US2057574A - Elastic boat, particularly applicable to seaplane floats - Google Patents

Description

- Oct. 13, 1936. R, Hopp 2,057,574

ELSTIG BOAT,- PARTICULARLY APPLICABLE TO SEAPLANE FLOATS Filed March 19, 1936 Patented Oct. 13, 1936 UNITED STATES ELASTIC BOAT,

PARTICULARLY APPLICA- BLE T SEAPLANE FLOATS Richard Hopp, Berlin, Germany, assigner to Reginald William Allo Application March 19,

tt, Yorkshire, England 1936, Serial No. 69,703

In Germany April 30, 1935 12 Claims.

This invention relates to elastic boats larly applicable to seaplane floats.

It is a known practice to construct boats with elastic framework and a skin or outer cover made of fabric; in which boats the stem also consists of elastic material, mostly of round or at steel. This steel must not be too thin otherwise the parts will not possess the requisite strength; on the other hand, even if the steel is of suitable thick- L0 ness, impacts of any great force against the stem will result in permanent deformation of the latter even when good spring steel is used, because the part struck will be strained beyond its elastic limit so that such a boat cannot be considered to l5 offer suicient resistance. In order to obtain the desired resistance, it is necessary to distribute the impact over Va fairly large section of the material.

The object of the present invention is to attain this desideratum.

According to this invention, in an elastic boat having a rigid keel frame and a. resilient framework, there is provided in combination a stem consisting of a helical spring and a tension member both attached at their opposite ends to the keel frame and the gunwale of the resilient framework.

A particular embodiment of the elastic boat according to this invention comprises a rigid keel frame, a framework consisting of resilient ribs, stringers and gunwale, bow and stern stems each consisting of a helical spring and a tension member both attached at their ends to the keel frame and gunwale respectively and a flexible skin covering the said framework.

In a practical construction the stem of my boat consists of a helical spring of ample dimensions let into the heavy keel frame at one end, while the other end is connected at the stem to the gunwale which is made of flat spring steel. Between the two end points of said spring a tensioning member is provided. The object of this is, primarily, to impart the necessary curvature of the spring forming the stem.

At the same time, the tensioning member is required in order by preventing the ends of the spring stretching to their full length and to increase the resistance of the spring, so as to make better use of its elasticity. Moreover, the tensioning imparts a stable form to the ends of the boat, preventing the point of the boat being pulled out, as happens in towing, and also preventing the after stem from yielding outwards under impacts on the forward part of the vessel. As the 55 spiral spring can yield in all directions it is capable of taking up lateral or oblique impactscoming from forward-such as occur particularly when landing on rock-bound coasts. Excessive mobility is prevented by the floorhead stringers 60- which are also of spring steel and are fixed to the particuf (C1. 9 6) springs both at stem and stern by means of a sleeve. In order to ensure the utmost possible resiliency of the hull of the boat, it is advisable to avoid riveting as far as possible and only to ladopt it at the ends of the ribs at the gunwale, while the floorhead stringers may be arranged in duplicate running in juxtaposition alternately, the ribs being worked under and over the ribs in the manner of adjacent strands of basketwork. The keel frame is very strongly built up of wood and crosses the ribs which are continuously connected with the keel in one piece running from gunwale to gunwale. The spring steel material should be as thin and narrow as possible with a view to elasticity. The thwarts are elastically suspended and are designed to take both tension and compression. The outer skin does not, as in collapsible boats, consist of a combined canvas and rubber skin, but of separate sheets, namely a fabric sheet inside and outside for protection and 20 a middle, very elastic, rubber sheet in between the fabric sheets.

The invention will now be described with reference to the accompanying drawing in which:-

Fig. 1 is a perspective view of an elastic boat constructed in accordance with the invention,

Fig. 2 is a section of a stem along the centre line of the boat,

Fig. 3 a section through one of the thwarts,

Fig. 4 is a similar View to Fig. 3 showing an alternative construction for supporting the thwarts, and

Fig. 5 is a section of a detail.

Referring to the drawing the stern, which may either be at the bow or the stern or both, is provided with a helical spring l attached at one end to the gunwale 2 and at the other end to the end of the keel frame 3 as at 4 (Fig. 2). A tensioning arrangement comprising a flexible cable or wire 5 is also attached in a similar manner to the gunwale 2 and the keel frame 3. The nuts fastening this cable or wire to the gunwale and keel frame permit the tension of the wire to be varied.

The framework of the boat is completed by means of ribs 6, which pass under the keel frame 3 as will be later described in greater detail, and by floorhead stringers 1, which are each formed of two strips of spring steel running under and over alternative ribs 6 and disposed adjacent to one another in the manner of adjacent strands in a basketwork. The floorhead stringers 'l which are attached at their ends by means of collars 8 to the helical springs I at each stem, carry the floor of the boat (not shown in the drawing) in conjunction with the keel frame 3.

The gunwale 2, the ribs 6 and the floor head stringers 1 are all made of strips of spring steel, which, being both strong and resilient, enables shocks received by the stem to be absorbed.

The thwarts 9 are carried of spring steel supports I each attached at their upper and lowerL ends to a rib 6 near the gunwale 2 and near the iioorhead stringers 1. This construction is clearly shown in Fig. 3.

Referring to Fig. 4, an alternative construction for supporting the thwarts 9 shown,-in which the ribs supporting the thwarts 9 are prolonged upwardly and bent over to form a loop Ii,"4 to the inner edge of which the thwarts 9 are attached.

Such arrangements for supporting the thwarts 9 enable rigid thwarts to be used since distortion in shape due to shocks received by the stem or the resilient frame are taken up by the supports I9 or 6a and are not transmitted to the thwarts.

planking II laid over the ribs 6, which are sup-4 ported by a layer of transverse planks I2 and a final layer of longitudinal planking I3, the whole series of planks being bolted together.

enclosing an elastic layer I7, e. g. rubber, is to the framework by 'the plate I8 and nut and bolt I9 shown in Fig. 5.

The boat is suitable for use as a lifeboat on ships, because launching it, even in a rough sea, will not cause it much damage. In this case, buoyant chambers would be provided which may be located under the thwarts. It can also be used as pilots lboat and landing boat on rock-bound coastsr or for expeditions. It is, however, particularly suitable for use as a float on seaplanes. v What I claim as my Vinvention and desire to secureby Letters Patent is:-

1. In an elastic boat having a rigid keel frame and a. resilient framework, the combination of a stem consisting of a helical spring and a tension member both attached at their opposite ends t0 the keel frame and resilient framework.

2. An elastic boat comprising a rigid keel'frarne,v

a framework consisting of resilient ribs, stringers and gunwale, at least'one stem consisting of a helical spring and a tension member, means for attaching said spring and, tension member at their and aresilient framework, the combination of a.

helical spring and a length of stout flexible cable,

meansforattaching'said,springend cable at their wale,

opposite ends to the keel frame and the gunwale of the said resilient framework, and means for varying the tension of said cable.

7. An elastic boat comprising arigid keel frame,

, a framework consisting of resilient ribs and gunow and stern stems each consisting of aV helical 8. An elastic boat comprising a rigid keel frame,

a framework consisting of resilient ribs, stringers and gunwale, bow and stern stems each consistrespectively, iloorhead stringers connecting the bow and stern stem springs, rigid thwarts, a strip framework.

11. An elastic boat comprising a rigid keel frame consisting of a strong keel beam, a layer of transa helical spring and a attaching both said stems each consisting of tensionV member, means for spring and tension member keel frame and gunwale respectively and a flexible skin covering the said framework. Y

12. An elastic boat comprising a rigid keel frame, a framework consisting of resilient ribs, stringers and gunwale, bow and stern stems each consisting of a helical spring and a tension member, means for attaching both said spring and tension member at their ends to the keel frame and gunwale respectively and a flexible skin consisting of an inner and an outer layerv of fabric enclosing an elastic layer covering the said Vframe-` work.

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