U.S. patent number 3,835,804 [Application Number 05/328,779] was granted by the patent office on 1974-09-17 for sail furling.
Invention is credited to Patrick T. Jackson.
United States Patent |
3,835,804 |
Jackson |
September 17, 1974 |
SAIL FURLING
Abstract
In a sailboat having a mast, a boom, and a sail furlable upon an
upright wind-up member such as a rotatable cable to which the luff
of the sail is affixed, the improvement wherein the mast comprises
a rigid shell providing a vertically disposed interior chamber
having an extended vertical opening therein facing aft the wind-up
member being disposed within the chamber and the edges of the
opening furnishing lengthwise support to the luff of the sail at
all boom positions.
Inventors: |
Jackson; Patrick T. (Boothbay
Harbor, ME) |
Family
ID: |
23282404 |
Appl.
No.: |
05/328,779 |
Filed: |
February 1, 1973 |
Current U.S.
Class: |
114/107;
114/90 |
Current CPC
Class: |
B63H
9/1035 (20130101) |
Current International
Class: |
B63H
9/00 (20060101); B63H 9/10 (20060101); B63h
009/04 () |
Field of
Search: |
;114/90,102,104-107,112 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Other References
The Rudder Magazine; April 1957; pg 46..
|
Primary Examiner: Blix; Trygve M.
Assistant Examiner: Goldstein; Stuart M.
Attorney, Agent or Firm: Hulbert; W. R.
Claims
I claim:
1. In a sailboat having a conventional stayed mast which in use is
essentially stationary, vertical and stepped on the center line of
the boat, a sail, a rotatable wind-up member supported by the mast
and to which the luff of the sail is made fast and on which the
sail may be furled and unfurled by appropriate rotation thereof as
the sail is hauled out or retracted, the improvement wherein
said wind-up member is flexible,
the mast is provided with a longitudinally extending aft-facing
slotted recess within which said wind-up member is housed and
through the opening of which the sail is hauled out and retracted,
said wind-up member with said luff attached having a diameter
greater than the width of said opening so as to be held therein by
engagement with the edges of said opening, the walls of said recess
providing support for said wind-up member to keep it in contact
with the mast during bending or flexing of the mast under wind
pressure on the sail and said sail engaging an edge of said slotted
recess at all settings thereof.
2. The combination of claim 1 wherein the edges of said opening are
smooth and non-fraying and shaped to retain the sail in proper set
position, whether fully extended or reefed, at all swung positions
of the sailboat with respect to the wind and flexed positions of
the mast under wind load.
3. The combination of claim 1 wherein said slotted recess acts as a
protective container for the sail when furled.
4. The combination of claim 2 wherein said slotted recess is formed
integrally with the mast structure.
5. The combination of claim 1 wherein said slotted recess is
provided by auxiliary members attached to a conventional mast.
6. The combination of claim 1 including means to adjust the
position of the lower end of said wind-up member in a fore and aft
direction.
Description
BACKGROUND OF THE INVENTION
The invention relates to sailboats and is concerned more
particularly with improvements in sailboats having roller furling
sails.
Roller-furling sails, set aft of the mast, have various advantages.
A serious disadvantage of such an arrangement, however, is the
slackening of the cable or other rotatable element to which the
luff of the sail is made fast when the mast bends to the wind thus
interfering with proper set of the sail which loses efficiency and,
if the sail is sheeted in too tight, it's drive can be made
negative. This sagging to leeward also alters airflow between sails
in multi-sail vessels thereby further reducing over-all
efficiency.
It is a principal object of the present invention to provide a
sailboat construction having a roller-furlable main sail but
avoiding the above-mentioned difficulties.
SUMMARY OF THE INVENTION
In accordance with the invention there is provided in a sailboat
having a mast, a boom pivoted thereto, a sail adapted to be trimmed
by the boom, a rotatable wind-up member, such as a rod or cable,
associated with the mast and to which the luff of the sail is made
fast and on which the sail may be furled and unfurled by
appropriate rotation thereof as the sail is hauled out along the
boom or retracted, the following improvement: the mast is provided
with a longitudinally extending aft-facing slotted recess within
which said wind-up member is rotatably housed, the recess
conveniently acting as a protective container for the furled sail.
The sail is hauled out and retracted through this slot and the
walls of the slot support the luff of the sail and the wind-up
member when the mast bends under wind-stress on the sail to prevent
sagging thereof as would be the case without such support. The
slotted opening has a cross-wise dimension which is less than that
of the wind-up member with luff attached to prevent withdrawal
thereof through the opening under stress on the sail and the edges
of the slotted opening are non-fraying and shaped to retain the
sail in proper set position whether fully extended or reefed and at
all swung positions of the boom and flexed positions of the mast
under wind load. The recess may be formed integrally with the mast
structure or may be provided by attaching auxiliary members to a
conventional mast.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects, features and advantages will appear from the
following description of a preferred embodiment of the invention as
illustrated in the accompanying drawings. In the drawings:
FIG. 1 is a partially broken away, fragmentary side elevation of a
sailboat mast which includes the features of the present
invention;
FIG. 2 is a view taken on line 2--2 of FIG. 1; and
FIGS. 3A and 3B are views similar to FIG. 2 of alternative mast
constructions.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Referring to FIGS. 1 and 2, there is shown a mast 10 comprising a
generally oval outer shell 12 and an internal reinforcing web 14,
which vertically divides the mast's interior into fore and aft
chambers 16 and 18, respectively. The chamber 18 has a vertically
disposed slot 20 in its aft portion permitting sail 22 to enter
chamber 18 where the luff is attached to vertically disposed
wind-up member 24 comprising a luff cable 26 and optional sheath 28
therearound. The diameter of sheath 28 is chosen to be larger than
the width of slot 20.
The luff cable 26 extends between upper and lower swivels 30 and
32, respectively. A pinion 34 is mounted on the cable 26 above the
lower swivel 32. A shackle 36 joins the swivel 32 to block 38. The
block 38 is mounted on horizontal worm 40 so that the fore and aft
position of the block 38 may be set rotation of hand wheel 42 which
drives worm 40. The block 38 is anchored to ring 43 attached to a
portion 45 of the vessel. The ring 43 has a flat open portion so
that to permit fore and aft movement of the block. Alternatively
the hold down for the block may be omitted entirely and hold the
strain down by the journals which support worm 40.
The upper portion of upper swivel 30 is attached to pulley 44.
Halyard 46 is made fast at the mast head as shown and extends
around pulley 44, then up over sheave 48 and down again (either
inside or outside of the mast) as at 50. A conventional mast cap
52, carrying the other needed mast head fittings, may be
provided.
Near the lower end of the mast 10 a hand hole 54, which
communicates with chamber 18, is provided for access to remove the
fittings from within the mast. Adjacent hand hole 54 the gooseneck
56, furnishing hinged attachment of the boom to the mast and which
includes the first gooseneck pin 58 and pivot 59, is attached to
the mast.
The lips of slot 20 are smooth to avoid damaging the sail 22. As an
additional precaution, a non-abrasive cushioning material 60 (FIG.
2) may cover the lips.
In operation, the sail 22 may be furled upon the elongated
rotatable member 24 by such an expedient as driving the pinion 34
by any suitable means. The furled sail is thus stored within the
chamber 18 of the mast 10. Upon unfurling and setting the sail 22
for use, the luff remains captured within the chamber 18 and is
supported by the walls thereof against sagging if the mast bends or
flexes because of wind pressure on the sail since the luff cable
and the sheath 28 cannot pass through the slot 20. It is thus clear
that with the construction described the luff of the sail is
prevented for sagging off as the mast bends to leaward, thereby
maintaining the sail's efficiency and reducing interference with
the airflow between sails in a multiple sail boat. The set of the
sail remains substantially constant at all reefed positions and all
swung positions of the boom by reason of the engagement of the slot
edges with the sail holding the luff at a position very close to
the vertical axis about which the boom swings defined by the pin
58. Because of this, effects on the trim of the sail of swinging of
the boom to different positions is minimized. Adjustment fore and
aft of the bottom end of the wind-up member 24 by mechanism 40, 42
also helps the sailor trim the sail to optimum set for any given
condition of wind velocity, reef and swung boom position.
From the foregoing description, it will be apparent to those
skilled in the art that numerous mast configurations are adaptable
to provide the benefits of the present invention. As examples, two
such configurations are illustrated in the sectional views of FIGS.
3A and 3B. In FIG. 3A a conventional solid mast 62 has been
provided with a vertical slotted chamber 66 by means of extra shell
64 affixed thereto and extending aft to accommodate the luff cable
26 and sheath 28. In FIG. 3B a hollow mast 68 of circular cross
section and a single interior chamber 70 is shown. With appropriate
materials and the stronger circular cross sectional shape, it is
then possible to avoid the requirement of an internal reinforcing
web within the mast as in FIG. 2.
Other embodiments of this invention will occur to those skilled in
the art and that fall within the scope of the following claims.
* * * * *