US1449910A - Fair-leader board - Google Patents

Description

Mar. 27, 1923,

M. OERTZ FAIR-LEADER BOARD Filed May 15, 19 21 2 sheets-sheet 1 NEE-nan I'll- Mar. 27, 1923 1,449,910

' M. OERTZ FAIR-LEADER BOARD Filed May 13, 1921 2 sheets-sheet 2 ticularly for deep sea fishing with bottom. trawling nets, consist of flat wooden plates reinforced with iron and are attached tothe towing ropes through the medium of Patented Mar. 27, 1923.

UNITED STATES PATENT OFFICE.

MAX OERTZ, OF HAMBURG, GERMANY, ASSIGNOR TO CAMILLO GASTIGLIONI, OF VIENNA, AUSTRIA.

FAIR-LEADER BOARD.

= Application filed. May is,

tain new and useful Improvements in Fair- Leader Boards, of which the following is a of eddies'at the rear edge and the resistance specification.

The otter boards which are most com monly used for bottom trawling, more 'par rods or chains. It has also'been proposed to construct flat otter boards with tail surfaces set at an agle which, however, are only able to exercise a certain amount of control over the otter board without improving its capacity for keeping the net open.

The spreading action of the otter boardson the net is dependent on the size of the,

boards, the angle at which the towing rope acts and the towing power or towing speed. Every increase in the spreading action of the otter boards may be regarded as equivalent to an improvement in the catching capacity, since, the other conditions of operation being the same, the width of the mouth of the net is more suitable and in some cases a larger net can be employed.

According to this invention the experience which has been gained in aircraft construction in connection with the formation of the supporting surfaces is utilized for increasing the spreading force of the Otter boards which for this purpose are cambered out-' wardly in and lateral to the direction of towing. This new shape of the otter boards which is similar to that of aircraft supporting surfaces on the one hand enables the towing force, i. e. the power of the engines, to be reduced without detrimentally affecting the catch and, with engines of the same size, makes it possible to use larger nets than hitherto and to increase the width of the mouth. been established that in consequence of the new shape, the increase in the spreading power relatively to that of the fiat boards hitherto used, amounts to from 40 to 49 percent, according to the setting.

In addition to the camber in and lateral to the direction of towing, the otter'board can be cambered outwardly by a slight amount in and lateral to the direction Onn'rz, residing at Hamburg, Germany, have invented cer-.

In the course of trials it has 1921. Serial No. 469,357.

of its height. At the same time the rearward portion of the otter board may be made thinner, that is to say the cross section of the board may be tapered rearwardly, in order to reduce the formation to towing thereby set up.

The invention is illustrated by way of example in the accompanying drawings in which Fig. 1 is a perspective view of one constructional form of the improved otter board,

Fig. 2 is a cross section of the otter board on line 2-2 of Fig. l,

Fig. 3 is a vertical section on line 33 of Fig. 1,

Fig. 4 is a vertical section on line l4 of Fig. 1,

Fig. 5 is a vertical cross section of a modification of the otter board slightly cambered 1n the vertical section,

Fig. 6 shows the complete arrangement of a trawl net fitted with improved otter boards,

Fig. 7 is a side elevation of a slightly modified form of an otter board,

Fig. 8 is a longitudinal section on line 88 of Fig.7,

Fig. 9 is a still further modification of the otter board, and

Fig. 10 is a horizontal longitudinal section taken on line 10-10 in Fig. 9.

Referring to the drawing, the otter board a has the form of a shallow trough which is slightly cambered in and lateral to the vertical direction and somewhat more cambered in and lateral to the longitudinal direction. To the inside of the camber are attached the angular rod members 7), 0, chains or the like. The tow rope (Z is attached at the apices of the angles formed by rods bc, and the net is attached to the eyes 6 and f on the somewhat tapered rear edge of the board. The rearwardly tapered cross section of the board is clearly shown in Fig. 2 as well as the shape of the board which is fashioned like that of supporting planes of aircraft.

Modifications of the improved otter board are shown in Figures 4 to 7, in which the board is constructed from pieces of uniform thickness which are rigidly connected to one another at an obtuse angle. The edges *of the. otter board surface.

tical section also, it is built up from com posite pieces in this direction also.- The iongitudinal cross section (that is the section parallel to the directionzo'f towing)- and in some cases also the vertical cross section of boards thus constructed are bounded by bent lines, the individual sections of which constitute chords or tangents to'th'e curves Even a board having only a single bend laid out according to this mode of construction,- for instance by building up the board from a' front and a rearward portion which at. the angle of in clination are rigidly j oined together (Figs. 7 to 10 inclusive), enables the spreading force to be increased to a considerable de- 'gree relatively to that of the hitherto-known boards. Otter boards of the description can easily be built up out of the old straight otter boards which are now used;

Figures Sand? show the mode of'con structing an otter board out of three parts joined together in the manner above de scribed. I

It will be obviousthat the parts which are joined together can be stiffenedby means of battens g and h, angle ir'ons tor the like, so

that the joints will be able to withstandthe high stresses to which they are subjected.

Having now particularly described and ascertained the nature of my invention and in what manner. the same is to be performed, I claim 1. An otter board, more particularly for bottom trawl nets, the section of the board being cambered outwardly in and lateral to the direction of towing in the manner of the supporting planes of aircraft.

2. An otter board with the section being cambered outwardly in and lateral to the direction of towing and in the manner of the supporting planes of aircraft, its thickness being decreased rearwardly.

3. An otter board curved n the manner 'of the supporting planesof aircraft being built up from pieces which are rigidly connected together at an angle in the longitudinal direction of the board so as to form a trough having the properties of aircraft supporting planes.

4. An otter board curved in the manner of the supporting planes of aircraft, the traction members engaging the board at its inner concave surface.

In testimony whereof I affix my signature in presenceof two witnesses. 7

MAX OERTZ. Vitnesses AUG. HAMAoHnR, HERM SAULES.

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