ would,’ in a sailing vessel,‘ be on the line 0-0; while the upper end of the blockpeak line e35 but because of the- said propeller-impelled cur is at theleft thereof, this being the location of . rent it is onthe fair curve D—qrand the shape these lines for a forwardly revolving propeller. 'of‘ the surfaces of the saidirudder edge are , In covering the rudder plate 24 with wooden 3545 obtained "from the. curve D—C, cheek pieces in practice the plan has been fol-2' 130 ' The center of the ?ow ofucurrentnbetween lowed-of fastening vertical wooden strips 1140 and ), the block 35 and, the rudder end‘ d4!) which is (Z40 over the sides of the rudder counterbalance impelledby the revolution of the propeller is above the cleft 26, vertical wooden strips D40 and Ythefair reversed curvedline Ep-Fwhich is ob I40 over. the sides ,of they said counterbalance 1.13.0 tained from the curves B—Av and D—C._ ' below the’ cleft 26‘and the horizontalwwooderf} .135 ‘ ,"The ‘drawing in Fig: 14 pertains to conditions ‘strips, 40, 40 on; both sidesjof therudder plate “above the. propeller shaft.‘ If,’ it“ were; drawn to rearward of the axis thereof; Preferably these f respresent-the direction 9f ?ow below the pro wooden cheek. pieces are fastened in place with peller 'shaftit would have to dowith the peak . bolts and nuts 41 as shown, the nuts and bolt e35 of thedower' part 9135. of the stream-line heads beingin‘ countersunk recesses which after-‘. ‘sternepost block the curved sides of which ‘are .ward are ?lled with Portland ;cement as; indi 'shownatj35and 1135, and the .peake‘iO of the cated at 42. - ' ~ ' - " forward end of the rudder thev curved sides of ; The stream-linecontour of the-rudder is shown /which_ areshown at 2240, M0; andthe center ; in the sectional viewsuthereof-r in Figs. 10, 11, .lineiof: vthecdiverted eurrent in the water would 12 and ,13. taken on‘ the lines 10,1, 12 and 132145 'p'a'ss'by the curved side 135 of. the stream-line :inFig. 1. Two views'on the line. 10——l0_being block and the curved side, 1710. of the rudder. showrnthe one in-Fig. ,10 beinghviewed from In the sternrof the particular boat herewith “above the said lineand the one shown in Fig. illustrated the hullv curves rearward above the . 11 beingviewed from belowthe said line. .75 propel1e_r__ blades and the stern-post is nearly ) While thebest results and. the. most improve-13150 1,973,783 3 ment in freedom of movement through the water movable, contra-propeller stream-line block and in maneuvering are obtained by closely fastened on the stern surface of the stern post following the stream-line construction described of the said boat forward of and adjacent the above, the class of boats above referred to are propeller of the boat, and the rudder of the said considerably improved by ?xing a block of tri boat including a central metal plate having a 80 angular cross-section on the aft surface of the rearwardly-extending cleft in the front edge stern-post and by adding to the thickness of the thereof alined with the axis of the said pro rudder and rounding the forward and stem peller, portions of the said front edge being edges thereof. These less developed improve curved outwardly above and below the said cleft 110 ments also are within the scope of my invention. in opposite directions, and stream-line-shape 85 Having thus disclosed my invention, what I cheek pieces fastened on both sides of the said claim as new therein and desire to secure by rudder plate covering the same. Letters Patent is, A boat structure including, a separately-re ‘ THEODORE M. THORSEN. 15 90

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