International 420 Basic Rigging Guide
By Peter Gray
Introduction
This manual contains a pictorial anatomy of the International 420 dinghy, and explains how the boat can berigged. It is based primarily on my own dinghy, and it’s particular fit out. Individual boats will differ slightly
in a number of areas, where there is scope for rigging variation within the class rules. The author makes noclaim that the described components or rigging method will comply with the International 420 class rules,
which can be found at http://www.sailing.org/1890.php.
The manual is aimed at new International 420 sailors who would appreciate a detailed reference guide. I have tried to be as specific as
possible when referring to the various rigging components, as nautical terminology can sometimes be confusing and lack consistency. Somebasic sailing knowledge is assumed.
Although there is no strict sequence required for all rigging tasks, the order of presentation is quite deliberate and based on what I havefound works best for me.
This document deals specifically with the International 420 as opposed to the Club 420. The Club 420 is made by Vanguard in the US and its
design is based on the International 420. The Club 420 design incorporates a number of modifications for intercollegiate sailing in the US.
Although the two boats are different in a number of ways, many of the Club 420 sailing principals and handling characteristics are similar to
the International 420. Many articles found on the Internet are for the Club 420, so be careful to identify which class is being referred to.
If you have any comments about the manual or corrections that you think should be made, please post them here.

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Manual Contents
Mast Setup
Mast Installation
Shrouds
Trapeze Cables
Jib - Rigging
Jib - HoistingTensioning the Rig
Jib Sheet/s
Mainsail
Mainsail - Hoisting

Cunningham
Mainsheet System
Bridle Adjustment
Boom Vang
Spinnaker
Rudder AssemblyCentreboard
Buoyancy Tanks
Bailing System
De-rigging

Links
View this manual on the Internet >> http://www.users.bigpond.net.au/redeye/index.htm
Why sail an International 420? >>http://www.users.bigpond.net.au/redeye/Why_Sail_an_International_420.htm
Hoofers Club 420 Sailing Manual - Recommended reading for International 420 sailors >>http://144.92.9.188/hoofers/sailing/Manuals/420_manual/420_manual.htm
Australian International 420 Class Association >>http://www.420.yachting.org.au/
Good tuning and technical resources for International 420 >>http://www.420sailing.org.uk/base.php?SessionCRC=956254882&PageSelect=TechnicalExcellent knots site >> http://www.animatedknots.com/index.php?LogoImage=&Website=
Another good knot site >> http://www.iwillknot.com/

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Mast set up
Description: It is assumed that the mast has been pre-rigged with the spreaders and stays already configured and the halyards andspinnaker topping lift controls correctly integrated to the mast.
Method: Check that theswage-hook-terminals at the
top of the shrouds are securely
seated in the bushed locating
slot below the trapeze locating
holes. If your trapeze cables
are not in place, fit them now,by placing the upper swagehook-terminal into the hole
above the shroud-locating-slot.
See right.

NB. Before you fully extend the main and spinnaker halyards by pulling them down the outside of the mast, ensure that the back ends ofthese halyards are terminated with a figure 8 knot, to prevent them disappearing up through the base of the mast. Re-threading these
halyards through the mast is no simple matter! Also check that the aft ends of the spinnaker pole uphaul/downhaul lines are similarly
terminated so as to prevent them accidentally disappearing up into the mast.

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Mast Installation
Method: Raising and seating the mast into position is difficult enough without having to repeat the process, so make sure that the forestay,
jibstay, spinnaker and main halyards are pulled down the outside of the mast far enough so they will be accessible when the mast is raised
into position. Next, make sure that all of the “dangly bits”are untangled and roughly in position. The forestay, jibstay and spinnaker
halyard should be positioned forward of the spreaders and shrouds, while the trapeze cables and main halyard should be located aft of the
spreaders and shrouds.
A single person from the side of the boat can perform the mast installation, but the assistance of another person to steady the mast isdesirable. NB. Before raising the mast, check above for any obstructions such as powerlines etc.
Stand the mast up beside theboat with the heel located aft ofthe step, the top of the masttilted slightly backwards andtowards you from the vertical
position. See near right.
Before you lift the mast
vertically, make sure that thefour lines exiting the sheaves on
the heel fitting are trailing aft sothey do not interfere whenmating the heel into the step.
See far right

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If you have an assistant,position them on the other sideof the boat, forward of yourposition, and have them steadythe mast with the forestay as
you lift the mast vertically andthen lower it into position,easing the heel gently into thestep.

Once the heel is firmly seated in thestep (see above right), the mast
should be eased forward into themast gate. See right

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The forestay is then secured witha shackle through the forward
hole of the stemhead fitting. Seenear right. The mast can now be
released, but it is unstable until
the shrouds are secured. The mast
may travel forward and come torest against the hull. The resultant
jolt may unseat the mast from thestep. To reduce this possibility
and limit the forward travel, insert
the mast chocks into the mast gate
before proceeding. See far right.
When the mast rakes aft under its
own weight and the forestay
comes under tension, the widest
section of the mast should bewithin the mast partners. See
drawing, right.

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Attach the shrouds to the shroud adjusters (also known as shroud plates)
Method: Remove the clevis pin
from the adjuster. Insert the shroud
swage-eye-terminator into theadjuster and replace the clevis pin
so that the shroud cannot be
removed. This is a safety device
and it prevents the shroud coming
loose from the adjuster if the fast
pin were to disengage. It also helps
hold the swage-eye-terminal inplace while you adjust and pin it.
See near right.
If you have not already done so,remove the fast pin (also known as
quick release pin). Determine theadjustment position you intend touse (this is a judgement call, andaffects the rake of the mast and rig
tension). See far right.

I use the 4th hole down or 71/2. This is a good starting point. If you have trouble pulling the eye terminal low enough to the desired pinning
position, you can pull down on the trapeze to extend the shroud lower and at the same time lift the shroud adjuster (it has a few millimetresof play from its anchor point).
Performing both of these tasks and attempting to pin the eye-terminal at the same time can be a bit tricky, and is made simpler if you haveyour assistant pull down on the trapeze while you pin the shroud. Finally, it is a good idea to wrap some adhesive tape around the adjuster,
covering the protruding pins and their split rings. This will prevent catching spinnaker sheets, or worse still, tearing the spinnaker cloth.

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Secure the trapeze cables
Description: The trapeze cables are held clear of the spreaders and ready for use by a fairlead and shock cord system.
Method: Take the shock cord loop and thread it through the small inner ring, then stretch it over the top of the large outer ring. Release theshock cord, then the trapeze ring. The trapeze cable is now out of the way and ready to use.

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Rigging the Jib
Description: The Jib is rigged withan internal forestay that is threaded
through the jib luff sleeve. When the
jib is hoisted the rig is supported by
the internal jib forestay and not thepermanent forestay. After you raise
the jib, you will notice that thepermanent forestay is quite loose.
When not in use, the jib forestay
should be lightly coiled in such a waythat the ends wrap around on the coilthus preventing the tension in the coilcausing it to unravel. Do not attempt
to coil the cable too tightly. This may
cause a kink to form, damaging thecable. See right.
Method: Unfurl the jib and unravel the jib forestay. Bring the jib-tack and the jib-stay swage-eye-terminal
together. See below left. Now introduce the eye-terminal into the jib luff sleeve, just above the cringle. See
below right.

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Now thread the jib forestay all the way up through the luff sleeve until the terminal emerges at the head of the sail. This is best
accomplished by holding the tack of the sail in one hand while feeding the cable into the sleeve with the other hand. To avoid damage tothe sail or the forestay during this process, have an assistant hold the head of the sail and keep the luff taught while you do this.
Alternatively, if you do not have ahelper, thread the transom pintle
through the jib-head-cringle to hold thehead end of the sail, while you keep theluff taught and feed the forestay in.
This method can also be used toremove the cable.

Next, locate the jib-stay swage-forkterminal over the stemhead fitting suchthat the fork-eyes align with the rearhole of the stemhead. At the same time,
position the Dee-shackle over theswage-fork-terminal, so that all foureyes align with the hole in thestemhead. Now secure all three parts
together with the shackle pin. See nearright.
The jib tack cringle can now be secured
to the Dee-shackle. I have used 3mm
spectra rope. Start with a bowline
through the cringle, then down andthrough the shackle, a rolling hitch
away from the shackle, then up andthrough the cringle again. Finish with
two half hitches locking below the firstrolling hitch. The object here is to keep
the tack secured and close to the deck.
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I use a similar method to secure the jib head to the jib halyard via a Long Dee-shackle. First, pass the shackle through the jib-halyardthimble and pin it to the jib-stay-swage-terminal. Secure the jib-head-cringle with a bowline, pass the rope up through the shackle, a rolling
hitch away from the shackle, then down through the cringle again and finish with a two half hitches, locking above the first rolling hitch.
The tension on this linkage is critical to achieving the correct luff tension on the jib. See above right.

Hoisting the Jib
Method: Before raising the jib, slacken and extend the rig tensioning system up to where the jib halyard strop exits the mast. Also check
aloft to see that the cable halyard is not tangled with any other lines. Take hold of the jib halyard-strop and pull it down by hand until thecable-loop-termination of the jib halyard appears from inside the mast. Secure the jib in the raised position by attaching the rig tensioner
snapshackle to the wire loop. See “Tensioning the Rig”next section.

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Tensioning the Rig
Description: The rig tensioner or rig
tensioning system is made up of two
blocks with six sheaves and one cam
cleat, threaded with a 4mm rope tail.
The upper block is permanently
attached to a fixed-eye snapshackle thatis used to connect the tensioning
system to the jib halyard loop
termination. See near right.
The lower block and cam cleat ispermanently attached to the mast. See
below right.
Having attached the snapshackle to thewire loop, the rig can now be tensioned
according to the prevailing sailingconditions.
The tension scale on the mast iscalibrated against the “hook”. The hookis the point where your jib halyard
connects to the snapshackle. See far
right
See tuning guide for your sails or
consult others such as this one by
Sobstad.
http://www.420sailing.org.nz/tuninggui
de.htmPage 12 of 38

The Jib Sheet
Description: The jib sheet is permanently rigged as follows:- The sheet passes through a fairlead and a cam cleat on one side tank, acrossthe cockpit, and continues through another cam cleat and fairlead on the other side tank. See below right. Both ends of the jib-sheet are
terminated with an eye splice. See below left.
Method:The jib sheet is rigged to form a continuous loop around the mast. The sheet-ends and jib-clew are joined together with a short link-rope.
One end of the link-rope has a permanent figure 8 stopper knot. The other end is passed through the first eye splice, the clew cringle, thesecond eye splice, and terminated with another figure 8 stopper knot. This arrangement effectively locks the clew together with the jib
sheet-ends. Alternatively you could use a Long Dee-shackle. See below left

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Rigging the Mainsail
Method: Presumably, your mainsail was previously rolled up from thehead to foot. If this is the case, orient the sail along the centre line of
the boat so that the clew end is aft and the tack end is forward. Having
done this, you only need to unwind enough of the sail to completely
expose the foot. See right.
Now you can begin to thread the sail onto the boom within the confinesof the hull, while the sail is still in a mostly rolled up and manageablestate (especially if it is windy).
Have your assistant stand near the mast and hold the tack end of thefoot. Alternatively, if you are rigging the boat on your own, you cantemporarily tie the tack to the Cunningham. See below left.

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Standing behind the transom, grasp the clew end and pull the foottaught. Introduce the clew-slug into the inboard end of the boom trackand ease the boom forward. See below.
Ease the tack inboard end of the boom towards the mast. Continue thisprocess until the slug is close to the outboard end of the boom. Runningthe boom onto the boltrope in this way (as opposed to pulling the sailonto the boom) retains control over the mainsail in its partially rolled
up state and puts less stress on the sail. See right.

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Secure the clew-slug with the line attached to theoutboard end of the boom. No tension is required on
this line. It is only there to limit the inboard travel ofthe clew and allow the boom to be raised together withthe mainsail.

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Hoisting the Mainsail
Description: I use a simple noose or overhand slip
knot to secure the mainsail halyard to the mainsailhead cringle.
Method: Pass the working end of the halyard
through the cringle, tie a double-overhand stopper
knot at the working end, and finish by tying an
overhand knot around the halyard. See below.
NB. It is critical that this knot is secure. If it were tocome lose, you may not be able to get the mainsailback up!

Once the head is attached, feed the luff-boltrope into the mast track. This is best
accomplished by standing on the port side. Put enough tension on the halyard to
hold the head a few inches up into the track, and then temporarily cleat the halyard
through the port clam cleat near the bottom of the mast. See above left and right.

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Adjust the tension on the long upper batten according to the prevailing sailing conditions
See http://www.xtremesailing.com/libraryItems/tuning_guide/420_GenTuningGuide.pdf (Sail Settings).

Continue raising the mainsail by hauling on the halyard
while at the same time feeding the luff bolt rope into themast track, tacking care not to snag the boltrope at themast track entry point.
As the mainsail head approaches the upper end of themast, the inboard boom end should be supported andengaged with the gooseneck spigot. See right.
Temporarily cleat the mainsail halyard at this point andsecure the mainsail tack (see next section).

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Secure the Tack
Description: I use a length of rope to secure thetack to the mast. This also locks the boom to thegooseneck.
Method:The rope is deadended or permanently secured to
the gooseneck with a bowline. Pass the working
end up through the cringle, then around the mastand through the cringle, twice, then down andunder the gooseneck fitting, then up and down
through the spinnaker-pole ring. See near right.
Finnish off securely with a rolling hitch and two
half hitches. See far right.
Place enough tension on this knot to hold thetack securely down and close to the mast. Thisanchors the tack in place, against which, both theouthaul and main halyard are tensioned.
The mainsail can now be fully raised and cleated
off. NB Not too tight! Luff tension is adjustedwith the Cunningham (see next).

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Rig the Cunningham
Method: The Cunningham is dead-ended (or secured) to the gooseneckwith a bowline. The working end is passed up on the port side, throughthe Cunningham cringle and down through the clam cleat below theboom on the starboard side. Adjust the Cunningham tension according to
the prevailing sailing conditions.
•
•
•

LIGHT
MEDIUM
HEAVY

Just enough to remove major wrinkles
Remove most wrinkles
Tight to very tight

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Rig the Outhaul
Method: Un-cleat the inboard end of the outhaul. See below left.
Thread the outboard end of the outhaul over the boom-end sheave, through the clew cringle, across the outhaul guide, tension
the line slightly, and cleat off over the jam cleat. See below right.
NB. Remember, outhaul tension is applied at the inboard end of the outhaul. See below left.

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Wrap the working end of the outhaul around the bottom endof the outhaul-sheave, through the cringle, and secure backover itself with rolling hitch and two half hitches. See right.
Set the outhaul tension according to weather conditions.
•••

LIGHT - Firm
MEDIUM - Eased a little so the foot shelf just “falls
in”.
HEAVY - Very tight

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Rig the Mainsheet System
Description: The International 420 uses a four-block
centre mainsheet system. The mainsheet is dead-ended tothe block that is connected to the bridle (bridle block).
Method: The sheet is routed up between the two boom
blocks, forward through the smaller forward block, down
and aft through the bridle block, back up between the twoboom blocks, aft through the bigger rear block, and down
through the block and cam-cleat that is mounted on thecentreboard case. See right and below.

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Page 24 of 38

Bridle Adjustment
Description: The bridle has two positions. One forlight winds and one for heavy conditions. For light
conditions the bridle is lengthened and the tie balls
are released from the snap-hook-shackles.

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Rigging the Boom Vang
Description: The boom vang or kicking-strap consists of a rope, fitted with five single-sheave blocks and adjusted with a clam-cleat andguiding block. The clam-cleat and guiding block are permanently fixed to the starboard side of the centreboard case capping andpermanently rigged with a rope tail. The vang system is permanently rigged. This block and tackle system employs three movable blocks
supported by 6 runs of rope, thus providing a mechanical advantage of 6:1
Method: Fully release the vangrope tail so that the system is fully
extended. See right.

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Grasp the vang system at thesnapshackle and thread it underneath thecentreboard uphaul, taking care that it isclear of all other lines. Attach the single
block (with becket and universal head)
via Dee-shackle to the permanently fixed
hanger near the base of the mast. See
right.

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Now attach the single loop snapshackle to the boom hanger. See below left. The Three movable blocks supported by six
runs of rope are pictured below right. Adjust the boom vang when underway, according to the conditions.

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Rigging the Spinnaker
To be written

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Buoyancy Tanks
Description: The boat has two side buoyancy tanks and one bow tank. Each tank has one inspection hatch and one drain plug.
Method: Insert and tighten all three drain plugs.
Fit and tighten all three inspection hatch covers.

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Fitting the Rudder Assembly
Description: The rudder assembly consists of an aluminium tiller and Dee shaped rudderstock. The rudder assembly is permanently riggedwith a retaining clip secured on a length of rope, and a rudder-locking pin secured on a length of shock cord. The rudder assembly is fitted tothe hull via the transom rudder-pintles. The rudder-blade or foil is fitted to the rudder assembly with a pivot bolt (bolt and nyloc nut) A
telescopic tiller extension is fitted to the tiller with a urethane universal join.

Method: Guide the upper and lower, pintle guide holes, down over therudder-pintles. Pin the top pintle with the safety-retaining clip. See right.
NB. The retaining clip prevents rudder dislodgement from the hull in theevent of a capsize.

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Remove the bolt and nyloc nut from the rudderstock gudgeons. Slide therudder-blade-head into the rudderstock so the straight edge of the foil isfacing forward when in the raised position. See right.

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Secure the rudder-head in the rudderstock by locating the pivot bolt
through the rudderstock-gudgeons and the rudder-head pivot hole. Seeabove right. Thread the nyloc nut to the pivot bolt. Use just enoughtension so that the rudder-head can swivel but with enough frictionthat the rudder is retained in the raised position when placed there.
See below.

When underway the rudder-blade is rotated into the fully down
position and the rudder-locking pin engaged through the rudderlocking hole. See right.
NB. To avoid damage to the foil, remove this pin and partially raise
the rudder-blade just before you return to shore/shallow water.

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Centreboard Operation
Description: The centreboard rotates forward and aft about the centreboard pivot pin, which is retained within the centreboard case. Whenfully raised the centreboard does not project below the hull surface, while the trailing edge is exposed above the centreboard case. See
below.

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Picture C1 right, shows the centreboard in
the fully raised position. To lower thecentreboard you must first release the port or
starboard uphaul from its respective clam
cleat. See picture C3 below.

Picture C1

The crew pulls up and aft on the centreboard
handle. This action lowers the centreboard byrotating it forward.
The centreboard downhaul, by virtue of theshock cord tension, assists with thismovement and helps retain the centreboard in
the fully down position. See right and below.

The downhaul consists of a length of rope
permanently fastened to the centreboard
handle which travels aft along thecentreboard capping until it is directedunderneath the capping and forward by abush seated in the centreboard capping.

Picture C2

The downhaul is terminated to a floating
plastic cleat. A length of shock cord isthreaded through the cleat. The cleat can be
moved forward or aft along the shock cord toadjust the tension on the downhaul. See right.

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The uphaul rope is permanently rigged througha block attached to the centreboard handle (See
Picture C1 above). Two blocks rout it aft. Oneon each side of the boat. See right.

Picture C3

The uphaul travels aft along the buoyancy
tanks on both sides of the boat and is secured
by a port and starboard clam cleat withintegrated fairlead. Both ends of the uphaul are
terminated with a figure 8 stopper knot toprevent them being pulled back though theclam-cleat fairlead.
To raise the centreboard the helmsman pulls
either the port or starboard uphaul while its
opposite end is cleated off.
This action raises the centreboard into thecentreboard case by rotating it aft.

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The Bailing System
Description: The transom drainage flaps areheld normally closed by shock cord until boat
speed and accumulated water, force the flaps
open and the water drains out.

The 420 is allowed one automatic self bailer.

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De-rigging
Method: Remove drain plugs and inspection hatches. While mounted on the dolly, raise the bow of the boat and allow any accumulated
water in the buoyancy tanks to drain. Release tension on all shock cord rigging. This helps preserve them.

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