WO2009141597A1

WO2009141597A1 - Retractable keels for boats

Info

Publication number: WO2009141597A1
Application number: PCT/GB2009/001245
Authority: WO
Inventors: William Harold Vernon Steynor
Original assignee: William Harold Vernon Steynor
Priority date: 2008-05-17
Filing date: 2009-05-18
Publication date: 2009-11-26
Also published as: GB201021441D0; GB2472561B; EP2293972A1; GB0809023D0; GB0908504D0; GB2472561A; GB2459984A

Abstract

A retractable boat-keel involves first and second pivoted keel-plates (1,2) which are retained retracted end-to-end in longitudinal alignment by a cable (16) attached to an interconnecting link (13) hinged to their bottom ends. The cable (16) is released for deployment of the keel, this allowing the first plate (1)to swing down and via the link (16) draw the second plate (2) with it. The second plate (2) has rollers (9) which run on rails (10) that descend tipping the second plate (2) forward so that it is propelled under gravity to be retained edge-on against the first plate (1). Upward movement of the keel from the deployed state by grounding, knock-down or roll, is blocked by abutment of stops (20) on the second plate (2) with lock-stops (21) on the keel- box (3), but retraction of the keel is achieved by pulling-in the cable (160. This draws the second plate (2) up the rails (10) under the lock-stops (21) and, via the interconnecting link (13), pivots the first plate (1) back with it into the retracted condition.

Description

Retractable Keels for Boats

This invention relates to retractable keels for boats.

According to the present invention there is provided a retractable keel for a boat, comprising first and second keel- plates that are hinged together end-to-end for longitudinal alignment with one another in the retracted condition of the keel, wherein the first keel-plate is pivoted for movement in a first of two senses about its pivot axis from the retracted condition of the keel and by such movement to draw the second keel-plate via the hinge connection between the two keel-plates to move into longitudinal abutment with the first keel-plate in establishing the keel in its deployed condition, and wherein the first and second keel-plates when in the deployed condition of the keel are restrained together in that condition by stop-means that blocks pivotal movement of the second keel -plate in the second sense about the pivot axis.

The pivotal movement of the second keel-plate may be blocked by abutment of the second keel-plate with the stop means in such movement. In this respect, the keel may include guide means for guiding movement of the second keel-plate into longitudinal abutment with the first keel-plate in the deployed condition of the keel, the guide means guiding the second keel-plate in its movement into and out of such abutment with the first keel-plate to move transversely clear of the stop means . The guide means may incline downwardly to cause the second keel-plate to descend into abutment with the first keel-plate under gravity

Deployment of the keel may take place under gravity. More particularly, first keel-plate may pivot in the first sense about the pivot axis under gravity for its movement into the deployed condition, and in this condition the second keel-plate may bear positively under gravity against the first keel-plate. A retractable keel for a boat, in accordance with the present invention will now be described, by way of example, with reference to the accompanying drawings, in which:

Figures 1 and 2 are, respectively a sectional side-elevation and a plan view of the keel of the invention as retracted into a box in the bottom of a boat, the section of Figure 1 being taken on the line I-I of Figure 2 and the plan of Figure 2 being of the keel with the lid of the box removed;

Figure 3 is an enlarged sectional end-elevation of the retracted keel; the section of Figure 3 being taken on the line III-III of Figure 1;

Figure 4 is a sectional side-elevation corresponding to that of Figure 1, with the keel deployed; and

Figure 5 is an enlarged sectional plan-view of the deployed keel, the section being taken on the line V-V of Figure 4.

Referring to Figures 1 to 3 , the retractable keel of this example comprises first and second keel -plates 1 and 2 respectively which are both of elongate form and which in the retracted condition shown, are housed extending end-to-end in mutual alignment within an elongate, rectangular box 3. The box 3, which is mounted lengthwise substantially horizontally under the floor (not shown) of a cabin of the boat, has side-walls 4, end-walls 5 and a lid 6, but its bottom 7 is open through the bottom of the boat.

The first keel-plate 1 is pivoted within the box 3 on a shaft 8 that extends between the two side-walls 4, whereas the second keel-plate 2 is supported within the box 3 on a pair of wheels or rollers 9 which run on guide-rails 10 mounted on the two side- walls 4. The two plates 1 and 2 are interconnected at their bottom-ends 11 and 12 respectively, by a hinged connection in the form of a link 13 that is pivoted to each of them individually. The link 13 is accommodated (as represented by a cut-away portion in Figure 1) at bottom-ends 11 and 12 of the plates 1 and 2 where they are both individually thickened on either side by the attachment of a pair of side-plates 14. More particularly, the link 13 is sandwiched between the pairs of plates 14, and pivot pins 15 that extend through them pivot it to the two keel-plates 1 and 2.

A cable 16 is attached to the centre of the link 13 and held taut to retain the two plates 1 and 2 horizontal substantially in alignment with one another wholly within the box 3, in the retracted condition of the keel. Release of the cable 16 to run out allows the two keel-plates 1 and 2 to swing down under gravity through the open bottom 7 of the box 3 with the plate 1 pivoting downwardly on the shaft 8 in the counter-clockwise sense (as seen in Figure 1) and the plate 2 pivoting downwardly in the clockwise sense (as seen in Figure 1) on the rollers 9. More particularly, as the plate 1 pivots downwardly, the plate 2 is drawn with it by the interconnecting link 13 causing the rollers 9 to run along the rails 10.

The rails 10 extend substantially horizontally towards the point beyond which further downward pivotal movement of both plates 1 and 2 would be arrested if the rollers 9 continued to be restricted to horizontal movement. Before this point is reached however, the rails 10 incline downwardly and thereby tip the plate 2 forwardly (further in the clockwise sense) on its rollers 9 so that it is propelled down the rails 10 under gravity. This allows the plate 1 to continue its full pivotal descent under gravity, with the plate 2 following to impact it edge-on. Under the action of gravity on plate 2 its leading-edge 17 continues to bear positively against the impacted trailing-edge 18 of plate 1 so that the keel formed as illustrated in Figure 4 by the abutting plates 1 and 2, is deployed fully, and remains so, under its own weight. The cable 16 attached to the link 13 is run out as the plates 1 and 2 descend into the fully-deployed condition. As deployment proceeds it enters a slot 19 (see Figure 2 especially) in the leading edge 17 of the plate 2 so as to extend down to the link 13 between the abutting edges 17 and 18 of the deployed keel.

As illustrated in particular by Figure 5, the two pairs of side- plates 14 that provide thickening of the keel-plates 1 and 2 at their bottom-ends 11 and 12 together form a bulb to the deployed keel.

The deployed keel acts like a fixed keel in that it remains in the fully-deployed condition when subjected to forces such as those experienced in the event of grounding, knockdown and roll (even of more than ninety degrees) of the boat. In this respect, forces of this nature tend to pivot the plates 1 and 2 in the clockwise sense on the shaft 8 and lift the rollers 9 from the rails 10. This movement, however, is quickly blocked by abutment of stops 20 on the plate 2 with lock-stops 21 of the box 3, so that the keel remains in the fully-deployed condition and is effectively automatically locked in this condition against such forces. Accordingly, there is no risk of damage to the boat from the keel even when the boat is inverted.

Retraction of the keel is readily achieved by pulling-in the cable 16. This causes the plate 2 to move rearwardly with its rollers 9 running on the rails 10 to break the abutment between its edge 17 with the edge 18 of plate 1 and pass the stops 20 transversely clear from under the lock-stops 21. As the cable 16 continues to be pulled in so the rollers 9 run up the incline and onto the horizontal portion of the rails 10 until the plate 2 has returned to its substantially-horizontal condition shown in Figure 1. In returning to this condition the interconnection with the plate 1 provided by the link 13 draws the plate 1 to pivot on the shaft 8 in the clockwise sense back into alignment with the plate 2 to restore the fully-retracted condition. The cable 16, which may be replaced by a strap or other form of line, may be wound in and out by a hand- or electrically-operated winch, and more particularly, instead of passing through an aperture 22 in the lid 6 of the box 3 as illustrated, may extend to the winch substantially horizontally within the box 3 so that it lies within the slot 19 of the plate 2 when the keel is retracted as well as deployed. A roller (not shown) may be mounted between the side-walls 4 just above the location occupied by the link 13 in the retracted condition, as a guide for the line or cable 16.

In one construction of a retractable keel as described above, the keel-plates 1 and 2 are of cast-iron, and the box 3 is 2.44 m in length and 0.33 m in depth. The keel in deployment extends by

0.94 m and has chord of 0.65 m and its maximum thickness is 5 cm whereas that of the bulb is 15 cm.

Claims

Claims :

1. A retractable keel for a boat, comprising first and second keel-plates that are hinged together end-to-end for longitudinal alignment with one another in the retracted condition of the keel, wherein the first keel-plate is pivoted for movement in a first of two senses about its pivot axis from the retracted condition of the keel and by such movement to draw the second keel-plate via the hinge connection between the two keel-plates to move into longitudinal abutment with the first keel-plate in establishing the keel in its deployed condition, and wherein the first and second keel-plates when in the deployed condition of the keel are restrained together in that condition by stop-means that blocks pivotal movement of the second keel-plate in the second sense about the pivot axis.

2. A retractable keel according to Claim 1 wherein the pivotal movement of the second keel-plate is blocked by abutment of the second keel-plate with the stop means in such movement.

3. A retractable keel according to Claim 2 including guide means for guiding movement of the second keel-plate into longitudinal abutment with the first keel-plate in the deployed condition of the keel, the guide means guiding the second keel- plate in its movement into and out of such abutment with the first keel-plate to move transversely clear of the stop means.

4. A retractable keel according to Claim 3 wherein the guide means inclines downwardly to cause the second keel-plate to descend into abutment with the first keel-plate under gravity.

5. A retractable keel according to Claim 3 or Claim 4 wherein the second keel-plate runs on wheels or rollers along the guide means .

6. A retractable keel according to any one of Claims 1 to 5 wherein the second keel-plate bears positively under gravity against the first keel-plate in the deployed condition of the keel .

7. A retractable keel according to any one of Claims 1 to 6 wherein the first keel-plate pivots in the first sense about the pivot axis under gravity for its movement into the deployed condition of the keel.

8. A retractable keel according to any one of Claims 1 to 7 wherein the first and second keel-plates are retained in the retracted condition by a cable, tape or other line attached to them.

9. A retractable keel according to Claim 8 wherein the cable, tape or other line is attached to the hinged connection between the first and second keel-plates for retaining them in the retracted condition.

10. A retractable keel according to Claim 9 wherein the cable, tape or other line in the deployed condition of the keel extends to the hinged connection via a slot between the abutting first and second keel-plates in that condition.

11. A retractable keel according to any one of Claims 8 to 10 wherein the condition of the keel is changed from the retracted condition to the deployed condition by run out of the cable, tape or other line, and from the deployed condition to the retracted condition by drawing in the cable, tape or other line.

12. A retractable keel according to any one of Claims 1 to 11 wherein the hinged connection between the first and second keel- plates is a link that is pivoted to each of them individually.

13. A retractable keel according to any one of Claims 1 to 12 wherein the first and second keel-plates in the retraced condition of the keel are housed within a box, the box has an open bottom through which the first and second keel-plates extend in the deployed condition of the keel.

14. A retractable keel according to Claim 13 wherein the first keel-plate is pivoted on a shaft mounted in the box.

15. A retractable keel according to Claim 13 or Claim 14 wherein the stop means comprises one or more stops mounted on the box for abutment by one or more stops respectively of the second keel-plate.

16. A boat including a retractable keel according to any one of Claims 1 to 15.