Harken MKIV OCEAN Unit 2 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 2
Installation Manual – Intended for specialized personnel or expert users
5391 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 2
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 2 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
7512.10 MKIV OCEAN Unit 2
5/16", 3/8" 8 mm, 10 mm
Rod Sizes
-12, -17 7.14 mm, 8.38 mm
Toggle Part No. Description Chainplate Clevis Pin Size
7412.20 5/8 Eye/jaw reversible 5/8" 15.9 mm
7312.20 5/8 Jaw/jaw 5/8" 15.9 mm
7312.20 3/4 Stud/jaw 3/4" 19.1 mm
7312.21 5/8 Long link plate w/toggle 5/8" 15.9 mm
7312.21 3/4 Long link plate w/toggle 3/4" 19.1 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 2
Preassembly Parts
Part No. Quantity Description
HFG994 1 Drum assembly with shackle
HFG995 1 Halyard swivel with shackles
Main Components
7512.30 1 Extra 7' (2.13 m) Foil
7512.31 1 Extra Connector with Bushings and Screws
Ordered Separately (For longer headstays)
Line
Part No. Quantity Description
HFG235 100' (30.5 m) 8 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
7512.FOILSET 1 Foils (Standard package)
Includes 87512.30 Foils 7' (2.13 m)
17512.33F 2' (610 mm) Bottom foil
Part No. Quantity Description
7512.31F 8 7" (177.8 mm) Connectors
HFG1016 1 Connector bushing set
Includes 8H-83692 Bushing connector half - top
8H-83693 Bushing connector half - bottom
HFG1008 1 Foil screw set
Includes 36 HFS1060 Foil screws (extras included)
HFG1009 1 Trim cap set
Includes
1H-83703 Trim cap half - top
1H-83704 Trim cap half - bottom
3HFS1127 Trim cap screws (includes one extra)
HFG1010 1 Feeder set
Includes 2H-83721 Feeder half
5HFS1119 Feeder screws (includes one extra)
Loctite is a trademark of Henkel AG & Company KGaA
Part No. Quantity Description
Various 4 Hex keys - 3mm, 4mm, 5mm and 6mm
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 2 5
Preassembly Rigging Parts Check/Tools
Tools You Will Need
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
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.
Stud/Jaw Toggle
7312.20 3/4
Long Link Plate w/Toggle*
7312.21 5/8
7312.21 3/4*
ROD RIGGING
Harken Rod Adapter
Stud Required
(Sold Separately)
Eye/Jaw Toggle Reversible
7412.20 5/8
ALL UNITS
Harken Toggle (Sold Separately)
Jaw/Jaw Toggle
7312.20 5/8
Rod Adapter Studs
7426 -22
7424 -12
7425 -17
Thread
5/8" - 18 RH
Thread
3/4" - 16 RH
Thread
3/4" - 16 LH
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.
Includes 3 x 7403; 1 x 7401;
1 x 7402; 1 Horn Cleat
7404 Lead Block Kit
(Sold Separately)

6 MKIV Ocean Unit 2
Feeder height
Max 46 9/32" (1175 mm)
Min 37 3/16" (945 mm)
Tack setback
1 5/8" (40 mm)
8 3/16 "
(208 mm)
2 3/4"
(71 mm)
6 7/32"
(158 mm)
Max 14 1/8" (358 mm)
Min 10 15/16" (278 mm)
Max 6 1/2" (164 mm)
Min 2 3/4" (70 mm)
Max 12 5/8" (321 mm)
Min 9 1/2" (241 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) 11/2" (38 mm)
(B) 3/4" (18 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 dimensions
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.
5/8" (15.9 mm) Clevis pin Add 161/16" to 81/4"(408 mm to 210 mm)
3/4" (19.1 mm) Clevis pin Add 139/16" to 511/16" (344 mm to 144 mm)
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 2 7
Preassembly Toggle Deductions/Stay Into Foil Options
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
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.
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.
4"
(102 mm)
Eye/Jaw Reversible
5/8" (15.9 mm)
Clevis Pin
Long Link Plate w/Toggle
*5/8" (15.9 mm) Clevis Pin
**3/4" (19.1 mm) Clevis Pin
*25/8" (67 mm)
**31/4" (83 mm)
Jaw/Jaw
5/8" (15.9 mm) Clevis Pin
Make sure your toggle
looks like this!
39/16"
(90 mm)
Stud/Jaw
3/4" (19.1 mm)
Clevis Pin
Make sure your toggle
looks like this!
115/8"
(295 mm)
51/4"
(133 mm)
Thread
3/4" - 16 LH

8 MKIV Ocean Unit 2
UNIT 2
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
5 x 84 = 420
6 x 84 = 504
7 x 84 = 588
8 x 84 = 672
9 x 84 = 756
5 x 2133.6 = 10668
6 x 2133.6 = 12801.6
7 x 2133.6 = 14935.2
8 x 2133.6 = 17068.8
9 x 2133.6 = 19202.4
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 20.7 526
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
7412.20 5/8 Eye/Jaw 5/8"15.9 mm 2.000" 51 mm
7312.20 5/8 Jaw/Jaw 5/8"15.9 mm 2.000" 51 mm
7312.20 3/4 Stud/Jaw 3/4"19.1 mm 5.125" 130 mm
7312.21 5/8 Long Link Plate w/Toggle 5/8"15.9 mm 18.125" 460 mm
7312.21 3/4 Long Link Plate w/Toggle 3/4"19.1 mm 18.750" 476 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.63 16
E24.0 610
F20.7 526
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 4 5/8"
(92 mm), go to page 9.
*Add 1 3/8" (35 mm) if using a 7303
halyard deflector.
Preassembly Top Foil Length

MKIV Ocean Unit 2 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 2
4 1/2114 5 3/4 146 1/2 13
4100 5 3/4 146 3/4 19
31/289 5 3/4 146 1 1/4 32
376 5 3/4 146 1 3/4 45
21/264 5 3/4 146 2 1/4 57
251 5 3/4 146 2 3/4 70
11/238 5 3/4 146 3 1/4 83
Unit 2
Top foil length from worksheet:
6 3/4" - 5 7/8" (171 - 149 mm)
No change necessary.
Unit 2
Top foil length from worksheet:
5 3/4" – 4 5/8" (146 – 117 mm)
Cut top trim cap to 5 3/4" (146 mm) as shown above.
Unit 2
Top foil length from worksheet:
41/2" - 11/2" (114 - 38 mm)
Actual Top Foil
5 3/4" (146 mm)
Do not cut top foil to length from worksheet. Cut top
foil to 5 3/4" (146 mm) and shorten trim cap
by 1 3/16" (30 mm) as shown at left. Shorten bottom foil
per chart below. Foil will be clamped in upper holes.
6 3/4"
(171 mm)
Cut 1 3/16" (30 mm)
off top trim cap
Cut-off Do not use.
5 3/4"
(146 mm)
Unit 2
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 6 3/4" (171 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 2
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 5/8" (16 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 - 5/8" (16 mm)
With halyard deflector 2" (51 mm)
If 7303 Halyard Deflector is used,
add 1 3/8" (25 mm)
5/8" (16 mm)

MKIV Ocean Unit 2 11
Assembly Top Foil
Cut foil to length using hacksaw. Deburr
inside edge using rat-tail file.
Drill two 1/8" (3 mm) holes in foil for self-
tapping screws.
Mark the location of the trim cap screws at
the cut end of the top foil.
Location: 3/4" (19 mm)down from top of
foil and 7/16" (11.7 mm) from center of the
sail groove. See dimensions below.
3/4" (19 mm)
7/16" (11.7 mm)
15/16" (23.4 mm)

12 MKIV Ocean Unit 2
Assembly Top Foil
The following instructions cover installing foils on stay starting
from the bottom. Foils slide over a swage stud fitting or wire
end where a Norseman-/Sta-Lok®-type stud is used after foil
assembly.
Tip: In some cases foils can slide over a marine eye. This
allows other assembly options:
• Assembly from both ends for faster assembly
• Over a marine eye located on the bottom of the stay
• From the top if lower terminal is part of turnbuckle
Check fit of marine eye before proceeding. This will
generally work with smaller wires within the unit's rigging
specifications.
Place halves of trim cap over wire and
insert into top foil. Use a small hammer to
tap in place if necessary.
Tip: With foil groove up, have
screw holes on the upper half.
Install self-tapping trim cap screws.
STA-LOK is a registered trademark of STA-LOK Terminals Ltd.
Alternate assembly
over marine eye

MKIV Ocean Unit 2 13
Assembly Top Foil
Assemble Halyard Deflector if used.
Red Loctite®
Halyard Deflector
Put a drop of red Loctite®in screw holes.
Place connector on wire with hooked side
up.
Red Loctite® in screw holes
Hooked side of connector
Use a hex key wrench to securely tighten
screws.
Loctite is a trademark of Henkel AG & Company KGaA

14 MKIV Ocean Unit 2
Assembly Foil/Connectors
Sandwich bushings on wire, mating hook
of plastic bushing with connector and
mating with four recesses in bottom
part of bushing.
Put a drop of red Loctite®into screw holes.
Red Loctite® in screw holes
Slide foil completely over bushings
and connector. Use a hex key wrench
to securely tighten screws. Continue
assembly of foil system.
Loctite is a trademark of Henkel AG & Company KGaA

MKIV Ocean Unit 2 15
Assembly Halyard Swivel/Drum Assembly
Slide halyard swivel onto foil. IMPORTANT!
Make sure up-arrow is up.
Slide drum assembly onto foil.

MKIV Ocean Unit 2 16
Insert two cotter pins and
spread. Clean excess Loctite®
from terminal body using
special care to ensure that
there is no red Loctite®on
threaded stud.
Assembly Rod Rigging: Rod Adapter Stud
Apply a few drops of red
Loctite®to threads of nosepiece.
Screw main threaded stud
portion onto bronze nosepiece
until flats align with two cotter
pin holes in terminal body.
Tip: Turn nosepiece completely
into threaded stud portion.
Flats will be close and may
only require a small half turn
to align with cotter pin holes.
ROD RIGGINGROD RIGGING
Loctite is a trademark of Henkel AG & Company KGaA

17 MKIV Ocean Unit 2
Washer
Assembly Attach Turnbuckle/Toggle
Up
Down
Jaw/Jaw Toggle Assembly
Assemble turnbuckle and attach Harken
toggle.
Note: If using Sta-Lok®or Norseman
stud, you must use a washer above
stud as shown below.
Stud/Jaw Toggle AssemblyEye/Jaw Toggle Assembly
Make sure shallow jaw is up.
Turnbuckle
Clevis Pin
Toggle
Clevis Pin
Crosspin
Norseman or Sta-Lok®
STA-LOK is a registered trademark of STA-LOK Terminals Ltd.

MKIV Ocean Unit 2 18
Assembly Attach Toggle/Long Link Plate
Apply Isolator.
Fasten one long link plate to drum assembly
using fasteners. Use blue Loctite®on screws.
Fasten second long link plate to drum
assembly and secure to toggle using
locknuts.
Determine height of link
plates to provide anchor
clearance and cut to length.
Cut at scribe mark. Deburr
edges.
Connect eye to toggle jaw
using special clevis pin.
Secure using cotter pin.
Toggle For Long Link Plates
Blue Loctite®
WARNING! Stay must attach
to toggle. Do not attach stay
to crosspin at drum assembly
because crosspin and plates
may fatigue and break.
Stay attached to toggle
Loctite is a trademark of Henkel AG & Company KGaA

19 MKIV Ocean Unit 2
Assembly Final
If stay length is set, use side cutters or
needle-nose pliers to bend cotter pin
to secure turnbuckle.
Clevis Pin
Crosspin at 90°
to Clevis Pin
Slide lower drum assembly over turnbuckle
and attach using long crosspin.
Use plastic washers provided.
WARNING! Crosspin must be
90 degrees to clevis pin that
attaches unit to boat. If pins run
same direction toggle will fatigue
and could break suddenly.
7312.20 3/4stud/jaw toggle
Lift foils so top of foils ride about
½" (12 mm) below upper terminal.
5/8" (16 mm)

MKIV Ocean Unit 2 20
Tip: To find hole position, sight into the
screw holes.
Assembly Feeder/Final
Sight into hole to determine
screw hole locations.
Secure using hex key. Use Tefgel on
screws. NOTE: You will likely adjust foil
height again once system is up on the mast
and turnbuckle adjusted.
Slide halyard swivel above feeder. Place
feeder tabs in position. Use a drop of 833
Blue Loctite®in screw holes. Use hex key
wrench to secure.
Blue Loctite® in screw holes
Loctite is a trademark of Henkel AG & Company KGaA