A sailboard rig has a mast and a boom running aft from the mast for holding and moving the sail. The boom is more specially in the form of a wishbone boom with the sail in its opening. The mast has a mast foot joint such that it may be turned and heeled over on the board. The sail is joined to the mast at its luff and the aft end of the boom is joined with an aft limit of the sail. In order to make possible better use of the wind and for increasing the top speed of the rig, the sail is made up of a lower panel and two upper panels and the mast is branched so as to have two upper arms spreading outwards towards leeches of the two upper panels of the sail. These upper panels are joined with the lower sail panel at a seam and are joined to the mast arms along luffs so that all in all there is a generally Y-like mast and a sail with a Y-like form of luff.

BACKGROUND OF THE INVENTION 
The present invention is with respect to a rig for a sailboard and more 
specially to such a rig having a mast and a wishbone or other boom for 
holding and changing the position of the sail that is held within the two 
sides or spars of the boom, the mast being without any stays so that it 
may be freely heeled and turned about a mast foot joint. The mast is 
joined with the luff of the sail forward while the clew is joined with the 
aft end of the wishbone boom. 
DISCUSSION OF THE PRIOR ART 
An example of a rig as widely used for board sailing is to be seen in the 
German Patent No. 1,914,604. This rig has a sail stretched out between the 
mast and the aft end of the boom and the mast may be turned about a more 
or less upright axis and furthermore heeled over rocked about the mast 
foot in relation to the sailboard and the wind. The form of sail normally 
used for such a sailboard is three-cornered with the luff joined to the 
mast. The clew is joined with the aft end of the boom by an outhaul. The 
wishbone boom is joined to the mast at its forward end some distance over 
the tack so that the sail is kept in position loosely stretched out 
between the mast and the boom head and between the two sides of the boom, 
the sail foot running down at an angle from the aft end of the boom to the 
tack at the mast. 
In this known rig however only small changes may be made in the size of the 
sail because of the limiting effect of the mast and the aft end of the 
boom. Because of this at a given wind force the top speed and the highest 
forward thrust are limited. 
Furthermore rig designs are known in which the sail has battens near the 
head of the sail for increasing the sail area somewhat. However, this does 
not make it possible to make any very much better use of the wind. 
GENERAL OVERVIEW OF THE INVENTION 
On the other hand one purpose of the present invention is that of designing 
a sailboard rig that makes it possible for much better use to be made of 
the wind. 
A further purpose or object of the invention is to make possible sailing at 
a higher speed at a given strength of the wind. 
For effecting these and other purposes, in the present invention the mast 
is generally Y-like with a lower mast section running up from the mast 
foot joint to a branch point and then further upwards in the form of two 
outwardly forked mast arms, the sail having a lower sail panel and two 
upper, outwardly and upwardly spreading panels in keeping with the Y-like 
form of the mast, and with a Y-like luff, the two upper sail panels being 
joined with the lower panel along a seam running to an aft limit of said 
sail. 
In keeping with a further development of the invention the boom is in the 
form of a wishbone boom and near their aft ends the two spars of the boom 
are branched each into upper and lower sections, the two lower sections 
being joined together at the aft edge of the sail and the two upper 
sections being joined together at the said sail edge, the leech of the 
sail running to the joining point of the top sections and the sail foot 
running towards the point at which the lower sections are joined together. 
In this case the sail is generally trapezoidal. Further forms of the 
invention are detailed in the dependent claims. 
The present invention makes possible a completely new form of sailboard 
rig, with which a sailboard may be sailed at a markedly higher speed under 
a light breeze or with a heavy wind than has been possible with prior art 
sailboards in these two different conditions. This is made possible by the 
Y-like mast running a three part sail. In other words the sail area is 
increased by having two upper spaced sail panels. At more or less all 
settings of the sail in relation to the wind the force thereof may be very 
much better profited from inasfar as the wind coming in at an angle to the 
sail area takes effect on the lee sail part as well so that the forward 
force is increased. It is only when the wind is from aft that the sail 
part that is further aft will be in the wind shadow of the other part and 
no better use may be made of the wind. If the board is sailed with the rig 
heavily heeled over into the wind the mast arm on the lee side will be in 
a more upright position than when the mast is generally upright so that 
this will be a reason for the forward force being increased. Because in 
this position of the sail the diverging mast arm on the windward side will 
be lowered towards the water, in this heeled over position the upthrust 
force acting on the board will be increased so that the board will be kept 
higher up in the water and the speed increased. In fact such upthrust 
forces produced by the rig and taking effect on the board will make it 
possible for the board user to get his board to jump over waves and to 
come completely clear of the water for short distances. 
On the other hand the very much larger sail area made possible by the 
invention will make for a smaller size of the mast, the wishbone boom, and 
the parts of the sail. This in turn makes for a lower center of gravity of 
the rig so that it is nearer the board, the rig and the board then being 
more, very much more readily handled than with a prior art rig. It is more 
specially, because of the shorter boom, then made possible that the danger 
of breakage thereof is decreased and the weight of the system generally is 
cut down. 
A further useful effect produced in this respect is that the sail may not 
be blown out to the lee so much or is less baggy. 
In keeping with the preferred form of the invention in which the aft ends 
of the spars of the boom are branched out into lower and upper sections at 
whose ends the sail is fixed, it is possible to have a markedly larger 
sail area than in the prior art and the forward force is greater. More 
importantly, however, because the sail is rigidly made fast to the two aft 
ends of the boom branching out from each other, it is possible to make 
certain that the leech of the sail is not overly blown out of place by the 
force of the wind. 
In keeping with a still further development of the invention the angle 
between the two outwardly branching mast arms may be adjusted, that is to 
say the two arms may be fixed in relation to each other at different 
angles as desired so that the sail may be trimmed to be in keeping with 
the strength of the wind blowing at a given time so as to get the greatest 
upthrust and forward forces. 
In line with one further development of the invention the boom is in the 
form of a spar having its forward end supported on the mast, as for 
example at the point of branching thereof where there is a support member 
for the separate mast sections or arms. This spar is placed right over the 
seam joining the lower sail panel with the two top panels. The sail is 
able to be trimmed at the end furthest from the mast. This makes certain 
that there is no chance of the sail blowing out as far as has been the 
case with the prior art so far even when sailing under a heavy weather. 
Furthermore on the two sides of the spar there may be outer sail holding 
parts, that are not stiff like the spars of a true wishbone boom but are 
in the form of a partly elastic or fully elastic grips or grip members 
hanging down for example like loose rope. This rope is made fast and 
trimmed at one end to the mast, preferably at the level of the branch 
point, and at the other end on the aft end of the spar. It will be seen 
from this that the sail is trimmed and pulled tight at the luff on the 
mast and at the clew at the aft end of the sail in the form of single- or 
two-point tightening system on the spar. 
Further useful effects and details of the invention will be seen from the 
account now to be given of the working examples to be seen in the figures 
herein.

DETAILED ACCOUNT OF WORKING EXAMPLES OF THE INVENTION 
In FIG. 1 the reader will see a rig 1 on a sailboard 3. The rig is made up 
of a mast or forked mast 5, that has a lower, single mast section 7 and 
two top outwardly forked or branched mast sections or arms 9. The sail is 
in the form of a double or tri-sail 11, that is made up of a lower sail 
section or panel 11a and two sail panels 11b and 11c joined together at 
the top edge of the lower panel. Not only the lower sail panel 11a, but 
furthermore the two upper sail panels, placed side by side in the form of 
a letter V, 11b and 11c have their luffs fixed to the mast 5 by way of a 
mast sleeve for example. 
The boom is in the present case in the form of a wishbone boom 13 having 
its forward end joined to the mast in a known way by lengths of line. At 
the aft end 15 of the boom 13 the sail 11 is made fast by an outhaul. The 
joint between the lower sail panel 11a and the two upper sail panels 11b 
and 11c is in this case in the form of a seam 17 on a level with the boom. 
The boom is fixed at a normal height on the mast, this being the height at 
which the mast is branched; that is to say, the mast is made up of a lower 
part 7 and two outwardly forked mast arms 9. The rig is joined to the 
board by way of a mast foot joint (not figured) without any stays so that 
it may be heeled over and turned about its own axis as necessary to keep 
the sail under control using the boom that is held in the hands. 
As is to be diagrammatically seen in FIG. 1 and as will be made clear in 
more detail later, there is a support part at the connection between the 
lower mast section 7 and the two upper outwardly sloping mast arms 9, the 
support part keeping the two mast sections or arms 9 at a fixed angle 
therebetween, which however may be adjusted. Furthermore the mast 5 may be 
so designed that it may be bodily adjusted in height. 
An account will now be given in detail of the function of the rig 1 using 
the FIGS. 2a to 2c. 
In each of these figures the rig will be seen diagrammatically, sailing 
towards the reader. In FIG. 2a the basic position will be seen in which 
the lower mast part 7 is more or less upright and at a right angle to the 
water surface, the two upper, outwardly branching mast arms 9 having an 
angle of 60.degree. to 100.degree. and more specially 90.degree. between 
them. In this position as well with only a medium wind the double form of 
the top part of the sail has the effect of greatly increasing the sail 
area and in fact in all settings of the sail in which the wind is acting 
at an oblique angle on the sail, the wind pressure will as well take 
effect on the sail section on the lee side as well so that the forward 
force will be increased. 
In FIGS. 2b and 2c the position of the sail under a stronger wind is to be 
seen diagrammatically. It will be clear from this that even when sailing 
in the strongest wind and with such a very large heel angle of the mast 
the lee sail panel is kept upright so as to be responsible for producing a 
very powerful forward force. Stated differently, because the sail panel 
11b on the lee side is in a more or less completely upright position 
offering the largest possible surface for the wind to take effect on, the 
maximum forward thrust is produced. The sail panel 11c on the windward 
side, that with this very great angle of heel is moved further and further 
downwards towards the surface of the water, is responsible for producing 
very strong upthrust forces that take effect on the board 3 by way of the 
rig 1 so that this form of the invention is responsible for producing the 
very greatest possible forward and upthrust forces as well as in the case 
of a hang-glider. For this reason the wetted area of the board is cut down 
and, more specially, wave jumping will be possible. 
FIG. 3 is a diagrammatic view of a further possible form of rig as seen 
from the side with one sail. The wishbone boom 13 is in this case designed 
with spars branching at their aft ends 21a and 21b and not unbranched and 
in the form of a simple oval as is normally the case. This makes it 
possible for the sail area, even in the case of a single sail, to be 
markedly increased inasfar as the leech 23 of the sail is higher up and 
the sail foot 25 running to the lower end 21b may be at a lower level, the 
sail being cut straight between the upper "clew" and lower clew so as to 
be generally parallel to the lower mast section 7. 
In FIG. 4 the reader will see a further development of the invention 
uniting the useful effects of the systems of FIGS. 1 and 3 together, that 
is to say with a forked mast and three sail panels 11a to 11c, the seam 17 
running from the forward point at which the boom is made fast on the mast 
5 to the aft top end 21a of the boom 13. In a way different to the system 
to be seen in the figure it is however possible for the branching of the 
two aft ends not to be symmetrical to the plane of the two boom spars 13a 
and 13b and in fact it may be such that the lower spar end 21b is in the 
same plane as the spars 13a and 13b and it is only the top end 21a that is 
out of (that is to say, higher up than) this plane. 
In FIG. 5 the holding member 19 for holding and supporting the two mast 
arms 9 on the mast lower section 7 is furthermore to be seen 
diagrammatically. When the rig is put together or taken to pieces the two 
outwardly branching mast arms 9 are threaded through (or slipped out of) 
the luff sleeves 27 on the top sail panels 11b and 11c and the arms are 
then fixed to the holding member 19. The lower mast section 7 is as well 
threaded into a sleeve 27 and locked in the holding member 19. This being 
done, the sail is then tensed using outhauls on the spar end or ends 21a 
and 21b. 
In this respect the design of the holding member 19 may be such, more 
specially, that the angle between the two upper mast arms and the height 
of the mast generally may be adjusted, although this is not to be seen in 
the figures. 
The sailboard is used like the well-known forms of board and rig. The sail 
is lifted up out of the water with a known form of inhaul fixed to the 
branch point of the mast. 
As one change possible in the design of the rig figured here, the mast may 
be V-like, the two panels 11b and 11c running down to a common sail foot 
without any common sail panel 11a. Because in their lower parts the panels 
only have a small distance between them, the use of the wind is not very 
much more efficient. 
Furthermore in the working example to be seen in FIGS. 1, 2 and 3 the three 
sections of the mast are in a single plane, although they may be bent out 
of it to some degree. However the two outwardly branching arms of the mast 
may be put at a slope somewhat so as to be running aft from the top of the 
lower mast section, the top sail panels 11b and 11c then, when looked down 
upon, being like the wings of a hang-glider. 
Turning lastly to the further form of the rig as in FIG. 6, that is to be 
seen on the port quarter, it is here again a question of a sail with a 
single common lower panel 11a and the two upper panels 11b and 11c. 
This form of rig has a spar 31 running, as roughly marked in the figure, 
from the branch point 18 of the mast 5 (at which its fixed or joined by 
way of a moving joint for example) to its aft end 35 that is joined to the 
clew of the sail by an outhaul and a cringle. The spar 31 is placed right 
over the seam 17 between the two outwardly and upwardly spreading sail 
panels 11b and 11c or halves. This system makes certain that there will be 
no such strong billowing or blowing out of the sail as is the case with 
known designs, while on the other hand the sail is tensed by the spar 3 
only. It would furthermore be possible for the spar to be in the form of a 
sprit taken up in a sleeve in the sail. In this case the sprit 31 may have 
freely swinging or loosely hanging, festoon-like grip members 33 that are 
partly or completely elastic in nature. The grip members will be joined at 
their forward ends to the mast, more specially at the branch point 
thereof, and joined at their aft ends to the aft end 35 of the sprit, for 
example by a piece of line. It will be seen that the grip members are not 
in this case in the form of outwardly curved, stiff spars like the sides 
of a wishbone boom, but in the form of lengths of material, hanging down 
between their aft and forward ends, to the two sides of the sail panel 
11a. 
If each grip member 33 is made at least partly elastic, it may be generally 
U-like, the open end of the grip member 33 possibly having, for example, 
two semi-circular support loops 39 so that the grip member 33 may simply 
be hooked inwards round the mast arms 9 at the branch point 18. The 
opposite end of the U-like structure 37 may be joined, for example by 
lashing, to the aft end 35 of the sprit, this making it simpler for the 
rig to be put together and the sail set and furled. The sprit 31 may be 
designed so that it may be unjoined from the mast 5 or the holding member 
19. However it would furthermore be possible to have a universal joint 
connection here so that after taking down the sail the sprit might be 
folded away against the mast to take up less space.