Tag Archives: mainsails

Full Length Battens-2c: To FB, or not to FB

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With apologies to you know who.

I have received another question and a related comment  from some readers on the LinkedIn forum “Sailing Network”. This  forum requires authorization but the  access is free once registered.

The question comes from Pippa who appears to be either the principal or a partner and is a RYA Yachtmaster Instructor (Sail) with Miramar Sailing School, Antigua

“I’ve been reading your comments and blog about Fully Battened Mainsails – I have a Jeanneau Sun Odyssey 40 which has sails that are probably the originals from 1996. The main is starting to look ‘tired’ and we have been considering getting a new sail with only leech battens – do you think this would be a retrograde step, or not make a significant difference to her performance? Obviously the current main being a bit out of shape won’t help, but will we regret not getting a replacement that is fully battened? Interested in your opinions!”

This is the comment from the same forum from a reader in San Francisco, DG Tilton-

“Get the full battens. I got about half a knot better in low winds. Most importantly, for students, better control in a jibe. The extra expense of new batten cars/slides for the mast was well worth the investment. The command of out haul for shape also improved performance as well. The difference between old and new is always an increase in speed. But the performance of my sail in 12 years is like new. I teach heavy weather sailing in SF Bay. Our typical winds of 25 kts to 35kt present dynamic conditions due to micro cells of wind vortex. Your lighter winds in Antigua make sail shape even more important. The difference is like releasing more energy for speed instead of drag.”

This is interesting because both correspondents seem to be in the sailing instruction business and both seem to sail in conditions of more than enough wind, most of the time.

I will point out here I am not writing to advocate for or against full battens. Each boat, owner, situation, skill and experience level, sailing plans and a sea-bag full of other factors influence any decision on a boat and the decision on FLB’s is no different.

These essays are to share what I have learned over a more than 15 years as a sailmaker sales rep. that is incorporated into over 50 years of sailing including roughly 40 in the marine trade.

As I read through the question and comment i received, I have the following questions for Pippa centered on her basic question to me:

Would getting a sail with FLB be a retrograde step OR make a significant difference to her performance?

Then the first thing is to go back to the first essay and review the discussion there in particular the part about performance increases after either:

Adding FLB to an old sail. Second is getting a NEW sail with FLB.

My question at the beginning of the first essay is:

Can the “increased performance” be attributed to the Full Battens, on the new sail

OR

Does the “increased performance” stem from the fact that the sail is new and so has all the advantages of a new sail?

These include of course a new(er) shape, perhaps “better” (more stretch resistant-even Dacron) materials than the old one, perhaps larger area via more roach, I note that OEM sails are notoriously “small” with regard to roach and the materials used in such sails are not so great, a superior shape design if from a different sailmakeing firm and or designer or simply what has been learned over the intervening years since that sail was designed.

I am not aware of truly empirical evidence that full length battens on THE SAME SAIL, ON THE SAME (class of) BOAT improve the PERFORMANCE of the boat. And how are we defining performance? Faster, higher or both?

Issues to consider when trying to answer that question include:

  • Does a FLB mainsail make the boat so equipped sail faster and or higher-compared to the “old” sail with out FLB?.
  • In what wind speed?
  • In what sea conditions,
  • Steered by whom?
  • With or without a prepared and smooth bottom?
  • With the same amount of stuff, in the same place in the interior?
  • With the same headsail, in the same “shape” condition as when the old main was being used?
  • Same rig setting?, rake, backstay, mast prebend cap shroud tension?
  • Same weight on the rail?
  • Same helmsman?

These all play a part in a boat’s “performance” and are some of the particulars that sailmakers want to have in place before even consenting to go on a sail speed trial. Organizing and executing such testing with two boats is a right royal tedious business too,even at the top end of the sport and is full lots of small details that are very hard to uncover. For instance I once did a sail for a fellow with a free standing cat rig spar. After delivery he called to complain that he could not keep up with some of the boats at the rally/rendezvous he was attending. After about 6 hours of sailing, questioning, measuring, reviewing details of the design, I discovered that this fellow had a mast step that was in totally different place than other boats I had measured on the dock adjacent to him and that his spar was, for reasons unknown it was larger in diameter…..He did not even know it was larger.

I can attest from my own experiences that determining if one sail is faster (and or higher) than another is a very long drawn out process. This experience comes from two America’s Cup campaigns and lots of hours sailing along in a straight line with lots of smart and experienced sailors and sailmakers trying to make the boat go as fast as it can, then changing nothing else except the sail in question and repeating.

Thus even with an identical Sun Odyssey prepared as closely as possible to Pippa’s boat in order to be as equal when sailing along side each other; there are still many variables to be incorporated before the “increased performance” of the sail can be attributed to the sail having Full Length Battens.

Read again my remarks in an earlier post as to why,” if FLB are faster”, why then does the J105 class not all have FLB mainsails for instance? The 105’s have no rules regarding batten length. The paragraph is about half way down the post.

The next part of a decision to incorporate FLB into a new sail has to do with, as I wrote in the first essay,  value and encompasses things like:

  • Extra cost for the (addition of the) battens on the sail.
  • Issues of moving FLB around by carrier if necessary. Long, and skinny is expensive to ship even if it light in weight. I am thinking, Spares.
  • What are you going to use for luff hardware, at what cost and thus value? In my going for the cheaper option is not sound. This is especially so on a 40 footer, used (I am assuming) as an instruction boat with the attendant minimal seamanship (as distinct from hours or miles of sailing) experience of the students, one assumes, in an area with more than enough wind most of the time.
  • Considerations of maintenance, specifically chafe: The Sun Odyssey 40 has spreaders with some amount of sweep to them. When running down wind the battens, especially the top couple will bear on the standing rigging and chafe due to the hard spot where battens in the sail cross the standing rigging. The chafe will be harder than a sail with conventional battens.
  • The mechanism for securing the sails into the pockets-Perhaps not a great issue on a boat that may not stray far from home. Regardless reefing any sailing 25-30 knots of wind always flogs the sail and invites battens to spear out the leech end.
  • Stowing the sail on the boom. Here is one area that the FLB are or can be superior and perhaps add the value but only if combined with a slippery track arrangement and some kind of sail containment. The SO 40’s I looked at on the web all have some kind of boom bag and lazy jacks for the sail to be captured by and stowed in. Again more money.
  • The battens and pockets, cars and batten boxes all add weight. I have memories of a mainsail for a 40 footer weighting 50-60 lbs. Add another 15 pounds for all “the stuff” if the sail has a really low friction track and car system.
  • The added weight of the track and the now heavier sail all sticking up in the air will have an effect of some magnitude on the boats stability. Whether or not it is visible to the human eye depends on other variables.

I am not going to recommend or not FLB. As I say above my goal is to lay out what I see as the issues that by experience many folks do not consider in their interest in and experience with FLB.

In sum the question for Pippa to contemplate is:

“Is all this worth the extra capital cost and the maintenance cost compared to the Value you get from them?”

Value being subjective but of course including performance (it will be a new sail after all), possible increase in ease of handling the sail-if appropriate sail capture kit is incorporated into the boat, additional weight to hoist, a less “aggressive” flogging” of the sail when it is not trimmed. This is because the battens slow up the frequency of the individual flaps, to and fro that are the components parts of flogging.

Pippa, you asked for my opinion, well here it is (grins) Mr. Tilton says that  the “extra cost” is worth it but that is a decision you will have to make for yourself and your own circumstances.

Were I consulting with Pippa on this sail in my previous life, these would be the questions I would be putting to her.

 

Full Length Battens: 2b. In mast furling

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A reader on LinkedIn posted a response-comment-observation regarding FLB and conventional battens  with respect to in-mast furling so I will add this essay as a small side bar. My apologies I do not have many pictures for this subject, so you will have to read it, not look at it…

The question posed by this fellow is this:

And then there is the roller furling main! New experience for me as I have always sailed a traditional main (with battens). Very difficult to get used to looking at my main with the foot not fixed to the boom. My sail does have battens but the one nearest the head had to be removed to allow for the sail to be completely furled within the mast. I have been told that battens are not really needed in the furling main but started showing up because there was a “demand” for them. i like to convenience, especially when single handling, but………..would appreciate comments.

First a bit of background/History:

Most of us know that the original in-mast furling was invented and brought to market by Ted Hood, sometime in maybe the early 1970’s. They were unique at the time, had the Hood Cache and were almost the default spar on a long list of various sized Little Harbor yachts and then later other yachts particularly bigger ones, up to 80 footers which were big then.

Compared to the current crop of in mast furling spars, the Hood spars were really easy to work with from a sailmaker’s perspective. Not the least because they were designed by a sailmaker rather than a mast maker. There are two primary reasons related to this ease: The cavity into which the sail rolled was large.  Second, the slot through which the sail passed was wide, perhaps an inch or more. Boat for boat both these items were larger than the same parts on spars today.

Between the time of the Hood Spars introduction and the early/mid 1980’s Hood was the 800 Lb Gorilla: There was Hood Sailmakers and Hood Yacht Systems with the latter incorporating the Sto-Away masts and later on an in-boom furling arrangement  for a time plus the Hood Sea Furl furler, another virtual monopoly-No Harken, Profurl, Schaefer, Facnor, Furlex. There were a couple of older makes of furling (not reefing) head stays, one by Hyde and another by Stearns but they were not designed for using the headsail reefed. There was a particular part of the Hood Sea Furl Systems that made this viable. Regardless, if you wanted an in mast furling spar you went to Ted.

But things change. Hood sailmakers was sold in 1986, which is when I went to work for the new owner but Ted kept Hood Yacht Systems and brought it with him from Marblehead/Little harbor to Melville in Portsmouth RI.

Over time other mast makers began copying the Hood Spar, but of course they needed to be among other things, cheaper than the original (Hood Spar) in order to get a foot in the door. Anyway we now fast forward to the 21’st. C. Hood Yacht Spars was sold to the UK distributor of Hood Spars who sold it to another UK spar company who eventually went broke. Hood Yacht SYSTEMS, largely the furler’s, remains in business based in Florida and is a division of POMPANETTE. Roughly parallel with this progression many spar makers who used to do production aluminum spars have switched over to carbon and so today there are three remaining heavy weights in the production aluminum spar (In–mast furling) business:

Z spars, Charleston Spars/SparCraft both French and Selden, Swedish.

And on the edges of the In-mast terrain there are, or used to be, a couple of products you can bolt on to the back of the existing spar and some folks have taken a normal headsail furler and attached that to their spar with custom parts.

With respect to the sentence in the fellows remarks above, on “demand”, sailmakers (and cloth guys too) are forever trying to do something that will set them apart from other sailmakers. Battens, full and leech, for in-mast furling sails is a classic example of this. I am pretty sure that a Hood Franchise in Sweden invented both the batten idea and the necessary mechanics and sail designs to make it all work. Hood in the US marketed them as Vertech Mainsails and promoted, as does every one, the idea of more roach as opposed to the standard battenless sto-main with leech hollow, like a headsail.

Very broadly speaking, as viewed from my perch at Hood Sails for 15 years, there has been since the 1980’s an increase in people coming to sailing who did not grow up with it and so have a different seamanship background than say my generation who was sailing from age naught. Thus people buying boats (as well as a lot of others) were attracted to the idea of doing everything from the cockpit, so the in-mast furler’s, are now more common again than for a while. Without doubt the ability to “get the sail out and be sailing in one minute” or variations on same are pitch’s that do not quite fill the air at boat shows but is close.

Remember though there are two primary differences between the present in-mast spars and the original Hood Spars and they are the internal diameter of the cavity-Where the sail rolls up and the width of the slot through which the sail enters and leaves this cavity.

For all sorts of reasons the newer masts are smaller on the inside and the slot is much narrower than a Hood spar. Since the customer has a specific boat with a specific mast sailmakers are obliged to come up with ways of making their sails fit what the owner has, at a price they can sell them for while making money and having them work with sufficient success that the owner can use it, maybe enjoy it and so may return for other sails.

So, to the sails:

There are three flavors of in-mast furling mainsails: No battens, partial battens and full length battens. The latter are inserted vertically into the sail from the foot. These battens are usually in sections so they can be connected in some way. The ones we used at Hood, screwed together with custom fabricated terminals. The length of the sections, at least in the US, is determined by the maximum length UPS will carry so they can be shipped economically compared to shipping”regular” of FLB by truck.

With regard to sails, we know that the corners of a sail are reinforced with layers of fabric, the so called corner patches. The bigger the sail the larger, in area, are the patches. They are also thicker-more layers of material laid into the corner. This latter issue has a direct impact on the process of getting the sail in and out of the spar. The short answer is that for the current range of production spars the patches need to be thinner than they should be. This has a direct impact on the life, the shape retention life, of a sail because the corners distribute the loads into the body of the sail, less distribution surface, more load.

This thickness issues plays out with battens too. Let me first mention a couple of points about battens. As a general rule a batten’s length ought to be long enough so that 1/3 is “outside” the straight line between head and clew and 2/3 are inside. So the “inner” 2/3 is holding the outer third in place. This gets to be more critical the larger the roach-Hence full length battens in the first place.

This batten length calculus is relatively easy to meet in a conventional mainsail. It becomes a bit trickier with an in-mast sail. This is because when the batten is vertical, the batten needs to be a lot longer overall, in order to meet the desired ratio of batten inside versus outside the straight line. When the batten is longer it needs to be stiffer to achieve the desired effect. Given a same material, say polyester fiberglass, a pretty common material for battens, then a stiffer batten is thicker than a batten doing the same job on a conventional sail which will be shorter.

Still with me?

Then there is the batten pocket: It adds thickness to the sail. Typically the batten pocket is a couple of layers of material of the same weight as the sail’s cloth.  The pocket has a pleat in it so the there is volume inside the pocket to accept the batten and there is some kind of mechanism to keep the batten in the sail. Velcro is a favorite these days as are folded over flaps with lashings as well. This construction is often as thick, or thicker, than the corners AND it is on the leech so all the battens, all four or five of them must be able to roll inside the mast….

All of the above is of course at reasonable hazard of chafe. The pockets where they go in and out of the slot. The sail skin itself is liable to chafe when being rolled in or out in any condition apart from head to wind. The chafe issue applies to all flavors of in-mast furling sails: plain or with battens. On the full battens, where the connections are, they are a tad wider than the neighboring batten material so when the sail is passing the edges of the slot, there is chafe at each of the perhaps dozen or so connections.

Re-read the remark in the original question above where the owner had to have the top batten removed so the sail would get into the spar. This means I hope that the attending sailmaker had to re-fair the leech too otherwise the “local roach” at that batten would either wave around in the wind or be pulled into a curl by the leech line. Any way I digress…

Now connect the particulars of a sail so designed and built with the newer masts with smaller cavities and narrow slots. The end result is that sailmakers need to make the sails “thinner” in order to fit into the spar. Plus the batten’s are thicker and there is added thickness for the batten pocket assembly.On more than one occasion a prospect was unable to purchase a battened in-mast sail for his boat, at least from us, because when I looked into the particulars of the mast he had and the boat (so I could spec. the sail appropriately) comparing the width of the slot to the thickness of the battens and related structure, there was barely enough wiggle room and this was without the sail skin or the pockets.  I can recall one spar I was looking at, from one of three makers cited above and the slot was quoted as being only 16 mm wide, perhaps 9/16″. The battens, the pocket and sail was close to 12 or 13 mm.

The same problems or issues occur too with full length vertical battens only there is the additional complication of having to install the battens in the sail with the sail fully unrolled. Think about this for a minute…Would you willingly unroll (or hoist) your mainsail at the dock in the marina and let it flap around for the time it took to get the battens in? Perhaps not. This drill is required though with the full length battens in order to get the batten (s) into the sail. For instance on a Little Harbor 46 footer with in fact a Hood Spar, so it was actually pretty easy to operate the sail once the battens were in the sail, it would take me 45 minutes to an hour to assemble the battens get the sail into the spar and the battens into the sail. And it could only be done either on a calm morning or with only a light air wafting across the boat from the direction in which the bow was pointed.

All of this would make one think that the in mast furling system is not possible to manufacture and sell which is patented not the case. Rather I am presenting some of the issues that go on behind the curtain. For the sail these are:

Thinner or lighter base material, smaller patching both in area and in total weight in the patch and thinner battens and/ or pockets.

So, I hope this has offered some food for thought as well as a bit of a glance around “behind the curtain” into what goes on in the minds of, and discussions of, sail makers, their reps and designers.

I’ll get back to “regular” full length battens-soon.

Full length Battens-2a: Girths

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Here is a bit more detail concerning the girths mentioned in Full Length Battens:-1.

As noted in Full Battens:-1, the Girth is the distance across a sail from the “same” points the luff and leech.

A quick glossary:

Girths: the distance across a sail from a POINT on the luff to the corresponding POINT the leech.

Point: the spot on the luff and leech of a sail corresponding to one of the following: 25, 50, 75 or 875. percent up from the foot. You need two  points to get a girth

Girths are universally described as: (Reading up from the foot of the sail)

MGL–Mainsail Girth Lower: The girth at the bottom 25% POINTS

MGM–Mainsail Girth Middle–the width at the 50% POINTS

MGU–Mid Girth Upper–the girth at the 75% POINTS

MGT–Mainsail Girth Top–the girth at 87.5% POINTS

The most common way to start measuring  the girths on your mainsail is to lay it out flat on the ground.

Lay the sail out flat on the ground.

Lay the sail out flat on the ground.

This exercise works better with two or three people, in fact for race boat programs, modest ones where not every one knows everything….. it is a nice little team building exercise for the winter. You can measure all of the sails so every one on board has an idea of what sizes the sails are. In this case though I used a screw driver pushed through the cunningham eye into the grass.

Secure the tack with, in this case, a screwdriver pressed into the soil.

Secure the tack with, in this case, a screwdriver pressed into the soil.

Take the head of the sail and fold it down to the tack. Jiggle the luff so that the top and bottom of the sail are straight like folding a sheet or towel and make a mark where the fold is. This is the MGM luff POINT

Fold the sail so the head comes down to where the tack is.

Fold the sail so the head comes down to where the tack is.

Make sure the two corners, the head and tack and then the head and clew are even.

The corners of the head and the tack need to be overlapped on top of each other.

The corners of the head and the tack need to be overlapped on top of each other.

Mark the fold in the sail with a pencil, a regular #2 is fine.

Make a pencil mark on the sail under the fold.

Make a pencil mark on the sail under the fold.

If you merely want the MGM, fold the head over to the clew, straighten out the leech and mark where the fold is on the leech.

Next take the head over to the clew and lign the corners up as for the tack.

Next take the head over to the clew and line up the corners as for the tack.

At this point, you can if you wish unfold the sail and lay a tape across the sail between the luff point and the leech point. You now have the Mainsail Mid Girth, MGM or 50% girth usually spoken as  “the mid girth.” As a practical matter when measuring sails it is better to mark all the points along one edge first then do all the corresponding points on the other edge.

The MGM is measured from the mid point luff to mid point leech.

The MGM is measured from the mid point luff to mid point leech.

To get the 3/4 and .875 girths, fold the head back to the MGM point as shown below.The picture below shows the 75% girth position on the leech. When you measure the 75% girth point(s) on the luff and leech you can measure across the sail and you now have your 75% girth or MGU, Mainsail Upper Girth.

With the sail folded in its original half, fold the head back so that the head meets the MGM fold. This determines the 3/4 girth, MGU

With the sail folded in its original half, fold the head back so that the head meets the MGM fold. This determines the 3/4 girth, MGU

 

By continuing to fold the sail back and forth, you can also get the .875% girth too, as necessary

Fold the sail back one more time to  get the .875% girth too, as necessary

From the 75% fold, fold the head back one more time to get the .875% point, as necessary. If you do the same drill with first the tack and then the clew folded to the half way fold you will get the dimension for the MGL, Mainsail Girth Lower.

It takes all of 15-20 minutes, to do this from pulling the sail out of the bag to getting it back into the bag and recording the dimensions but this does depend on the size of the sail, where you are doing it and how many people are involved.

Remember that to meet MOST racing rating rules the girths must meet the lengths equal to the percentage of the foot as outlined in Full Battens-2 Scroll down about half way.

Sailmakers use all of  this information regardless of what kind of mainsail they are designing. For cruising boats, you and the sailmaker need this information in order to make the sail so it does not overlap the backstay too much UNLESS this is something you have discussed with them.[ See here: Scroll down to the bottom two images]. It is necessary too for in boom mainsails because these booms are very precise on how much roach a sail can have-Too much and it will not roll properly. The roller booms come with a 30 (or so)  page manual for the sailmakers. With the advent of battens for in-mast sails girths come into play too. For race sails, even for Wednesday night racing, of course you want the sail to be legal.

If you are taking the measurements off the boat yourself one thing they may ask for is the distance from the gooseneck, aft and parallel with the boom, to the backstay.  In other words the position on the backstay where the boom would intersect the backstay ( if it was that long) If this distance does not have its own check box in the measuring form, make a note in the “comments” section of the form. These dimensions give the sail designer a triangle that outlines the area in which the sail might fit, unless you have come to terms with them for something else-Like a oversized roach. In other words a triangle with sides: Luff, the distance from head to boom/backstay intersect AND distance boom /backstay intersect. With this information the sail designer can place the backstay on the design software and so know where the girths are going to be relative to the backstay.

One last detail regarding girths….

Girths can obviously have an impact on how much ROACH a sail has, BUT remember that the sail designer needs to take into account mast bend too. Sails have shaping in the luff and on a mainsail it is generally called luff ROUND, or sometimes positive, because it protrudes forward. The opposite is hollow, or negative.

In this picture of the Laser sail, you can see the luff ROUND outside the straight line between the head and tack.

luf curve 1

The relationship between ROACH and LUFF ROUND varies depending on many things but boat type, rig type, fractional Vs. masthead, degree of mast bend on either are some of the main ones. At the end of the day, the girths are one of the variables a sailmaker uses when determining how to design a sail and they have an impact on the sails roach. And the roach has an impact on whether or not the sail needs, or requires full length battens and if so what kind of sliders and related hardware is desirable.

These measuring protocols are the same for head sails and spinnakers. Remember this when we get to Code zeros in a while.

Full Length Battens-1: What they do, don’t do and why

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A very common opinion regarding Full Length Battens is that they improve performance. Let’s look at that theory for a moment.

The square head main provides more area but something more too-Read on.

The square head main provides more area but something more too-Read on.

A mainsail with FLB has either has been refitted with Full Length Battens (FLB) or it is built from scratch as a new sail  with FLB’s. There are a couple of things that happen in these two scenarios that lead to the “better performance” theory.

If an old main is retro-fit with FLB, one assumes there is a reason for it and it is usually to “improve the shape” often in conjunction with the owner’s desire to get another couple of seasons out of an old sail. We know that a sail’s shape degrades over time/use. Typically the original designed-in shape migrates to the aft part of the sail,or aft of where one would like it to be for optimum performance. The of course happens over time and so more or less creeps up on you. The observant owner will note that the shape IS migrating but more commonly he/she sees boats he used to be able to beat, sail past him, either racing or “not racing” if such a condition does in fact exist with two boats within sight of each other….. After the FLB retro fit, ideally done in such a way to “push” the shaping back towards where it needs to be, commonly the sail is now “faster” than before. After all that is what the owner spent a not small amount of money on.

Most sail boats are constrained either by the backstay or a rating rule or often both

Most sail boats are constrained either by the backstay or a rating rule or often both. This Sabre 38 main just overlaps the backstay at the top batten by about 4 inches. See the profile  picture below

Thus there is a connection in the owners mind that FLB are faster than Non-FLB…

So the meme is that FLB are faster. Well kind of.

What happens if a new sail is ordered WITH full length battens? A few things:

Today there is a much greater likelihood that the roach on a mainsail designed within the past 10 years or so is going to larger than one from before that time. Sail making design uses lots of input from “racing” sails even when designing non-race sails and it is my experience that when an owner comes to replacing a sail for the same boat, and with Hood it might have been a fifteen or twenty year old sail, that the roach on the new sail is significantly greater than the old sail. More sail area never hurt any boat in the search for speed.

This sail has full length battens but could easily support the roach with "regular" battens

This sail has full length battens but could easily support the roach with “regular” battens

Second, simply having a new sail you are going to be faster than with an old sail-Just ask any one design sailor. Connected to this is the improvement in sail making materials, both Dacron and the rest of the fibers and manufacturing techniques for laminated sails.

Third, the above cited “improvements” in shaping ideas (and more powerful and detailed sail design software) can also come from a sail designer with a greater or different, skill, experience, attitude to designing a sail.

Another way to look at this question is to study for instance the J-105’s. They are a very competitive one design class with fleets all over the place. If one postulates that FLB ARE faster, then in theory all J-105’s would have full length battens. BUT even though the batten length is not restricted, or even mentioned in this class at least according to the class rules of 12 Feb 2012, section 6 to 6.4.1 Mainsails, if FLB WERE faster, then one would expect to see, in such a close racing fleet as the 105’s, all boats using FLB. But they are not. So what does this say about the performance of FPB?  Are the FLB really “faster”?

Thus we now have a new sail with superior (compared to 10, 15, 20 years ago) shape holding properties. It is “bigger”, is almost certainly of a different design. AND it also has full length battens.

But which characteristic is making the sail faster? Is it the material, design(er), the extra roach, the newness of the sail and performance of the material or the battens?

Another detail to contemplate here is that the real advantage of FLB is the ability to support a bigger roach. This is doable in the majority of the boats on the market in the production arena but it is constrained by at least two things: Backstays and rating rules.

This Apogee 50 is used for cruising AND racing upgraded this older Hood Main. The new one was made to the largest possible "girths" and so is much bigger than this one

This Apogee 50 is used for cruising AND racing upgraded this older Hood Main which was about 12-13 years old and had seen lots ocean cruising miles. It was not designed with “girths” in mind. The new mainsail was made to the largest possible girths  (for DH racing) and so is bigger than the old one pictured above..

Rating rules: as anyone who races even casually is aware one needs a handicap rating for their boat. One of the items in a rating is of course how big the sails are. A mainsail is measured not only by the P and the E but by at least one and up to as many as four so called “girths”. Briefly a girth is a dimension from a specified point on the luff, at a minimum 50% of the luff length across the width of the sail to the corresponding position on the leech that is 50% between the head and clew. Boats that are raced regularly are measured at 25%, 50%, 75% and sometimes 87.5% locations, reading up from the foot. At each measurement point the mainsail cannot be wider than a percentage of the foot. The current versions of these width percentages are:

MGT: The 7/8 point– 0.22% of E

MGU:  next one down, ¾ points– 0.38% of E

MGM: Middle 50%–0.67% of E

MGL: the bottom ¼ points—0.89% of E.

Try this math on your own mainsail. There is a formula in the ORR rule for calculating the actual area including roach, if you have these measurements. Calculate the mainsail area: P x E x 0.5 which gives the basic triangle area. The inclusion of the girths gives the actual area. As a rule of thumb actual area is abut 20% more area than the basic triangle area.

The width of the mainsail on the majority of boats is constrained by either the backstay or a rating requirement. This mainsail for a Sabre 38 is built to the maximum girths permitted by the PHRF of New England. If you look carefully, the upper leech is just overlapping the backstay by an about 4 inches.

The width of the mainsail on the majority of boats is constrained by either the backstay or a rating requirement. This Sabre 38 mainsail  is built to the maximum girths permitted by the PHRF of New England. If you look carefully, the upper leech adjacent to the top batten, is just overlapping the backstay by about 4 inches.

Generally speaking these girth requirements constrain the width of the average mainsail to what we all commonly see on boats unless they are multi-hulls or open class offshore race boats, or high performance skiffs of the Sydney Harbor 18 footer type. That is a pretty basic triangle, like the one on the Sabre pictured above.

Backstays: The next item that constrains boats from having really big roaches is the backstay. Yes some boats come out of the box with provision for large roach mainsail and I am thinking of the Quest line of performance cruisers and race boats, designed by Rodger Martin and built by Holby Marine thru the 1990’s. They and others have girth restraints that allow for a wider main than those cited above, but the general rule for the vast majority of boats confirm to the cited percentages.

This cruising main has a very conservative roach, almost nothing. The owners commissioned a new sail and specified a much larger roach, so big in fact that when tacking they had to lower the mainsail a few feet.

This cruising main has a very conservative roach, almost nothing. The owners commissioned a new sail and specified a much larger roach, so big in fact that when tacking they had to lower the mainsail a few feet. Notice the backstay is very close to the end of the boom which limits the roach/upper girths if you do not want the roach to hit the backstay.

The interesting thing is these “regular” girths, from the formulas above, keep the roach of the mainsail on most boats to just about where the backstay is plus or minus a few inches usually.

A large roach mainsail for a cruising boat. The roach is so big the mainsail must be lowered to tack, this at the owners request.

A (new) large roach mainsail for the cruising boat pictured above. The roach is so big the mainsail must be lowered to tack, this at the owners request. The backstay is indicated by the red line that terminates in the bottom right hand corner of the image.

Some cruising boats, most prominently the Deerfoot range of fast offshore cruising boats pioneered by the Dashews have much larger roaches BUT their rig layout, allows for this. The backstay is a long way aft of the end of the boom, so the roach can be big without fouling the backstay.

So bearing in mind all the foregoing, as to the question as to when FLB’s “might” be faster, one has to get outside the scope of “normal” racing rules, PHRF, IRC, ORR and so on and look at open class boats and other high performance boats-Aussie and Kiwi skiffs, most performance multi-hulls and so on. Here we find a mainsail, that has FLB but most commonly another feature not seen on the usual production cruiser racer or plain cruising boats-Square head mainsails.

 

 

 

 

The yellow line leading from the head, at the bottom of the image, to the clew at the top, is the straight line leech. All the sail to the image left of this line is roach. This of course requires considerable detail (read cost) in making sure the sail will be robust enough for hard offshore work typical of Deer foot owners.

The yellow line leading from the head, at the bottom of the image, to the clew at the top, is the straight line leech. All the sail to the image left of this line is roach. This of course requires considerable detail (read cost) in making sure the sail will be robust enough for hard offshore work typical of Deer foot owners. The blue line at the head is part of the tackle for the leech line which leads over the head of the sail so it can be adjusted at the tack.

The so called Square Head mainsail seen in the image at the top of this essay, takes advantage of the unrestricted nature of the sail area calculus of open class offshore boats and the various skiff classes’ by providing certainly more sail area, but also reducing drag at the top of the mast. This topic we will take up in Full Length Battens-3

Full length Battens

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YES, NO, MAYBE, WHY?

The subject of full length battens and whether or not you and your boat need them is one of the longer discussions sailmakers and their customers have. Like much else around the boat, there are plusses & minuses and maybes’ and what if’s. This series is intended to outline the various issues to be contemplated when you get the idea to have full length battens on your boat or new sail.

Briefly

What they can do:

A Class 40 with a so called Square Head mainsail

A Class 40 with a so called Square Head mainsail

 

a)      Full length battens can support a more pronounced roach than a sail without full length battens.

b)      They can be retrofitted to revive the shape in an older sail

c)       They can make the mainsail “smoother” minimizing bumps, creases or hard spots at the forward end of short battens

d)      Maybe easier to flake and fold

Side rails to attach lazy jacks to.

Side rails to attach lazy jacks to.

e)      They can make capturing the sail as it is lowered less of a dance IF the boat has either a Dutchman OR a dedicated Lazy Jack’s system designed for the sail

f)       Reduce drag at the top of the spar, square head only

g)      They make the sound of the sail flapping less loud which has its own many benefits above the longevity of the sail fabric.

 

Issues to consider:

a)      Make the sail jump into its kennel all by itself–NOT

b)      Rating issues (if you do any kind of racing, an “oversized” mainsail will get a new handicap allowing for the perceived speed gain) with oversize roach, except when purely cruising or sailing open classes.

Kress LJ ears (1)

c)       Are they really faster as some have remarked?

d)      In the case of the large roach/square head sail the compression on the luff from the batten is considerable.

e)      Chafe esp. with aft swept spreaders. Also the batten pocket OR sail will chafe where the batten crosses the lee rigging when sailing down wind. It is perfectly possible to saw a hole through a sail overnight (I have inspected a sail so damaged) if this is not either addressed on the boat or in the construction phase of the sail.

f)       Whether to employ luff loading batten pockets or not. By this device the battens are inserted in the luff end of the sail with the leech end sewn shut thus making it really hard, as in you must really try to shake the batten out of the back of the sail. Much harder but not impossible.

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g)      The larger the boat (mainsail) the more likely the sail needs low friction track and cars.

h)      Additional costs related to the detailing on the sail and the cost of the hardware.

A selection of available batten hardware

A selection of available batten hardware

i)        Value versus regular length battens

j)        Potential for damage when sailing-Like an all standing gybe where the sail lands up against the formerly windward runner usually with a great shock.

k)      The material from which the battens are made, there are mainly three flavors.

l)        Carrying spare (battens and parts) on voyages including the stowage on board, the shipping if necessary, the ease with which a long batten can be removed from the sail if the batten breaks

m)

 

Batten sliding systems

There are two categories:

  1. Those using a dedicated track and

  2. Ronstan track and car system

    Ronstan track and car system

  3. Those that do not have a dedicated track but rather the “cars” run in the mast’s original track/groove.

Within “A”: there are two sub-decisions, ball bearing cars and slider cars without bearings.

Within “B” there is one variation from the almost universal use of simply some kind of slippery plastic and that is a car that has bearings incorporated into the car itself. I am aware of only two products that fit this last description.

 

Components

There are three components to the fully battened system.

  1. The “cars” these may be simply a beefier version of the sail slug/slide the sailmakers might use anyway on a small boat’s mainsail. OR on bigger installations with ball bearing cars they are substantial pieces of engineering.
  2. The “batten box”, aka batten receptacle. The device into which the forward end of the batten is captured. This is in turn attached to the car by:
  3. Toggle”, aka universal. This can be as simple as webbing on a small sail or as complex as an unlimited multi axis universal ball joint on bigger hardware/boats.

There are of course all manner of small parts, screws bolts, nut, balls or slider inserts that are included in the various parts outlined above, but you get the idea

 

Do I want them or not?

Considering all the above the rational human would surely ask him/herself do I really want this headache versus what will I gain from having full length battens?

 

Read on.