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Preassembly – Harken 948 MKIII Jib Reefing & Furling User Manual

Page 15

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Preassembly

Determining Headstay Length

March 2001

Unit 2.5 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.

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 necessar y

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 necessar y 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.

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 943, may be purchased from your Jib Furling dealer or distributor.

You will also need a standard marine eye which can be pur chased 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.

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 mesure supérieur et inférieur.
Oberer und unterer Messpunkt für Verstaglänge.
Punti di misurazione superiore e inferiore dello strallo.

Isomat

T-Ball

Upper
Measurement

Point

Upper
Measurement

Point

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