WO1998012105A1 - Jib-roller for two independent sails on same stay - Google Patents

Abstract

The object of the invention is to have at the same time two sails set one above the other on the same stay of a sailing vessel and to allow to roll up any one of the two independently of the other, or both simultaneously: the system can thus be defined as a single jib-roller permitting independent modification of each surface of the two superimposed sails.

Description

DESCRIPTION Jib-Roller for Two Independent Sails on Same Stay

TECHNICAL FIELD My invention permits to have aL the same time two sails set one above the other on the same stay of a sailing vessel and allows to roll up any one of the two independently of the other, or both simultaneously: the system can thus be defined as a single jib-roller permitting independent modification of each surface of the two superimposed sails.

BACKGROUND ART All jib-rollers commercialized at present have the rolling-up mechanism installed at the foot of a stay and connected to a groove set around the stay. This groove extends from the mechanism (generally a drum) to the upper end of the stay on which it is free to rotate: the rotation permits rolling up the sail in a continuous way from full extension to completely furled. The relevant snags can be shortly described as follows:

- one only sail can be set and trimmed on a stay;

- because of its draught the sail does not give full performance especially in partial rolled positions due to the turbulence created by the bulk at its luff: in fact present jib-rollers are considered efficient mainly as sail "furlers" ; - a considerable effort is necessary to roll up the sail, especially when beginning rolling on account of the large pressure of the wind on the sail necessarily large being the only sail on the stay; this inconvenience is taken care of by increasing the diameter of the drum taking the control rope or steel cable, generally operated from the cockpit;

- the bulk of the drum at the foot of the stay considerably limits movement at the bow, a dangerous impediment for the crew; it moreover makes it difficult to handle the anchor, which is generally situated at the bow.

DISCLOSURE OF INVENTION Preliminary Notes: a) The dimensions indicated in the following description of the system refer to a prototype already existing and tested on a 35' boat; b) Photographs showing different operating conditions are available c) an existing jib- roller can be modified to be used with system. In this case nearly all the existing elements can be used: upper end-piece, groove, halyard swivel and bottom end-piece (except the rolling drum) . The existing sail can be modified by having it. cut and reshaped into the two sails to be used by the system. The essential parts of the system are the following:

A) The rolling-up mechanism

B) The two sails connected to A C) The element connecting the two sails

D) The controls of the mechanism

BRIEF DESCRIPTION OF THE DRAWING Fig. DENIA 001 (attached) shows the different sail plans that can be obtained (it is to be borne in mind that the term "reduced" is used here to mean also "totally reduced" ) :

- Option 001a: both sails completely open - Option 001b: upper sail reduced; lower completely open

- Option 001c: upper sail completely open; lower reduced

- Option OOld: both sail reduced Option 001a

The two sails, connected through D) , assume the shape of a normal Genoa partially battened. Option 001b

The lower sail can be used as a storm staysail (not on a small boat due to the reduced height on the sea level) . The lower sail can easily be changed (the mechanism -see later- is connected to the stay at man-height above the foredeck for the great majority of boats) : it is thus possible to increase the total surface when sailing under Spinnaker or MPS by using a lighter lower sail. Option 001c Even a partial reduction grants good visibility (with only small reduction in efficiency) . This is especially useful when sailing in crowded waters or during night passages. The parts forming the system are described hereafter. A) The Rolling-up Mechanism

It is rigidly connected to the stay at a point P projection of the sheet point. Two different solution are possible:

- The mechanism is firmly connected around the forestay;

- The mechanism is mounted (in the position P) at the top of a metallic rod on which the rigging screw is mounted.

It is formed by the rotating parts (Al) and by the standing part (A2) .

Al) Rotating Parts

They can be realized both by teflon rotating boxes and by ball bearings.

Al.l) The lower and upper rotating drums are connected respectively at the lower sail's head point and dL the upper sail's tack point.

A1.2) The rolling drums are 10 mm high and 170 mm in diameter.

Al.3) The distance between the two rolling drums is less than 25 mm.

A1.4) Such small distances have the purpose of:

- minimizing the size of the mechanism in order to reduce its negative effect on the air flow;

- minimizing the space between the two sails to reduce the the loss of sail area close to A) . For the large part of the two sails this is achieved by D) . A2) Standing Part It supports the first sheaves which permit bringing the control cables to the cockpit. The control cables exit in front (bow side) of the stay.

B) The two sails connected to A

The upper sail is hoisted by ordinary means (i.e. hoisting swivels, halyard, etc.) as found in all existing jib- rollers.

The lower sail in most cases can easily be set manually: this depends only on the distance foredeck-mechanism. The two sails are cut (or existing sails are modified) perpendicularly to the stay and have separate sheets.

A distance of approx 60 mm is left between the foot of the upper sail and the upper edge of the lower sail. This space is eliminated by C) .

To minimize the negative effect on the airflow ot the bulk made by a disorderly rolling, a cloth or some other component of a size and thickness calculated to remove the draught of the sail is inserted in the luff of the sail.

C) The Element connecting the two sails

An element with a double opposite groove is connected to A2 to permit an orderly rolling of the sails, each of them set in one of the grooves where it can slide during the rolling.

This element is shorter than the distance L between the point P and the mast or the lower shrouds to avoid problems when tacking. This element is realized by means of a double groove band and is very light and flexible.

This element is supplied in its aft part with a sort of opening sheet fairlead so that when both sails are partially open there is only one trimming point for both sail:; (it coincides with the terminal part of the element. With the sails completely open the whole system is like a Genoa partially battened. D) The controls of the mechanism

A 7*19 steel cable d.4 is adopted for each sail,- they are brought to the cockpit in the usual way.

Claims

CLAIMS The System is characterized by the following points: 1) It permits to install on the same stay two sails, one above the other, independently set and rolled up. 2) The two sails are connected between them by a rolling-up mechanism previously solidly connected on the stay; the mechanism permits to roll up any of the two sails separately or both sails together from fully open to fully furled. 3) The mechanism is made by one part to be solidly attached to the stay and by two sets of parts that can be rotated independently from each other. 4) The mechanism is positioned on the stay at a distance greater than 1000 mm from the deck of the boat. 5) Two sails are connected to the mechanism fixed to the s ay. 6) The coupling of the rotating parts to the standing part of the mechanism can be made both by rotating boxes and by bearings . 7) The rolling-up drums are less than 40 mm apart.

8) The distance between the lower surface of the upper drum and the upper surface of the lower drum is smaller than 50 mm.

9) The outer diameter of the circular plates of the drums is smaller than 250 mm.

10) The weight of the mechanism (except the elements connecting to the grooves) is smaller than 3 kg. 11) The mechanism can be contained in the volume occupied by a double cone with a single face of 400 mm diameter and a height of 200 mm between the two vertices.

12) The tack of the upper sail is attached to the upper drum and the head of the lower sail is attached to the lower drum.

13) The two control cables exit of each the respective drums in front (bow side) of the stay, always in the lee of the sails and do not prevent either the connection of the two sails, or tacking.

14) The two sails to be set on the same stay can be made of cloth of different weights.

15) Each sail can be supplied in its forward side (immediately abaft the luff) with a reinforcement in cloth or other material of such a dimensions and thickness to permit, when rolling up the sail, to take care of the draught of the sail and to permit a correct rolling of the sail on the groove.

16) The upper edge of the lower sail and the lower edge of the upper sail have textile flexible rope, which permits setting the sail in a groove.

17) A highly flexible and light element is connected to the fixed part of the mechanism.

18) This element has two opposite grooves in which slide the two flexible ropes connected to the sails.

19) This element is made such that it allows a correct rolling up of the sails.

20) This element is supplied at its free end by opening fairleads. 21) This element is designed in such a way that the sails can be touching and/or overlapping at the exit point of the element. 22) A normal stay (composed of the metallic cable and the rigging screw) can be substituted by a group of three elements of the same total length: a) the metallic cable; b) the upper two parts of the rigging screw; c) a metallic rod threaded at the top on which the rolling mechanism is mounted. In other word it is as if the lower screw of the rigging screw is substituted by the above described rod.