Rigging guide for Goat Island Skiff – Efficient lug sails

How do you rig your Goat Island Skiff or other Lug Sail Rigged Boat – step by step details below.

This page is to assist setting up of lug sails. selection of rope, rope lengths and show all the rigging details. Scroll down to read the information. Some of the methods will be highly relevant to other Lug rig and Lateen rigged boats.

Link – All our core Lug setup articles with many tricks and tweaks
Link – Fittings list for the Goat Island Skiff

• We also make sails including lug sails see our sailmaker here.
• Goat Island Skiff Information here.

Why do Traditional Rigs like Lugsails have a bad reputation?

We know they GO. Which is a great advantage when turning up to an open regatta. The Regatta Handicapper won’t!

In the past many or most lug setups are pretty poor – mostly because the much of the writing and the understanding about the rigs were not properly documented. And much of the documentation was based on repeating out of date information.

This has changed as the better designers and more sailors have spent more time sailing with the wee beasties. We have played a significant part in this education process with the extensive information on this website on lug rigs that we started compiling from about 2004 that led to the articles in this link.

Link – All our core Lug setup articles with many tricks and tweaks

Much of the old misinformation was based on not knowing to tension one part or another. Also many designers are hampered by being unaware – or even reactionary toward – some of the advances and improved rigging materials that modern boats use. And others don’t document what they know so the builder can set up the boat optimally.

There are designers who really know their stuff as well. And it is well worth following every detail.

For those who think traditional rigs are slow and cumbersome – they are in for a lesson. Properly set up a balance lug rig (in particular) has very similar performance to any mainstream conventional sailboat rig when fitted to boats without trapeze or leaning racks.

Modern and novice sailors are horrified about the lugsail being distorted by pressing against the mast on one tack but regular racing of the Oz Geese has shown little difference – and the Goose sailors and Traditional Breton sailors know the side with the sail against the mast is the fast one.

As a result of fleet racing in the Philippines we know the conventional wisdom about which is the “bad tack” is the wrong way round. So their theory about the crease in the sail is wrong and it always has been.

There isn’t much difference in speed from side to side if the steerer is attentive upwind. With the mast on the leeward side, and the crease, the speed is easier and it is hard to sail the boat badly. With the mast on the windward side the same speed is achievable, but it takes more attention.

Dramatic cost savings to rig a sailing boat without performance compromise

The great thing is that where a mainstream rig might cost you hundreds or a thousand dollars by the time you have fitted

• stays
• jib and sheeting system
• boom vang
• big bunch of mast rigging
• downhaul

The lug rig will cost a fraction of the same money and offer 90 to 95% of the performance. In fact our Oz Goose rigging package is Spectra Line, Rudder fittings, three simple mainsheet blocks; and for the halyard a SS ring at the top and a $2 horn cleat. That’s it!

Here is a comparison of lug vs sloop rigs between two similar sized boats. A single sail lug like the Goat is even cheaper.

A good equation if you ask me! (I know you didn’t – but I’ll tell you anyway!)

* The exception to the advantages of the rigging system shown here is that the halyard system is prone to chafe on long ocean trips. The halyard on the boat pictured above is 12 years old – and is in excellent condition. But the wear and tear is different on larger boats that will spend extended periods making coastal or longer voyages. But for smaller boats it is well worth considering

Learnings from a century of racing lug boats make our rigging guide.

Also I had a long discussion with Brian Pearson who races traditional lug boats in a regular race fleet. While his rigging setups are perhaps more complicated than my simpler and easy to rig version, there may be something of serious interest to those seeking more performance from their lug rig. My feeling is the single most useful addition is a loose footed mainsail which allows the rig to be powered up more. However this will require the boom of my boats to be made a bit heavier to prevent excessive bend.

General Information on the Goat Island Skiff (GIS) is here
Detailed plans – easy enough for a 1st boatbuilding project

The picture above is of Peter Hyndman’s GIS “Gruff” which is now 12 years old.  Everything is original too – showing how cheap lug rigs are to run.  The pictures below are also of Peter’s boat.

If you don’t want all the details but just to look at the pictures that show you how to rig the boat then skip down to the Case Study heading below

Spars for Lug Rigs

This drawing from the plan is much more important than it looks. When you have the sail rigged properly this will be the position of the sail. The main thing is that the back of the boom should be higher than the front to give the crew plenty of space. The most common error in rigging is that the boom ends up too low at the back.

Every good boat plan has a well thought through drawing that looks like this. It is the singe most important guide to how the sail should look when properly rigged and is the major resource when the boat is unergonomic to sail, sails like a cow or has some odd bad habits. Now we sell sails we spend a lot of time debugging new sails. A most useful resource is a side on sailing photo of the boat and the sailplan drawing from the plan.

A good reason for a bit of lawn sailing the day before launching.

The main requirement for the lug spars is that the mast be relatively stiff but the yard and possibly the boom be flexible.

With the rig set up this way the boat will have the gust response of a modern rig as the yard and boom bend and allow the sail to twist.  That’s why such a light boat can carry a large sail but still be easy to handle in brisk conditions.

The GIS spar tapers have been specified to achieve this result. A builder or two have substituted aluminium spars but have found that it makes the boat quite hard to hold up in stronger conditions (article).  Generally because they have chosen sections that are too stiff.  Aluminium will work but just have a look at the pictures  on this page.

Sail Setup for Lug Rigs

The sail has to be cut to allow for the bend of the spars.  When the downhaul is tensioned correctly for most wind strengths there is about 50mm of bend in the boom and yard.  Most modern sailmakers will know what to do to allow for this bend.

Fittings cost is vastly reduced with a  lug rig

My general choice of fittings for lug rig setup is to choose parts from the budget range of marine fittings manufacturers.

Ball bearing blocks (pulleys) are just not required – leave them to the racing guys who are happy spending $700 to get a stay tensioning system working smoothly.

Thinner Ropes

The biggest development in recent years in racing classes has been the use of thinner ropes.  When run through the blocks used for the older, thicker lines there is so much clearance that the friction is hugely reduced.

The other thing that is reduced is the cost – THINNER ROPES ARE CHEAPER!

This is of course assuming that you want to go to the bother of getting the best performance – and you would probably only be reading all this if you have some interest :-)

Use rope purchases for tension

Another place I economise is by reducing the number of blocks by using simple rope purchases – like Trucker’s Hitch Knots.  With conventional racing boats these are a no no because of the friction – but with traditional rigs there is not that much adjustment – about the only line that need regular adjustment is the downhaul to get tension in the luff of the sail which can be adjusted for different wind strengths if desired.

A lot of adjustment a few years ago anyhow was just to take up the slack as the ropes stretch – but using some high tech ropes like spectra/dyneema or vectran mean that they don’t stretch – so need little or no adjustment.

See how it works?  Modern ropes mean less adjustment which means you need fewer blocks.

Easy!

Ropes and types for the Goat Island Skiff and other Lug rigged boats

Huge leaps have been made with ropes in recent years.

You can setup the lug rig for the GIS with cheap ropes if you like but I would like to suggest using modern high tech ropes in one place at  least.

One of the big advances with small boat rigging has been the use of small diameter ropes.  They are less likely to rub when they pass through blocks (pulleys) so have less friction and are easier to adjust.

Spectra/Dyneema

Before I wrote “I would use spectra in a few other places if budget allows”.

Now there is so little price difference use Spectra for everything except the mainsheet and lacing along the yard and boom

The one place where you should definitely consider using a high tech rope is for the main halyard (the rope that pulls the sail to the top of the mast) – or indeed the halyard on any boat.

The beauty is that they stretch very little.  So if you hoist the sail at the beginning of the day it will be still in the same position after 6 hours of sailing.  With  a conventional rope it has to be tightened every hour or so over the same period to retain the sail shape.   In reality most people don’t realise and wonder why the boat seems so sluggish and hard to get home at the end of the day.

A second advantage is that spectra and dyneema have fantastic UV resistance.

Tip 1 – We also use them to provide strong built in loops for the downhaul rather than using deck eyes or other stainless steel fittings. Blue loop next to the mast. Two holes. Spectra loop with figure 8 knots under the deck. Keep it short.

Tip 2 – Another trick is that most spectra lines have an outer rope and an inner rope – double braid construction. The outer rope is just there for easy grip. All the strength is in the inner rope. For the corner lashings we often remove the outer and just use the inner so the lashing will go through the holes in the yard and boom more easily. Pic below

Choosing a slightly smaller diameter is important with high tech ropes.  When ropes stretch there are two phases

1. Initial stretch – The twisted or braided threads that make up the rope are pulled as straight as the geometry allows.  All ropes made the same way stretch about the same during this phase – no matter what material they are made of.
2. When the threads have pulled straight the load goes onto the fibers themselves – so spectra will stretch much less than polyester.

The result is that if you use too thick a rope all the stretch will be in phase 1 where the rope will stretch the same as something cheaper.  A bit thinner and you start to get a performance advantage.  The halyard is an ideal rope as the only time it is handled is to pull the sail up or drop it – both times when the loads are quite light.  But once the downhaul is tensioned it takes higher loads than any of the other ropes on the boat.

Vectran

is another rope type that has even less stretch and can be considerably cheaper than Spectra/Dyneema.  

But Vectran doesn’t have the extremely good resistance to ultra violet light of spectra/dyneema.  

Fine for a small boat that will be kept out of the sun but if it spends extended periods outside Vectran is a poor choice. Particularly for a multi role boat like the Goat that can be used for years without much deterioration. The Vectran will whither and die.

Prestretch

Most conventional rope is made of polyester or terylene.  With prestretch they make the rope then stretch it under very high load so that it will stretch less when put on the boat.

Spectra is so close to the price of prestretch now … I would go with 4mm spectra for everything but the mainsheet and lacings along the yard and boom.

If you don’t want a spectra halyard then prestretch is the next stop down – much inferior in my opinion – but might be OK for sails under 3 sq metres (30sq ft) – small canoe sails and the like.

Ronstan/Marlow makes a good one called Excel that instead of stretching a braided rope the inside is not braided at all – the fibres just run straight – so it operates as a prestretch.

Double Braid

Is a polyester that is set up to be really sof t and pliable to handle.  It is perfect for the mainsheet and any other sheets on a boat as they are the ones that spend the most time in peoples hands.  Often there is a tendency to get a big thick rope that feels easier to hold.  It is a bad choice – it makes the rope move very slowly through the blocks when released unless they are oversized (and expensive).

VB Cord/lacing cord

So fully battened mains and short footed jibs for the most part – and hullweights that end up weighing with fittings around 10lbs/foot.
This is a cheap white or coloured cord made of  polyester – it is very cheap and is good for lacing sails along the length of the the yard and boom.

Shock Cord

This is a line made up of a bundle of elastic rubber with a woven casing around the outside to keep it all together.  It is used as a bungee cord in a number of useful applications.

CASE STUDY – Setting up the GIS balance lug rig

The Goat Island Skiff (pictured above is a 15ft 6″ (4.73m)  long boat with a 105 square foot (9.75sq m) balance lug sail

The hull has a good performance potential in modern terms because of the fineness of the entry and the light weight of the hull.  So the rig and setup also need to match the performance potential of the hull.

Here I go through the process of rigging a GIS and most lug rigged dinghies for the first time.

Rope Sizes and Conversion – Diameters

Rope sizes and lengths for GIS
Rope diameters and types should suit dinghy sails from 70 to 115 square feet
GIS has 105sq ft mainsail
Note – Rope lengths are an estimate.  I have tended to overestimate.

Attaching the corners of the sails to the spars.

Line choice – We like to use multiple turns of thinner line to do the corner lashings. They should be kept separate from the lacing along the edge as they are a separate function and pull in the opposite direction.

One way we get thinner line is to use the same 4mm Spectra/dyneema with polyester outer used for most of the rigging and use the spectra core only by removing the outer. See video below

Holes  – One improvement is that at the front of the yard and at the front of the boom we drill two holes usually around 3/8″ or 8mm. One 20mm 3/4″ from the end, the second around 45mm or 1 3/4″ from the end. At the back end of the boom and yard you only need one hole.

Corner Lashings – The correct way to lash the corners of a sail are according to the drawing below.  To get the proper shape in the sail the corners need to be pulled out toward the ends of the spars as well as held in.

Often you see corners lashed as in the picture on the left.  The picture on the right is the correct way.

Initial Tension

The sails need to be pretensioned on the spars – which can be drilled with holes – 8mm (3/8″).  This means that there should be a crease in the sail along the length of the yard.  Don’t sweat it really tight – but firm so a obvious crease is formed as shown below.  After that the  sail is laced with the VB cord.

Here is a picture of the lacing on the GIS sail.  Instead of using the spiral lacing I tend to introduce half hitches so the rope is a bit more aerodynamic as far as the wind is concerned as most of the lashing hides along the edge of the sail inside the wake of the spars.  This is more relevant for the yard than the boom.

Now that the sail is attached to the yard and boom it stays there – no need to undo all those knots!

One good trick is to ask the sailmaker to make a long sailbag that the sail still attached to the yard and boom can fit in.

Setting up the Lug Rig mast

There are two things that have to happen with the mast.

Top of the Mast

Some of the cheapest and lightest pulleys have very high breaking strains for the top of the mast.

eg RF571 from Ronstan has a 19mm sheave diameter and very high breaking load.

Preferred Method – is to drill two holes 6mm diameter one above the other near the top of the mast.

Thread a pulley or a 1″ stainless steel ring onto a piece of 4mm spectra, thread forward through the holes and put figure 8 knots as short as possible to hold the rope in place.

Alternative – A deadeye fitted to the top for the halyard.  An alternative is to use a block and saddle, but this deadeye has been working fine for 10 years.  It goes on the back of the mast. It is plastic with a stainless steel ferrule in the hole to prevent wear.

If going toward cheap – you can just drill a hole through the mast and clean it up with sandpaper and files so there is a smooth radius for the rope to pull through – termed a “dumb sheave”.  I don’t really like it except for very small sails as there is a lot of friction and it chews up the varnish so the mast is unprotected.  Some people fit a metal strip to protect the varnish but that’s more hassle than the method here.

Halyard Cleat on Mast

For hoisting the sail on a lug rig setup we need a cleat for the halyard.  This goes on the side of the mast – bottom of pic below.  It is on the side opposite the downhaul saddle, spectra rope loop or U-Bolt fitted to the deck adjacent to the mast.  The cleat is positioned around 350mm (14″) above deck level. The screws or machine threads that hold it in place should be epoxied into the mast

We will come back to this pic later as there is a change eliminating the square lashing.  This photo is still fine to understand the cleat position on the opposite side of the sail.

General Theory of attaching Blocks to Spars – Booms and yards.

Some people like to screw or bolt blocks to spars.  I’ve used simple rope loops on lug rig setups since I started building and sailing weird wooden boats rather than high performance conventional boats.

The funny thing is that high performance conventional boats now swung toward rope lashings and loops! :-)  The main reason is that they don’t have to drill any holes in the boom and risk weakening it.

Actually it is not my method – it is probably a thousand years old using a simple cowhitch to attach the block to the spar.  The loop is tied with a reef knot and the length of the loop is exaggerated in the middle drawing. The length of the loop should result in it looking like the last illustration in the series.

The Mainsail Halyard

This is the rope used to pull the sail to the top of the mast.

Some designers use a two part system where there is a loop of rope to hold the yard against the boom and a separate halyard to pull the yard up to the top of the mast.
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That system is prone to jamming as if the halyard is eased the back end of the yard drops down which tightens the other lashing garrotlike around the mast.

The method I use was drawn from the canoeing chapter of “The Dixon Kemp Manual of Seamanship” from about 1870.  It is a brilliant system which uses one rope to do both jobs as well as keeping the yard horizontal during hoisting and dropping.  The only other designer I have seen use it is Iain Oughtred, but he doesn’t specify it for all his boats.

One end of the halyard is tied through the forward hole in the yard – unlike the pic below I usually pass it through the hole then take it one time right round the yard before tying it with a bowline – this eliminates the risk of splitting the end of the yard.

The photo shows a block is attached at the midpoint of the yard using a rope loop as above. We used to recommend a block on the yard. But have found a better way.

This is the alternative way of attaching the halyard to the midpoint of the yard. We take a spectra or prestretch rope three times around the yard (red rope) at the midpoint and tie it with a reef knot.

Then the halyard blue rope it taken through TWO of the loops only. The tension on these makes sure the last loop will firmly grab the yard and not slide around.

The only downside of this system has is in terms of wear and tear on larger ocean going boats.  I did suggest it once to a fellow who was cruising with a lugger.  He found it worked well in terms of raising and lowering the sail and reefing but it was prone to chafe.

This is not a problem with small and medium size boats – particularly if you use spectra halyards – my halyard on the BETH sailing canoe is around 10 years old and the one on the Goat Island Skiff here is about 12 years old.

Downhaul – the single most important adjustment on a lug rig.

The downhaul is used to tension the sail – so is the most highly loaded rope in the boat. It is probably the most important adjustment in terms of creating the correct sail shape.

If your boat does not perform well this aspect of lug rig setup is most likely the culprit. Don’t be afraid of damaging the sail – It can handle more then you can throw at it.

Downhaul needs to be medium firm for light winds – until the boat is moving reliably.

Very firm once the boat is moving well but is not difficult to sail nice and flat in the water.

Fiercely firm once the boat starts to be harder to hold up – it flattens the sail considerably which reduces power.

It is attached to the deck beside the mast. This can be a stainless steel fitting like a saddle or a deck eye. We have started using spectra loops in the Philippines as in the photo below on one of the Oz Goose sailboats. We just cannot get the stainless fittings. If using a loop make it as short/low as possible.

The diagram below shows two alternatives  The only flaw in the diagram is that the block needs to be higher closer to the boom.

Note that the plans suggest that the boom should be 200mm above the partner – this is a mistake – it should be 200 to 250mm above the sheerline as shown in the drawing in the section above.  With a loose footed boom or using the downhaul as a vang it might be necessary to prevent the purchases of the downhaul from sliding with a small saddle/deckeye on top of the boom or a small timber hook screwed and glued to the top of the boom.

Controlling the boom so it stays in contact with the mast

There has been some discussion about whether this is necessary.Back to the photo used earlier. But every couple of inches the boom moves away from the boom is a degree less pointing ability. Simple trigonometry

We now use a preventer, which some of us jokingly call a “Bleater” … it is a Goat after all.

This is the system.

The blue rope is the Bleater. It is a bowline around the boom behind the mast. Then it ties to the front of the boom to make sure the boom can’t move forward.

As an advanced technique beyond the scope of this page the “bleater” also works well if  the degree of vanging is to be increased by moving the downhaul back along the boom a modest amount.  Read more about vanging and bleaters for sail twist control and more performance here

Position of sail sets the position of the front of the boom and the halyard attachment point

The sail needs to be set in the right position relative to the mast.  Peter’s boat has the front corner of the sail where it attaches to the boom around 350 to 400mm (16″) in front of the mast.  For boats of other design looks closely at the designer’s sailplan for the boat and duplicate the position and angle of the boom in the drawings for the boat.

Peter fitted the neat leather chafe guard to protect the varnish after sailing a few times.  Basically soak some leather in water for a day or two, cut it slightly undersize (about a 10mm gap), punch some holes in the edges that you want to sew.   Sew tight – when it dries it will be really tight.

Note that the plans suggest that the boom should be 200mm above the partner – this is a mistake – it should be 200 to 250mm above the sheerline as shown in the drawing above

Traveller and Mainsheet the simple way

Mainsheet Block set up to drop out of the way when rowing

The plans show a block bolted or screwed to the top of the middle seat.  Peter came up with a much better solution that doesn’t risk pain and inconvenience to certain tender regions.

He used a simple bridle from the limber holes in the seat.  That way when the sail is not in use the block just drops to the floor.  Generally it is good idea to use a ratchet block which reduces the load your hand has to carry when holding the mainsheet.  A small simple ratchet block is perfect – no need for a fancy upmarket one and is worth the cost in terms of making the boat simpler and more fun to sail.  If you haven’t seen one before get them to show you in the shop – you don’t need one with an on/off switch.

Simple rope traveller

The traveller is a rope that goes across the back of the boat above the tiller (yellow in the picture below).

There is a block threaded onto it that is free to move across the boat.   Make sure the block lines up with the fore and aft axis of the boat – if it is crossways then the system will jam.  If you can’t buy a block that will sit facing the right direction buy a shackle and put the shackle on the bottom of the block with the shackle running on the traveller line.

The ends of the traveller line simply tie round the inwale as shown around the bulkhead frame.  The screws through the inwale into the heads of the frames will take the splitting loads.

The mainsheet is tied through the eye at the back corner (clew) of the sail. Then thread like the purple coloured rope in the photo above. Or the more detailed shot below (green rope).

Mainsheet can be left tied to the back of the boom and put away with the sail.

Setting the sail.

We have a complete run through on our sister website

1. Point the nose of the boat into the wind – it makes everything easier
2. Put the mast in place. The halyard is already threaded with both ends made fast to the horn cleat.
3. Unroll the sail. Yard and boom are left permanently attached. Thread the main halyard
4. Tie the preventer to stop the boom moving forward
5. Hoist the sail almost to the top
6. Attach and tighten the downhaul. Store it lashed permanently around the boom.
7. Thread the mainsheet

Setting up the Rudder and Centreboard

The plans are pretty good with this information, but here are some pics to show what it looks like and how it works.

LINK – How to protect your beautiful Centreboard and rudder for little cost

This is the rudder attached to the transom.  I prefer the single pin type rudder attachment.  It cuts the risk of the rudder coming off the boat.

A couple of tricks – make sure the rudder pin is not so long it goes in the water.

The white flecked cord is shockcord – it provides the tension to hold the rudder blade in place.

Rudder blade in place – not loop handle – i’ve coloured it yellow with Photoshop so it stands out against the sand.

This is the centreboard – note loop handle..

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If the centreboard slides up and down or won’t stay down you can set up a piece of shockcord tied to the mast below deck one end and tied to the centreboard handle at the other.  The tension of it pulling the board forward provides enough friction to make the board stay put.

There is a lot more information on other small details that utterly change the performance of any homebuilt sailboat or boat component.

Sails for the Goat Island Skiff and other Lug Rigs

Buildng a GIS is now about $300 cheaper – than any comparable boat.  Sails are available from reallysimplesails.com a partner company I helped set up and developed the sails for.

More performance info that’s relevant to every small to medium size lug rigged boat.*

More GIS articles and information

Sailboat Performance WIKI – theory and methods

Trailering a flat bottom sailing dinghy or utility boat

The trailer set up for a flat bottomed boat like the GIS is very simple.  Here is a picture of Peter’s flat bed trailer.

The cross pieces go through directly under bulkhead 2 and bulkhead 4 so the boat has the maximum level of support.

And here is the tie down on the front of the boat.  Bolt it through at a height just above the front seat level.

The fitting has a metal plate that is fitted inside the boat and Peter has glued a 6mm plywood pad under that area to prevent the risk of the stem splitting.

The Value of Discussion

Our active facebook groups are excellent for working out rigging and sail issues. They are a route for sharing good information and filtering out ideas that might not be quite right. Our members keep them very much on target.

Facebook Groups for lug and other rigs

• Goat Island Skiff for about the best in depth discussion for details of boat setup and technical details. Sailing and building. Useful for other boats too.
• Really Simple Sails has setup and tuning information as well
• Storer Boat Plans is the best place for general questions. It does have a much more general direction about wider issues in design, structure and sailing.
• Open Goose is more oriented toward the specific boat with a more introductory flavour.

Who said box boats with lug rigs are slow? They are fast enough to be interesting indeed!