Controlling lug sail twist with a vanghaul – Goat Island Skiff, Oz Goose, OzRacer

Storerboats Dinghy Building and Sailing Wiki > Storerboats Wiki > Sails and spars > Controlling lug sail twist with a vanghaul - Goat Island Skiff, Oz Goose, OzRacer

One of the great things about the vanghaul system is that it uses exactly the same parts and fittings as the original GIS setup.  Not one single extra part to get.

I received this from Justin Davis, who is buying the fittings for his Goat Island Skiff

I am in the process of gathering materials for my goat island skiff build.

I have acquired the various ropes and lines necessary but am lost on the hardware side- ratchets, blocks, cleats, etc. I am planning on building it with a loose footed sail with the vanghaul system and traveller described on your site.

What hardware in what quantities will I need to rig this way? I am not new to boat building but have no.experience sailing so figuring this out is intimidating for me. If you could give me a list of what I will need to rig this way I would greatly appreciate it. I have all of the lines in the lengths mentioned in the plans, but all 5/32 lines were replaced with 3/16 because it was more readily available.

Hi Justin,

The hardware is exactly the same as the original downhaul method.

This page on sail twist control and vang/kickers for lug rigs covers the original setup and the potential changes.  But the comments below narrow it down to the most simplified system.

Every effort should be made to have the sail in the same position as shown in the plan as a starting point.  This goes for all boats.  If the sail is not where the designer specifies relative to the mast and with the right angle to the mast then the boat is unlikely to sail well.

The vanghaul is the bottom drawing of this set of three.  The first one is the original downhaul.  The second one is a more complicated setup and the last one shows the original downhaul moved a modest amount back along the boom.

controlling sail twist using a vang or kicker on a lug rig - storer boat plans

Generally it is set up so it attaches to the boom between 150 and 300mm (6 to 12″) behind the intersection of the boom with the mast as shown in the boat plan.

This might seem like a very small amount back from the mast to those used to conventional boom vangs, but here the lever is from the tack (front corner of the sail) to the vang and not from the mast as they are used to.

You need a small wooden block or a deckeye/saddle on top of the boom so the vanghaul won’t slide forward.

The vanghaul itself is exactly the same setup and parts as the original downhaul for the boat.  As you can see from the first and last drawing in the above figure, they are identical.

The problem now is that the vanghaul will tend to push the boom forward.  We can use this!

The original rig setup used a simple loose square lashing to keep the boom in contact with the mast.

alternative ways of rigging a lugsail to control twist and get more performance - storer boat plans

The square lashing in the original rigging is used as the “bleeter”.  This is the bleeter.  I recommend the moderate bleeter as the strong one can bind on some masts.  But it is easy to try both.

controlling thrust from vang on lug rigs to get better performance - storer boat plans

Simply tie it through one of the holes in the front end of the boom, it then is tied with a loose loop around the mast. Its purpose is to stop the boom moving forward when the vanghaul is pulled on. It also as a side effect holds the boom close to the mast.

Remember that in light wind when the boat won’t move easily the vanhaul can have a light tension.

When the boat has reliable speed tension the vanghaul or downhaul has high tension.  Be serious about it!

When the boat starts to be overpowered use EXTREME tension.  This flattens the top of the sail.

It is important that the foot (bottom) of the sail is never too flat.  It should always have some depth as shown here.  If you have lacing along the foot the sail should look like this before the lacing is done.

This is one of our prototype Goat Island Skiff sails.

inexpensive sails for Goat Island Skiff


Also be aware that we are now manufacturing quality sails for the GIS and OzRacer series in the Philippines at about half the cost of regular sailmakers.  Please see their website at

This is the final RSS sail in use on a GIS in Uruguay. - Cheap sails for Goat Island Skiff, OzRacer, OzGoose, PDRacer, PDgoose

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