GB2037686A - Sailboat masts - Google Patents

Abstract

A mast for a sailboat comprises a mast main body 11 and a sail-attaching portion 17 with a space between the main body 11 and the attaching portion 17 for passage of air therethrough to render the mast and sail aerodynamically efficient. <IMAGE>

Description

SPECIFICATION Sailboat masts The present invention relates to masts for sailboats.

Various masts having an improved aerodynamic efficiency relative to the wind have heretofore been developed for use in sailboats. They include a rotatable mast, and also the masts which are shown in Figures 1 to 4 of the accompanying drawings. In the Figures 1 to 4 a mast of circular cross-section is seen in Figure 1, a mast is shown in Figure 2 and resembling a pear in cross-section; another mast of modified D-shaped cross-section is illustrated in Figure 3 and a wing mast is shown in Figure 4. These masts, however, still involve problems in performance and handling.

The mode of attachment of a sail to a mast can also lead to problems. Referring to Figures 5 to 8 of the drawings, it was for a long time common practice to fasten the sail to the mast with a rope as shown in Figure 5 or tie the sail to rings fitted around the mast, as seen in Figure 6. These methods nevertheless are cumbersome and aerodynamically inefficient. According to a common method present ly employed, a boltrope stitched to an edge of the sail is passed through a straight luff groove formed on one side of the mast, as shown in Figure 7.

Alternatively a looped portion of the sail is fitted around the mast as illustrated in Figure 8.

When the sail is attached to the conventional mast of a sailboat in such a known manner, the fastened edge portion of the sail subject to the wind to aerodynamic separation or stagnation of the air flow. This results in the serious drawback that the sail fails to act efficiently relative to the wind.

An object of the invention is to provide a mast which can be designed to overcome the foregoing drawbacks of the conventional masts for sailboats.

The present invention provides a mast for a sailboat comprising a mast main body and a sail attaching portion with a space provided between the main body and the attaching portion for passing air therethrough.

According to a preferred embodiment of the invention, the mast main body comprises a pair of wings arranged in parallel with a suitable space provided therebetween.

According to another preferred embodiment of the invention, the mast main body comprises a substan tially semicircular tube with its circular arc surface facing toward a direction opposite to the said attaching portion.

Embodiments of the present invention will now be described by way of example with reference to Figures 9 to 17 of the accompanying drawings.

In the drawings: Figures 1 to 4 are perspective views showing conventional masts for sailboats; Figures 5to 8 are perspective views illustrating conventional modes for attaching a sail to a mast; Figure 9 is a perspective view showing a mast according to the present invention; Figure 10 is a cross-sectional view showing of the mast of Figure 10; Figure 11 is a plan view schematically showing the mast of Figures 9 and 10 as it is mounted on a sailboat; Figure 12 is a plan view schematically to illustrate the airflow with the mast of Figures 9 and 10 aligned against the wind; Figure 13 is a perspective view showing another embodiment of the present invention; Figure 14 is a cross-sectional view of the mast of Figure 13; Figures 15 and 16 are plan views schematically showing the mast of Figures 13 and 14 as it is mounted on a sailboat; and Figure 17 is a plan view schematically to illustrate the air flow with the mast of Figures 13 and 14 against the wind.

With reference to the drawings, Figures 9 to 12 show a sailboat mast embodying the present invention. A mast main body 1 comprises a pair of wings 2 and 3 arranged in parallel with a suitable space provided therebetween. The pair of wings 2 and 3 are interconnected in an assembly by a suitable number of plates 4.

At an intermediate portion between the rear end 5 of the wing 2 and the rear end 6 of the wing 3, namely at the rear end centre portions of the connecting plates 4, there is provided an attachment portion 9 having a groove 7 open to the rear for attaching a sail 8 to the mast.

Preferably the mast is mounted turnably on a sailboat 10 for turning as shown in Figure 11.

When the mast is against the wind, the mast is subjected to the airflow shown in Figure 12. The wind blowing into the space between the pair of wings 2 and 3 of the mast main body 1 flows through the space between the main body 1 and the said attaching portion 9 rearwardly along the curved surfaces of the sail 8.

Accordingly the edge of the sail 8 attached to the mast main body 1 as well as the main body 1 will not be subjected to the aerodynamic separation or stagnation of the flow, so the mast acts as if it were a slotted wing which would retard the stalling of aircraft for the safety of aviation.

Figures 13 to 17 show another sailboat mast embodying the present invention. A mast main body 11 is in the form of a substantially semicircular tube having a circular arc face 12 on one side and a planar portion 13 on the other side.

A suitable number of support plates 14 are attached to the planar portion 13 of the mast main body 11. An attaching portion 17 having a groove 15 open to the rear for attaching a sail 16 to the mast is provided at the rear end centre portions of the support plates 14.

The mast may be rotatably mounted on a sailboat 18 as seen in Figure 15 or fixedly mounted thereon as shown in Figure 16.

When the mast is against the wind, the mast is subjected to the air flow shown in Figure 17. The wind passing over the circular arc face 12 of the mast main body 1 and also through the space between the mast main body 1 and the sail attaching portion 17 flows rearwardly along the curved surfaces of the sail 16.

As is the case with the first embodiment, the main body 11 and the edge of the sail 16 attached thereto will not be subjected to the aerodynamic separation or stagnation of the flow, so the mast acts as if it were a slotted wing which would retard the stalling of aircraft for the safety of aviation.

According to the conventional method shown in Figure 6, the sail is attached to the mast with a space formed therebetween, but the space inherently differs from that of the invention: the rope gives resistance against the wind and the attached edge of the sail will turn relative to the mast.

Although the invention has been described above with reference to specific embodiments, it is to be understood that various changes and modifications can be made.

Claims (5)

1. A sailboat mast comprising a mast main body and a sail-attaching portion with a space provided between the main body and the attaching portion for passage of air.

2. A mast as defined in claim 1 wherein the mast main body comprises a pair of wings arranged in parallel.

3. A mast as defined in claim 1 wherein the mast main body is in the form of a substantially semicirculartube with its circular arc surface generally facing a direction opposite to the sail-attaching portion.

4. A mast as defined in any one of claims 1 to 3 wherein the sail-attaching portion comprises a grooved member four receiving a boltrope attached to the said edge.

5. A sailboat mast substantially as hereinbefore described with reference to and as illustrated in Figures 9 to 17 of the accompanying drawings.