Harken 7411.11 1/2.BLACK MKIV 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/manuals for updated versions.
PLEASE SAVE THESE INSTRUCTIONS
MKIV UNDERDECK JIB REEFING & FURLING
Unit 1, 2, 3
Installation Manual – Intended for specialized personnel or expert users
4656 v1 08/21
Preassembly
Parts 4–5
Rigging Parts Check/Tools 6
Dimensions/Sailmaker's Instructions 7
Stay Length Deductions/Stay Into Foil Options 8
Hub Assembly
Deck Flange 9
Install Hub Assembly in Bow 10–11
Assemble Drum Components 11
Underdeck Lead Block 12
Preassembly
Top Foil Length (Unit 1) 13
Top Foil Length (Unit 2) 14
Top Foil Length (Unit 3) 15
Short Top Foil (Unit 1) 16
Short Top Foil (Unit 2) 17
Short Top Foil (Unit 3) 18
Confirm Foil Length 19
Assembly
Foils/Connectors 20–26
Halyard Swivel 26
Torque Tube Assembly 27
Rod Rigging 28
Attach Turnbuckle/Foils to Boat 29–31
Feeder/Final 32
Commissioning
Turnbuckle 33–34
Lead Line to Cockpit 35
Halyard Swivel Height/Angle 36
Halyard Restrainer/Tension 37
Operation
Halyard/Headstay Tension 38
Raise Sails/Storm Sails/Reefing 39–40
Secure Sail 40
Race Conversion 41
Maintenance
Clean/Lubricate/Inspect 42
Confirm Deck Flange/Tack Swivel Gap 42
Replace Line 42
Storage/Transporting 42
Remove Furler 42
Troubleshooting/Warranty

Parts Descriptions
Parts Description
1
3
2
4
5
6
7
89
10
11
12
13
14
15
1) Lower Jaw/Jaw Toggle
2) Threaded Stud
3) Length Adjuster Nut
4) Hub Assembly
5) Flange Assembly
6) Guard Assembly
7) Cover Assembly
8) Deck Flange
9) Tack Swivel
10) Tack Shackle
11) Bearing Caps
12) Upper Jaw/Jaw Toggle
13) Torque Tube Universal
14) Torque Tube Assembly
15) Foil Clamp
16) Bottom Foil
16
17
18
19
2. Harken does not recommend drilling boat’s chainplate or toggle.
Bushings may be available to fit boats with smaller clevis pin sizes.
Part No. Size Wire Size Rod Size Clevis Pin Ø
Standard
Headstay Length
Max.
Headstay Length
7411.11 1/2.BLACK Unit 1
1
/ 4 ",
9
/ 32 ",
5
/ 16 "
6 mm, 7 mm, 8 mm
-8, -10
5.72 mm 6.35 mm
½"
12.7 mm
45' 11"
13.99 m
52' 11"
16.12 m
7412.11 5/8.BLACK Unit 2
5
/ 16 ",
3
/ 8 "
8 mm, 10 mm
-12, -17
14 mm, 8.38 mm
5
/ 8 "
15.9 mm
60' 4"
18.38 m
67' 4"
20.51 m
7413.11 3/4.BLACK Unit 3
7
/ 16 ",
1
/ 2 "
11 mm, 12 mm
-22, -30
9.53 mm, 11.1 mm
3
/ 4 "
19.1 mm
75' 1"
22.88 m
82' 1"
25.02 m
7413.11 7/8.BLACK Unit 3
7
/ 16 ",
1
/ 2 "
11 mm, 12 mm
-22, -30
9.53 mm, 11.1 mm
7
/ 8 "
22.2 mm
75' 1"
22.88 m
82' 1"
25.02 m
2 MKIV Underdeck Unit 1, 2, 3
WARNING! Do not drill boat's chainplate or toggle.
This may result in rig failure. Use the correct
size toggle and clevis pin.
Size Check
1. Check headstay and clevis pin
dimensions in chart below.
WARNING! Strictly follow all instructions to avoid potential
hazards that may kill or hurt you and others. See www.harken.com/
manuals, for general warnings and instructions.
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.
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/manuals.
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
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.

Preassembly Sizing Check
23
19
20
21
22
24
25
26
17) Feeder
18) Connector Bushing
19) Bottom Connector
20) 7' (2.13 m) Foil
21) Connector Screws
22) Connector Wedge
23) Connector
24) Halyard Swivel
25) Trim Cap Screws
26) Trim Cap
Unit Part No. A B C D Max E F G Min G Max H Min H Max I J
17411.11 1/2.BLACK 5
1
/ 2 "
140 mm
4
9
/ 16 "
116 mm
4
11
/ 16 "
119 mm
1
1
/ 2 "
38 mm
3
11
/ 16 "
94 mm
2
5
/ 16 "
58 mm
4
5
/ 8 "
117 mm
9
5
/ 8 "
244 mm
10
5
/ 8 "
270 mm
15
5
/ 8 "
397 mm
1
/ 2 "
12.7 mm
4
1
/ 8 "
105 mm
27412.11 5/8 BLACK 6
5
/ 8 "
167 mm
5
1
/ 16 "
129 mm
5
1
/ 4 "
134 mm
1
13
/ 16 "
46 mm
4
3
/ 16 "
106.5 mm
2
3
/ 4 "
70 mm
5
3
/ 8 "
137 mm
11
5
/ 16 "
287 mm
12
11
/ 16 "
322 mm
18
9
/ 16 "
471 mm
5
/ 8 "
15.9 mm
5"
127 mm
37413.11 3/4 BLACK 8
3
/ 16 "
208 mm
6
1
/ 2 "
166 mm
6
3
/ 4 "
172 mm
2
1
/ 2 "
64 mm
5
7
/ 16 "
138.5 mm
3
5
/ 8 "
92 mm
6
7
/ 8 "
175 mm
14
3
/ 8 "
365 mm
16
1
/8"
410 mm
23
5
/ 8 "
600 mm
3
/4"
19.1 mm
6
5
/ 16 "
160 mm
37413.11 7/8.BLACK 8
3
/ 16 "
208 mm
6
1
/ 2 "
166 mm
6
3
/ 4 "
172 mm
2
1
/ 2 "
64 mm
5
7
/ 16 "
138.5 mm
3
5
/ 8 "
92 mm
7
5
/ 16 "
186 mm
15"
381 mm
16
9
/ 16 "
421 mm
24
1
/ 4 "
616 mm
7
/ 8 "
22.2 m
6
5
/ 16 "
160 mm
H
F
G
J
I
D
E
Will Drum Fit in Bow?
Note: If length of stud does not allow attachment to chainplate, link plates
between chainplate and toggle must be fabricated.
Furler Requires Drained Compartment
Harken’s Underdeck Furler is designed to keep much of the water from
entering the bow compartment. Water will drip through the furler during
rain or when sailing in heavy weather. Furling compartment must drain.
A B
C
MKIV Underdeck Unit 1, 2, 3 3
This manual shows both black and clear foils.
In April 2021 MKIV furlers began shipping with
black foils. Clear anodized foils also available.

Preassembly Parts
Main Components
Torque Tube
Assembly
Halyard Swivel
7' (2.13 m) Foils
Flange Assembly
Cover Assembly
Guard Assembly
Part No.
Description Unit 1 Unit 2 Unit 3-3/4 Unit 3-7/8 Qty
Halyard swivel H-39812 H-39794 H-39392 H-39392 1
Torque Tube Assembly HFG927 HFG928 HFG929 HFG929 1
Hub Assembly HFG923 HFG924 HFG925 HFG926 1
Cover Assembly HFG683 HFG686 HFG689 HFG689 Pair
Flange Assembly HFG684 HFG687 HFG690 HFG690 Pair
Guard Assembly HFG685 HFG688 HFG691 HFG691 Pair
Unit Forward Ø
Min Break
Strength Aft Ø
1
1
/ 4 " (6 mm) 2500 lb (1130 kg)
5
/ 16 " (8 mm)
2
5
/ 16 " (8 mm) 3740 lb (1700 kg)
3
/ 8 " (10 mm)
3
3
/ 8 " (10 mm) 5000 lb (2270 kg)
7
/ 16 " (12 mm)
Line Specifications
Line (Not included with Furler)
Note: Line is not included with furler. Drum of unit is smaller to allow it to fit
into narrow bow sections. If overlapping sails are used, standard diameter
line will fill up drum and jam furler. To prevent this, use small diameter, high
strength line at forward end and have a rigger add a cover at aft end where
line is handled.
Description Unit Part No.* Qty
7' (2.13 m) Foil 17411.30.BLACK 6
2' (610 mm) Bottom foil 7411.33.BLACK 1
7' (2.13 m) Foil 27412.30.BLACK 8
2' (610 mm) Bottom foil 7412.33.BLACK 1
7' (2.13 m) Foil 37413.30.BLACK 10
2' (610 mm) Bottom foil 7413.33.BLACK 1
Foils (Standard Package)
Hub Assembly
4 MKIV Underdeck Unit 1, 2, 3
2' (610 mm)
Bottom Foil
Silver foils available
*Clear foils available. Replace "BLACK" with "CLEAR"

Bow Shackles
Plastic
Connector
Wedges
Foil Screws
Prefeeder
5200
Adhesive
Injector
Preassembly Parts
Trim Cap
Unit 1 Unit 2 Unit 3 (3/4, 7/8)
Description Part No. Qty Part No. Qty Part No. Qty
Connector bushing set HFG295
(12-H-42062/12-H-42063) 1HFG296 (16-H-42032/16-H-42033) 1HFG297 (20-H-42073/20-H-42074) 1
Plastic connector wedge set HFG299
(14-H-39625) 1HFG300 (18-H-39487) 1HFG324 (22-H-39487) 1
Foil screw set HFG343
(28-HFS1105) 1HFG348 (36-HFS1106) 1HFG349 (44-HFS1106) 1
Trim cap set HFG680
(H-37361/H-37362) 1HFG681 (H-37403/H-37404) 1HFG682 (H-39751/H-39752) 1
Trim cap screw set HFG629
(3-HFS1126) 1HFG672 (3-HFS1127) 1HFG672 (3-HFS1127) 1
Prefeeder 947 1947 1947 1
Feeder with screw and tab H-39683 1H-39559 1H-39756 1
Injector, 1 oz. 5200 Adhesive HFG725 1HFG725 1HFG725 1
Loctite®Blue 833 1833 1833 1
Loctite®Red HFG739 2HFG739 2HFG739 2
Other Components
Unit 1 Unit 2 Unit 3 (3/4, 7/8)
Description Part No. Qty Size Part No. Qty Size Part No.Qty Size
Connector 7411.31 5 7" (177.8 mm) 7412.31 7 9" (229 mm) 7413.31 9 9.75"(248 mm)
Bottom connector 7411.32 1 10.75" (273 mm) 7412.32 1 13" (330 mm) 7413.32 1 14" (356 mm)
Bow shackle 2110 3 6 mm 2117 3 8 mm 2124 3 10 mm
Description Unit Qty
2.5, 4, 5 mm 1 1 Each
3, 4, 5, 6 mm 2 1 Each
3, 4, 6, 10 mm 3 1 Each
Hex Keys (Supplied)
MKIV Underdeck Unit 1, 2, 3 5
Blue Loctite®
Hex Keys
Red Loctite®
Feeder
Trim Cap Screws
ConnectorsBottom
Connector
Connector Bushings

1. Stud/eye turnbuckle components are not included and
must be purchased separately. See page 8.
2. Rod rigging requires Harken rod adapter stud.
3. Order Harken Lead Blocks and one additional
7403 if necessary. Fits 1" (25 mm) stanchions.
Preassembly Rigging Parts Check/Tools
Tools You Will Need
MKIV Furlers are shipped with 3M 5200
adhesive. Use adhesives on dry connectors
and foils using the special injection system
described in the assembly section. Parts
may immediately be exposed to rain. Cure
is best at 70F (22C) with 50% humidity. Do
not apply at temperatures below 40F (5C)
and above 100F (38C).
Although adhesive has not cured it will
remain in place on foil joints whether
they are left on the ground or raised up
on boat. Foils can be raised immediately
after assembly and sails fitted.
Note: A small amount of adhesive may
bulge out of injection ports. If possible
let system sit for a couple days before
sailing. If adhesive gets on sails remove
using acetone. For faster-curing adhesive,
purchase 4200 Fast Cure.
Note: Damaged foils can be repaired.
Use a hand-held propane torch to heat
joints until foils can be pulled apart.
Adhesive Alert
Unit 1, 2
7404 Lead Block Kit
(Sold Separately)
1. Long tape measure 6. Side cutters 11. Center punch 16. Hole saw
2. Short tape measure 7. Rat-tail file 12. Rigging or black tape 17. Deck sealant
3. Power drill 8. Hex Keys (provided) 13. Scissors 18. Box end wrench
4. Drill bits (see chart) 9. Slotted/phillips screwdrivers 14. Metal straight edge 19. 6 mm bolts, nuts and washers
5. Hacksaw 10. Needle-nose pliers 15. Hammer
10 13
12
11
8
7
6
5
3
2
1
14
9
ROD RIGGING
Harken Rod Adapter
Stud Required
(Sold Separately)
Unit Part No. Thread Ø
17422 -8 1/2" - 20RH
7423 -10 1/2" - 20RH
27424 -12 5/8" - 18RH
7425 -17 5/8" - 18RH
37426 -22 3/4" - 16RH
7427 -30 7/8" - 14RH
Rod Adapter Stud
349, 2652
131, 047
Unit Turning Thru-Deck
1349 131
22652 047
32600/137/071 HC7981
Recommended Furling
Compartment Lead Blocks
Unit
Deck
Flange Ø
Hole
Saw Size
13.7"
(94 mm)
3 ¾"
(95 mm)
24.2"
(106.5 mm)
4 ¼"
(110 mm)
35.45"
(138.5 mm)
5 ½"
(140 mm)
16
Unit
Wrench Size
for Length Adjuster
1
7
/ 8 "
(22 mm)
21"
(25 mm)
31.25"
(32 mm)
18
Use 6 mm bolts and washers to
mount deck flange. To figure bolt
length, add
3
/ 8 " (10 mm) to deck
thickness. Minimum thread
engagement must be 9mm.
19
17
4
Unit Drill Ø
1
1
/ 8 " (3 mm) ,
1
/ 4 " (6.25 mm)
2
5
/ 32 " (4 mm) ,
1
/ 4 " (6.25 mm)
3 (
3
/ 4 ,
7
/ 8 )
5
/ 32 " (4 mm) ,
1
/ 4 " (6.25 mm)
15
6 MKIV Underdeck Unit 1, 2, 3

Preassembly Dimensions/Sailmaker's Instructions
Luff Length
Note offsets above and below sail.
A shorter luff may be required if a halyard restrainer is necessary
(page 37) 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 36.
Tack Setback
Find setback "C" for tack shackle in chart below and modify sail
accordingly. Setback is measured to luff tape of sail.
Luff Tape Size
All units require #6 (6/32" or 5 mm) luff tape.
Luff Tape Length
Cut off top of luff tape so it is 18 to 24" (450 to 600 mm) below
head of sail. This allows head to lag behind rest of sail to help
flatten sail. It will also help head to roll more smoothly.
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. The minimum inside dimensions
of standard head and tack shackles are: A
B
Unit Part No. A B C D E F G
17411.11 1/2* 4
3
/ 4 "
120 mm
7"
177 mm
1
15
/ 16 "
49 mm
1
/ 16 "
2 mm —37
13
/ 16 "
960 mm
3
5
/ 8 "
92 mm
27412.11 5/8* 5
5
/ 8 "
143 mm
9
1
/ 8 "
231 mm
2
5
/ 16 "
59 mm
1
/ 16 "
2 mm
9
/ 16 "
14mm
41
1
/ 16 "
1043 mm
4
1
/ 16 "
104 mm
37413.11 3/4* 7
5
/ 16 "
186 mm
11
5
/ 8 "
296 mm
3
3
/ 16 "
81 mm
1
/ 16 "
2 mm
7
/ 16 "
11mm
47
3
/ 16 "
1199 mm
5
3
/ 8 "
136 mm
37413.11 7/8* 7
5
/ 16 "
186 mm
11
5
/ 8 "
296 mm
3
3
/ 16 "
81 mm
1
/ 16 "
2 mm —46
1
/ 16 "
1170 mm
5
13
/ 16 "
148 mm
G
E
C
D
F
A
B
MKIV Underdeck Unit 1, 2, 3 7
Unit A B
111/16" (27 mm) 1/2" (13 mm)
213/4" (44 mm) 11/16" (17 mm)
317/8" (48 mm) 13/16" (21 mm)
Suncover
Suncovers may be installed on either side of sail. Be
sure to match other sails in the customer's inventory.
*Actual part numbers have ".BLACK" or ".CLEAR" at the end to designate foil color.

Preassembly Deduction for Stay Length/Stay Into Foil Options
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. Rod adapter nosepiece for Harken rod adapter stud: Threaded
nosepiece must have a positive lock as well as adhesive.
Use Harken stud with cotter pins. See page 28.
Options for Snaking Stay into Foils
Unit Part No. A B C D
17411.11 1/2*
1
/ 16 "
2 mm 3
5
/ 8 "
92 mm 10
5
/ 8 "
270 mm 15
5
/ 8 "
397 mm
27412.11 5/8*
1
/ 16 "
2 mm 4
1
/ 8 "
104 mm 12
11
/ 16 "
322 mm 18
9
/ 16 "
471 mm
37413.11 3/4*
1
/ 16 "
2 mm 5
3
/ 8 "
136 mm 16
1
/ 8 "
410 mm 23
5
/ 8 "
600 mm
37413.11 7/8*
1
/ 16 "
2 mm 5
13
/ 16 "
148 mm 16
9
/ 16 "
421 mm 24
1
/ 4 "
616 mm
8 MKIV Underdeck Unit 1, 2, 3
C
D
B
A
WARNING! Using a threaded nosepiece with only
adhesive at the upper rod eye terminal may result
in headstay system failure. Make sure there is a
mechanical lock.
*Actual part numbers have ".BLACK" or ".CLEAR" at the end to designate foil color.

Assembly Deck Flange
Carefully locate center point in deck to
locate deck flange. Line from mast to
under deck chainplate must intersect this
center point. Mark center fore/aft and
athwartships line. Use template to mark
four outer holes and center pilot hole.
Make sure closer pair of holes is forward.
If deck does not fall within these angles,
shims must be made using structural
adhesive to avoid excessive pressure
on deck and deck bearings.
72
1
/ 2 ° – 74
1
/ 2 °
Use 6 mm screws and compound to fasten
deck flange.
Note: There must be a minimum of
3
/ 8 "
(9 mm) thread engagement into deck flange.
Note: Deck flange angle
matches a stay angle of
73
1
/ 2 ° when compared
to deck. Angles can vary
between 72
1
/ 2 ° and 74
1
/ 2 °.
Once you are certain hole is located in
line with chainplate and any required
shimming is done, drill hole 90° to deck.
Make sure hole is just large enough so deck
flange bears against deck. It is better to
make hole slightly smaller and file opening
larger to fit. Use template to mark large hole
and bolt holes. Use hole saw to drill deck.
Tip: After pilot drill bit clears deck, drill final
hole from bottom using pilot hole to line up
hole drilled from top. This will prevent glass
from chipping.
MKIV Underdeck Unit 1, 2, 3 9

Assembly Install Hub Assembly in Bow
Adjust length so toggle is lined up with chainplate hole. Slide pin
into chainplate and secure with cotter pin.
Slide hub assembly into deck
flange. Turn adjusting nut to
lengthen or shorten threaded
stud as needed.
Stud Length Turn Adjusting Nut
Shorten Clockwise
Lengthen Counter-Clockwise
1
/ 16 "–
1
/ 8 "
2–4 mm
From on-deck, pull up on unit to check height between deck flange and
tack swivel. Make sure tack swivel is free to rotate when there is upward
pressure on unit. Check this again when stay is up and tensioned.
Distance between bottom of
tack swivel and deck flange
must be
1
/ 16 "–
1
/ 8 " (2–4 mm).
10 MKIV Underdeck Unit 1, 2, 3

Assembly Assemble Drum Components
Place halves of plastic flange in
lower groove on hub assembly
so smooth side of flange is up.
Tip: Line up flats in flange with
flats in groove.
Place halves of plastic cover in
grooves so flats in cover align
with flats in groove.
Tip: Rotate each screw hole
towards the stern.
Use blue Loctite®on flathead
screws (provided).
Use blue Loctite®on flathead
screws (provided).
Assemble line guard so enclosed
opening faces lead block. Do not
use Loctite®on threads.
Tip: Loosely thread both screws
turning guard so it can be rotated
to its final position. Finish
tightening final screw when
enclosed opening faces lead
block.
Tighten screws using hex key
(provided).
Tighten screws using hex key
(provided).
MKIV Underdeck Unit 1, 2, 3 11

Assembly Underdeck Lead Block
Mount lead block so that line exits furler
at 90° to line of headstay as shown.
Remember block will split angle and raise
up slightly under load. Mount thru-deck
block. You may want to angle it toward
stanchion block.
Mount thru-deck block. You may want to
angle it toward stanchion lead block.
12 MKIV Underdeck Unit 1, 2, 3
90°

UNIT 1
Length Chart
Dimensions Inches mm
ACenter of Pin to Bottom of Terminal
BBottom of Terminal to Top of Foil
.50 13
CTop Foil Length
DNumber of Foils ________ x 84" (2133.6 mm)
EBottom Foil 24 610
FBottom of Foil to Jaw/Jaw Toggle 15.25 387
Pin-to-Pin Length
Measure A and add to this chart
and length chart below
Inches mm
A
B.50 13
E24 610
F15.25 387
Total A+B+E+F
Make sure upper
measurement points
of A and pin-to-pin
are the same.
1Pin-to-Pin Length
2Subtract ABEF –
3Result (Pin-to-Pin – ABEF)
4Subtract D –
To find “D” pick number from chart below that is clos-
est 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
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
After completing worksheet above fill in A, C and D below. Add “A”
through “F” to confirm total equals your pin-to-pin measurement.
Length Check
Alternate
Measurement
Point A
TOP FOIL LENGTH WORKSHEET
Preassembly Unit 1—Top Foil Length
A
C
D
E
F
Pin
to
Pin
B
MKIV Underdeck Unit 1 13
Pin
to
Pin

UNIT 2
Preassembly Unit 2—Top Foil Length
Length Chart
Dimensions Inches mm
ACenter of Pin to Bottom of Terminal
BBottom of Terminal to Top of Foil
.63 16
CTop Foil Length
DNumber of Foils ________ x 84" (2133.6 mm)
EBottom Foil 24 610
FBottom of Foil to Jaw/Jaw Toggle 18.45 469
Pin-to-Pin Length
Measure A and add to this chart
and length chart below
Inches mm
A
B.63 16
E24 610
F18.45 469
Total A+B+E+F
Make sure upper
measurement points
of A and pin-to-pin
are the same.
1Pin-to-Pin Length
2Subtract ABEF –
3Result (Pin-to-Pin – ABEF)
4Subtract D –
To find “D” pick number from chart below that is clos-
est 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
After completing worksheet above fill in A, C and D below. Add “A”
through “F” to confirm total equals your pin-to-pin measurement.
Length Check
Alternate
Measurement
Point A
TOP FOIL LENGTH WORKSHEET
A
C
D
E
F
Pin
to
Pin
B
14 MKIV Underdeck Unit 2
Pin
to
Pin

UNIT 3 (3/4, 7/8)
Length Chart
Dimensions Inches mm
ACenter of Pin to Bottom of Terminal
BBottom of Terminal to Top of Foil
1 25
CTop Foil Length
DNumber of Foils ________ x 84" (2133.6 mm)
EBottom Foil 24 610
FUnit 3-
3
/ 4 –Bottom of Foil to Jaw/Jaw Toggle 24 610
FUnit 3-
7
/ 8 –Bottom of Foil to Jaw/Jaw Toggle 23.4 594
Pin-to-Pin Length
Measure A and add to this chart
and length chart below
Inches mm
A
B 1 25
E24 610
F23.4 594
Total A+B+E+F
Make sure upper
measurement points
of A and pin-to-pin
are the same.
1Pin-to-Pin Length
2Subtract ABEF –
3Result (Pin-to-Pin – ABEF)
4Subtract D –
To find “D” pick number from chart below that is clos-
est to, but not greater than total from step 3.
Inches mm
7 x 84 = 588
8 x 84 = 672
9 x 84 = 756
10 x 84 = 840
11 x 84 = 924
7 x 2133.6 = 14935.2
8 x 2133.6 = 17068.8
9 x 2133.6 = 19202.4
10 x 2133.6 = 21336
11 x 2133.6 = 23470
Example–If result from Step 3 is:
800 inches “D” = 756 inches 20,000 mm
“D” = 19,202 mm
5Result (C) Top Foil Length
After completing worksheet above fill in A, C and D below. Add “A”
through “F” to confirm total equals your pin-to-pin measurement.
Length Check
Alternate
Measurement
Point A
TOP FOIL LENGTH WORKSHEET
A
C
D
E
F
Pin
to
Pin
B
Preassembly Unit 3—Top Foil Length
MKIV Underdeck Unit 3 15
Pin
to
Pin

16 MKIV Underdeck Unit 1
Preassembly Unit 1—Short Top Foil
If top foil is shorter than 7" (177.8 mm), use one of the following special techniques to ensure sufficient bearing
surface for the foil in the area of the halyard swivel.
21/2(64 mm)
2" (51 mm)
11/2" (38 mm)
1" (25 mm)
7" (178 mm) No special treatment required.
7" (178 mm)
6"–5" (152–130 mm) Do not use plastic bushing above
top connector.
6"–5" (150–130 mm)
41/2"–4" (115–102 mm) Do not use plastic bushing
above top connector. Shorten top of connector and if
necessary shorten trim cap.
41/2"–4" (115–100 mm)
31/2"–3" (90–75 mm) Do not use plastic bushing above
top connector. Cut connector right at cross formed by
glue dispersion channels. Use single foil screw in top
foil only.
31/2" - 3" (90 - 75 mm)
Under 1" (25 mm) Eliminate top foil and run foil higher
in torque tube.
Under 1" (25 mm)
Top Foil
Length from
Worksheet
1. Initial
top foil
cut length
2. Cut through
middle hole in
top foil.*
3. Shorten
full length
adjoining
foil by
cutting
through
middle
hole.*
4. Shorten
connector
5. Shorten
trim cap
Resulting Top
Foil Length Length
21/2"
(64 mm)
57/8"
(149 mm)
41/8"
(105 mm)
31/2"
(89 mm) No
2"
(51 mm)
53/8"
(137 mm)
35/8"
(92 mm)
31/2"
(89 mm) No
11/2"
38 mm)
47/8"
(124 mm)
31/8"
(79 mm)
31/2"
(89 mm) Yes
1"
(25 mm)
43/8"
(111 mm)
25/8"
(67 mm)
31/4"
(83 mm) Yes
21/2"–1" (64–25 mm) Shorten top foil and adjoining
full length foil so two screws are used to assemble joint
instead of four. Do not use plastic bushings above top
connector.
*To allow for saw cut, position blade so upper half of
middle hole is preserved.
Cut-Offs – Do Not Use
Cut-Offs
Do Not Use
Do not use
upper bushing
Cut-Offs
Do Not Use
UNIT 1

Preassembly Unit 2—Short Top Foil
If top foil is shorter than 811/16" (221 mm), use one of the following special techniques to ensure sufficient
bearing surface for the foil in the area of the halyard swivel.
3" (76 mm)
21/2" (64 mm)
2" (51 mm)
11/2" (38 mm)
1" (25 mm)
811/16" (221 mm) No special treatment required.
811/16" (221 mm)
85/8" – 63/8" (219–162 mm) Do not use plastic bushing
above top connector.
85/8"–63/8" (219–162 mm)
6"–51/2" (152–140 mm) Do not use plastic bushing
above top connector. Shorten top of connector and if
necessary shorten trim cap.
6"–51/2" (152–140 mm)
51/4"–35/8" (133–92 mm) Do not use plastic bushing
above top connector. Cut connector right at cross formed
by glue dispersion channels. Use single foil screw in top
foil only.
51/4"–35/8" (133–92 mm)
Under 1" (25 mm) Eliminate top foil and run foil higher
in torque tube.
Under 1" (25 mm)
Top Foil
Length from
Worksheet
1. Initial
top foil
cut length
2. Cut through
middle hole in
top foil.*
3. Shorten
full length
adjoining
foil by
cutting
through
middle
hole.*
4. Shorten
connector
5. Shorten
trim cap
Resulting Top
Foil Length Length
3"
(76 mm)
71/4"
(184 mm)
51/8"
(130 mm)
41/2"
(114 mm) No
21/2"
(64 mm)
63/4"
(172 mm)
45/8"
(117 mm)
41/2"
(114 mm) No
2"
(51 mm)
61/4"
(159 mm)
41/8"
(105 mm)
41/2"
(114 mm) No
11/2"
(38 mm)
53/4"
(146 mm)
35/8"
(92 mm)
33/4"
(95 mm) Yes
1"
(25 mm)
51/4"
(133 mm)
31/8"
(79 mm)
33/4"
(95 mm) Yes
3"–1" (76–25 mm) Shorten top foil and adjoining full
length foil so two screws are used to assemble joint
instead of four. Do not use plastic bushings above top
connector.
*To allow for saw cut, position blade so upper half of
middle hole is preserved.
Cut-Offs – Do Not Use
Cut-Offs
Do Not Use
Cut-Offs
Do Not Use
Cut-Off
Do Not Use
MKIV Underdeck Unit 2 17
UNIT 2
Do not use
upper bushing

18 MKIV Underdeck Unit 3
Preassembly Unit 3—Short Top Foil
If top foil is shorter than 93/4" (248 mm), use one of the following special techniques to ensure sufficient bearing
surface for the foil in the area of the halyard swivel.
31/2" (89 mm)
3" (76 mm)
21/2" (64 mm)
2" (51 mm)
11/2" (38 mm)
93/4" (248 mm) No special treatment required.
93/4" (248 mm)
95/8"–71/8" (244–181 mm) Do not use plastic bushing
above top connector.
95/8"–71/8" (244–181 mm)
7"–51/2" (178–140 mm) Do not use plastic bushing
above top connector. Shorten top of connector and if
necessary shorten trim cap.
7"–51/2" (178–140 mm)
53/8"–4" (137–102 mm) Do not use plastic bushing
above top connector. Cut connector right at cross formed
by glue dispersion channels. Use single foil screw in top
foil only.
53/8"–4" (137–102 mm)
Under 11/2" (38 mm) Eliminate top foil and run foil
higher in torque tube.
Under 11/2" (38 mm)
Top Foil
Length from
Worksheet
1. Initial
top foil
cut length
2. Cut through
middle hole in
top foil.*
3. Shorten
full length
adjoining
foil by
cutting
through
middle
hole.*
4. Shorten
connector
5. Shorten
trim cap
Resulting Top
Foil Length Length
31/2"
(89 mm)
69/16"
(167 mm)
5"
(127 mm)
47/8"
(124 mm) No
3"
(76 mm)
61/16"
(154 mm)
41/2"
(114 mm)
47/8"
(124 mm) No
21/2"
(64 mm)
69/16"
(167 mm)
4"
(102 mm)
47/8"
(124 mm) No
2"
(51 mm)
51/16"
(129 mm)
31/2"
(89 mm)
43/8"
(111 mm) Yes
11/2"
(38 mm)
49/16"
(116 mm)
3"
(76 mm)
33/4"
(95 mm) Yes
31/2"–11/2" (89–38 mm) Shorten top foil and adjoining
full length foil so two screws are used to assemble joint
instead of four. Do not use plastic bushings above top
connector.
*To allow for saw cut, position blade so upper half of
middle hole is preserved.
Cut-Offs – Do Not Use
Cut-Offs
Do Not Use
Cut-Offs
Do Not Use
Cut-Off
Do Not Use
UNIT 3
Do not use
upper bushing

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 along-
side stay with turnbuckle components
and torque tube assembly. Pull stay out
straight. Line up turnbuckle eye with a
point just above bottom of torque tube
assembly. This point will line up with
Jaw/Jaw toggle pin. See chart above right.
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.
Unit Pin
Jaw/Jaw Toggle Pin to Bottom of
Torque Tube Assembly
1
1
/ 2 " (12.7 mm)
7
/ 16 " (11 mm)
2
5
/ 8 "(15,9 mm)
1
/ 4 " (6 mm)
3
3
/ 4 " (19.1 mm)
5
/ 8 "(16 mm)
3
7
/ 8 "(22.2 mm) 1" (25 mm)
MKIV Underdeck Unit 1, 2, 3 19

Assembly Top Foil
Deburr inside edge using rat-tail file.
Cut foil to length using hacksaw.
Prepare top foil for drilling.
Tip: Mark top foil to distinguish
from cutoff piece.
Scribe line on top of foil to mark drill
holes. Lay top foil alongside cutoff
piece and use a flat metal object
(i.e. metal ruler) to scribe top
line of foil.
20 MKIV Underdeck Unit 1, 2, 3