Preassembly
Determining Headstay Length
March 2001
Unit 0 MKIII
8
Pin-to-pin headstay length is a measurement which is used in many steps of assembly and also for measuring
sails. After determining the length of your headstay, write the length on the outside back cover of this manual for
easy reference in the future.
Pin-to-pin is measured from the center of the pin
holding the headstay to the masthead toggle to the
center of the pin holding the headstay assembly
to the stemhead chainplate.
Be sure that the turnbuckle is set to the correct
length before measuring.
The measurement should include all turnbuckles
and toggles at the lower end, but should not
include the masthead toggle.
All headstays must be secured to a toggle at the
masthead.
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Additional Stemhead Toggles
Your furling system has an integral toggle at the lower turnbuckle fitting. An
additional
toggle is not required at the lower end but
may
be fitted if the headstay wire is too short,
or if it is desirable to mount the drum higher off the deck than normal, say to provide
more clearance for an anchor.
Should an additional toggle be fitted to the headstay, be sure to subtract the pin-to-pin
length of the toggle from the overall length of the headstay.
Some boats with very narrow bows or with bowsprits may find that the furling drum, in
its normal position, will not fit inside the pulpit. It may be necessary to use a toggle to
raise the drum to avoid these problems.
The system is designed to keep the sail as close to the deck as possible. While it may be necessary to raise the drum
to provide clearance for an anchor or to fit inside a pulpit, do not mount the drum higher than required. Raising the
drum reduces sail luff length and increases heeling. If you need better visibility under your genoa, mount the drum
as low as possible and see the instructions on page 30 of the manual.
Furling units should not be mounted above turnbuckles or long link plates. If you are considering this, discuss your
installation carefully with Harken before proceeding.
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Isomat Masts
Isomat type masts have an unusual fitting at the top of the headstay. This "stemball" must
be cut off and a special stemball adapter placed on the upper end of the headstay. This
adapter, Harken part #940, may be purchased from your Jib Furling dealer or distributor.
Be sure to specify the clevis pin size; 5/16", 3/8", 7/16", 8 mm, 10 mm, or 12 mm. You will
also need a standard marine eye which can be purchased from your rigger. This marine
eye will be swaged to the upper end of the headstay.
When measuring headstay length, use the center of the
new eye on the wire as the upper measurement point.
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T-Ball Fittings
Some boats have T-ball swage fittings as the upper terminal. They do not require
an additional toggle. Use the elbow in the fitting as the upper measurement point.
See diagram.
Upper and lower measurement points for headstay length.
Points de measure supérieur et inférieur.
Oberer und unterer Messpunkt für Verstaglänge.
Punti di misurazione superiore e inferiore dello strallo.
Upper
Measurement
Point
Upper
Measurement
Point
Isomat
T-Ball
