US2364426A - Boat with means for enclosing the propeller when not in use - Google Patents

Description

Dec. 5, 1944. D.' DANIELSEN 5 BOAT WITH MEANS FOR ENCLOSING THE FROPELLER WHEN NOT IN USE Filed May 28. 1940 2 Sheets-Sheet l I f & 1A 4.?

ATTORNEY 5, 1944. D. DANIELSEN 2,364,426

BOAT WITH MEANS FOR ENCLOSING THE PROPELLER WHEN NOT IN USE Filed May 28, 1940 2 Sheets-She e t 2 III 111 II INVENTOR WWXTTORNEY Patented Dec. 5, 1944 UNITED STATES PATENT OFFICE BOAT WITH MEANS FOR ENCLOSING THE PROPELLER WHEN NOT IN USE Dybwad Danielsen, Buffalo, N. Y.

Application May 28, 1940, Serial No. 337,609

3 Claims. (Cl. 114-67) when the propeller is not inguse, is not deleteriously alfected as to maneuverability or speed because of the propeller and propeller opening. Another object of the invention is to permit the propeller to be conveniently and quickly enclosed either when the boat is at rest or is under way. Another object of the invention is to provide a simple and inexpensive propeller enclosing means which may be readily installed on boats of various sizes and proportions, and will be positive and reliable in action and not liable to leak even when in service for a considerable period of time. Another object of the invention is to protect the propelleragainst physical injury when not in use, and also to prevent its theft when the boat is drawn up on shore for its winter hibernation. Numerous other collateral objects of the invention and practical solutions thereof are disclosed in the following specification and in the accompanying drawings, wherein:

Fig. 1 is a side elevation of the rear end of a typical auxiliary sail boat.

Fig. 2 is a fragmentary, Vertical, longitudinal, phantom section thereof.

Figs. 3 and 4 are enlarged, substantially horizontal, fragmentary sections thereof taken on correspondingly numbered lines of Fig. 2.

Figs. 5 and 6 are enlarged, fragmentary sections similar to Figs. 3 and 4 but disclosing a modified form of the invention particularly adapted to the use of a feathering or a variable pitch propeller.

Similar characters of reference indicate like parts in the several figures of the drawings.

At the present time it is accepted as axiomatic by all authorities that, when any sail boat is provided with a motor and a propeller, its maneuverability and speed as a sail boat are very materially reduced, because of the variable eddy currents which are formed in and around the propeller opening due to the lateral pressure of the sails upon the hull. This fact is not so important in the case of a motor boat which is.

provided with auxiliary sails that are practically never used, but it is of very great importance in the case of an auxiliary sail boat whichis driven practically all the time by its sails alone and only employs its mechanical propelling means to a very limited extent.

The present invention permits the use of a propeller in a sail boat without in any way detrimentally affecting its maneuverability or speed when being driven by the sails alone.

Figs. 1-4

The numeral I0 indicates the hull' of a typical auxiliary sail boat having a deck ll, a keel or skeg l2, a keel extension l3, a stern timber M, a propeller I5 arranged in the propeller opening it and journaled in the outboard. propeller bearing I1, a rudder l8 and a propeller shaft l9. Preferably set in flush with eachouter, vertical, longitudinal surface of the keel extension 13 are two pairs of substantially vertical, parallel guide bars 20, 2| and 20, 2| which are secured in place by screws 22 or otherwise, and are preferably of U shaped cross section as shown in Fig. 4. Slidably arranged in these pairs of guide bars are rectangular, sheet metal covering plates 23, 23 which are preferably rabbeted at 24, '24 along their substantially vertical, longitudinal edges so as to slidably engage with the grooves of their companion guide bars 20, 2| and 20, El with their outer faces flush with the outer faces of their companion guide bars, and hence also flush with the outer faces of the keel extension 13. These covering plates are adapted to be raised or lowered so as to cover or uncover the propeller opening [6 and its propeller IS. The lower face of said propeller opening is preferably sheathed with a metal striking strip 25 which may be secured in place by fiat head screws 26, or otherwise, to the keel I2. This striking strip prevents the lower edges of the covering plates, from chewing up the keel when they are inadvertantly forced down with excessive pressures. V

Said covering plates project up into the hull ll] of the boat thru a pair of thin, obliquely disposed but substantially longitudinal slits 27, 21 which are suitably formed in the stern timber M in alignment with their companion guide bars 20, 2| and 20, 2!. Arranged in alignment with said slits are a pair of substantially vertical wells 28, 28' which are preferably formed of sheet metal and have welded to their lower ends suitably formed companion flanges 30, 30' which are secured by screws or bolts 3|, 3| to the upper face of the stern timber M. If desired a thin soft gasket (not shown) may be interposed between the lower faces of said flanges 3t, 30 and the upper face of the stern timber I4 so as to more positively ensure against any leakage thru these joints. The upper ends of the wells are preferably braced to the hull of the boat by suitable cross timbers 32 and 33.

Secured detachably by bolts 34 or otherwise within the upper ends of each of wells 28, 23 is a thrust block 35 which is provided with a hub 36 that rotatably receives the upper end of a companion; longitudinally disposed screw 31 or 31. Each of these screws is restrained against vertical movement relatively to its companion thrust block by suitable thrust collars 38, 39 which respectively bear against the upper and lower faces of their companion thrust blocks and are pinned or otherwise suitably secured to their companion screws.

Manual rotation of each of these screws is effected by a detachable handle 40, the hub of which fits over the upper squared ends of the screws 31, 31. To enable this operation to be effected, the deck ll of the boat is provided with a suitable stern hatch 43. The lower end of each screw 31, 31 is threaded thru a companion cleat 44, 44 which is suitably secured to the upper end of its companion covering plate 23, 23. Thus, when the detachable handle 40 is placed upon the one or the other of the screws and is manually rotated, its companion cover plate 23 or 23' is either raised or lowered, as may be desired. To prevent any whipping of the lower ends of each of these screws when its companion covering plate is in its extreme upper position, the extreme lower end of said screw is of reduced, cylindrical form and is journaled in a companion brace tongue 45, which is formed integrally with its companion flange 30, 30' and extends a suitable distance into the bore of its companion well. These brace tongues do not, however, interfere with their companion covering plates and hence, when it is desired to remove the same, the detachable bolts 34 of each thrustblock 35 are removed and said thrust block, together with its companion screw 31 or 31 and covering plate 23 or 23' is slipped up and out of its companion well 28 or 28' thru the stern hatch opening 46. When these parts are slipped back into place the cleat 44 or 44 of each covering plate guides the lower, reduced, cylindrical end of its companion screw into its bearing in its companion brace tongue 45 or 45'. In actual practice, from a commercial point of View, it will probably never be found necessary to remove the covering plates, and hence it is deemed practical to eliminate the hatch opening 46 entirely and have the two screws 31, 31 project up thru the deck ll thru suitable openings.

To accommodate the screws 31, 31' and their companion cleats 44, 44, the wells are bulgedout at 41, 41' and their companion flanges 30, 30' suitably curved outwardly at 48, 48 to conform therewith. Such a construction provides a means of enclosing the propeller without requiring any glands which are apt to leak, there being only one place where leaks could possibly occur in the present construction, namely, the joint between the flanges 30, 36' and the top face of the stern timber. This joint being stationary, and kept tight by a considerable number of screws or bolts 3|, 3|, no leakage is likely to occur even after the boat has been in service a considerable length of time.

It should be noted that advantage is taken of this hatch opening 46 to gain access to the quadrant 50 of the rudder l8 and to its cables 5|, 52 and also to its squared upper end 53. Thus, if one or other of said steering cables should break, a

- 64, 64, said brace wrench or other suitable tool may be engaged with said squared end 53 of the rudder and the boat temporarily steered in this manner.

The stock 54 of the rudder i preferably of hollow, tubular form, as illustrated, and is rotatably mounted in the usual manner at its upper end in a rudder tube 55 which is threaded at its lower end 56 into the stern timber l4 and is braced at its upper end by the hull cross timber 33. The lower end of said rudder stock 54 is provided with the usual detachable heel bearing 51 which is journaled in the heel 58 of the keel [2.

The blade portion of the rudder is, however, of novel design. Secured preferably by welding at 60 to the rear face of the rudder stock 54 are a plurality of sheet metal, cantilever brace bars 6 I, 62 and 63 which taper off to zero at their rear ends. Secured by welding or otherwise to the outer edges of these cantilever brace bars is a pair of rudder plates 64, 64 whose front, sub stantially vertical, straight edges are secured by welding or otherwise at 65 to the outer rear faces of the rudder stock 54. The curvilinear rear edges 66 of these rudder plates are welded or otherwise secured together so as to provide a strong, light, stream-lined rudder. As illustrated, the cantilever brace bars 61, 62 and 63 are disposed perpendicular to the rudder stock 54, but, if it is desired to ploy very thin rudder plates ars may be disposed substantially parallel to the flow of the water at this point so that deformations of the rudder plates 1 will not increase the skin friction of the rudder.

This same effect may be obtained by filling the hollow interior of the rudder with wood or water. In the latter case it is considered preferable to seal the water in, but it is deemed to be satisfactory to provide a plurality of apertures which will allow the rudder to automatically fill itself when the boat is put in the water and to reduce substantially to zero the differences in pressure on opposite sides of each rudder plate.

In combination with the present invention it 5 preferable that a two bladed propeller be used, as

shown. This is because, in the first place, such a propeller enables the cover plates 23, 23 to be placed so close together that their front edges are positioned flush with the keel extension l3 as shown in Fig. 4. In the second place, when a two bladed propeller is used, it does not, with the present invention, have to be turned to any certain position before lowering the cover plates 23,

23. This is because, if one of the cover plates is lowered completely before its mate is lowered, the first named cover plate will automatically engage with the blades of the propeller and turn it to the position shown'in Fig. 4, whereupon the other cover plate may be lowered without danger of interference on the part of the propeller. Also a. two bladed propeller, if properly balanced, is more efficient than a three or four bladed propeller, if there is suflicient space to swing it.

When the cover plates are thus lowered, no eddy currents can form in the propeller opening "5 and hence the boat can be handled as sweetly as tho it had no propeller or propeller opening at all. While such an enclosing of the propeller is of particular advantage in an auxiliary sail boat it is to be understood that the invention is applicable to otherboats as well. For instance when applied to a motor driven dinghy, such a dinghy may be towed astern with a minimum of danger of injuring the propeller because of floating logs, etc. Also in the case of any boat In certain hull constructions the propeller is located in a propeller pocket which is only open at one side. It is obvious that such a construction requires only a single cover plate to close said pocket.

Figs. and 6 In the previously described construction of Figs. 14 the wells 28, 28' were shown as having individual flanges 30, 30' and having their screws 31, 31' located unsymmetrically inside their cover plates 23, 23". Such a construction, while having certain advantages, does not permit the cover plates to be placed as close together as is desirable in some boats having a narrow keel Ma and a narrow feathering or adjustable pitch propeller l5a. In such an installation it is deemed desirable to mount both of the Wells. 28a, 28a on a single flange 30a secured by screws 3la to the top face of the stern timber I 4a and with the screws 31a, 31a located symmetrically outside their companion cover plates 23a, 23a. Otherwise the construction is the same as that of Figs. 1-4.

I claim as my invention:

1. An auxiliary sail boat having a keel extension provided with a propeller opening and having a stern timber provided with a pair of Iongitudinal slits whose outer faces are in alignment with the outer faces ofsaid'keel extension; a propeller arranged in said opening; a pair of guide bars on each side of said keel extension in proximity to the sides of the opening thereof; a

pair of sheet metal wells arranged in alignment With said slits and each having a longitudinal bulge and also a flange at its lower end for attachment to the upper face of the stern timber; a brace tongue on each flange projecting into the bulge of its companion well; a detachable thrust block arranged in the upper end of each well; a covering plate arranged in each well and engaging with its companion pair of guide bars; a cleat on each covering plate arranged in the bulge of its companion well; and a screw also arranged in the bulge of each of its companion wells and journaled at its opposite ends in its companion thrust block and brace tongue andintermediately threaded thru its companion cleat.

2. An auxiliary sail boat having-a propeller-receiving opening extending transversely thru its hull and comprising: a propeller arranged in said opening and rotatable on an axis which lies in a vertical plane positioned longitudinally of the boat; a pair of covering (plates slidably disposed at the opposite ends of said opening; a pair of thrust blocks detachably connected to the hull of the boat; and a pair of actuating screws journaled in said thrust blocks and in threaded engagement with said covering plates.

3. An auxiliary sail boat having a slit thru its hull andhaving a skeg disposed below said slit and having a propeller-receiving opening in said skeg and comprising: a propeller arranged in said opening and rotatable on an axis which lies in a vertical plane positioned longitudinally of the boat; a well secured to the boat in align-- ment with said slit; 3, covering plate arranged in said well and said slit; and an actuating screw journaled in said well and in threaded engagement with said covering plate.

DYBWAD DANIELSEN.

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