GB2367796A

GB2367796A - Counterbalanced rigging arrangement for a multi-hulled sailing boat

Info

Publication number: GB2367796A
Application number: GB0025176A
Authority: GB
Inventors: Robert Colin Harvey Webb
Original assignee: Individual
Current assignee: Individual
Priority date: 2000-10-13
Filing date: 2000-10-13
Publication date: 2002-04-17
Also published as: GB0025176D0

Abstract

A multi-hulled sailing boat where the mast, rigging and sail or sails are counterbalanced and kept in an erect position against the effect of the wind by the weight of the crew acting around a pivoting mechanism. The counterbalancing effect may be supplemented by muscular action taken by the crew. The pivoting mechanism may comprise a longitudinal pivoting bar 2 having a socket 1 for the base of the mast at one end and a platform 8 mounted to the other end of the pivoting bar by means of a lever arrangement 5 and 6, on which the crew can stand or sit. The weight of the crew acting on the platform provides a reactive force to the load applied to the mast by the wind acting on the sails, keeping said mast in an erect position.

Description

A METHOD FOR MAINTAINING LATERAL STABILITY IN CATAMARANS AND MULTI-HULLED SAILING BOATS This invention relates to a method for maintaining lateral stability in catamarans and multi-hulled sailing boats.

In the following descriptions the use of the word'catamaran'should be taken to include also'multi-hulled' craft and the use of the word'man'should be taken to mean also'woman'.

Most catamarans rely, for their lateral stability against the pressure of the wind, upon the width between the hulls and the the weight of the crew on the windward side of the boat. In addition the crew may hang outwards to windward to exert a greater leverage against the wind effect on the sails and hence the boat may be induced to go faster.

However there are certain disadvantages: 1. to allow for the crew to get from one side of the boat to the other easily when going about, a form of decking has to be provided and this adds weight. Because of this most catamarans need some form of trailer to transport them.

2. there is the need for the crew to be fairly athletic to be able to scramble from one side of the catamaran to the other quickly when going about.

3. there is always the possibility that with squally winds an error of judgement may be made and the catamaran will overturn. If this happens, with the crew in the water, catamarans, in general, can be difficult to right and the situation may even turn hazardous.

The above disadvantages make, in general, the sailing of catamarans a) expensive and b) limited to athletic and experienced sailors. This therefore necessarily limits the market.

It is therefore felt desirable to provide a system which will : 1. allow for the production of a catamaran that is lighter than current catamarans, less bulky and less expensive 2. allow for the production of a catamaran that is easy to transport, for instance on the top of a small car 3. reduce the need for atheleticism of the crew 4. reduce the risk of overturning and therefore make the sport less hazardous 5. allow for the production of a catamaran that is easy to sail 6. increase the comfort and enjoyment of sailing without lessening the excitement of speed 7. increase the overall market by making catamaran-sailing available to a wider public According to the present invention there is provided a system whereby a catamaran has a mast that is pivoted at the base and kept erect by the weight of the crew standing on a platform which is part of the pivoting mechanism. The effect of the wind against the sails is counterbalanced by the weight of the crew and in a squall the mast tips further to spill wind and prevent capsizing. Because the mast tilts about a longitudinal pivot bar which can be approximately only 2. 75ft above the water and because the effect of the wind to capsize the catamaran necessarily acts at this pivot line, the capsizing effect is less than with a standard catamaran where the force to capsize acts higher up the mast.

There is also a certain control that can be exercised optionally by the helmsman where, by pulling up on a bar (the'hang-on'bar) which is part of the boat structure, the effective weight of the helmsman can be increased. In doing this the mast will tilt less, the sails will take more wind and the boat will go faster. The force producing the apparent extra weight is transferred to the boat and the boat itself will heel over more.

The helmsman in this instance is sailing the boat more as a standard catamaran However the chance of overturning is much less because of the speed with which, if feeling via his hands and arms the added sudden pressure of a wind-squall, he can release his pull on the'hang-on-bar'and allow the mast immediately to tilt further and spill wind For the helmsman to be able to sail the catamaran from the position of the swinging platform, a pre-set rigging is used which incorporates a'through-boom'. This revolves around the mast and there is one boom-sheet only to control; this rigging is now established commercially and does not feature as one of the claims of this invention.

A specific embodiment of the invention, which in this case applies to a catamaran for a single sailor, will now be described by way of example with reference to the accompanying drawings in which: Sheet 1/4 Figure 1 is a side view of the catamaran and shows the principle of the invention Sheet 2/4 Figure 2 is a plan view, looking downwards, to the same scale as Fig 1. It shows the swinging platform mechanism and also a conventional twin-rudder system. On this sheet are indicated the sections A-A, B-B and C-C.

Sheet 3/4 Figure 3 is a view looking forward from section A-A and shows the forward bearer Figure 4 is a view looking forward from section B-B and shows the aft main bearer with the helmsman's platform (but without the seat) Sheet 4/4 Figure 5 is a view looking aft from section C-C and shows the mast-lock mechanism (not shown in Fig 4 for purposes of clarity) Figure 6 is an expanded and perspective view (looking forward) of the tiller-wheel segment shown in Fig 4 (Sheet 3/4) Figure 7 is a perspective view (looking aft) of the helmsman's platform plus part of the swing-arm mechanism which slots into the platform; the figure also shows the optional seat . Note: To distinguish the rudder lines from the fixed structure of the catamaran the rudder line's number, 13, is also marked by a KEY on the drawings: viz: KEY = 13 The following is a description of these Figures: Sheet 1/4 Fig 1 shows the whole catamaran from a side view with its floats, mast and sails, and the pivoting system. The mast slots into a mast socket 1 (and secured by a latch, not shown) which is fixed to the longitudinal pivot arm 2. The pivot arm 2 pivots between the forward bearer 3 and the the aft main bearer 4. The aft end of the pivot arm 2 supports a down-arm 5 which is connected to a longitudinal actuating arm 6. The angle of the down arm 5 is strengthened by the stay 7. The actuating arm 6 slots into the helmsman's platform 8 which supports the weight of the sailor. The junction between the actuating arm 6, the downward arm 5 and the stay 7 is strengthened if necessary by inserts at 9. The helmsman's platform 8 swings to port or starboard with the movement of the mast acting via the downward arm 6. The platform can pivot on the slot-in actuating arm 6 but remains horizontally positioned by the control of two swinging arms 24 (not shown in Fig 1 for reasons of clarity but portrayed in Fig 4 on sheet 3/4). At the forward part of the platform is a toe-guard 10 which is also shown in Fig 7 on sheet 4/4.

For clarity in this Fig 1 the down arm 5 is shown slightly to the left (forward) of its actual position in which it would be partly obscured by the aft main bearer 4. Also for the sake of clarity a mast-locking arm 25 which is an upper extension of arm 5 is not shown here but in Fig 5 on sheet 4/4.

There is an optionally removable seat 11 which is seen slotted into the aft part of the platform 8 This is also shown in Fig 7 on sheet 4/4.

Sheet 2/4 Fig 2 is a plan view, looking downwards, of the catamaran with its hulls, and is to the same scale as Fig 1 sheet 1/4. The longitudinal pivot arm 2 with the mast socket 1 is shown pivoted between the forward bearer 3 and the aft main bearer 4. The down arm 5 is shown together with the actuating arm 6 and helmsman's platform 8. This platform is shown in a position as if the wind had caused the mast to tilt to starboard with the platform swinging to port. Shown also is a conventional twin-rudder system which has the link-arm 12. This link-arm is controlled by the movement of rudder lines 13 (see KEY) which lead back via pulleys 14 to the base of the aft main bearer 4 and up to the tiller wheel segment 21 as shown in Fig 4 sheet 3/4.

Referring to Sheet 3/4, Fig 3 shows the forward bearer 3, which in this embodiment of the invention is composed of 11/2"diameter aluminium alloy tube. The view is looking forward from section A-A (Fig 2).

At the top of front bearer 3 is a bearing plate 15 in which, on assembly, the pivot arm 2 (not shown in this figure) rests and pivots. The bearing plate has a snap-down lock (not shown) to keep the pivot arm in position. There is a lateral stay 16. The lower ends (legs) of the forward bearer slot into appropriately sized receptor tubes 17 which are incorporated in the structure of the hulls and which project sufficiently to allow for appropriate conventional latches (not shown) which hold the bearer legs securely in position without the possibility of twisting.

Sheet 3/4 Fig 4 shows the aft main bearer 4 of similar 11/2"diameter aluminium alloy tube as the forward bearer and of the same curvature. The view is looking forward from cross section B-B (Fig 2). A crossplate 18 is bolted to the aft part of the rear bearer 4 and houses the aft pivot arm socket 19 and a spindle-bolt 20 (the end only is indicated) on which rotates the tiller wheel segment 21 with the tiller arm 22. The tiller wheel segment functions forward of the crossplate 18 and underneath and within the dimensions of the curvature of the rear bearer 4. The tiller arm 22 is mounted on the tiller wheel segment in such a way that it is staggered back and can project upwards aft of the top of the aft main bearer (see Fig 6 sheet 4/4). The rudder lines 13 (KEY 13) pass via pulleys 36 and 23 to the conventional twin rudder system at the stem of the catamaran (see Fig 2 sheet 2/4).

The helmsman's platform 8 slots over and pivots on the actuator arm 6 and is held in a horizontal position by control arms 24 swinging from the crossplate 18. The'hang-on'bar 25 gives the helmsman something to hold on to when the platform is moving with the swing of the mast. It is also the means by which, if he pulls up on the bar, he can effectively increase his weight and thereby keep the mast more upright and gain greater speed. Fixed to the'hang-on bar'are cleets 26 for securing the boom sheet. At 27 there is an indication of the angle of the mast when the the helmsman's platform is in the position as shown. As with the forward bearer the bottom ends (legs) of the rear bearer, slot into appropriate tubes in the hull and can be securely fixed.

Sheet 4/4, Fig 5 shows a mast-lock system which has been omitted from previous illustrations for the sake of clarity. The view is looking aft from section C-C. 28 is an upward extension of the down-arm 5 shown in Fig 1 sheet 1/4.29 is a lateral pivoted arm with a slot 30. When the catamaran has reached its mooring, the boom sheet released, the sails let go and the mast nearly upright, the hold-up latch 31 is released and this allows the lateral arm 29 to drop and ride on the moving top end of extension arm 28.

Gentle movement of the platform allows this extension arm to engage with the slot 30. The mast is then held securely in an upright position for the helmsman to disembark. This system functions in a position, relative longitudinally to the boat, within the width and underneath the hang-on bar 25 and just in front of the tiller wheel quadrant 21.

Fig 6 shows a perspective view of the tiller wheel segment 21 with its staggered tiller arm 22. At 32 can be seen the twin grooves for the tiller lines. At each end of the tiller wheel segment at 33 are fixed spring-cleets. When reference has been made to'rudder lines'this plurality has referred to the ends of one long line. At the assembly of the catamaran prior to sailing, the centre point between the two ends of the rudder line has been fixed by a suitable catch (not shown) to the centre point of the rudder system link arm 12 (Fig 2 sheet 2/4). The ends of the lines are then threaded round pulleys 14 (Fig 2), round pulleys 23 (Fig 4 sheet 3/4) and up and over pulleys 36. The starboard line is brought over the tiller wheel segment in one groove and fixed to the cleet on the opposite side. The reverse happens to the port line. By this means an appropriate tension for the lines is set.

When the tiller is moved hard to port or starboard the rudder line will follow a more direct path from the end of the segment near the cleet point 33 to the pulley at 36. This means that the line loses tension. By the design of the angle of the tiller wheel segment this loss of tension can be made to match the gain of tension caused by the angling of the tiller line at the junction to the link arm at point 12 (Fig 2 sheet 2/4), where the tiller line deviates from the straight path between the two pulleys 14.

Figure 7 shows a perspective and exploded view of the helmsman's platform 8 with the toe-protecting plate 10, the optional slot-in seat 11 and actuating arm 6.34 shows the end of the receptor tube (built in to the platform) which receives the actuator arm 6, and 35 indicates the fixing points for the ends of the swinging control arms 24.

Claims

CLAIMS 1. A catamaran or multi-hulled sailing boat where the mast, rigging and sail or sails are kept in an erect position by the weight of the crew acting round a pivoting mechanism.
2. A catamaran or multi-hulled sailing boat as claimed in Claim I where the mast-tilting effect of the wind on the sail or sails is counterbalanced by the weight of the crew and where this counterbalancing effect can be supplemented by muscular action taken optionally by the crew.
3. A catamaran or multi-hulled sailing boat as claimed in Claim 1 or in Claim 2 where the pivoting mechanism takes the form of a longitudinal pivoting bar or tube or hollow section on which a mast socket is fixed and where, joined by appropriately angled bars or tubes or hollow sections, another bar or tube or hollow section at a lower point can support a platform where the sailor or sailors can stand or sit and where the weight of this sailor or these sailors has a counterbalancing effect to keep the mast and sail or sails in an erect position against the tilting effect of the wind.
4. A catamaran or multi-hulled sailing boat as claimed in Claim 3 where the longitudinal pivoting bar or tube or hollow section has pivoting points which are supported by bars or tubes or hollow sections which form cross members between the hulls.
5. A catamaran or multi-hulled sailing boat as claimed in Claim 4 where the pivoting points are supported by bars or tubes or hollow sections which are connected to the cross members between the hulls.
6. A catamaran or multihulled sailing boat as claimed in any preceding claim wherein the pivoting mechanism and the counterbalancing weight of the sailor or sailors allows the effect of the wind on the sail or sails to tilt the mast and sail or sails to variable degrees according to the area of the sail or sails, the wind strength, the weight of the sailor or sailors, and their optional muscular activity.