GB2099773A

GB2099773A - A rowing rig

Info

Publication number: GB2099773A
Application number: GB8202203A
Authority: GB
Original assignee: BOOTSWERFT EMPACHER KG
Current assignee: BOOTSWERFT EMPACHER KG
Priority date: 1981-06-05
Filing date: 1982-01-26
Publication date: 1982-12-15
Also published as: IT1139196B; DE3122433A1; IT8124310A0

Abstract

A racing rowing boat comprising a rigid hull 10, a fixed seat 60 and a longitudinally movable rigid oar support/foot support unit 12, 24 which is positively located on the hull by roller arrangements 28, 29, 30, 31, 33 on both sides. The oar support 12 comprises a cross-strut having a central portion 17 which is curved to substantially follow the shape of the hull and opposed limbs 15 and 15' which support rowlocks 16 at ends 14 and 14'. The cross-strut is of a torsionally rigid sandwich construction and is rigidly connected to the foot support 24 by an arrangement of tension and compression members 18 to 23. <IMAGE>

Description

SPECIFICATION A rowing boat Technical field The present invention relates to a rowing boat, and is more particularly concerned with a racing rowing boat having at least one fixed seat and associated foot support means which is movable relative to the seat longitudinally of the boat, the foot support means being connected to spars which support a rowlock to locate a scull or oar.

Background art In a racing rowing boat the spars which support the rowlock and the foot support means are usually connected rigidly to the hull of the boat while the seat is a so-cailed sliding seat and slides with the aid of roller bearings on slide tracks. The rower bends his knees to a fairly large extent in the boat during each rowing stroke and therefore slides his body backwards and forwards by approximately 65cm longitudinally of the boat.

Because of this displacement of weight and the additional movement of the oars through the water, the boat proceeds with a jerky motion which is simply called a ducking moment or ducking. In this conventional type of rowing boat, the rower has to be so trained that the ducking moment is kept as small as possible since the boat is always slowed down by the non-forward displacement in the water. In the past this disadvantage of the ducking moment has been alleviated by making the boat itself longer.

However, the longer a boat is, the greater is its surface area in the water and, therefore, the greater is its frictional resistance in the water.

Relatively long boats are therefore by their nature slower than short boats.

In order to eliminate this disadvantage of racing rowing boats it has long been known for the rowlock-supporting spar and the foot support means to be movable longitudinally of the boat, instead of the seat; cf German Patent Specification No.27 (1883). Despite many attempts with such an arrangement however, it has not heretofore been possible to implement it instead of the sliding seats introduced in 1882, since there are design difficulties in providing for the spar and foot support means to be movable relative to the hull. For example, according to a recent proposal, the foot support means and the spar are to be fixed to a metal carriage which slides in metal rails fixed on both sides to the rim of the boat; cf British Published Application No.

2044706A.

Since relatively large forces are to be transmitted with as little frictional loss as possible (the average maximum rowing force of a rower is greater than 1000 A-cf Messtechnische Briefe, 15 (1979), volume 3, page 53), all of the designs in accordance with the immediately preceding paragraph which have been proposed in the past were too heavy because of the mechanically rigid design which was necessary. The combined carriage, spar and foot support means usually weighed more than the hull and were inconvenient in their shape since they had an unfavourable effect on the centre of gravity of the boat. One-man racing boats of the type under consideration here may be approximately 800 cm in length, 29 cm in width at the upper edge of the hull, and they may only weigh approximately 17 kg.

An object of the present invention therefore is to refine and modify the known movable spar/foot support arrangement for rowing boats such that it forms a flexurally and torsion resistance assembly facilitating rowing which can be positively connected to the boat and is movable backwards and forwards in relation to the fixed seat along the longitudinal axis so as to achieve shorter and therefore faster racing boats by avoiding ducking moments.

Statement of invention and advantages According to the present invention there is provided a rowing boat comprising a rigid hull, a seat fixed on the hull and associated foot support means which is movable longitudinally of the hull, a cross-strut which is adapted to support at least one scull or oar and is rigidly connected to the foot support means in longitudinally spaced manner therefrom by tension and compression support members, with the cross-strut comprising a torsionally- and flexurally-resistant, integral torsion box of which a portion extends across the hull, said portion being shaped to extend into the inside of the hull, and low-friction displacement means provided on the foot support means and on the cross-strut which are displaceable relative to associated means on the opposed upper edges of the hull.

The cross-strut/foot support unit described in the immediately preceding paragraph may be extremely light but rigid and can be positively located with respect to the hull while being freely movable backwards and forwards so that the rowing forces of the rower can be applied to the water with optimum efficiency. Since the hull of the boat can now be designed without reference to ducking moments, further optimisation is possible which can result in considerable gains in terms of speed. The advantages of the portion of the cross-strut which extends into the inside of the hull are that said portion is now clear of the knees of the rower at all times and that it lowers the centre of gravity of the boat as compared to prior proposals.

It is important that the hull of the boat be as rigid as possible, at least in the region of the cross-strut/foot support unit and the seat and conveniently the seat serves as a strut which assists in torsionally rigidifying the hull.

Furthermore, the hull is advantageously reinforced in the regions which support the or each seat and the means thereon associated with the low-friction displacement means by unidirectional carbon fibres which are laminated thereto. The hull will usually comprise two inherently rigid portions secured together.

Generally, each low-friction displacement means will comprise a roller and the associated means comprises a track provided on each opposed upper edge of the hull. The aforementioned positive location of the cross strut/foot support unit may be provided by each said displacement means comprising two rollers which engage respective upwardly- and downwardly-facing surfaces of the track to positively locate the cross-strut/foot support means unit on the tracks.

The cross-strut is preferably rectangular in cross-section and comprises at least one kinked limb extending laterally of the hull from said portion that extends into the inside of the hull on which one scull or oar is capable of being supported, and where it is for sculling (i.e. a one man boat), two opposed kinked limbs may be provided to support respective sculls or oars, the cross-strut having an approximately V-shaped profile.Advantageously, the torsion box is of closed sandwich construction (i.e. the core, which may be a honeycomb structure, is enclosed) in which the outer plates have unidirectional carbon fibres laminated into the compression and tension regions thereof and said outer plates are bonded to the core subsequent to them setting, and the whole cross-strut is wrapped in a fibrous layer which is saturated in resin, the fibres in said layer being directionally arranged diagonally and cross wise.The rigid construction of the cross-strut/foot support unit is preferably provided by a support member extending at an angle to the longitudinal axis of the boat between the cross-strut at a location adjacent the position at which the or each oar or scull is to be supported and the uppermost part of the foot support means on the same side of the hull as said oar or scull support position, and two further support members extending in diverging array from substantially the centre of said portion of the cross-strut which extends into the inside of the hull to respective lateral ends of the lowermost part of the foot support means.Additional rigidity can be provided by two further support members which extend from respective lateral ends of the lowermost part of the foot support means to respective extremes of the aforesaid portion of the cross-strut adjacent the upper edges of the hull.

Figures in the drawings Two embodiments of a rowing boat in accordance with the invention will now be described by way of example only, with reference to the accompanying illustrative drawings, in which: Figure 1 is a pian view from above of a sculling boat in the region of the cross-strut/foot support unit; Figure 2 is a cross-sectional view taken along line Il-Il in Figure 1; Figure 3 is a cross-sectional view showing a displacement means for the cross-strut of the boat shown in Figure 1; Figure 4 is a longitudinal part-sectional view of the portion of the boat shown in Figure 1; Figure 5 is a perspective and part-sectional view of a part of the cross-strut, and Figure 6 is a view similar to Figure 2 but of a modified embodiment of the boat, which is shown in plan view in Figure 7.

Detailed description of the drawings A cross-strut 12 is associated with the hull 10 of a racing rowing boat 11 which is only shown in part in Figure 1. As Figure 2 shows, the crossstrut supports rowlocks 1 6 which locate sculls or oars on the outer ends 14 and 14' of its liinbs 15 and 1 5', and its centre portion 1 7 projects into the inside of the hull almost to the level of the lower edge of a foot support 24 which is rigidly connected to the cross-strut 12 by means of compression and tension rods 18, 19, 20, 21,22 and 23.This connection is such that the crossstrut 12 and the foot support 24 form an inherently rigid and extremely iight crossstrut/foot support unit (to be described hereinafter) which is positively connected to the racing rowing boat at the upper edges 26 of the hull with the aid of roller bearings 28-33 which are still to be described but which can be moved backwards and forwards.

In order to achieve this, rollers 28-33 are rotatably mounted on the uppermost end 27 of the support 24 and on parts of the cross-strut 12 which are at approximately the same height and these rollers move along one of two slide tracks 35 and 36 which are fixed to respective upper edges 26 and 26' of the hull 10.

As Figure 3 shows, a matching roller bearing 38-43 is associated in an adjacent plane with each of the said rollers 28-33 by way of an arm 37 and the matching roller bearings engage the slide tracks 35 and 36 from the opposite side such that the cross-strut/foot support unit is positively supported.

Although three pairs of rollers 28-33 are shown only two pairs may be used. However, the cross-strut 12 is given better support by two pairs of rollers 30-33 than by one pair so that three pairs of rollers are used in preference.

The cross-strut 12 comprises a flexurally resistant torsion box-as Figure 5 showsin the form of a sandwich which has a rectangular cross-section and a core 50. As Figure 2 shows in particular the cross-strut is formed approximately in V-shape longitudinally and comprises the limbs 1 5 and 15' with ends 14 and 14' which support the rowlocks 1 6 and the centre portion 1 7 which projects towards the inside of the hull. The centre portion 17 is substantially arcuate and of similar shape to the cross-section of the hull. At its centre, the portion 1 7 is connected to the foot support 24 by means of the compression rods 22 and 23, which extend in diverging array from the portion 1 7 to respective ends of the lower lateral support 27'. Also extending from respective ends of the lower lateral support 27' are tension rods 21 and 20 which are connected to the cross-strut at the bend areas 46 and 47 between the centre portion 1 7 and the limbs 1 5 and 15'. Tension rods 18 and 19 extend from respective ends of the upper lateral support 27 of the foot support 24 at an acute angle to the longitudinal axis to respective ends 14' and 14 of limbs 15' and 15 to be connected adjacent the location of rowlocks 16.

The sandwich core 50, which may have a honeycomb structure, is covered by four cover plates 51-54 comprising Preprexmats which are adhered to the sandwich core as well as by respective end plates (not shown). Uni-directional carbon fibres (not shown) are laminated into the cover plates 51-54 along their compression and tension regions. The cover plates 51-54 are adhered to the sandwich core only after the cover plates have themselves hardened. In the regions of the bearing points around the rollers 30-33 and rowlocks 1 6 suitably shaped aluminium plates 57 are inserted into the cross-strut and adhered there.Finally, the whole of the crossstrut is surrounded by a fibre wrapping 58 which is saturated in resin and in which the fibres are aligned diagonally and cross-wise. Additional cladding may give further streamlining. After hardening, the cross-strut 12 may be connected at its respective bearing points to the tension and compression rods 1 8 to 23 which have already been mentioned and may be equipped with rollers 30 to 33 and 40 to 43 which have also already been mentioned.

In order to give the hull 10 of the boat the required torsional rigidity in the region of the slide tracks 35 and 36, a cross-member 59 which forms part of the seat and provides its support on the hull is located between the walls of the hull, and the hull 10 is also reinforced in the region of the slide tracks 35 and 36 with unidirectional carbon fibres laminated thereinto. The boat hull itself essentially comprises a sandwich construction of known type.

A seat member 60 is fixed to the crossmember 59, so as to be selectively adjustable in height and inclination as well as longitudinally of the hull. The rear edges of the seat member are formed as upwardly turned portions 61 which serve as a body support or abutment in order to provide the rower who is sitting on the seat member with support during movement of the foot support 24.

Obviously the racing rowing boat described with reference to Figures 1 to 5 may be adapted for several rowers and this is shown in Figures 6 and 7. In this case a cross-strut 70 is provided with a limb 1 5 on one side only in each case instead of the cross-strut 12 which overhangs the walls of the boat symmetrically. The cross-strut 70 is identical to the cross-strut 1 2 on its side having a kinked limb 1 5 and it also has a centre portion 71 identical to the portion 17. However its end remote from the limb 1 5 is supported by a bearing 72 which engages a slide member 73 mounted on the adjacent upper edge of the hull.

The bearing and slide member arrangement 72, 73 may be an inverted assembly of the unit 30, 35 and 38 shown in Figure 3 or any other suitable assembly which provides low-friction displacement of the cross-strut 70 as well as positive support.

As Figure 7 shows the cross-struts 70, which are unsymmetrical in relation to the hull of the boat, overhang one or other wall of the boat alternately in the form of cantilevers. Each crossstrut 70 is connected to an associated foot support 24 in identical manner to the cross-strut 12 except that the tension rod 1 8 or 19 not associated with a limb 1 5 extends from the respective end of the upper lateral member 27 to the cross-strut adjacent the bearing 72. In order to facilitate uniform rowing it may be advisable for the individual foot support/cross-strut units to be rigidly connected together by means of further rods (not shown).

Both embodiments share in common the fact that the spars are rigidly connected to the foot supports such that the spacing between rowlocks, as compared to the centre of the boat, is always the same irrespective of the longitudinal position of the foot support and the cross-strut in each case, and that the force is not transmitted by the rower to the boat via the oar mounting but rather via the seat. Additionally, the ends 14 and 14' of the limbs 15 and 15' in either embodiment may develop from the rectangular construction hereinbefore described to an aerofoil section as shown in Figure 4.

Claims

1. A rowing boat comprising a rigid hull, a seat fixed on the hull and associated foot support means which is movable longitudinally of the hull, a cross-strut which is adapted to support at least one scull or oar and is rigidly connected to the foot support means in longitudinally spaced manner therefrom by tension and compression support members, with the cross-strut comprising a torsionally- and flexurally-resistant, integral torsion box of which a portion extends across the hull, said portion being shaped to extend into the inside of the hull, and low-friction displacement means provided on the foot support means and on the cross-strut which are displaceable relative to associated means on the opposed upper edges of the hull.

2. A rowing boat as claimed in claim 1 in which the foot support means extends at least partly within the hull and wherein the lowermost part of the foot support means extends to a greater depth within the hull than the lowermost part of said portion of the cross-strut.

3. A rowing boat as claimed in claim 1 or claim 2 in which the foot support means comprises a framework to which the shoes of a rower may be connected.

4. A rowing boat as claimed in any one of claims 1 to 3 in which the cross-strut is rectangular in cross-section and comprises at least one kinked limb extending laterally of the hull from said portion that extends into the inside of the hull on which one scull or oar is capable of being supported.

5. A rowing boat as claimed in claim 4 in which two opposed kinked limbs are provided to support respective sculls or oars, the cross-strut having an approximately V-shaped profile.

6. A rowing boat as claimed in claim 4 or claim 5 in which the cross-strut comprises a torsion box of closed sandwich construction in which the outer plates have unidirectional carbon fibres laminated into the compression and tension regions thereof and said outer plates are bonded to the core subsequent to them setting, and wherein the whole cross-strut is wrapped in a fibrous layer which is saturated in resin, the fibres in said layer being directionally arranged diagonally and cross-wise.

7. A rowing boat as claimed in claim 6 in which bearing members are inserted into the cross-strut prior to said fibre wrapping at locations to provide support for the or each oar or scull and for each low-friction displacement means.

8. A rowing boat as claimed in claim 7 in which said bearing members are of aluminium.

9. A rowing boat as claimed in any one of the preceding claims in which a support member extends at an angle to the longitudinal axis of the boat between the cross-strut at a location adjacent the position at which the or each oar or scull is to be supported and the uppermost part of the foot support means on the same side of the hull as said oar or scull support position, and two further support members extend in diverging arrayfrom substantially the centre of said portion of the cross-strut which extends into the inside of the hull to respective lateral ends of the lowermost part of the foot support means.

10. A rowing boat as claimed in claim 9 in which two further support members extend from respective lateral ends of the lowermost part of the foot support means to respective extremes of the aforesaid portion of the cross-strut adjacent the upper edges of the hull.

11. A rowing boat as claimed in any one of the preceding claims in which each low-friction displacement means comprises a roller and the associated means comprises a track provided on each opposed upper edge of the hull.

1 2. A rowing boat as claimed in claim 11 in which each low-friction displacement means comprises two rollers which engage respectively upwardly- and downwardly-facing surfaces of the track to positively locate the cross-strut/foot support means unit on the tracks.

13. A rowing boat as claimed in any one of the preceding claims in which the fixed seat is selectively-adjustable longitudinally of the hull and for height and inclination.

14. A rowing boat as claimed in any one of the preceding claims in which the seat has an integral rear portion which is turned upwardly to serve as a backrest.

15. A rowing boat as claimed in any one of the preceding claims in which the seat serves as a strut which assists in torsionally rigidifying the hull.

1 6. A rowing boat as claimed in claim 4 or any one of claims 6 to 15 when dependent therefrom in which a plurality of cross-strut/foot support means units and associated seats are provided in longitudinal alignment.

1 7. A rowing boat as claimed in claim 16 in which all said units are rigidly connected together.

18. A rowing boat as claimed in any one of the preceding claims in which the hull is reinforced in the regions which support the or each seat and the means thereon associated with the lowfriction displacement means by unidirectional carbon fibres which are laminated thereto.

19. A rowing boat as claimed in any one of the preceding claims in which the hull comprises two inherently rigid portions secured together.

20. A rowing boat substantially as herein described with reference to Figures 1 to 5 of the accompanying drawings.

21. A rowing boat as claimed in claim 20 but modified substantially as herein described with reference to Figures 6 and 7 of the accompanying drawings.