Small fathead mainsails, where the roach of the sail is increased due to a considerably wider head of the sail, are starting to pop-up on the racecourse and they are proving to be a winner. Getting extra sail area on your boat can be really hard without taking a big rating hit, but increasing your crane size will give you that extra bit needed without too much out-of-pocket cost or dramatically affecting your rating.

Some yacht designers are already doing this in their new designs like the J/70 and J/88, for example. These are a great example of a boat getting extra area without having a very tall mast. To get the same amount of power while also reducing tipping weight and decreasing drag aloft.

Ratings

The extra area gained is only from the top quarter of the mainsail, in the photo below you can see the pink line.

extra area gained is only from the top quarter of the mainsail

This means that the only rating change is on the MUW measurement which only moves out a tiny bit. Your headboard increases from 0.15 m out to 0.45 m or larger depending on the crane size you can add. This is a very big increase in sail area which is almost free at the top of the sail from a rating perspective.

Design

Drag off the pin head main

The extra area makes a marginal speed increase upwind but it does reduce drag a fair amount. In the photo above, you can see the drag off the pin head main which is considerable compared to a slightly fatter head main. Importantly, the airflow sticks to the top of the sail longer creating less drag and generating more lift.

This bigger mainsail really comes into its own downwind and reaching. Off the wind is where the fathead main can be of most effective! The draft at the head of the sail will move slightly aft as you twist off the sail. But it also allows you to open and close the leech of the main quickly—letting you power up the boat or dump more quickly as the sail twists more.  See the photo below.

Off the wind is where the fathead main can be of most effective!

Mast

Normally, increasing the crane size from 0.15 of a metre to 0.4 is a big structural job. You will need to check with your mast builder to see if it can be done. The primary area to consider is the mast's bend characteristics, which will change, making the luff curve of the main slightly different. As the crane increases and applies more load on the top of the mast, it bends more while also applying a lot more load above the forestay. You will need to confirm your forestay can take the additional load. The side plates of the crane will move further down the sidewall of the mast to try and take this extra load, but it's best to check with your mast builder to ensure you don't break the crane off.

Halyard

With a fathead mainsail, it's important to add a 2:1 halyard. This allows the head of the sail to articulate and not point load on the sheave. It also balances the main going from a beat to a run as the very top corner of the mainsail luff tape is pulled away from the mast on a beat. The 2:1 halyard will take this load and balance it out so there is no point loading, pulling the head of the main into the mast at all times. The mainsail designer will move the head ring aft to allow for this.

Conclusion

Adding extra area to the top of your mainsail will give you extra power, less drag, and a more efficient mainsail. However, it's totally dependent on your mast builder saying it is possible and practical. Trust me, it works really well on most modern yachts.

So, if you need some power and you're all maxed out, look up the answer is in front of you.

Racing a J/109 in IRC has its compromises because you're sailing with asymmetrics, you're limited to certain angles and only so much boat speed is generated both up-wind and down. While living in Hong Kong, I raced the J/109 Whiskey Jack in class 2. This is an extremely completive class dominated by three A35s and other boats such as Sunfast 3600s, an X-35 and a 34.7. We had to sail our arses off to do as well as we did.

The owner of Whiskey Jack wanted to see how he could improve his J/109 to be more competitive. Realising he probably would have to leave some of the boat's one-design components in the rear-view mirror, he contacted UK Sailmakers Ireland having seen what we had done with J/109 ratings in Ireland. To get an overall evaluation of the entire boat (including sails, rig, set-up, etc.) I got onto Kevin Dibley who I have worked with a lot at Dibley Marine. Over more than a few cups of tea, we checked out all aspects of the boat to see where we could improve upwind and down.

J109 Whiskey Jack Racing in the St James Place China Coast Regatta 2020. Photo: Guy Nowell

We set for ourselves three objectives: 1) increase her upwind boat speed, 2) improving her pointing ability and  3) to reduce her IRC rating. Not a small assignment!

We started by considering how to improve her upwind VMG. We set out to reduce the wetted surface area of the boat while maintaining the waterline as much as we could. To achieve this, we looked at reducing the internal weight in the boat; but we also looked at the external weight and what could be done there.

To get the internal weight out, we replaced as much of the loose furniture as we could with lightweight carbon foam boards from ZLXC. The carbon boards were cut down to match the floorboards and painted in white non-skid. Next, we went to work on the exterior of the boat. We started by replacing the original aluminium mast with one made of carbon manufactured by Axxon. Swapping out for a lighter mast saves us a lot of weight and, importantly, the reduction in tipping weight would keep the boat upright. The set-up of this mast would be exactly the same as a standard J/109 mast apart from one small aspect…the material from which it was made and the masthead crane.

J109 Whiskey Jack - the original aluminium mast with one made of carbon manufactured by Axxon Photo: Guy Nowell

Having reduced the hull and mast weight by a significant 200 kg, we set out to optimise her upwind performance. We started by focusing on a power-to-weight ratio so that the boat would perform at her optimum rating at 8-12 kts, the typical wind speeds in HK. Reducing the 140 % overlapping genoa to nonoverlapping headsails gave a big reduction in her rating, but we then had to make sure she could still perform. The worst thing we could have done was to create a scenario where we left the boat terribly underpowered. But using the "twist" designed headsail that we developed in 2019, we found we were able to achieve the optimum pointing angle and balance upwind. That met one of our objectives. We then added UK Sailmakers carabiners on the headsail luff to make the hoist and drops faster to get the asymmetric to set quicker and stay up longer.

Carabiners were added to the headsail luff to make the hoist and drops faster and to get the asymmetric to set quicker and stay up longer

We had made major strides at this point, but we weren't done yet. We worked further on the balance of the boat while focusing on getting the maximum drive out of the mainsail roach. We ended up increasing the crane width on the mast so we could align the girths on the mainsail. The mainsail maintained its luff curve but increased the J/109 girths, and the head of the mainsail became a lot wider (0.4 m), made possible by the larger masthead crane of the new mast. This was key to reducing drag and increasing the power at the top of the rig. We were able to do this while maintaining the balance of the boat and its increasing pointing ability by adjusting the rake of the mast.

A deeper running asymmetric, slightly larger than the J109 Class standard was used for Hong Kong’s light airs

Given the lighter airs in HK, we designed a deeper running asymmetric with an area of 111m², slightly larger than the J109 Class standard. The new kite, combined with the reduced wetted surface area and a new fat head main, allowed Whiskey Jack to sail deeper and more square than the other asymmetric boats. She was able to creep away downwind at a lower and faster angle than her opposition. With the reduction in rating from 1.028 down to 1.019, the boat now enjoyed a massive reduction in rating while increasing her boat speed upwind and down. Whiskey Jack went on to clean up at this year's China Coast Regatta in HK.

The boat now is superbly balanced and sails higher and faster than she ever did and she does not heel as much

The owner went on to say after his victory: "The most significant differences in my view were the change to the carbon mast, the new Titanium sails from UK Sailmakers and a well-tuned rig with an appropriate mast rake. The boat now is superbly balanced and sails higher and faster than she ever did and she does not heel as much – i.e., I can sail the boat flatter than before – that gives the extra height and speed in my view.

Once again, UK Sailmakers put together a team of experts to make a boat faster, easier to sail, and a better experience for the owner. What more could anyone ask for?

UK Sailmakers Ireland in Cork Harbour say they remain open during the Covid-19 Level 5 restrictions as the Crosshaven sail loft is treated as a manufacturing facility and a full production loft.

As they continue to repair, service and produce sails, loft manager Barry Hayes says customers can come to the door of the loft but not inside, given the latest restrictions. "They just need to call 021 483 1505 and we will come out to them", he adds.

The video clip below shows the loft sail plotter working away this week as observed by faithful Layla. As Afloat reported back in April during the last COVID lockdown, UK Sailmakers was to the fore then in the manufacture of scrubs and other PPE equipment for front line workers. 

What has Brexit got to do with your winter sails service this year? Barry Hayes of UK Sailmakers Ireland, explains the situation and why it’s such an urgent matter.

Dear customers, I want to let you know it’s really urgent if you need your sails washed and laundered to get them into us ASAP. The issue is Brexit, and specifically tariffs that will apply in the New Year without a trade deal in place.

If you need your sails washed, they need to go to Tiptop in England who are the only people who wash sails properly to UK Sailmakers’ standards. To get them washed and cleaned and back to Ireland before the Brexit tariffs will be applied after 1 January, time is now running out.

I know the season has been short and your sails haven’t been used much. But the service team at UK Sailmakers Ireland have the space and knowledge to get them serviced correctly and at the right price. Our team at the loft check every detail of your sail, making sure it’s ready for the new season.

Being mindful of the delayed season start with COVID-19 and associated restrictions, now as we get to the end of the season it’s more urgent than ever to get your sails in for service. Doing so now gives you the best option to be in early for the next season and make the most of 2021.

We are the most experienced people in the business at servicing your sails and have been doing so for more than 50 years, getting your every detail right so you can enjoy your coming season sailing. We have the space to stretch out your sail, fully hang it up to repair and replace a full UV cover, giving your sail the greatest longevity possible.

Contact UK Sails service manager [email protected] 

Barry Hayes from UK Sailmakers Ireland with tips on the dos and don'ts of reefing a sail for racing and cruising

Times have changed, and this season we have moved to more ISORA short course, offshore sailing. This trend will probably continue into next season. With these shorter courses, having the optimal sail set-up at all times is critical. Knowing when to reef your mainsail to achieve the right balance for the boat is key to your upwind, heavy air performance. This is particularly the case as we head into winter club racing when the colder air is denser.

When to reef: racing

It is always a challenge to decide if you are better off depowering the boat with a reefed mainsail (and going through the "process" of reefing/unreefing") or waiting for the wind to lighten when your full main would be more effective. One determining factor is the size and abilities of your crew (can they quickly throw in a reef and release it when necessary) and how much weight you have on the rail (effecting how overpowered you are). The decision of when to reef is more complex than that.

If your sailing doublehanded or shorthanded, you will want to reef early. A good benchmark is reefing at 20 kts; the boat will still be relatively easy to handle and it reefing at a lower wind strength dramatically reduces the workload. If your fully crewed, your benchmark is more in the 25 kts range.

With those benchmarks in mind, every boat is a little different and when to reef has to do with the balance of the boat and how light it is. A First 34.7, for example, will go faster upwind with a reef in the main and full headsail in 20+ kts then with a full main because the s a light boat and quite tippy so you may want to reef sooner than later. For a high stability boat, like and XP 44, it's going to be into the 28 kts range before you put in a reef.

If you get a 20 – 25 kts day and you're out sailing, it's worth practising with and without a reef and seeing the difference in boat handling and boat speed. You might find it's easier to get around the course not being loaded-up and being fully under control at the marks. But again, each boat and team is different, so practice makes perfect.

How to do a racing reef quickly

When you are putting in a reef, prepare the main halyard so it's ready to go and then hoisted quickly and cleanly. It's all in the pit person's hands, so it's critical to have enough halyard ready to ease (figure a minimum of four metres for the first reef or four long arms full of slack). Usually, there is a snap shackle at the gooseneck of the mast that you clip into a soft shackle (see the photo (C) below - we use these to save weight on the sail) or ring on the luff of the sail. Then, get the halyard back up tight before you start trimming the line to get the clew locked in. We mainly use thimbles on racing sails which are lightweight and don't put excessive loads the sail's reefing line.

A Snap shackle at the gooseneck of the mast clips into a soft shackle

Most racing boats don't bone the foot of the sail when reefing, this keeps a little shape in the foot and avoids stretching out the foot of the sail. Leaving a few inches of camber in the foot really makes a difference to the longevity of the sail.

Most racing mainsails designed for reefing come with webbing between the normal clew and the reefing clew (see the attached photos (D) below. This webbing creates a natural fold in the leach when you reef, helping protect the sail material. This also lifts the "skirt" of the main up onto the boom so it is out of the way. Additionally, this webbing massively helps reduce the amount of water that collects in the sail in heavy seas. With this webbing, you rarely need to use the reef diamonds along the reef line to tidy the sail away, making it easier set and release a reef while racing.

Mainsails designed for reefing come with webbing between the normal clew and the reefing clew

When to reef: cruising

If the breeze is up, a white sail cruising reef is typically set well in advance of the passage. Making sure it's set up right in calm waters is dramatically more manageable and safer than trying to do it at sea. For slab reefing, follow the same steps as a racing reef. Get the reef tack on and then raise the halyard slightly more than snug to allow for some movement in the halyard. Then tighten the clew reef line, so it's close to the boom without crushing the sail.

I don't use the eyes under the boom to attach the reefing line as they are never in the right positions. Every time you reef, the tension is different, so the sheeting angle on the clew is always wrong with the eyes under the boom. Just take the line around the boom and back onto the reef line itself with a bowline or a timber hitch. This will give you a good clean reef every time, and a knot that can be "broken" after the pressure is taken off it.

If you're using single line reefing, then make sure all the lines are working correctly and are free to move. Setting the reefing line and marking it is key to clean single line reefing. It also lets you know your reef is set at the correct point before you raise the halyard. If you aren't sure where to mark your setting, remember that it's better to have them a little looser then tighter.

I normally have the single line reefs about 3 inches above the boom to allow space. This prevents point loading the reefing lines or causing chafe. Having a lazy cradle makes it much harder to see where your reefing lines are, so having marks on the line and the mast is recommended. Most of today's lazy cradles will roll away onto the boom and not cause any issue when reefing.

Lazy cradles will roll away onto the boom and not cause any issue when reefing

In conclusion, if you believe your boat will be overpowered, out of balance, and harder to sail with a full main, you are better reefing. Practice this evolution, then, when it's time to do it for real, talk through what each person's role will be, what potential problems to anticipate (knots in the lines?), and confirm everyone on board is ready to execute their job before saying "go." Remember, if you're reefing it's because the boat is healing excessively, so make sure your crewmembers scurrying around the deck are wearing their PFDs and/or are tethered to the boat.

Next Thursday week (September 8th) is the last evening race in the 2020 Dublin Bay Sailing Club season writes Barry Hayes of UK Sailmakers Ireland.

As the summer season draws to a close, it is time to consider what we can do to improve your 2021 season.

Take advantage of the autumn sailing season to assess your sail wardrobe needs and where you can improve.

Bolster your sail wardrobe for maximum performance

New sails make a big difference to your boat's performance both on and off the race track. Getting the right sail for your boat is key to planning your new season on the right foot.

(From left) "Outrajeous" Sovereign's Cup Champion – "Rockabill VI" ISORA Champion (partial inventory) – "Mermaid IV" Dun Laoghaire Week Coastal Champion (partial inventory

And there is no better time to buy than during the autumn period with up to 15% off retail pricing. Make the most of your autumn sailing.

It's also a great time to take advantage of the new VAT rate of 21% on top of your winter discount.

Contact any of us for advice, guidance, and a quote today. See contact details below.

We've been working hard this weekend to keep the 1720 sportsboat boys in the game at the AIB Southern Championships at Royal Cork Yacht Club.

When you rip it, UK Sailmakers Ireland can fix it in time for the next race! 

That has certainly been the case this weekend after a very breezy start to the championships on Friday leading to lots of sail repairs required at short notice.

See some examples of the overnight work at the loft below that included some tricky torn spinnaker luffs!

This red 1720 Asymmetric had a small hole in the leech. We cut out the broken area and repaired it

This white 1720 Asymmetric tore the luff at the spreader so we replaced the panel

Cork Harbour sailors Mel and Kieran Collins from Crosshaven describe how they transformed Coracle VI, their vintage Olson 30, into an 'IRC weapon'

Prior to buying the boat, we did extensive research on which boat to buy and why. The Olson 30 designed by George Olson of Santa Cruz, CA, around 1978 was built around the same time as the Half Tonners; but the boat was a strict one-design class in the U.S. and was a predecessor of the sports boats that came 15 years later. For its day, the Olson 30 is a highly unusual boat in that it planes downwind in about 20 knots. To put it another way, it needs about two knots more wind to plane than a 20-year newer design like the 1720. Loads of useful background info on the Olsson can be found here

Going in, we wanted a boat that was both enjoyable to sail and competitive for club racing. It turned out better than we hoped. Working out whether it would be competitive in IRC rating, however, was the difficult thing.

A few Olsson 30s had raced IRC in the states, but IRC just really is not the dominant rating rule there. So, while we had an idea what the handicap would be with the 155% overlapping genoa, we did not know how competitive that would be on IRC here. The only thing we could do was use a spreadsheet to convert PHRF handicaps to IRC and compare boats that we know raced in Europe, too. The J/109 and J/24 were the most obvious contenders, but there were a few others. We also had access to quite a few good ORC handicap calculations and the Olson 30 compared favourably to boats we knew.

Coracle VI under spinnaker Photo: Bob Bateman

After buying the boat, we started off trying out the 155% #1 genoa, the 130% #2 genoa, and 100% #3 headsail. The feeling was the 155% needed eight crew and really had the boat overpowered over 10 knots. It was also quite difficult to handle a bigger crew as the cockpit in the Olson is quite small. The Olson was designed as an offshore boat.

With that information, we contacted UK Sailmakers Ireland about a large new spinnaker so that we might be able to plane a bit earlier and an overlapping genoa, 140% genoa designed to fit the to the max area.

This proved a competitive setup for the Olson 30. We were unbeatable if we got over 20 knots of breeze in planning conditions with the genoa and larger kite.

In light conditions, we could keep up with, and race very closely with the Half Tonners, if not quite beat them; we could beat pretty much most other boats in these conditions in our class as well.

Getting the design of the sails and area right took a fair bit of thought and design. We were lucky enough to work with UK Sailmakers Ireland who were able to 3D model the sail design so we could see what we were getting before we ordered. As such, we knew we were going in the right direction.

Ideal conditions for the Olson 30 in Cork Harbour

Breezes of 10-15 knots is about ideal condition against most boats except Half Tonners; we were fast downwind and get the most out of the 140% overlapping genoa upwind. Still, we only start to beat the Half Tonners over 12 knots. Unfortunately, at 13 knots the larger boats, like a J/109, would come into their own and we would struggle. Regardless, this left us in a good position in that if we got mixed conditions, we would be competitive.

There really was no weakness, but to be sure of a win we needed 20 knots plus, which is rare in our racing area. We were not happy to just leave it at that. We looked at a few other enhancements at his point: an asymmetric spinnaker and adding weight to the boat (as it is exceptionally light – 1,600 kg) Neither made any real difference to the IRC rating on trial certs.

In 2020, we decided to look to optimize the boat further. We focused on optimising the sail plan and the hull displacement, we looked at reducing the spinnaker area a little as we felt we didn't get the benefits in light air from the very large spinnaker unless we were reaching. Dead downwind it was hard to fly. While a real weapon in the 10-20 knots wind range, we felt the larger chute did not help much under 10 knots.

A 100% non-overlapping headsail

The second thing we did was move to a 100% non-overlapping headsail. We worked with UK Sailmakers to design a headsail that would fit the foretriangle to the max plus a new, slightly smaller optimised S2 symmetrical spinnaker. The sails were designed in 3D, so it fit the rig perfectly with the max area. We worked out the headsail area from that and ran a trial cert.

By moving from a 140 % to a 100 % headsail and the smaller spinnaker, we received a 12-point drop in our rating.

Our feeling was that, in light air under 10 knots, we may still struggle with Half Tonners, but we should be still competitive against all other boats. We do not expect much difference from the smaller optimised spinnaker but would expect to see some drop-off upwind in the lighter air. A change of 12-points is a big gain rating wise, so we will have to see how it all works out.

By moving from a 140 % to a 100 % headsail and the smaller spinnaker, we received a 12-point drop in our rating

In 10-20 knots. we still should go quite well if a little slower than before, but the 12-point handicap difference should easily make up for this. It also allows us to sail with one or two fewer crew; the boat is generally pretty cramped anyway.

We will now rate close to Half Tonners so should still be competitive against them and, as the wind goes up to 10 to 20 knots, we should be much more competitive against the big boats like J/109 also.

Really, the big risk is in sub 10 knots but over 10 we believe it will be a net gain.
Onboard Coracle VI in light airs

Barry Hayes of UK Sailmakers Ireland has been showing off a new 'Code D' gennaker that's been designed for simple and easy use.

The Cork Harbour sailmakers say the cruising sail furls easily every time as he demonstrates in the vid below.

Hayes also says the new sail design can also be hoisted before leaving the dock. And, as it’s on a ratchet lock, it can be opened whenever is required.

The Code D is top-down furling sail so, says Hayes, 'it’s a perfect furl every time'. 

Now that’s a wrap!

In this article, Barry Hayes (UK Sailmakers Ireland) and Pat Considine (UK Sailmakers Chicago) explain headsail vertical camber and why it’s so important to boat speed and performance of the boat. In reality, understanding headsail vertical camber is the modern headsail trimmer’s main tool to getting optimum speed and power out of the sail.

Headsail horizontal camber is always spoken about regarding how the sail needs to develop the right shape, but vertical camber is also critical to the performance of the sail.

UK Sailmakers’ sail designers use vertical camber tools in their design programme to optimise a sail’s horizontal camber. The superior shape-holding characteristics of today’s moulded sails require proper setting of the car, halyard, and inhauler to get the horizontal and vertical camber correct.

The red line indicates the sail’s vertical camber

In the photo above, the red line indicates the sail’s vertical camber. The trimmer’s goal is to get the vertical camber line smooth and straight (as a plane’s wing), while keeping the twist in the leech of the headsail and getting the top of the headsail to open up and match the main sail slot (green line).

"you want to visualise a straight line down the back of the sail to the deck"

Looking at the back side of the headsail on the horizon will help you see the vertical camber and see how deep the sail is. When you’re looking for max power for the pressure you’re in, you want to visualise a straight line down the back of the sail to the deck.

Setting-up a headsail to achieve correct vertical and horizontal camber is the key to power-generating headsail trim

Setting-up a headsail to achieve correct vertical and horizontal camber is the key to power-generating headsail trim. There is nothing wrong by having the foot full in the headsail in light air, it’s like having the flaps down on a plane's wing when taking off to generate lift and power. In a headsail, a full foot provides power and pushes the bow down in light airs helping to balance the boat. It’s only when the boat reaches hull speed does this effect start to change whereby you need to flatten the horizontal camber in the sail, taking more foot round out of the headsail, and flattening the overall shape of the sail. To achieve this shape, you’ll probably want a tighter halyard, tighter sheet, and an eased inhauler. This is normally about 8 – 10 knots depending on your hull shape and stability.

Sail twist

In the photo above, you can see the sail is twisting open, much like the ailerons on a plane’s wing, allowing the air flow to accelerate into the slot. This is the perfect amount of twist-to-vertical camber relationship in the sail. Having too little twist in the head will choke the slot and not allow the air flow to accelerate. To build boat speed, open the slot a little more as this will increase the air flow. When you’re up to speed, reduce the twist again so you’re making the most efficient use of the slot. Actively opening and closing the slot as speed and wind pressure vary, while minding vertical and horizontal camber, will allow you to get the maximum power out of your headsail.

Excellent vertical camber on the Beneteau 50 Mermaid

As you can see in the above photo, the First 50 MERMAID has excellent vertical camber. The headsail is almost touching the lifelines in 8 knots of wind. The leech is nicely twisted open which creates max power and aerodynamic performance.

As you get up past hull speed in heavier airs, you need to shift your focus with your headsail trim. Creating the least amount of drag possible and with the most efficient drive and leeway.

As you can see in the photo of a J 3 headsail below, the foot still has shape to match the vertical camber. The sail is not over inhauled so the boat is balanced and easy to steer upwind. Having the foot too flat and not match the vertical camber in the sail will not give the helm enough power to push the boat through waves and also increases the heeling effect. Remember, you need some power in the foot of the headsail to balance the vertical airflow in the headsail. If the sail is too flat in the foot, the airflow will separate too early creating a vacuum and slowing the boat down.

The foot of the J3 headsail still has shape to match the vertical camber. The sail is not over inhauled so the boat is balanced and easy to steer upwind

Pat Considine, UK Sailmakers’ lead sail designer, added, “From an aerodynamic point-of-view, your objective is to have the foot of the headsail full in light airs and having the top of the leech twist open nicely (see photo below). This allows the headsail to deliver the most power without causing too much drag. You also can see in the photo how the air flow exits the top of the slot and flows quickly around the mainsail. At the same time, the lower portion of the sail’s air flow is moving at half the speed, generating power with smooth vertical camber in the headsail.”

Having too little foot round in the headsail is sub-optimal because it reduces the overall vertical camber in the headsail

Having too little foot round in the headsail is sub-optimal because it reduces the overall vertical camber in the headsail and reduces the power generated by the airflow moving over the headsail. Conversely, in 12 knots, having too much foot found not enough leech twist will give you lift but at the expense of speed.

The ratio of vertical camber to leech twist is critical. Having a straight line down to the deck is a really good visual key to help you get the headsail trim right. While watching the twist in the top of the leech.

To learn more about both vertical and horizontal camber in a headsail, contact UK Sailmakers below.