Harken MKIV Unit 1 User manual

Please read these instructions carefully before installing, servicing, or operating the equipment.
This manual may be modified without notice. See: www.harken.com/en/support/manuals/ for updated versions.
PLEASE SAVE THESE INSTRUCTIONS
MKIV OCEAN - JIB REEFING & FURLING
Unit 1
Installation Manual – Intended for specialized personnel or expert users
5390 03/21
Preassembly
Safety Precautions/Parts Description 2
Sizing Check 3
Parts 4
Rigging Parts Check/Tools 5
Dimensions/Sailmaker's Instructions 6
Toggle Deductions/Stay Into Foil Options 7
Top Foil Length 8
Short Top Foil 9
Confirm Foil Length 10
Assembly
Foils/Connectors 11–14
Halyard Swivel and Drum Assembly 15
Rod Rigging 16
Turnbuckle/Toggle 17–18
Final/Feeder 19–20
Commissioning
Turnbuckle 21
Lead Line to Cockpit 22
Halyard Wrap/Prevent Halyard Wrap 23
Pendant/Halyard Restrainer/ Halyard Tension 24
Operation
Spinnaker Halyards/Headstay and Backstay Tension 25
Raise Sails 26
Furl/Reef 26–27
Secure Sail 27
Maintenance
Clean/Inspect 28
Replace Line 28
Storage/Remove Furler 28
Troubleshooting/Warranty 29
Parts Lists 30-31
Contact Harken 32

2 MKIV Ocean Unit 1
Safety Precautions/Parts Description
Introduction
This manual gives technical information on installation and service. This information is destined exclusively for
specialized personnel or expert users. Installation, disassembling, and reassembling by personnel who are not
experts may cause serious damage to property or injury to users and those in the vicinity of the product. If you
do not understand an instruction contact Harken.
The user must have appropriate training in order to use this product.
Harken accepts no responsibility for damage or harm caused by not observing the safety requirements and
instructions in this manual. See limited warranty, general warnings, and instructions in
www.harken.com/en/general-warnings-instructions/
Purpose
Harken®Jib Reefing and Furling is designed for rolling sails on sailboats to reduce sail size or to completely roll
so wind has little effect on the sail. Use of this product for other than normal sailboat applications is not covered
by the limited warranty.
Safety Precautions
WARNING! This symbol alerts you to potential hazards that may kill or hurt you and others
if you don't follow instructions. The message will tell you how to reduce the
chance of injury.
4
1
2
3
5
7
6
8
9
1) Toggle Assembly
2) Crosspin
3) Shackles
4) Drum Assembly
5) Foil Clamp Screws
6) 2' (610 mm) Bottom Foil
7) Feeder Assembly
8) Connector Bushing
9) Bottom Connector
10) 7' (2.13 m) Foil
11) Connector Screws
12) Connector
13) Halyard Swivel
14) Trim Cap
15) Trim Cap Screws
CAUTION! This symbol alerts you to potential hazards that may hurt you and others if
you do not follow instructions. The message will tell you how to reduce the
chance of injury.
WARNING! Strictly follow all instructions to avoid potential
hazards that may kill or hurt you and others. See
www.harken.com/en/general-warnings-instructions/
for general warnings and instructions.

MKIV Ocean Unit 1 3
2. Harken does not recommend drilling boat’s chainplate or toggle. In some cases bushings are available
to fit boats with smaller clevis pin sizes.
3. Will drum fit on bow? See page 6. If necessary, use an additional toggle to slightly raise unit. To clear
anchor use a Harken Long Link Plate which can be cut to various lengths.
Sizing Check
Unit Part No. Description Wire Sizes
7511.10 MKIV OCEAN Unit 1
1/4", 9/32", 5/16" 6 mm, 7 mm, 8 mm
Rod Sizes
-8, -10, -12 5.72 mm, 6.35 mm, 7.14 mm
Toggle Part No. Description Chainplate Clevis Pin Size
7411.20 1/2 Eye/jaw reversible 1/2" 12.7 mm
7311.20 1/2 Jaw/jaw 1/2" 12.7 mm
7311.20 5/8 Stud/jaw 5/8" 15.9 mm
7311.21 1/2 Long link plate w/toggle 1/2" 12.7 mm
7311.21 5/8 Long link plate w/toggle 5/8" 15.9 mm
Chainplate Clevis Pin
Size Check
1. Check headstay and clevis pin dimensions in chart below.
WARNING! Do not drill boat's chainplate or toggle. This may result in rig failure. Use the correct
size toggle and clevis pin.
Preassembly Sizing Check
10
11 8
12
13
14
15

4 MKIV Ocean Unit 1
Preassembly Parts
Part No. Quantity Description
HFG990 1 Drum assembly with shackle
HFG991 1 Halyard swivel with shackles
Main Components
7511.30 1 Extra 7' (2.13 m) Foil
7511.31 1 Extra Connector with Bushings and Screws
Ordered Separately (For longer headstays)
Line
Part No. Quantity Description
HFG233 70' (21.3 m) 7 mm double braid polyester
Line
Hex Keys
Connectors
2' (610 mm)
Bottom Foil
Trim Cap Trim Cap Screws Feeder and Screws
Red Loctite®
Connector Bushings
Halyard Swivel
Foil Screws
Drum Assembly
7511.FOILSET 1 Foils (Standard package)
Includes 67511.30 Foils 7' (2.13 m)
17511.33F 2' (610 mm) Bottom foil
Part No. Quantity Description
7511.31F 6 7" (177.8 mm) Connectors
HFG1015 1 Connector bushing set
Includes 6H-83382 Bushing connector half - top
6H-83383 Bushing connector half - bottom
HFG1005 1 Foil screw set
Includes 26 HFS980 Foil screws (extras included)
HFG1006 1 Trim cap set
Includes
1H-83390 Trim cap half - top
1H-83391 Trim cap half - bottom
3HFS1127 Trim cap screws (includes one extra)
HFG1007 1 Feeder set
Includes 2H-83419 Feeder half
5HFS1407 Feeder screws (includes one extra)
Loctite is a trademark of Henkel AG & Company KGaA
Part No. Quantity Description
Various 5 Hex keys - 2.5mm, 3mm, 4mm, 5mm and 5mm Long
HFG739 1 Red Loctite®(for foil screws)
833 1 Blue Loctite®(for feeder screws)
Supplied Tools and Adhesives
Foil Assembly Components
7' (2.13 m)
Foils
Blue Loctite®

MKIV Ocean Unit 1 5
Stud/Jaw Toggle
7311.20 5/8
Jaw/Jaw Toggle
7311.20 1/2
Long Link Plate w/Toggle*
7311.21 1/2
7311.21 5/8 Rod Adapter Studs
ROD RIGGING
Harken Rod Adapter
Stud Required
(Sold Separately)
1. Harken toggle assembly required. Sold separately.
2. Mating turnbuckle components must be purchased separately.
3. Headstay may require cutting and shortening to fit Harken toggle.
Headstay may remain uncut by replacing lower stud of turnbuckle
with stud/eye thus eliminating extra toggle.
4. Rod rigging requires Harken rod adapter stud.
5. Order Harken 7404 Lead Block Kit and one additional 7403 if
necessary. Fits 1" (25 mm) stanchions.
Preassembly Rigging Parts Check/Tools
Tools You Will Need
Includes 3 x 7403; 1 x 7401;
1 x 7402; 1 Horn Cleat
7404 Lead Block Kit
(Sold Separately)
1. Long tape measure 6. Side cutters 11. Rigging or black tape
2. Short tape measure 7. Rat-tail file 12. Center Punch
3. Power drill 8. Hex keys (provided) 13. Hammer
4. Drill bit – 1/8" (3 mm) 9. Slotted/phillips screwdrivers
5. Hacksaw 10. Needle-nose pliers
10
11
12
8
7
6
5
3
2
1
13
4
9
Eye/Jaw Toggle Reversible
7411.20 1/2
ALL UNITS
Harken Toggle (Sold Separately)
7424 -127422 -8
7423 -10
Thread
1/2" - 20 RH
Thread
5/8" - 18 RH
Thread
5/8" - 18 LH
WARNING! A stay that is old or
damaged may break suddenly,
causing an accident. Headstay
condition should be checked by a
professional rigger before reusing.

6 MKIV Ocean Unit 1
Feeder height
Min 37 3/16" (945 mm)
Max 38 3/16" (970mm)
Tack setback
1 1/4" (32 mm)
6 5/8 "
(168 mm)
2 1/4"
(57 mm)
4 7/8"
(124 mm)
Min 8 13/16" (223 mm)
Max 9 13/16" (249 mm)
Min 2 3/4" (70 mm)
Max 3 3/4" (95 mm)
Min 7 11/16" (195 mm)
Max 8 11/16" (221 mm)
Luff Tape Length
Note feeder height and extend bottom of luff tape downward so it is below
feeder. This will prevent luff tape from catching in feeder as
sail is lowered.
Tack and Head Shackles
Make sure tack and head shackles fit sail
rings. Minimum inside dimensions of
standard head and tack shackles are:
(A) 11/16" (27 mm)
(B) 1/2" (13 mm)
Sun cover
Sun covers may be installed on either side of the sail.
Be sure to match other sails in the customer's inventory.
Long link plate note: If a long link plate is used, add the following dimen-
sions to feeder, tack shackle, and drum height (based on whether plate is used
full-length or shortened to one of five hole positions). Do not add to halyard
swivel or top terminal dimensions.
1/2" (12.7 mm) Clevis Pin Add 131/4" to 63/8"(337 mm to 162mm) to min.
5/8" (15.9 mm) Clevis Pin Add 11 1/4" to 43/8" (286 mm to 111 mm) to max.
A
B
Luff Length
Note offsets above and below sail.
A shorter luff may be required if a halyard restrainer is necessary
(page 24) or a toggle or long toggle assembly is used to raise drum.
If luff of sail is not long enough to put halyard swivel near top of
headstay foil, a pendant must be added (see page 24).
Tack Setback
Note setback for tack shackle and cut the sail accordingly. Min is for eye/jaw
and jaw/jaw toggles. Max is for stud/jaw toggles. See long link plate note.
Luff Tape Size -6 (5 mm or 6/32")
J - Finished luff tape size: 5.5 mm (0.215")
K - Luff rope size: 4.8 mm (6/32", 3/16")
L - Max Ø in sail groove: 6.5 mm (0.26")
M - Gap in sail groove: 2.4 mm (0.096")
J
K
L
M
Preassembly Dimensions/Sailmaker's Instructions

MKIV Ocean Unit 1 7
Most boats have a chainplate with a single tang.
If boat has two plates forming a jaw, reverse
eye/jaw toggle so eye is down.
Important! Remove black plastic caps and
install them so crosspin will be 90 degrees
to lower clevis pin.
Crosspin
Fork
Attachment
Crosspin
Tang
Attachment
For tang-down installations,
switch plugs to this position.
Options for Snaking Stay into Foils
31/4"
(83mm)
Eye/Jaw Reversible
1/2" (12.7 mm)
Clevis Pin
Jaw/Jaw
1/2" (12.7 mm)
Clevis Pin
Make sure your toggle
looks like this!
3"
(76 mm)
Use dimensions of Harken toggle below to build stay to correct length.
Tip: Turnbuckles should be 1/2 to 2/3rds open to allow shortening for new wire stretch and for
fine-tuning mast rake.
Long Link Plate w/Toggle
*1/2" (12.7 mm) Clevis Pin)
**5/8" (15.9 mm) Clevis Pin
*25/16" (59 mm)
**211/16" (68 mm)
Stud/Jaw
5/8" (15.9 mm)
Clevis Pin
Make sure your toggle
looks like this!
37/8"
(98 mm)
87/8"
(225 mm)
Thread
5/8" - 18 LH
1. Swage stud at end of wire.
2. Open end of wire and install Norseman or Sta-Lok®
stud after foil is assembled.
3. When using smaller wires, marine eye may fit. See page 12.
4. Rod adapter nosepiece for Harken rod adapter stud.
WARNING! Using a threaded nosepiece with only
adhesive at the upper rod eye terminal may result
in headstay system failure which can cause an
accident, damage to your vessel, personal injury,
or death. See www.harken.com/en/general-warn-
ings-instructions/ for additional safety information.
STA-LOK is a registered trademark of STA-LOK Terminals Ltd.
Preassembly Toggle Deductions/Stay Into Foil Options

8 MKIV Ocean Unit 1
UNIT 1
Alternate
Measurement
Point
Pin
to
Pin
A
Make sure upper
measurement points
of A and pin-to-pin
are the same.
1Pin-to-Pin Length
2Subtract ABEFG –
3Result (Pin-to-Pin – ABEFG)
4Subtract D –
To find “D” pick number from chart below that is closest to,
but not greater than total from step 3.
Inches mm
3 X 84 = 252
4 X 84 = 336
5 x 84 = 420
6 x 84 = 504
7 x 84 = 588
8 x 84 = 672
3 x 2133.6 = 6400.8
4 x 2133.6 = 8534.4
5 x 2133.6 = 10668.0
6 x 2133.6 = 12801.6
7 x 2133.6 = 14935.2
8 x 2133.6 = 17068.8
Example–If result from Step 3 is:
500 inches “D” = 420 inches 12,000 mm “D” = 10,668 mm
5Result (C) Top Foil Length
Pin-to-Pin Length Worksheet
Dimensions Inches mm
ACenter of Pin to Bottom of Terminal
BBottom of Terminal to Top of Foil
.5 13
CTop Foil Length
DNumber of Foils ________ x 84" (2133.6 mm)
EBottom Foil 24.0 610
FBottom of Foil to Crosspin 16.4 416
GCrosspin to Clevis Pin
Pin-to-Pin Length
After completing worksheet above fill in A, C, D and G below. Add
“A” through “G” to confirm total equals your pin-to-pin measurement.
Length Check
G Toggle Distance from Lower Clevis Pin to Crosspin Hole
Toggle Part No. Type Clevis Pin G Distance
7411.20 1/2 Eye/Jaw Reversible 1/2"12.7 mm 1.75" 44 mm
7311.20 1/2 Jaw/Jaw 1/2"12.7 mm 1.75" 44 mm
7311.20 5/8 Stud/Jaw 5/8"15.9 mm 4.00" 102 mm
7311.21 1/2 Long Link Plate w/Toggle 1/2"12.7 mm 15.00" 381 mm
7311.21 5/8 Long Link Plate w/Toggle 5/8"15.9 mm 15.25" 387 mm
Note: If long link plate is shortened, dimension must be changed or foil will be too short.
Measure distance from crosspin down to where clevis pin attaches toggle to boat and
use this dimension in G above.
Measure A and add to this chart
and “length chart” below
Inches mm
A
B.5* 13*
E24.0 610
F16
.4 416
G
Total A+B+E+F+G
A
C
D
E
F
Pin
to
Pin
B
G
IMPORTANT! If top foil
length is less than 3 5/8"
(92 mm), go to page 9.
*Add 1" (25 mm) if using a 7302 halyard
deflector.
Preassembly Top Foil Length

MKIV Ocean Unit 1 9
Preassembly Short Top Foil
Top foil length
from worksheet Actual top foil
Shorten bottom of
bottom foil by this
amount
in mm in mm in mm
UNIT 1
31/289 4 1/2 114 1/2 13
376 4 1/2 114 125
21/264 4 1/2 114 11/238
251 4 1/2 114 251
11/238 4 1/2 114 21/264
Unit 1
Top foil length from worksheet:
5 1/2" - 4 5/8" (140 - 118 mm)
No change necessary.
Unit 1
Top foil length from worksheet:
41/2" – 3 5/8" (114 – 92 mm)
Cut top trim cap to 4 1/2" (114 mm) as shown above.
Unit 1
Top foil length from worksheet:
31/2" - 11/2" (89 - 38 mm)
Actual Top Foil
41/2" (114 mm)
Do not cut top foil to length from worksheet. Cut top
foil to 41/2" (114 mm) and shorten trim cap
by 15/16" (24 mm) as shown at left. Shorten bottom foil
per chart below. Foil will be clamped in upper holes.
5 1/2"
(140 mm)
Cut 15/16" (24 mm)
off top trim cap
Cut-off Do not use.
4 1/2"
(114 mm)
Unit 1
Top foil length from worksheet:
1" - 1/2" (25 – 13 mm)
Do not use short top foil. Use full length foil and
clamp foil higher in drum assembly.
Use one of the following special techniques for foils under 5 1/2" (140 mm) to ensure sufficient bearing surface for
foil in area of halyard swivel.
Cut-Offs
Do Not Use
Upper holes
In this method only the upper holes
are used thus there is limited up/
down foil adjustment.

10 MKIV Ocean Unit 1
Preassembly Confirm Foil Length
Line up bottom foil so foil clamp is just
above or below center of notches in
bottom foil.
Confirm foil length by laying foils alongside
stay with turnbuckle components.
Pull stay out so it is straight. Attach Harken
toggle to bottom of stay. Make sure toggle
straps are straight. Adjust turnbuckle so
that length of stay with Harken toggle will
fit boat. Ideally, turnbuckle will be half to
two-thirds open to allow for rig adjustment.
Line up drum assembly so holes below
drum line up with holes in Harken toggle.
Make sure toggle is tensioned when
measuring.
Note: Position top foil so that with top
cap the foil will ride 1/2" (13 mm) below
terminal. If wire fitting at top of stay is
swage, foil must ride just below shoulder
of swage. Mark cut line on foil. Wrap tape
around foil as a guide so cut is straight.
No halyard deflector - 1/2" (12 mm)
With halyard deflector 1 1/2" (38 mm)
If 7302 Halyard Deflector is used, add 1" (25 mm)
1/2" (12 mm)