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For expert advice, articles and videos on setting up the 'A' Cat, both Foiling and Classic designs, click on each section to open a dedicated page for that subject.

Top tips from the European #6 and GBR #1 Classic sailor Hugh Macgregor on how to sail and set up the classic boat and rig.

Hugh is a professional sailor and coach.  He has been a multiple Champion across various classes.

Hugh Macgregor

I sail a Classic straight board 2009 Tool, with Hammer deck sweeper sail, Saarberg stiff untapered mast, Exploder boom, and Exploder asymmetrical winglet rudders, I am around 100Kg.  The A Cat world is very diverse, my settings will not work exactly the same with your setup, but may help you generate a starting point.  As I write this I am preparing for the Euros in Garda, and am trying to get my boat and myself as prepared as possible, in order to justify the expense of going.  It’s a bucket list, once in a lifetime opportunity to tick off a Garda event.


I have worked hard to optimise my boat, the hull finish is perfect, the foils are damage free, and prepared to 3000 wet and dry, which makes them silent at speed.  I have the rudder blades parallel, with no toe in.  I have spent time adjusting the rudder rake and mast rake to make my boat want to sail in a straight line when powered up upwind, with no weather helm and light steering.  My T foil rudders are set to half a degree of lift, more lift is good upwind, but pushes the bows down too much downwind.  The T foils allow you to safely push much harder downwind, it’s a modification I would recommend.  I bought a Saarberg stiff mast to suit my weight, and Micky Todd (Hammer sails) made a very nice sail to fit both my mast and my weight.  I make extensive use of Micky’s tuning guide, and thank him for his coaching and advice, he showed me what an A Cat can really do.  I have a Harken 40mm 9:1 mainsheet system with 8mm swiftcord, and 2 Harken 60mm auto ratchets to help manage the load.  Good gloves are a must, the high aspect A Cat rig is all about mainsheet action.

Rig setup:

A deck sweeper sail is a must have, it moves the power of the rig lower, where you can use it, making the boat faster and better mannered.  A curved boom gives much better control of the foot than a boomless one. I currently sail with about 45mm deflection in my spreaders, and a diamond tension of 26 on the loos gauge, I don’t adjust these unless I change sails.  My rake is to halfway between the aft beams and the transom, about six degrees, I find this is where my boat balances the best upwind.  I go one shroud hole down (seven degrees) for days I should probably not sail, and one hole up (five degrees) for very very light days, but I mostly keep it in the neutral position.  My shroud tension is 12 - 16, if I have more than 14 I cannot get enough mast rotation downwind in light winds, but more makes the boat feel more settled in upper wind bands.  I tie my video tape streamers 1.5 meters up from my forestay fittings, and have them long enough to touch the mast upwind.  It is worth getting a tuning guide from the sailmaker for the sail you use, to give you a starting point for settings.


Sail setup:

My main calibration when I prepare a sail I have not used before is the downhaul.  Firstly, I pull on the downhaul until the sail is at its fullest, ie the most camber in the top half, then put a calibration mark on the mast.  This is now my minimum setting, 0%, I pull it to this setting before the start, and never ease beyond this setting until after the finish, even in the lightest winds.  I then pull on as much downhaul (and mainsheet) as I dare, until the top half of the sail becomes perfectly flat, then mark the mast/sail again. This gives me a range of 0% to 100% for the downhaul.  The downhaul is the main power control you have, it is worth servicing and maintaining your downhaul system to make it as friction free and reliable as possible.  If you cannot consistently get enough downhaul, because of lack of range or purchase, or old knackered blocks, you will be slow upwind.  If you rip your sail with downhaul, it is a sign you need a better mainsail, not that you used too much downhaul.  I have a 24:1 downhaul, as it allows me to adjust it more accurately, and make it easier to ease, with a more flexible mast 12:1 or 18:1 should be adequate.

The outhaul I always have as eased as possible, I try to have it set so 2/3rds of the sail is touching the curved boom when fully powered upwind.  If the boat feels a little sticky, I ease it another inch.  My calibration on outhaul is so I can always set it to the exact same amount, if it is an inch too tight, I find myself very slow upwind.  I never adjust it to the wind strength, for me it’s set and forget.  Power at the top of the mast can be useful, or it can just trip you over.  Power at the bottom of the rig is always helpful, it is your main engine room.

The batten tension should be only just enough to stop sail creases developing across the batten when sailing.  Mark your top batten when you’re happy with the tension, so you can always retie it in the same place, too much top batten tension or too little messes with your head.


Upwind modes:

Note:  traveller always on the centreline.  Video tape forestay streamer always touching the mast.

Upwind Light winds:  before trapezing, approximately 1 - 5 knots wind.

Downhaul - 25%, but maybe up to 50% if very light winds making the rig sticky, or if you have a very full sail, and I usually pull on 50% downhaul for tacking to aid flicking the battens.  Mast rotation - pointing to the daggerboard, I use my foot on the mast base to force it to rotate.  Fore and aft trim - Sitting up at the main beam, or a little ahead, try and get the bow knuckle in the water.  Mainsheet - it is very easy to stall an A cat rig with too much mainsheet tension in these conditions, I try to keep enough twist to avoid stalling, if in doubt let it out.

Upwind Transitioning: from sitting to trapezing, 5 - 8 knots of wind.

This is the hardest mode change to get right, as the apparent wind doubles in this range.  Downhaul - 0% when sitting, but immediately up to 25% when you start trapezing.  Mast rotation - start bringing it back to halfway between daggerboard case and back beam.  Fore and aft trim - I move to behind the shrouds go out on the trapeze, if there is enough wind once on the wire I stay where I can just have the leeward bow knuckle at the water line, but if I am struggling to stay on the wire, I crouch in front of the shrouds, and really immerse the leeward bow, this helps with pointing.  Mainsheet trim:  In this mode, I try to have no twist in the rig whatsoever.  You will find that there is a point when, as you pull in the mainsheet, firstly the twist reduces, then at a certain point, the camber in the upper rig starts to reduce.  It is just before the camber starts to reduce that the rig is generating maximum power, ie minimum twist maximum camber, this is where you need it when you first get out on the trapeze. 

Upwind:  power band, 8 - 13 knots of wind.

This is when nothing that floats can touch an A Cat, it’s a magic carpet ride that makes all other boats look like traffic cones to go around.  Downhaul - This is the range where my downhaul never stays the same for long, in 8 knots of wind it is at 25%, in 13 knots of wind it is at 100%.  Mast rotation:  by 13 knots, it will be pointing at the leeward rudder.  I never bring it further in than the leeward rudder, it is worth having a strop on your mast rotation control system to prevent this.  Fore and aft trim:  aft of the shrouds, keep the bow knuckle just at the waterline, not in, not out.  Mainsheet tension - tension the mainsheet for zero twist as a starting point.  Most people when they transition into A Cats from other boats have a tendency to pinch into the wind too much in these conditions.  If my video tape streamer wants to sit to windward of the mast under full mainsheet tension, I pull on more downhaul to flatten the top half of the rig, to bring the streamer back down to the mast.  If my streamer is to leeward of the mast, I have too much twist in the sail, I pull on more mainsheet tension, and maybe ease a little downhaul, to bring it back up to the mast.  Once the wind increases to the point where I am constantly easing the mainsheet (ie adding twist) to avoid pinching, I have the downhaul on at maximum 100%.  Try to use more mainsheet action and less steering to get through the gusts and lulls, it’s faster.  Remember, easing the mainsheet without pulling on downhaul, increases camber therefore power / drag at the top of the rig, where you least want it.  If there is enough wind that you are introducing twist into the rig, you need to flatten the top half of the rig first.  Downhaul is your primary tool to flatten the top half of the rig.

Upwind, 13 to 22 knots: 

Here is where you guys with C boards and T foils can really take off, if you take a step back to get the first meter of boat out of the water, and keep easing the mainsheet to keep the streamer on the mast, you can get the boat into a skimming mode.  If it all gets a bit too hectic, try dropping the traveller by a couple of inches, try lifting the daggerboards by 150mm, just to calm it down.  If you find you cannot make the top half of the sail flat enough with downhaul in these conditions, you can try getting a stiffer set of top 4 sail battens, or old school would be to turn your top battens around, luff to leech, it all makes the boat a little less twitchy, at the expense of downwind power.

Downwind Modes:

Downwind, Mild thing, 1-5 knots of wind.

Downhaul - 0%.  Mast rotation - off, force the mast to 90 degrees, with your foot or an over rotation control.  Fore and aft trim - sit forward at main beam, to get the transoms out of the water.  Traveller - maximum ease.  Daggerboards - if straight boards, both up, if C board, windward one up.  These are the most difficult conditions to get a A Cat downwind, it is very easy to stall the rig, and very hard to build speed. I aim to keep the apparent wind between 5 and 10 degrees forward of the beam.  Keep the rudder use down to a minimum, keep the tiller extension planted on the deck to reduce movement.  Mainsheet:  Take the mainsheet directly from the clew for maximum sensitivity.  Sheet in and reduce twist very gradually, as you build speed and bear away, but be prepared to head up and ease sheet again if you stall the rig.  Twist is useful in these conditions, as it means at least some of the rig will be working at all times, if you have no twist, the rig is either stalled or working, not very helpful in light shifty winds.

Downwind, Transition, 5 - 10 knots.

Downhaul - 0%.  Mast rotation off.  Fore and aft trim:  start moving aft, in these conditions, I am aiming to keep both hulls on their design waterline, bow knuckles and transoms just skimming.  Traveller - from just inside of leeward hull to 400 mm inside of the leeward hull.  Daggerboards - both up or windward one up.  Mainsheet - Sheet for minimum twist maximum camber, I use the mainsail telltales to help me same as upwind use, but always being ready to ease an armful if it stalls.  Once the breeze gets closer to 10 knots, the traveller starts to act like an accelerator, allowing you to go faster with very little increase in height.

Downwind, Wild thing, 10-16 knots.

My current rule of thumb, if there is enough wind to trapeze and fly a hull consistently upwind, then there is enough wind to fly a hull downwind.

Downhaul - 0%.  Mast rotation - off.  Fore and aft trim - just in front of rear beam to just behind rear beam.  Traveller - leeward toe strap.  Daggerboards - windward one up or both down. Mainsheet:  Sheet for minimum twist, maximum camber and get the boat going fast before trying to lift a hull.  Once up to speed, a quick little luff should unstick the windward hull before a big bear away and lots of playing the sheet to keep it flying.  Prioritise accurate steering and sheeting over moving your weight around.  In 10 knots of wind, I try to get my feet under the leeward toe strap before I pop a hull, in more wind, I try to get both feet under the windward strap and my arse wedged on the aft beam before lifting a hull, I like to be locked into the boat before it leans over too far.  Bear away and ease sheet in the gusts, head up and sheet in for the lulls, and use mainsheet to smooth out the ride height.  If the bow does start going under water, a sharp ease on the sheet will let it pop back up.

I am not agile enough to combine wild thing with trapezing, and I have straight boards so my boat does not generate lift with speed, there are a few modes I am probably missing out here, there are many more qualified sailors than me to explain them.

Downwind, 16 - 22 knots:

Downhaul - 25% - 50%, Mast rotation off, Fore and aft trim - as far aft as you can go.  The convention is to point the boat deep downwind, with traveller up to inside of leeward hull.  Ease sheet a bit and head up to build speed, and bear away and over sheet to calm it down, reversing the airflow over the mainsail leech to luff when required in the bigger gusts.  I very rarely try to fly a hull in these conditions, as on my straight board boat I need all the buoyancy I can get.  Another mode you can play with is to drop the traveller right down, ease the sheet, and keep the apparent wind on the beam, with the sail luffing slightly, and 50% downhaul.  It has the advantage that you can always sheet in for more power and ease for less, it can help you make a leeward mark layline when you’ve misjudged your last gybe, and end up coming in a little hot.  Whatever happens, the further back you can get your bum, the harder you can push it downwind without sticking the leeward bow in.  If you do stick a bow in, you have a good chance of saving a capsize if you are properly wedged in to the aft beam and toe straps, if your bum slides forward, it’s swim time.  Capsizing is slow.

Finally, maintenance - keep your boat in good condition.  A minor breakage can often snowball on the water, a broken trapeze line or tiller extension joint can lead to much greater damage, a planned maintenance schedule can be useful,  2 years for a UJ, 2 years for trapeze strings, 3 years for shrouds, forestay, and their shackles, 5 years for downhaul equipment etc.  Carefully check all your shackles, split rings, rudder fastenings etc after a big day.

Most damage to A Cats happens in the dinghy park, the mast can flap like a sail during a gale, and damage your boat, and push up the insurance premiums for all of us.  To avoid damage, tie your mast spanner to the toe straps so the mast cannot rotate.  Use your tiller extension to pass a line around your mast above the spreaders, and tie it down to the aft corner, this kills any resonance vibration that can damage the rig.  Most importantly, tie your trapeze strings down tightly to hard points either side of your boat level with the main beam.  Don’t leave your mast up in winter.  Finally, tie down your neighboring boats, so they don’t blow onto your boat.

The best way to learn, and to optimise your boat and sailing style, is to come to A Cat events, it’s a friendly class, everyone will help you get up to speed as much as they can.  A Cat’s are pretty bad handicap boats, but in class racing they offer some of the most intense and rewarding racing in the sailing world, accessible to all ages and for a wide weight range, there is not a better place to be on the water.


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