Category Archives: EQUIPMENT

Discussion of the things I know from experience and things I have an opinion about, related to suitability for use when double handed sailing

Newport to Bermuda Race-What sails?

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Sails for offshore and the Newport to Bermuda Race:

The Newport to Bermuda Race, sailed in even numbered years and it’s counterparts that are sailed in odd numbered years, The Marion to Bermuda Race and The Bermuda 1-2 are something of a right of passage for many US sailors, especially those in the north east. While not particularly long in terms of famous ocean races, the weather across the track can make for some pretty hard going, more so for the unprepared. The Bermuda race is roughly the same distance as the Sydney to Hobart race and the Fastnet race but as has been seen in both these races distance is not the only factor to contend with when preparing to race (sail) ‘only’ 650 or so miles.

The Newport to Bermuda Race committee is rightly proud of their safety record (only one loss of life in the race’s history) and so the organizers hunt and peck from a variety of sources and mandate a few of their own safety regulations in some cases.

The default regulations for offshore sailing, including things like required equipment, the boat’s structure and training are the Offshore Special Regulations, known as offshore regs.

Front cover of the World Sailing Offshore Special Regs, aka the 'Offshore Regs.'

Front cover of the World Sailing Offshore Special Regs, aka the ‘Offshore Regs.’

This booklet-sized document contains these regulations promulgated by International Sailing Federation, ISAF, now called World Sailing. It covers all manner of particulars to do with getting to the finish in the same boat you started with and all the same crew you started with. It is EXTREMELY hard won information and a very informative read for anyone thinking of going maybe anywhere in a sailing boat.

It is however somewhat Euro-centric in that everything is cross-referenced to an ISO number. For the layman it is a bureaucratic black hole. To make things a bit easier for US sailors US Sailing started a few years ago to develop their own prescriptions for requirement for races in the US. The result is a document a normal person can read and defines the gear required for the boat for three categories of racing, not six, called by USSailing: the Safety Equipment Regulations (SER’s) and the three categories are Ocean, Coastal & Nearshore.

Finally the Bermuda Race Organizing Committee list their own requirements based on their very extensive research, surveys after each race and the vast experience in some very un-hospitable areas of the worlds oceans of the members of the CCA.

In the view of some the safety requirements for much of the Offshore Regs. are becoming more and more complex. I have over the past few years been told by at least two people I can think of that they are stopping doing offshore races due to the rigmarole and cost of the safety kit.

Regardless, the requirements for sails have generally remained pretty stable for several years. There are really only two principal changes to sails lately: Storm Jibs and Storm trysails manufactured after 1 Jan. 2014 are required to be ALL high visibility, usually orange, in color. So, the sail requirements for the Newport to Bermuda race are as follows.

There are three required sails and an assumed fourth one, the mainsail.

REQUIRED SAILS

The three required sails are: a Storm Jib, a Storm Trysail and what is called a Heavy Weather Jib. These are very specifically defined in the safety equipment section of Bermudarace.com. The mainsail has only one requirement and that is:

3.33.1 Reefing: A yacht shall have mainsail reefs capable of reducing the area of the sail by an amount appropriate for the weather conditions possible on the racecourse.

This phraseology is intended to push back to the owners and the master, the responsibilities for going to sea. This is in fact embedded in the Racing Rules of Sailing and RRS Rule 4 is here:

DECISION TO RACE

The responsibility for a boat’s decision to participate in a race or to continue racing is hers alone.

From a practical and seamanship perspective, contemplating sailing across this course on a boat with only one reef, would be a risk, way riskier than the reward of a few pounds less weight in the mainsail.

The Heavy Weather Jib (HWJ) is from a sailmaker’s perspective and design and engineering wise, are ‘merely” small, flat and heavily constructed jibs. But they must meet the rules for HWJs though which are-for the Newport to Bermuda Race:

3.33.3 Heavy Weather Jib:

A yacht shall carry a heavy weather jib (or heavy weather sail in a yacht with no forestay) of area not greater than 13.5% height of the fore-triangle squared.

In practice it turns out that on many, if not most boats an forestay sail, like the one seen on this Bristol 41-1 suffice as the Heavy Weather Jib but you should do the calculations or have your sailmaker do them, ideally with you.

Forestaysails commonly qualify as Heavy Weather Jib

Forestaysails commonly qualify as Heavy Weather Jib

A line item in the HWJ definition from World Sailing Offshore Regs is:

‘A heavy-weather jib (or heavy-weather sail in a boat with no forestay) with: area of 13.5% height of the foretriangle (IG) squared and a readily available means, independent of a luff groove, to attach to the stay.’

In practice this means grommets installed at suitable intervals in the luff of the sail immediately aft of the luff rope that enters into the headfoil on the boat.Thru these grommets may be passed lengths of line suitable for lashing the sail to the headstay in the event of damage to the foil.

The “alternative methods” of securing the sail to the stay has been edited out in the Bermuda race’s own rules. This now abandoned rule stems from the days of aluminum head foils being damaged by spinnaker poles bashing into them, rendering it impossible to get a sail up the foil. Today’s headfoils are made from plastic and spinnakers much less likely to be set on poles but at sea if something can fail, and this is everything, there must be a Plan B.

In the case of the HWJ, having your sailmaker install grommets up the luff so the sail can be secured to the foil (by short lengths of line premade for the purpose and stored in the emergency took kit, right?) is a very good idea. You can also leave the lines in the sail permanently because IF the foil fails AND you need to set this HWJ, having the lines already installed will be a lot easier than having a couple of crew sitting in the bow lacing the lines they the grommets for 30 minutes or so. And as a practical matter their presence will have zero impact on the performance of the sail for those thinking abut windage

Here is another Cooper TIP too. Backup grommets are something to think about for all headsails. Apart from the fact the head foil will not get un-busted when the breeze abates and having a way to set headsails is generally a good idea in an ocean race there is another utility made available by such grommets in the luff.

During the headsail changing process sails so equipped can have a length of light line woven back and forth, Dutchman like, through these grommets. The bottom end is made off with a figure eight knot so the line does not pass thru the grommets. All of this does a couple of things. It helps keep the luff of the sail forward in the flaking process. It offers a way to tie off the bulk of the forward end of the sail. This gives the crew at that end of the procedure a bit more freedom to wrestle the sail back into its turtle. If push comes to shove, a sail can be tied off to the boat at the forward end and it is perfectly possible for one man or woman to get a headsail into a turtle by themselves. Just ask anyone who did the sewer on a 12-meter, back in the day. Finally when changing back to this sail as the wind diminishes, the upper end of this line can be temporarily tied off until the sail is really ready to get hoisted. This makes it a bit harder for the (forward end of the) sail to go over the side.

STORM SAILS:

Sail offshore long enough (and or sail with no reefs in the mainsail) and you WILL meet conditions that will require all your seamanship skills, those of your crew AND small sails. The Newport to Bermuda Race requirements for the storm sails are:

3.33.2 Storm Trysail:

A yacht shall carry a storm trysail, with the yacht’s sail number displayed on both sides, that can be set independently of the main boom, has an area less than 17.5% of “E” x “P”, and which is capable of being attached to the mast. Storm sails manufactured after 1/1/2014 must be constructed from a highly visible material. Commonly this is an orange, yellow or pink material.

Trysail sheeted to boom

Trysail sheeted to boom

 

Rugg J 105 Storm Try tied around the boomA trysail sheeted to the boom: The traditional sheeting method for trysails is to lead the sheets to the quarter blocks in the stern. This causes chafe, where the sheet passes over the life lines, results in a poor shape when the sail is eased, leaves a lot of sail flapping around in tacks or gybes or needs more people to perform these manouvers. A very viable alternative is to set the trysail off the boom as seen above. In this case a reef lines is used. HOw ever the sail is set one must be on constant guard for chafe.

3.33.4 Storm Jib:

A yacht shall carry a storm jib not exceeding 5% of the yacht’s “I” dimension squared, and equipped with an alternative means of attachment to the headstay in the event of a failure of the head foil. Storm sails manufactured after 1/1/2014 must be constructed from a highly visible material.

Storm sails built after 2014 are required to be a high visibility color.

Storm sails built after 2014 are required to be a high visibility color.

The decision to set a trysail or not (and how to lower and stow it, don’t forget) is largely driven by the size and type of boat and by extension the skills of the owners and crew. The age, physical dexterity, strength, skill, sailing ability, seamanship and experience are all factors in sail handling in these conditions. And the last two are not always the same as sailing skill. One magazine article cannot address the many variables in methods for using and lowering a trysail let alone the variables on the course.

I would strongly recommend practicing as often as you can with all the crew and especially in crappy, windy weather doing all the evolutions and especially reefing and headsail changes.

Frankly the forgoing requirements for racing boats present very sound information for anyone bound offshore. AND yes, I get that people don’t want to carry Storm Sails around but they have uses outside of conditions over 50 knots.

Next up, what sails do I NEED for the Bermuda races

 

SAILS-Mainsail measuring

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Measuring for a new mainsail:

Sailmakers require many more details than just the luff and foot length and the color of the sail numbers. Here is a review of three of the core elements of the 10-15 details that are needed for a mainsail

TACK/REEFING DETAILS.

Getting the small details right is an important part of the thinking that most sailmakers put into the building of sails. If the following details are not right, they can have a visual or practical effect on the sail. This post will focus on the tack, clew and reefing information sailmakers need.

The TACK & REEF set backs are taken from the AFT face of the mast.

The Tack SET UP is taken from the top surface of the boom,  In this image, below, I can get the tack set back: This is the distance aft from the aft face of the mast to the bearing point (Aft side of the pin of course) of the tack pin known as Tack Set Back. We abbreviate this to the TSB.

In this photo, below, the TSB is 3 3/4″

OLYMPUS DIGITAL CAMERA

 

Tack SET UP, is the same idea but measured vertically from the top surface of the boom UP to the bearing surface of the tack pin as seen below. IN this case the TS UP is on the order of 7/16″ and the TSB is about 2.5 inches. And yes this is a dinghy, but the principals remain the same

IMG_3703

 

BELOW: The TSB is measured FROM the aft face of the MAST to the FORWARD side of the tack pin, the bearing surface of the pin. In this case TSB is 20 mm. or /3/4″

Tack set back in an Olson 29

 

Below: In some cases the tack set up is zero, or is noted as being in line with the bolt rope as on this Halberg-Rassey 31 with, again, Selden spars. The tack is secured with string because the tack shackle was missing the day I was there. And notice also the distance aft of the mast the bolt rope is. This sail had full length battens and so that hardware pushes the sail ‘skin’ aft too.

Lorteau tack detail

 

 

BELOW: this is a detail of the tack area of a Saga 40 with a Selden Spar. In this case the boat will not use the ‘J’ Hooks because it has single line reefing.

Saga 40 main tack detail

 

BELOW: Reef Ring Set back on the same boat. In this instance the boom has a single line reefing arrangement where the luff reef line exits at the top of the boom and attaches to the reef tack. This naturally enough causes the bearing surface of the reef grommet to be some distance aft, like about 4+ inches in this case. IF the RRSB is too far forward, THEN the sail will drift aft until it is restrained by the reef line. IN this case it is most likely to place a heavy load on the slide immediately above the reef point. Worst case scenario, this slide will tear the sail.

Luff reef 2

 

 

BELOW is another version again on a Selden mast, of the same kind of detail. IN this case the line goes thru a block in order to reduce the (tremendous ) friction that single line systems have. In both these setups one needs to be careful to not grind the luff down on top the blocks on the top of the boom, or in the case of the version above, onto the tack fitting and related metal work as it is here. This was a test set up a the dock. We subsequently marked all the lines.

Selden reefing system with block at luff

 

BELOW: These so called ‘floppy rings’ make it a lot easier to get the ref secured to the ‘J’ hooks, rather than trying to bend the cringle in the sail bent around the hooks.

 

OLYMPUS DIGITAL CAMERA

I can also get the same detail for the reefing arrangement at the luff of the reef. The two inverted metal “J”s receive the luff reef ring. Called by Sailmakers the Reef Ring Set Back, RRSB. We would put “floppy rings” in the luff reef in this case.

OLDER WOODEN BOATS: With roller reefing booms. The details on these booms/goosenecks clew ends are a little bot more tricky. As seen below, the tack shackle is a long way aft, I have seen as much as 6 inches. IF this is not captured in the sail, AND the tack ring in the sail is not the right amount of setback, the loads really come on the first second sometimes third slide above the boom.

 

BELOW: this older Alden design has an original roller reefing boom from the 1950’s or earlier. There are two details here. ONE is the big Tack Set Back. There other detail is there is not reefing mechanism, no obvious and easy way to secure a reef in the mainsail

OLYMPUS DIGITAL CAMERA

 

SO: Tack set back is that distance aft of the mast at which the bearing point of the pin that takes the tack load is located.

SO: Reef ring set back is that distance aft of the mast at which the bearing point of whatever secures the reef grommet takes the load.

 

CLEW details

 

 

Preparation for solo sailing offshore

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Just because you are sailing “alone” does not mean there is not a team behind you. Even if it is sailing across the bay…There is the yard, perhaps your S.O., mechanically or electronically inclined mates-we all have our Rolodex of favourite helpers who are “there” for us even if not aboard.

Rob Windsor, left and Hugh Piggin applying the logo for CBL insurance of NZL to Joe Harris's mainsail.

Rob Windsor, left and Hugh Piggin applying the logo for CBL insurance of NZL to Joe Harris’s mainsail.

Witness, Joe Harris, preparing for a non-stop circumnavigation on his Class 40 Gryphon Solo 2-(with an ETD of This Sunday 15 November 0900 at Castle Hill in Newport RI, if you are up for it) gained a new sponsor this week. CBL Insurance New Zealand (where else for sailing of course?) is according to their website, “…… the largest and oldest provider of credit surety and financial risk in New Zealand.”

CBLK insurance NZL logo going onto Joe Harris's mainsail

CBLK insurance NZL logo going onto Joe Harris’s mainsail

Of course this happend “just in time” meaning this week. As with sailing, solo sailing and of course life, one must be ready to expect the unexpected & take advantage of opportunities. So this (Saturday) morning about 0700 I had a call from Hugh Piggin, (on the right) one half of Manuka SEM, the organizers of, amongst other events, the Atlantic Cup for Class 40’s and supporters of Joe’s voyage, looking to get into the Hood Loft in Middletown. He and Rob Windsor, (on the left) the boat manager for Joe needed to lay out the mainsail to get the CBL Insurance logo on the sail.

Last minute Logo layout.

Last minute Logo layout.

So, inside of 24 hours to go with the boat all buttoned up for a lap of the Blue Marble, we find our two heros at the Newport Shipyard removing the mainsail, lashing it to the racks on the borrowed Shipyard pick-up truck, driving the two miles up to the Hood loft , laying the sail out on the loft floor, sticking the CBL logos on and reversing the process. Good goin’ guys and thanks to the CBL guys on Joe’s behalf.

With logo's as with sails, measure twice, cut, or in this case, stick, once.

With logo’s as with sails, measure twice, cut, or in this case, stick, once.

 

IMG_0159

Updates on Gryphon Solo 2’s attempt at beating the present circunmavigation time for a 40 footer of 137 days will be presented here along with my two cents worth of interpretation.

Cheers

C

Sailing Seminars for this winter

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Seminars on sailing are a great way to keep the juices flowing in the winter. The menu below is a summary of the seminars I have already prepared. I can also develop custom seminars for dedicated audiences. Interested? Need to learn more?

Drop me a note joe@joecoopersailing.com and let’s discuss what can be done to keep your group fired up in February.

PASSAGE MAKING

Preparing for your next “long passage”: This seminar discusses Seamanship and 8 things to think about before you undertake any voyage so we don’t read about you in WindCheck. Regardless of the size of boat and the intended passage, whether it is to Block Is. Nantucket, Maine or Bermuda and beyond. The thinking needed is the same regardless of the destination. This seminar discusses key elements of the boat to be reviewed before leaving the dock.

Steering cables on a 40 footer mis-aligned. This will ultimately damege both the cables and the quadrant

The teering cables on this 40 footer are mis-aligned. This will ultimately damage both the cables and the quadrant.

Mis-aligned cables will wear on anything they touch.

Mis-aligned cables will wear on anything they touch.

FULL LENGTH BATTENS

Separating the hype from reality: Just what is the VALUE in a FB SYSTEM? This seminar discusses the aerodynamics behind the FB phenomenon, the realities for most sailors with “normal” boats, the hardware, its use, cost and the relative value for sailors.

Full Length battens CAN provide los of roach, but in this case there is not backstay. BUT this is a custom built boat intended to have no backstay.

Full Length battens CAN provide los of roach, but in this case there is no backstay. BUT this is a custom built boat intended to have no backstay but rather runners.

 

But in order to REALLY slide up and down easily demands a comprehensive look at the sail, mast and the sailing plans plus how YOU like or want to sail

In order for a FULLY BATTENED sail to REALLY slide up and down easily demands a comprehensive look at the sail, mast, the sailing plans plus how YOU like or want to sail.

SAILCLOTH AND SAILS

Separating marketing from facts to get to Value: A discussion of sail cloth, details to look for and why for various types of sailing. What does “Premium Dacron” really mean? Why every sail maker has “The world’s best sails” What’s the difference? Why the price spread? Woven, Laminates, fibers, molded, not molded, a glossary and guide to sail-maker speak.

Laminated staysail on a 30 footer.

Do you need a “high tech” sail fabric such as this laminated staysail on a 30 footer?

Or a woven material. What gives YOU the best VALUE for your sailing?

Or a woven material? In this case a full battened mainsail made from woven Vektron on a Beneteau 40.7. What gives YOU the best VALUE for your sailing?

CRUISING SAILS & RIGGING:

Options for sail inventory: How to set up your boat for your cruising goals, now and 5 years out. What you need, why and how to maximize Value without a boat full of sails.

A cruising kite is, after you get co mfortable with it a great value when sailing in medium air. The condition most passages are made in.

A cruising kite is  really an easy sail to get comfortable with and it is a great VALUE when sailing in medium air, the condition most passages are made in.

A "solent" stay is a good way to have a small sail without having to "change" headsails.

A “Solent” stay is a good way to have a small sail without having to “change” headsails when the roller headsail is too much sail. They are easy to install and can greatly expand the wind speed you feel comfortable sailing, pretty quickly.

PREPARING FOR SUCCESSFUL RACING:

It’s not just wet sanding the bottom: A review of the steps the good guys take to give themselves the best shot at being successful.

 

Even for low key racing, the hard work is before you leave the dock

Even for low key racing, the hard work is before you leave the dock. © Don Miller Photography. Bermuda 1-2 start. 2007

Even for single-handed events a team is an integeral component of the program.

Even for single-handed events a team is an integeral component of the program. Spreading the passion for sailing to my son, as my dad for me.

THE AMERICA’S CUP:

How a 7-year old kid ended up in two America’s cups. A look back thru the history of the Australian challenges for the America’s Cup beginning in 1958. How Australia got into the act, how a 7 year old kid was infected with the disease and what it was really like sailing a 12 meter in the late 70’s and early 80’s. Cooper was the youngest crew in 1977 and the boat keeper on Australia in 1980-working for the syndicate for 18 months and sailing as Grinder/Sewer man.

One of the signature images that lured me to the America's Cup. The 12 meter Dame Pattie pricticing in Sydney Harbor in 1967. I was 12 years old.

One of the signature images that lured me to the America’s Cup. The 12 meter Dame Pattie practicing on Sydney Harbor in 1967. I was 12 years old.

13 years later: Crew members from the Australian teams were popular and coveted guests ar Newport summer parties.

13 years later: Crew members from the Australian teams were popular and coveted guests at Newport’s summer parties. The Australie Challenge, July 1980. The beginning of the end…..

A PASSION FOR SAILING: (NEW- First presentation at Black Rock YC, second to be at Stamford Yacht Club 28 Jan 2016)

A life spent sailing & reflections on key areas of sailing that have shaped my life: Family, community, independence, experiences & personal philosophy.

Early exposure to sailing set me on a course for a life time in boats.

Early exposure to sailing with my dad set me on a course for a life in boats.

nComing full circle--Coaching The Prout School, high school sailing team in Newport RI

Coming full circle–Coaching The Prout School, high school sailing team in Newport RI.

Coaching the next generation of young sailors is one of the most rewarding activities I do today

Coaching the next generation of young sailors is one of the most rewarding activities I do today

Mast bend and mainsail shape

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Bending the mast is a fast and simple way of managing the power on your sail boat

As discussed here mast-rake and mast bend are two different aspects of mast “tune” that affect the boats balance and so feel and ultimately performance. This essay discusses mast BEND. There is an element of headsail shaping connected to mast bend but we will get to that in future posts.There are other tools in the mainsail shaping tool box, but this essay is about mast bend

The Basics:

More wind requires a flatter sail

Less wind prefers a fuller sail.

Mainsails have shaping both across the sail (broad seaming) and at the luff, known as Luff Curve

This “curve” is intimately connected with the characteristics of the mast, and so, of the boat. There are differences in the amount of luff curve required between masthead and fractional rigs, masts with spreaders in line–that is to say where the cap shrouds are perpendicular to the mast-Or with “swept back” spreaders, such as many newer boats have.

Some Definitions:

Chord: Is an imaginary line between the luff and the leech

Depth: (and draft, camber & shape-They are quite synonymous and generally used interchangeably by Sailmakers in their jargon) is that distance, perpendicular to the chord line, at which the sail’s surface is furthest away from the chord line.

In the sketch below:

The line ZZ is the chord line.

The portion “C” is the chord LENGTH on the sail.

The distance “a” is the chord DEPTH (draft camber shape…).

The distance “b” is the POSITION of the draft measured aft of the leading edge of the foil which is in this case to the right of the image. Thus a/c is the draft and b/c is it’s position.

Chord (length) draft and location of draft are all depicted in this image.

Chord (length) draft and location of draft are all depicted in this image.

Power: over and under (powered)

Power (force, energy …wind speed) is what gives the sensations you feel thru the wheel or tiller and via the heel angle of the boat. With headsails, managing the power is relatively easy: Too much power, then put up the small (er) one-Or more likely today either partially roll up the genoa or roll it up all the way and motor-sail.

Sail size and shape:

Having the right (sized) sails of the right shape for the conditions is, for those who prefer to sail for the sensations of how the boat feels thru the tiller/wheel, a key part of this sensation. Too much sail and/or sails that are too full makes the helm feel heavy and generates too much weather helm. In this condition the boat heels more than you want and always inclined to want to round up. This is of course unpleasant, occasionally quite noisy, slow and not infrequently intimidating for some on board.

The sensations of being underpowered are less dramatic, noisy, violent and so less intimidating.

Power on a sailing boat comes of course from the sails. Having the right shape in the sails is therefore key to getting the boat to “feel good” and sail well.

Managing the power

One tool in the box of adjustments available to sailors is adjusting the camber of the mainsail-What many folks refer to as the belly of the sail. Camber is the “depth” of a sail at a given point on the sail. (NB when we/you say the sail is blown out, usually this refers to the draft being further than 50% aft on the sail)

This picture shows me and a high school intern measuring the draft amount and location on a 420 mainsail strung up in the loft.

This picture shows me and a high school intern measuring the draft , the amount and its location on a 420 mainsail strung up in the loft.

The camber on any foil is expressed as an amount, at a location. So you might hear Sailmakers say something like…”it was 8% at 35% aft.” This means that what they were looking at was 8% of the fore and aft span (of the chord line) perpendicular from that line and that position was 35% aft, from the luff. Translated: the sail was 8% deep at 35% aft.

Another picture of working with Tristan discussing issues surrounding sail shape: Chord, draft position and so on.

Working with the intern and discussing issues surrounding sail shape: Chord, draft position and so on. This sail looks quite full because the mast is not bent.

So for example if the chord span (“c” above) was 10 feet and 8% of 10 feet is 9.6 inches so the sail surface was (“a” above) 9.6 inches away from the Chord line, and this point is (“b” above) 3 and a-half feet aft along the span from the leading edge.

So far so good?

Luff round

Now sails are not just triangular (Yes, mainsails have roach but many/most “cruising boat” sails have very little), the point is they are curved at the luff too. This is called, no surprise, “luff curve or luff round”. How much curve and at what position on the luff and how these points is determined are all components of the sail’s design.

On this J 30 main, the area of the sail to the left of the left hand tape is called luff round. There is a lot of it on a J 30 because they have relatively bendy masts, especially above the hounds.

On this J-30 main, the area of the sail to the left of the left hand tape is called luff round. There is a lot of it on a J-30 because they have relatively bendy masts, especially above the hounds.

Luff round and mast bend are intimately connected. If the luff curve and the mast bend “match” is correct, you have a 6-speed stick shift gearbox. If the mainsail luff curve and the mast bend are not mated, pretty closely, then you have a 1953 shift on the column three speed with no fluid in the transmission, as it were. It is really critical and the more performance oriented the boat the more critical it becomes. AND this is why having a back stay adjuster (and knowing how and when to use it) is a great thing to know, if you like sailing your boat, as opposed to being on while it is sailing.

Sketch of a mainsail set on a straight mast

Sketch of a mainsail set on a straight mast

Briefly stated, when you bend the mast, you can flatten the mainsail. A flatter sail is to be preferred in more wind. Flatter sails reduce power in the sail, that is reducing load on the tiller/wheel. When you bend the mast, in windier conditions you will feel the helm go lighter, all other things being equal.

Mast bend flattens the mainsail

Mast bend flattens the mainsail. When the mast is straight …”straight mast” the sail is fuller. When the mast is bent, as at point “a”, the luff curve gets pulled forward and so flattens the sail.

 

Mast bend on the 12 meter Australlia ion 1980

Mast bend on the 12 meter Australlia in 1980. The defender, Freedom is to weather.

The picture above shows the 12 meters Australia and Freedom coming off the starting line in one of the 1980 races for the America’s Cup. The Australians had fabricated a fiberglass top to one of their spars that would bend much more dramatically than an aluminium one. The top of the mast was controllable, apart from the regular topmast backstay, by “jumpers” and “diamonds” all controlled by hydraulics in the mainsheet trimmers cockpit. It gave the boat the abiity to have more mainsail and the rounder shape to the top of the mast was more efficient. In under about 9 kts of wind we were faster than Freedom. We won one race and were in front by 20 minutes when the time limit expired.

The large roach not withstanding, study the luff on the let. IT has a degree of "luff curve". This will match the mast bend on the boat and so be used to de-power the sail.

The large roach not withstanding, study the luff on the left. It has a degree of “luff curve” about 6 inches to my eye. This will match the mast bend on the boat and so be used to de-power the sail.

If you do not have any mechanism to bend the mast, consider adding a way to do so. For almost all boats there are a variety of pretty simple solutions.  If you cannot find one or need help, contact me….It is not impossible that the money spent on such a set up will be good value with respect to making the boat more agreeable to sail in breeze and so less uncomfortable for all hands.