Cruising Sails - Good versus bad, what difference does it make?

When talking to sailmakers about new sails, many people quickly get bogged down and preoccupied with the myriad of different fabric choices that are available and what can be large differences in price between one sailmaker and the next for what appears to be a similar product. Fabric choice is important of course as it will have a bearing on how well the sail lasts and how well it performs across time but it is really easy to over-look the rather fundamental issues of design and engineering when choosing your sails.

Of course fabric selection does make a difference, but it is the design itself, the actual aerofoil that the breeze gets deflected around that makes the biggest difference with regards to how the boat behaves and performs.

One question we often get asked is ‘all sailmakers these days design their sails on computers, so they should all be the same shape shouldn’t they?’

No! The computer is just a tool which the designer must be able to manipulate in order to produce the best shapes. Obviously the fabric choice is very important, but the advantages of having the best fabric are lost if the designer does not have the skill and experience to use the tools at his disposal. Similarly, the characteristics of a poor fabric cannot be covered up by clever computing. The advent of Computer Aided Design (CAD) and clever design programmes has meant that the difference between a bad sail and a good sail is not as obvious as it once was, but the differences are still there which is why it is even more important to err on the side of quality and reputation.

Believing that all sails are the same because all the sailmakers use computers to design them is akin to saying that all tailors use tailors dummies, so all suits are the same. As we all know, this is most definitely not the case!

The fact is there is no standardised aerodynamic shape for a given sail on a given boat. It is up to the sail designer to determine what the optimum shape might be and this will depend on the characteristics of the boat, the type of sailing it is likely to do (inshore or offshore, short handed or fully crewed etc), teh conditions it is likely to encounter and the level of experience of the owner. The sail designer will call upon his own experiences to determine what is best and the solution will clearly be slightly different from one designer to the next. 

The designer does not just concern himself with cloth selection and shape however. The designer is also responsible for the size, shape, and orientation of the reinforcing patches, the design of the batten pockets, positioning of hardware such as slides and cleats, making sure that as far as possible batten pockets aren't coincident with spreaders (including the reefed positions) and every other detail that you find on a sail. Typically, a more expensive sail will have had more time and effort afforded to it at the design stage, and will be more carefully engineered and manufactured to ensure the perfect fit first time, to ensure that the sail flies as intended and that it is as user friendly as possible.

So fabric choice, the skill of the designer, engineering and build quality are all contributing to the cost of the sail, but what will the differences actually be on the water?

The modern cruising sailor is increasingly aware of the benefits of having well engineered and constructed sails. Sails that hold their shape across a wider wind range allow for

·        Higher pointing: a well designed sail will point higher than a not so well designed sail. It will also be easier to trim

·        Less heeling: a boat that is heeling unnecessarily can be quite intimidating and uncomfortable for anybody, let alone the inexperienced or the family on a weekend passage. This will also affect the balance of the boat: less heeling means less weather helm.

·        Easier handling: a sail that holds its shape as the wind increases, or doesn’t go baggy when it is furled will ultimately be easier to handle. It is also likely to flog less which will contribute to the overall longevity of the sail.

·        The overall result is that the boat will get from A to B not only quicker but more easily.

Many cruising sailors may well feel that going faster is not important to them. This aside however, lets be really conservative and say that well designed sails will give you an extra 0.2 knots of boat speed for doing nothing else other than having them up and flying. An extra 0.2 knots equates to 400 yards an hour. On an 8 hour passage this is 3200 yards, or over 1.5 miles. How often would 1.5 miles translate into a missed tidal gate or missing a mooring for example? Being more realistic about the boat speed gain will result in the increased distance sailed or the time saved adding up considerably. It may also mean the difference between stemming a foul tide and having to kedge.

We have established then that the price differences between sailmakers can be attributed to quality of the fabric used, the skill and experience of the designer, and the quality of manufacture.

If you were buying a new washing machine you'd quickly establish that at one extreme you could buy one for maybe £150.00 but at the other extreme you might have to spend £1000.00 or more. Well they both just wash clothes don't they? At that point you'd start asking a few questions and you'd find out that the more expensive one has better quality components, it is better engineered, the manufacturer has a better track record, the after sales service is better, it is less likely to go wrong, it is more efficient (using less water and less electricity) and what do you know it actually makes a better job of its primary function, i.e. washing clothes (they come out cleaner and drier). If you still want to buy the cheap one at least you have made an informed decision.

When buying new sails you should have a similar set of considerations, price is important of course but it shouldn't be the primary driver in the decision making process and don’t be afraid to ask the sailmaker a few pertinent questions……

Starting Tips - from the RORC Red Funnel Easter Regatta

Anyone starting out in sailboat racing will quickly learn the importance of start line bias and most sailors, most of the time will be pre-occupied with starting in good shape at the 'favoured' end of the line in the minutes leading up to the start gun as a good start goes a long way towards securing a good result. However, the 'favoured' end of the line might not necessarily be the end where the bias is.

Over the Easter weekend at the RORC Red Funnel regatta I was sailing on the Half Tonner ‘Chimp’ in IRC 4. On day 1 the wind had an average direction of 020 though being a North Easterly there were significant shifts either side of that number with the shifts becoming more pronounced the further up the beat you went, i.e. the closer you got to the shore. The start line was set more or less square to the average wind though clearly the bias on the line depended on which phase the wind was in.

So the big question was which end of the line to start at? The general strategy was to play the right hand side of the beat because all the forecasts were predicting the wind to slowly veer right as the day wore on. As our start time approached the wind was in the left meaning that there was a notable port bias on the line of around 15 degrees. I felt that was too much to give away so elected to start towards the port end on starboard with a view to getting onto port tack (the lifted tack) quickly. Although we executed a good start we unfortunately ended up with a slightly quicker boat on our windward hip which didn’t share the same enthusiasm as us for being on the other tack. By the time we did manage to get onto port we were on the left hand side of the beat and all of the main contenders in our fleet had gone the other way. The breeze had also now started to swing the other way meaning that we were now on the unfavoured tack on the unfavoured side of the course. We struggled to find clear air and struggled to get back in phase with the shifts and although we sailed the rest of the race pretty well we ended up a disappointing 7^th from the 18 starters.

Conditions were similar for race 2 but this time we adopted a different strategy. Even though there was still a port bias on the line we decided that our priority was to get onto the favoured tack as a matter of urgency so that we were in phase with the shifts and heading to the correct side of the course even if that meant giving up the line bias. In reality the start line wasn’t that long so we weren’t giving up an awful lot of distance anyway. So, we started on starboard, on a header with nobody to windward of us, flipped immediately onto port tack and sailed for several minutes on the port lift before the next anticipated right hand shift came in. We tacked immediately and were able to cross the boats from the left that had taken the line bias. Now, perfectly in phase with the shifts, sailing in clear air and sailing in the best pressure we were second around the windward mark comfortably ahead of all the boats except one that gave us lots of time. In other words, in shifty / oscillating breezes the line bias was less important than being on the paying tack at the earliest possible opportunity and that factor would therefore dominate our starting strategies from then on.

So what were the other salient points from the day? Firstly, if the breeze was in the left, although there might be a few minor oscillations, the next significant shift would be to the right so it was important to position the boat accordingly to take full advantage of that when it happened. Secondly, try to get a feel for the timing of the big oscillations, how long did they tend to stay in for? Thirdly, when the pressure was up the breeze tended to be more to the left (the gradient direction). The breeze tended to go right in the sunnier spells when it was also a little lighter. Looking at the sky and the water further up the track provided some good indicators of what might happen next; if you needed a right hand shift, head for the sunny patch though bear in mind that the wind might be lighter there!

On days like this it is impossible to cover all the bases all of the time. On the first beat you need to be on the correct side of the first few shifts in order to take care of the bulk of the fleet. On subsequent beats when the fleet is more spread out you can use the shifts to pick off individual boats.

In summary, in deciding where to start, consider the line bias of course but also consider where you want to position the boat in order to take advantage of the next shift and get fully in-phase with the oscillations. 

4T Forte - One piece composite sails for racing & cruising

In 2007, OneSails introduced the first continuous fibre sails built without the use of resin or glue, eliminating delamination issues at a stroke. Now OneSails goes a step further, by introducing 4T FORTE™ membranes made from exclusive Multi Micro Structure (MMS™) technology (patent pending).

The 4T FORTE™ composite structure incorporates high modulus fibres such as STR Solid Stripes, a new low stretch component of MMS™ technology which eliminates both glue and the mylar film, so often the weak element of a laminate sail. Using a multi micro layered structure, elements of the membrane are fused together in a cross linked, polymerised matrix resulting in a stable, stretch resistant, and durable sail. By doing away with both glue and mylar film these sails are significantly lighter than conventional laminate sails. Not only is 4T FORTE™ intrinsically lighter than alternatives, but weight saving is enhanced by the fact that a 4T FORTE™ membrane does not need to be covered with extra woven taffeta fabric to protect it from UV or improve durability. Using components derived from recent developments for the military and biomedical science, MMS™ technology provides a robust and reliable sail skin, manufactured with the minimum of environmental impact and allowing realistic recycling options. Since glues, resins, and solvents have been replaced by heat activated fusion and the base polymer is 100% recyclable in a standard waste separation process, 4T FORTE™ sails can claim to be truly "green sails".

Multi Micro Structure (MMS™)  technology represents a leap forward in the production of sail material, leaving traditional mylar based laminates in its wake. A core structural grid, constructed from high modulus fibre takes care of the principal loads, whilst oriented micro layers provide strength in other secondary directions. The entire skin is encapsulated between ripstop "shields", which are UV, moisture, and mildew resistant. The whole skin, with its continuous fibres, is vacuum cured in a heat activated cross polymerisation process. which fuses the components together so that every single element in the structure contributes to shape holding. As a result, a 4T FORTE™ sail membrane not only exhibits superior structural integrity, but the use of more efficient components creates a sail up to 25% lighter than film based alternatives.

Thermo Moulded Sails

Unlike most of the membranes in the market that are built with the use of resins or glue, 4T FORTE™ membranes are made by a vacuum cured heat-activated cross polymerisation process. This ‘thermo moulding’ technology ensures superior structural integrity with no extra weight in the way of adhesives added to the sail. The cohesion of the different layers that create the flexible composite is obtained through the vacuum fusion of the thermoplastic elements which is why adhesives are not necessary. An added advantage of this process is that because no resins or glues are involved delamination is not possible and this term is therefore inappropriate with regards to 4T FORTE™.

STR Solid Stripes

For many years carbon has been the ultimate and dominant fibre in performance sailmaking. In 4T FORTE™ OneSails has instead introduced ‘STR Solid Stripes’ which have a better strength/weight ratio than carbon and a huge number of other advantages including being more robust, having higher tenacity and a full resistance to the harsh factors of the marine environment such as UV, temperature and moisture. These latest generation polymers have been developed relatively recently using a truly innovative synthesis processes. They are characterized by low specific weight and very simple chemical chains that are linked and rigid and which resist deformation by various aggressive spoiling agents.

STR Solid Stripes are similar to other products used in sailmaking such as Dyneema and Spectra, but they should be regarded as entirely distinct because they are not subject to the same kinds of issues such as shrinkage and creep. Moreover, they do not exist in the form of bundles of microfilaments, but as 'stripes' or thin homogeneous ribbons, presenting a significant contact surface and enhanced cohesion in the multi-layered microstructure within which it integrates perfectly.

As a consequence of the enhanced properties of these flexible composites, there will be a shift away from regarding racing sails as ‘disposable’ as 4T FORTE™  sails will be more durable with improved performance and better shape stability. In the cruising market the impact will be even bigger because it will be possible to have sails that last well, but which at the same time are lightweight, soft, dimensionally stable and with an attractive appearance.

Because 4T FORTE™ is a multilayer composite it can consequently be produced in many configurations with the modular style of construction lending itself to adaptation to meet the requirments of different end uses and budgets. At present the entry level version features structural yarns of Twaron with the next level featuring STR Solid Stripes. The premium version features a higher modulus version of STR Solid Stripes for larger boats and instances where performance cannot be compromised. The cruising variants of these three options feature a robust outer skin which offers enhanced UV, moisture & mildew resistance without the need for a heavy taffeta layer.