CM’s supplier of choice is the North Sails loft in Cape Town and we’re very happy with that option. North need no introduction and a local loft is likely to be an advantage as the wide range of options means that each CM rig will, to some extent, be a prototype – the odd tweak may be needed after trials – a process that’s not new to me! That said, North in CT made and tested the sails on the first CM46, so they have a head start.
Fabric: Mainsail – Solent – Staysail
We gave a lot of thought to our choice of sailcloth – trying to balance all the pros and cons. We’ve opted for North’s NPL Tour Xi. It seems a good compromise between 3Di (which probably offers the best combination of shape stability, light weight and durability… but is expensive) and a woven cloth (which is durable but heavy and lacks shape-stability). We had Hydranet woven sails on the Pogo and they were bullet-proof so we’d have liked to go that way, but they were heavy and began to loose shape after a few years – not unreasonable considering the 10,000 miles under the keel. Having opted for a carbon mast and textile rigging on the new boat, however, it doesn’t seem logical to use heavy sails. Catamaran rig loads are higher than monohull’s so, particularly on a cat with real performance potential, low stretch sailcloth is even more important to maintain shape, speed and pointing ability, especially as the sail ages.
North’s Tour Xi fabric achieves its stability through a laminate of mylar with aramid fibres, sandwiched between polyester taffeta on both sides for durability and UV protection. Lamination processes have improved significantly in recent years and North have confidence in the durability of this fabric, which they promise is well-proven, so we’re embracing this advice!
https://www.northsails.com/sailing/en/sails/materials/npl/tour
Mainsail
The main will have a biggish square head, approximately 40% of the foot length. Square heads improve the efficiency at the top of the rig. Hard to sum it up in a sentence (I’m not a sailmaker) but basically you get better airflow because there’s more sail working beyond the turbulent area behind the mast (the top of a pinhead sail is largely in turbulent flow, especially on a non-rotating mast) and a properly designed square head helps the leech twist open in gusts, de-powering/reducing heeling moment automatically, powering up again as the gust eases.
The boom is low above the cabin roof to minimise the height of the Centre of Effort and maximise boat stability and efficiency. The low boom is possible because sail controls are at side deck level (keeping our heads below the parapet) – and there’s no need for boom clearance over high helm spray hoods because the CM’s wheels can be swung down under the roof for shelter.
The main will have the usual three reefs and, less commonly, leech reef hooks. They’re popular on offshore race-boats but the hooks are expensive and they’re less common for cruising. Have a look here to see how a reef hook operates if you’re not familiar – fundamentally the leech reef line is winched in as normal until the hook (attached to the boom) engages onto a Dyneema loop on the leech and takes over the load. All the chafe and stretch associated with the reef line is eliminated. The hooks can be disengaged remotely by a release line.
Julian recommends leading only the 2nd and 3rd reefs back to the cockpit (they can also be operated at the mast), to minimise line congestion. The 1st reef will be led to the mast winch only as it will be used when the conditions aren’t severe. We can always go straight to the 2nd reef from comfort of the cockpit if the wind builds fast or one of us is alone on watch.
Solent Jib
Not sure whether the name “Solent” is widely used with cat sails (funnily enough, it seems to have originated in France) but it describes a genoa which overlaps the mast by a small amount – circa 110% of foretriangle J measurement. Anyway, we’ve opted for a Solent because the advantage over a self-tacking jib (sheeted in front of the mast) is that it adds area low down – which lowers the CoE and the overlap helps build the slot effect between the headsail and mainsail, particularly in light winds. This improves power and upwind performance. The downside is that we won’t be able to tack while holding a mug of tea – we will have to wind a sheet!
The Solent will set on a structural furler on the forestay and have four vertical leech battens to enable a small amount of roach – helping the slot effect further. It will sheet through 3D leads – low friction rings with inhaul / outhaul controls – on either side of the cabin top which are lighter and more adjustable than tracks.
In normal circumstances we’ll only use the Solent fully unfurled – and change down to the staysail when we want to reduce area. As normal, a UV strip on the leech and foot will help protect the sail from the sun when furled and, hearing how aggressive the degradation can be in the tropics, I think we’ll also get one of those zipped tube covers that we can hoist over the furled sail when moored.
Staysail
Our Rig blog post describes why the staysail is such an important part of the rig and we foresee this sail being used a lot on our boat – upwind as soon as the breeze is into the mid teens and, potentially, when reaching with the Code sail in light airs.
We’ve specified a torsion cable luff and continuous line furler so the sail will be hoisted furled (no flogging) and tensioned by a purchase at the tack, led to the mast winch. It won’t need a separate stay. It can be hoisted and left ready to go on passages where conditions are changeable – or it can be dropped onto the trampoline to open the foretriangle and allow easy short-tacking with the Solent.
The staysail will sheet to a self-tacking track on the cabin top, just forward of the mast – easy manoeuvres, with tea, in breeze. It’ll have UV strips.
Storm jib
We’ll need a small, tough, woven cloth sail – also with a torsion cable luff so that it can be set using the same furler, halyard and self-tacking sheet track as the staysail.
Offwind Sails
There are many options for the off-wind sail wardrobe with our goal, in common with most cruising sailors I guess, being to effectively cover all angles using the minimum number of sails. Fewer sails mean fewer sail changes, lower cost, less weight and more space in the locker! I suppose increased redundancy would be an upside of a wider wardrobe.
These are our choices to, hopefully, best suit the boat and our sailing:
Code 65
North offers the choice of three Code sail designs – Code 0, Code 65 and Code 55. They are progressively narrower at half height and flatter cut for higher wind angles.
The CM will be fast, so will quickly pull the apparent wind forward and this leads to going smaller and flatter than a Code 0. Equally, as we’ll have the Solent (rather than a self-tacking blade jib) we’ll have less need to use a Code sail upwind, which would otherwise have steered the choice to a Code 55. The Code 65, therefore, should be the most versatile option within our set-up – to be used as soon as we put the bow down (in under 15 knots), until the apparent wind is just behind the beam.
The Code 65 will use North’s Xi Code T fabric (Mylar, Aramid fibres and single polyester taffeta outer ply) and have their Helix luff design. This relatively recent design development shares the luff load between a lighter torsion cable and the sail itself. It’s a great evolution, requires less luff tension and creates a more versatile sail with increased luff projection.
It will be set from the forward end of the longeron on another continuous line furler – tensioned by a tack purchase, in exactly the same way as the staysail.
We’ll also have UV strips on the leech and foot of this sail to maximise protection when the sail is up and furled, but we should take it down if it’s not likely to be used again soon. It could be stowed in a long bag on the trampoline underway, still connected and ready to re-hoist.
https://www.northsails.com/sailing/en/downwind-sail
G1 Gennaker
This sail overlaps slightly with the deepest angles possible with the Code 65 so in very light winds we’d choose the G1 for more power. The G1 will also have a Helix structured luff and North sound very enthusiastic about the versatility (wide range of wind angles) that the Helix luff allows this sail to cover. The extra luff projection helps the sail continue working to deeper angles and this extends further if you ease the halyard as you go deep. It will even be possible to pull the tack over to the windward bow and go down to around 160T, although I think only experience will tell us whether that’s preferable to sailing higher, pulling the apparent wind forward and going faster.
The G1 will share the furler with the Code 65 and we gather the Helix design makes furling much easier, with less luff tension required and less chance of the sail wrapping. We’re also told that, as long as we can apply reasonable luff tension, it will even be possible to furl the sail with the tack pulled across to the windward bow.
Symmetrical Runner
So, that just leaves the question of dead running on long tradewind legs… The CM will generally efficiently VMG to the destination by heading up, bringing the apparent wind forward and sailing the angles at greater speed. But (from endless vlog watching and other equally scientific research) we envisage legs when dropping the main and running on the rhumb line at lower speed would be a relaxing and easy way to go, especially if it meant the waves would be directly behind. In this mode an intrinsically light, quick boat will still benefit from its ability to attain decent boat speeds from the resulting low apparent wind speeds, surfing when the conditions are right.
In over 25 knots we may have enough horsepower by running with the Solent and staysail goose-winged – with barber haulers to stabilise them. So perhaps the window for an extra running sail is small. We haven’t finalised this call yet… Another sail, another mode decision, added expense… Or, on the other hand, the go-to set up on tradewind legs with the bonus of added redundancy…??
We need to decide soon whether to add an extra sail – and, if so, there are two options. The obvious one is a smallish symmetrical spinnaker with a sock. The other option, possibly un-cool on a rocket-ship cat, is a Tradewind sail (North’s name – also known as a Bluewater Runner by Elvstrom). Basically, two light genoas, joined at the luff, furled together. They can be set goose-winged or one side of the sail can be gybed onto the other (like a 2-ply genoa) to halve the area – perfect in a squall or to reach at higher angles. This mode would add some redundancy if the Code 65 were damaged. Poles aren’t needed for either of these options, due to the catamaran’s beam. Big handling win.
If a Tradewind sail could be big enough, without becoming unstable, to achieve the same performance as a small symmetrical spinnaker, it seems to offer a number of benefits. I need to pluck up courage and discuss it with the purist experts!
I’ll add an addendum to this post to let you know the outcome.
