SAILS-Mainsail measuring

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

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

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

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.

 

 

 

Headsails, 150, 130 what’s it mean?

Image

One of the most quoted yet least understood phrases used in discussions about headsails, their size, is the “LP”. Customers and prospects alike use phrases like 130, 150 or 100 regularly. But when I inquire as to their understanding of the number, it is rare for the average weekend sailor to get it defined correctly. It is actually very simple. The initials L.P. stand for Luff Perpendicular, usually written as LP. This is a dimension, but not an edge, of the triangle that is a headsail. Its definition is:

“A line drawn at right angles to the luff and that passes through the clew of the sail.”

The LP is drawn from the luff or the sail and passes through the clew. In this image, the line , parallels to the luff is indicated by the pencil. THe distance between the clew and the LP is "x" The percentage of LOP is then x/J

The LP is drawn from the luff of the sail and passes through the clew.  The distance between the clew and the LP is “x” and the percentage of LP is then x/J.

The “size” of a headsail is determined by taking the LP length  and dividing this number by the boat’s “J” The J dimension is, for the purposes of this discussion, is the distance from “the forward face of the mast at the deck to the intersection of the deck and the head stay pin at the stem head”. The J dimension and the LP are inseparably connected.

The LP number, this 150, 120 percent etc., is the length of the LP dimension divided by the boats “J”.  So for example if the boat’s “J” is 10 feet and the LP dimension on a sail is 13 feet, the sail has an LP of 130%.

Two sails, for the same boat can have the same LP yet have different clew heights

Two sails, for the same boat can have the same LP yet have different clew heights

In the image above, there are two sets of dashed liners. the red dash lines are the LP length.The green l one, long with short dashed between is the trim line. That is the axis along which the sail will want to sheet.  It is worthwhile noting too that the LP and the height of the clew of the sail are connected only by the fact that both a low clewed sail and a high clewed sail can both have the same LP.

I often am asked about all the missing area at the bottom of the sail, with respect to a high-clewed sail. There is no area missing if the sail has the desired LP. It is merely that the clew is high rather than low. The area of a genoa is arrived at by the formulae: LP x Luff length x 0.5. A moment’s reflection will indicate that the length of the foot, the most common answer to my question “what is the LP?” is incorrect.

The clew height is a function of where the sail is proposed to sheet AND the LP for the sail. And these are a  function of the purpose and use of the sail.

The clew height is a function of where the sail is proposed to sheet AND the LP for the sail. And these are a function of the purpose and use of the sail.

The length of the foot of the sail is a function of the LP and the clew height.

In the move image/sketch there are two LP lines the red dashed lines. They are the same length. You can see that there are however two clew positions. The clew positions are a function of the “trim” line, basically where on the deck the sail will sheet.

So, the height of the clew is governed by several variables but is driven by firstly what sort of sail it is, for what boat, for what use, where, and then so where the sail needs to sheet. This will be discussed in another post.