sail cloth, sail fibers, sail making

 

I am presenting a lecture seminar on the subject topic this Thursday, tomorrow, 16 Feb 2017 at Newport Yacht Club, Long Wharf in Newport. All are welcome.

This is the presentation overview and the things I will be discussing.

Fiber, fabric, film and fabrication

  • What does a sail have to do?
  • What is required to do this?
  • Background on fibers and their properties
  • Weaving 101
  • Mylar properties
  • Laminates
  • Laminated method
  • “String sails”
  • What’s next?
  • What does the weekend sailor make of this?

And thanks to Hood Sailmakers and Dimension Polyant for the cloth samples.

Hood Sailmakers is paving the way by sponsoring the drinks to the tune of the first $150 of drinks served.

This is the email flier that Roy Guay, my host for the evening and the Chairman of the Bermuda 1-2 distributed to the club’s membership.

On 16 February at 1830 the Newport Yacht Club is trying to start a Winter Lecture Series. Our own Joe Cooper will be giving a talk on Sailcloth and Sails: “Separating marketing from facts to get to Value: A discussion of Sailcloth and things 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? Woven, Laminates, fibers, molded, not molded, a glossary and guide to sail-maker speak.”

If you are in the neighborhood drop on by. All are welcome.

Roy Guay
Offshore Chairman

Cooper in action at a seminar in California last year.

Cooper in action at a seminar in California last year.

Hope to see you there.

Cheers

Coop

 

Hall Spars Carbon mast for a Gunboat 90

One of the great aspects of my life is I get to wander around boat yards and so see lots of really interesting and innovative things to do with boats. Very kid in a candy store stuff. A couple of days ago I was at the Hinckley/Hunt marina complex in Portsmouth RI when I came across two Hall technicians prepping a Carbon mast to be returned to its boat, a 90 foot Gunboat catamaran.

Hall Spars has long been a leader in the construction of Carbon fiber masts. Brothers Ben and Eric Hall have been building spars for pushing 40 years and carbon masts, booms, kite poles and other carbon bits for probably 25 plus years. This brief post shows some pictures of parts of the mast and some commentary from me. Enjoy.

This first image, below, is of the bottom of the mast. The rig is a partial wing mast (NOT a wing sail), which means that it is perhaps 700 mm long (fore and aft-Compare with the ladder or my coffee cup on the ladder) and is much more wing shaped, albeit thicker, as wings go, than a conventional spar.

gunboat-mast-step-1

There are a number of reasons for using a wing shaped mast on a fast boat, not the least of which is to reduce drag as the airflow begins to pass over the sail. The drag from conventional shaped, (roughly oval in cross section) adds up when you do the math to sum the cross sectional frontal area exposed to the wind. An additional benefit of wing masts is there is a lot less standing rigging required to hold the mast up-This has long been a benefit of multihulls because of the wide staying base.

A wide staying base reduces the loads on the mast, and also the amount of rigging needed to keep it up. With the elimination of multiple sets of spreaders, and intricate standing rigging, the mast can be this wing shape.

Today, composite standing rigging is certainly lighter and stronger than any metal rigging, but composite standing rigging is thicker in cross section, so having less of it is a big plus. The image below is of the ‘bobstay’ securing the top of the deck spreaders to the hull on No way out, the latest IMOCA 60 from VPLP/Verdier. The acute angle demands stronger, so thicker material, but  you get the idea.

img_0682

The bobstay, is secured to the hull in some invisible fashion, below. Notice that all of this is so the boat can have its own partial wing mast, or vice versa…

img_0681

Finally the drag goes up exponentially with the speed, so a cat or tri (Like Spindrift, shown in the featured image) is incorporated into the sail area and sail shape for considerations of sail shape.

The facility of wide shroud base has transitioned into the IMOCA 60 boats, (seen below is ‘No way out’) such as those in the Vendee Globe presently underway.

This latest generation IMOCA 60 has the now common deck spreaders and wing shection mast. The spreaders are to get a wide shroud base, to minize the compression on the spar so it can be a but lighter. Many many Excel spreadsheet Cells were sacrificed in figuring out the cost benefit of this arrangemebt.

This latest generation IMOCA 60 has the now common deck spreaders and wing section mast. The spreaders are to get a wide shroud base, to minimize the compression on the spar so it can be a bit lighter. Many, many Excel spreadsheet Cells were sacrificed in figuring out the cost benefit of this arrangement.

The variations in the size of wing masts are as varied as the boats themselves, as this picture below, of Spindrift, shows. (Spindrift Racing was kind enough to let me have some of the Prout Sailing Team visit Spindrift a couple of years ago.) On the forward side of the mast, at the base, you can see the rotating quadrant with tackle attached. See too, the knife in the yellow sheath, just next to Julia’s left calf…..

img_5602

Back to the Gunboat mast.

Because it is a wing mast, it is deck stepped so it can be rotated. (Or perhaps it is the other way around. It is stepped on deck so it CAN BE a wing mast). To achieve this rotational ability, there are two unique details. The bronze colored circle in the middle is the fitting, slightly concave, which lands on top of its mate on the mast step, on the boat. It is basically a bearing surface for the mast to sit on, so it can rotate.

gunboat-mast-step-2

The half circle looking part is on the forward side of the mast. It is, and so acts like, a quadrant, in a wheel steering system providing a lever arm to move the spar. There are control lines mounted to it and when actuated, these lines can turn the mast thru, what looks like 90 degrees, but is probably only 45 degrees, either side of fore and aft, in practice. You can see these more clearly in the Spindrift images, above.

This closer detail shows a remarkable piece of carbon detailing and finish work. Smooth, shiny and undoubtedly strong. It is as much a work of artisan craftsmanship as an engineering part for a 90-foot high-speed sailboat.

gunboat-mast-rotation-quadrent-detail

Built into the base of the mast is a detail to accept the halyard turning blocks. This design is necessary because the (aft side of the) mast moves thru, perhaps 12-18 inches when being rotated, so incorporating the blocks mounted onto the mast eliminates the traditional idea of mounting them to the deck with big pad eyes thru bolted.

gunboat-mast-base-blocks

This traditional method would not be very successful in any event because the halyard’s lead out of the mast would be moving all over the place as the mast rotates. In keeping with the proliferation of using cordage in lieu of metal for securing things to the boat, these Harken blocks are looped onto the mast with large diameter spectra. The Harken Velcro straps stop the loop from separating when there is no load on the block. The little piece of light line is probably to keep the Velcro attached to the boat when working on the block

At the loads the sails on these boats generate the engineers must consider the transfer of this load thru the (main) sail’s leech to the mast track.  In this picture, a section of track is the pewter colored piece on the aft side, the bottom, of the of the mast in the image. The loads on this boat, when sailing full speed, close to the wind, with a fully hoisted main are considerable. Bear in mind that a 90 foot cat, particularly a light fast one, generates the kinds of sail loads roughly equal to a 140-150 foot monohull

gunboat-masthead-track-reinforcing

And just as much load is generated when reefed. This next image shows the beefy metal (I did not ask what) at the reefs too. The luff track/batten car slider system is suitably large Ronstan ball bearing equipment. This construction detailing on the spar of course requires considerable communications between the Sailmakers and the mast builders as to where the head of the sail will land when the sail is reefed.

gunboat-mast-track-reinforcement-for-reefs

Another detail to do with the huge loads on this (these) boat (s) is that they do not use ‘conventional’ jib halyards & furlers but rather the foresails are on ‘free luff’ furlers. These furlers have become pretty commonplace on high test boats from Class 40’s to Ultimate trimarans, like Spindrift, above.The dead weight of the sail and furler combination is lighter than a conventional aluminum section (or Carbon sections on bigger boats) and can offer the option, quite often exercised of removing the sail and stay completely. The benefit to this of course is to, again, reduce drag and weight aloft and, incidentally, improve stability. The concept and equipment for this kind of free luff furler comes from the reaching Genoas used on furlers for the solo offshore race boats for perhaps the past 20 plus years that has now trickled down to all manner of boats. In order for the loads to be accommodated, the sails/stays are secured by halyard locks. The idea of halyard locks has been around for a while–many smaller boats, Finns, Etchells, and so on have halyard locks, for the mainsail at least, and have had for years.

gunboat-halyard-lock-2

The contemporary high-load halyard lock is a bit more sophisticated though. The rigging of this halyard lock and free luff sail arrangement involves a ‘stay’of a lightweight composite fiber manufactured for the purpose, being captured inside a luff tape on the jib and secured to the head and tack of the sail.This idea is basically like the luff-wire in the jib of a 420-dinghy jib for instance. The rolled up sail is hoisted on a ‘halyard’ that is really just a length of line, robust enough, to hoist the sail and, when hoisted, the top of the stay is introduced into this metal lock and is thus held in place with no load on the ‘halyard’. The lock is held to the suitably reinforced part of the mast with Spectra loops, seen below.

gunboat-halyard-lock-1

This reduces weight in the mast because the sheave area does not have to be so strong as to resist the halyard tension, rotating over the sheave at about a 160 degree turn and the (hoisting) sheave itself can be much smaller, just big enough to sustain the loads of pulling the sail up. This absence of halyard load reduces the compression on the spar,(cf halyard loads in previous sentence) another element contributing to the weight (savings) in the mast. No (conventional) halyard means fewer blocks at the base of the mast, or winches and clutches on the mast and so on. The lock is probably one of the few metal parts on this mast. The lock hardware thus has a padded jacket around it to protect the (beautiful) carbon work the mast represents.

gunboat-halyard-lock-3

The above view is up through the tunnel which the part to be locked, the top of the stay, fits.

The stay is tensioned by some combination of tackle, winch or hydraulics as seen on, again, the IMOCA 60, No Way Out.

Stay tensioning system on IMOCA 60 No way out

As noted, wing masts have a lot less standing rigging that a conventional mast, but they are not without some rigging. The picture below shows the additional layers of carbon laminated in  and around where the spreaders pass thru the mast. The technique the Hall folks use is a layup over a mandrel, so the outside of the mast shows all the effort put into the work by the technicians actually laying the fibers onto the  spar. Truly, art meets science. The shiny-ness of the mast is probably due to a clear coat paint job.

 

gunboat-mast-spreaders-reinforcing

The engineering of these masts is pretty complex and must take into account all manner of multi-directional loads, both static AND dynamic and peak loads, as when sailing into the back-side of a wave at 30-35 knots and slowing down rapidly to 20 knots or less. The composite lay up for the boat’s gooseneck must withstand this loading and have a suitable safety factor to boot. This probably accounts for the size of the gooseneck. My thumb is at 21 inches.

gunboat-mast-gooseneck

A proper seagoing mast ought to have a tunnel inside the spar to run the cabling for all the electronic and electric stuff. An innovative variation on the typical round tube held to the inside of the mast is this sheath fabricated from some light sailcloth. All the cabling is captive inside this sheath. It is held in place and tensioned by, at the bottom, the piece of  lightweight Spectra, the blue colored one. The reddish piece of Spectra is probably mouse line for installing and removing cabling.

gunboat-mast-cable-run-inside-spar

Certainly not all of us have the means to own and operate a gunboat 90, but as noted above, hanging around in boat yards is, for many water rats, a fine thing to do.

Feature image Spindrift Racing, 30 meter Trimaran.

Picture courtesy Spindrift racing

 

 

Vendee Globe the pace slows but the race gets tighter at the front

Picture copyright Vendee Globe Banque Populaire Armel le Cleac’h aboard Banque Populaire in the Vendee Globe 2016/17

The Vendee Globe is a sailing race like no other for various reasons. This years edition has pushed the edges of performance probably a couple of hurdles further than normal boat evolution with the new foiling boats. Foiling leapt to the sailing limelight in the America’s Cup in 2013. Foiling sailing boats have been around for at least, today, close to 100 years. The most prominent recent example of a foiling sailing boat, this side of the foiling AC 72’s, is the French program L’Hydroptère. This remarkable vessel is the life’s goal of Frenchman (of course) Alain Thebault who has dedicated the past 30 years to foiling sailing.

Photo sent from the boat Hugo Boss, on November 15th, 2016 - Photo Alex Thomson Photo envoyée depuis le bateau Hugo Boss le 15 Novembre 2016 - Photo Alex Thomson

Photo sent from the boat Hugo Boss, on November 15th, 2016 – Photo Alex Thomson
Photo envoyée depuis le bateau Hugo Boss le 15 Novembre 2016 – Photo Alex Thomson

Fast forward to the 2016/16 Vendee Globe, seven of the entries are the latest generation designs by VPLP/Verdier. Three of them have been on a cracking pace led by Brit Alex Thompson who as of this writing, (Saturday 26 November) remains in the lead over Frenchman Armel Le Cleac’h who has, however, run down the tenacious Brit from 120 or so miles behind two days ago to 12 miles as of 1500 race time today. And five of the top seven are latest generation foilers

One of the interesting details in a race full of interesting details is the spread between the foiling boats even within themselves. Thompson and le Cleac’h are alongside each relatively speaking but they have broken away from the remaining pack. In third, now over 300 miles astern is Seb Josse in Edmund De Rothschild, fourth is a non-foiling boat, (albeit the 2012/13 winner under the command of then wunderkind Francois Gabart), skippered this year by Paul Meilhat at almost 900 miles astern with fifth, six and seventh at 900, 1200 and 1700 (roughly) miles behind respectively. The last remaining foiler is under the command of Dutchman Pieter Heerema at almost 3,000 miles astern. So what accounts for this huge spread?

This latest generation IMOCA 60 has the now common deck spreaders and wing shection mast. The spreaders are to get a wide shroud base, to minize the compression on the spar so it can be a but lighter. Many many Excel spreadsheet Cells were sacrificed in figuring out the cost benefit of this arrangemebt.

This latest generation IMOCA 60, this one belonging to Dutchman Pieter Heerema, has the now common deck spreaders and wing section mast. The spreaders are to get a wide shroud base, to minimize the compression on the spar so it can be a but lighter. Many, many Excel spreadsheet Cells were sacrificed in figuring out the cost benefit of this arrangement. Joe Cooper Sailing photo

The top three skippers are all within a couple of years of the same age, at around 40, They are underway in their fourth, fourth and third Vendee globes respectively. These three are sponsored by, and have possibly the best funded and organized teams-Thompson has 13 people working for Alex Thompson Racing and is sponsored by the German clothing company, Hugo Boss. Second and third are funded by two banks and all three are long term sponsors, with Thompson serving Hugo Boss for 16 or so years while the two banks, Banque Populaire and Edmond De Rothschild, have been in the sailing game for at least that long, albeit with different skippers.

It is reported that Thompson’s boat while being from the same design office is ‘different’. Obvious differences are the dreadnought bow and sloping foredeck, a reportedly narrower boat and wider foils. Thompson is using Doyle sails, something of a departure from the ‘standard’ North France that the other two are using. Can it be ‘just sails? Hardly, but perhaps it is one of those situations where a lot of small details add up to a greater whole? Even more remarkable in the case of Thompson is the 6 months his boat was out of action after breaking in the last TJV and being abandoned, recovered and rebuilt. And on top of this he has already broken his starboard foil in a collision with something in the water. Thompson is considered a tough nut, which is saying something in a world of tough nuts.

Picture of Pieter Heerema’s boat ‘No Way Back’ (the yellow boat) by Joe Cooper

Pictures via Vendee Globe Press office except where noted.

Banque Populaire feature picture via Armel Le Cleac’h aboard Banque Populaire Vendee Globe

Reuse of pictures is prohibited.

 

Vendee Globe-Solo record still possible

The foiling IMOCA 60’s are giving a good impression of multihull speed over the course of the first 19 days of this edition of the Vendee Globe, solo circumnavigation. As of 1700 EST, Brit Alex Thompson aboard Hugo Boss has had the pedal down despite breaking a foil on something in the water a few days ago. (It is worth noting that at the moment four boats have hit something and broken the boat obliging three of them to abandon the race).

The VG tracker has a number indicating the percentage of the race the leader has completed. After 16 days Hugo Boss had completed 25% of the calculated great circle length of the race. Extrapolating on this data brings one of course gets to a 64 day circumnavigation. Will this be the end result? Too soon to say fo course. BUT I just did it again for 19 days at 30% which is 62 and some days, so they are not backing off at all.

Thompson has been able to get back up to full foiling speed having gybed to starboard for a while today allowing him to deploy the ‘good’ foil for a while. But sail boat racing regardless of what the boat or the course is needs wind and they appear to be light on for such at the momenet, light being the operative word.

The biggest hurdle the two front runners, now 25 miles apart (at 1700 Race time) is the wind petering out and becoming confused and light. Thompson reports basically sailing into the back of the front.

Oops- pays to pay attention. The 2200 race time position updates places The Boss stretching again over Armel LeCleac’h, (aka The Jackal in French solo terms) at 31 miles over his earlier 25 miles. AND the Boss has the juice again at 22 knots versus 18 of The Jackal.

British Bull Dog lives to fight another day.

The following link/news update courtsy of the VG press office.

http://www.vendeeglobe.org/en/news/16495/the-jackal-is-on-the-hunt

 

Offshore sailing-Ideas from single-handed sailing

Regular readers will know of my interest in the Mini Transat, OSTAR, Vendee Globe, Figaro and similar solo and double-handed races. Apart from the actual racing itself, these boats represent a melting pot of ideas and were lots of smart people invent ways to sail fast when alone or with only two people. The majority of cruising sailors sail with a crew of only two people aboard anyhow. Short-handed boats prepared for racing have been at the forefront of most of the ‘advances’ that cruising sailors take for granted today.  So when I see boats from this short-handed cohort of yacht racing, I am always curious to see what the thought process is and if there any new ideas I can pinch.

I was at Sail Newport last Sunday and I noticed the Mini Transat boat that, a couple of weeks ago was in the water, had been pulled out. I was interested in this boat because it had a canting keel, but there was no obvious dagger board or other device to resist leeway, at least as viewed from the dock with the boat in the water.

Not only canting side to side, but moving fore and aft close to a meter the fin on this Mini Transat class boat requires some pretty careful attention to detail.

Not only canting side to side, but moving fore and aft close to a meter the fin on this Mini Transat class boat requires some pretty careful attention to detail. That she had a canting keel is evident by the lines exiting the cabin bulkhead under the cowling-see below-(and passing thru jambers) These lines are part of  a three or four to one tackle inside the boat and  then lead outside to a winch so as to lever the keel side to side.

The large clutch on the deck secures the line controlling the canting keel.

The large clutch on the deck secures the line controlling the canting keel. The lines are set up to lead to a winch. The boat was set up with a canting keel but where the dagger boards?

 

This mini, designed by Simon Rogers for Australian Tom Braidwood and built in Sydney, Aust. 2006 has both a canting keel and the keel moves fore and aft too.

This mini, designed by Simon Rogers for Australian Tom Braidwood and built in Sydney, Aust. in 2006 has both a canting keel , articulating from side to side and the keel moves fore and aft too.

574 looks, at first glance, like a ‘normal’ (And not like mine) mini: beamy, twin rudders, skinny fin with a big bulb, huge rig, and articulating bowsprit

Apart from the ‘canting keel but no dagger boards’ question, a second interesting detail was the mast. It is longer in section (fore and aft)  than ‘normal’ mini masts and has only one set of spreaders. Hummm me-thinks.

MAST and Rigging

Tis boat has a maast with only one set of spreaders. IT can do this because the mast is longer in the fore and aft plane and probably thicker walls too. The underlying scheme here is to minimize windage, drag, from the rigging. The configuration of 574 is likely to have less exposed stays and certainly spreaders, than a 'normal rig'.

This boat has a mast with only one set of spreaders. It can do this because the mast is longer in the fore and aft plane and with probably thicker walls too. The underlying scheme here is to minimize windage, drag, from the rigging. The configuration of 574 is likely to have less exposed stays and certainly spreaders, than a ‘normal rig’.

Almost all of these speedy little boats, the custom ones, anyhow, have composite rigging today. Securing the shrouds to the boat is a wonderful throw back to the ‘old days when stays were lashed to the deck with lanyards and pad eyes.

The stays are secured to the deck/chainplates with Spectra line, with multiple passes around the chainplate and the stay. The black tube is what amounts to a reaching strut. This is inserted into a hole built for the purpose in the side of the hull. The end result is to holt the bow sprit after guy out away from the boat at a wider angle.

The stays are secured to the deck/chainplates with Spectra line, with multiple passes around the chainplate and the stay. The black tube is what amounts to a reaching strut. This is inserted into a hole built for the purpose in the side of the hull. The end result is to hold the bow sprit after guy out away from the boat at a wider angle.

 

This image shows the hole in the side of the boat to accept the strut.

This image shows the hole in the side of the boat to accept the strut.

Underwater: The keel and canard

It turns out that this boat has a lot going on down below. The keel swings, or cants in the parlance, port to starboard. It also can move fore and aft 800mm according to the designers website.

Here you can see the root of the fin disappearing into its own mechanism to handle the canting. The longer orange rectangle is the pathway for the fin to slide fore and aft.

Here you can see the root of the fin disappearing into its own mechanism to handle the canting. The longer orange rectangle is the pathway for the fin to slide fore and aft.

The fin on a canting keel boat enters into the hull through a suitable sized slot. There is an axel with bearings on it that passes through the fin fore to aft and is secured to the boat. Around the hole is a V shaped box, the top of which is above the LWL. This box has some kind of pretty waterproof cover on it too. The top of the keel pokes up thru this and has a block and tackle on the top. The l ine from this tackle is led outside thru a ferrule in the cabin wall as shown a few pictures above.

The fin on a canting keel boat enters into the hull through a suitable sized slot. There is an axel with bearings on it that passes through the fin along the fore & aft axis  and is secured to the boat. Around the hole is a V shaped box, the top of which is above the LWL. This box has some kind of pretty waterproof cover on it too. The top of the keel pokes up thru this and has a block and tackle on the top. The line from this tackle is led outside thru a ferrule in the cabin wall as shown a few pictures above. I am not certain that the area around the keel entrance to the hull is race ready, but it seems to me there are a lot holes and slots that would create drag when sailing, especially, fast. ON the other hand this boat did correct to third in class in the Pacific Cup in

The object when designing a racing boat of course is to have a boat that can, and will, win races. All manner of calculus goes into the design engineering and building of such a boat. One of the curious aspects of this boat is the engineering and building detailing required to make the keel more fore and aft. This requires a lot of additional designing, engineering and boat building time and skill. All of this of course consumes (extra) money. In simple terms, what is the risk reward, or if you, like the cost benefit ratio.

x

The white ‘thing’ sticking down to the left is the canard, set forward of the keel. This is deployed to resist leeway, acting like a ‘normal’ keel on normal boats. That it can be canted too is a benefit because when the boat is heeling, the canard can be vertical and so be working most efficiently.

This boat is a close sister-ship to the one Jonathon McKee (a prominent and successful US sailor from the Pacific North-West) sailed in the Mini Transat in 2003. Sadly he was dismasted while leading the second leg of the race. I don’t know what style of mast McKee had, but the one on 574 is configured in a way that many of the new IMOCA 60’s are, which is interesting since this boat is 10 years old now. The idea is that the mast and standing rigging has a certain amount of drag.

Another view of the canting Canard

And finally back to the mast

If you do the math on the surface area of the standing rigging on your boat—Sum the total length of standing rigging, multiplied by the various thicknesses, it is a lot of square units. Ignore for now the radar, radar reflector, satellite dome, spare halyards, the bulk of the furled headsail or staysail etc. Now, for the average 45 foot cruising boat, this kind of drag is repressed into oblivion by Bimini’s, dinghy davits and so on and traveling at 5 to 7 or 9 knots, BUT on a boat traveling at 15-20 knots, like a Mini or an IMOCA 60 traveling, as the boats currently leading the Vendee Globe are, at over 20 knots most of the time, for the foiling boats, drag becomes something to think about. Minimizing drag becomes especially important for boat traveling fast because the drag goes up exponentially with boat speed. Hence the wing masts and lots of effort art educing drag on fast Multihulls of IMOCA 60’s

This latest generation IMOCA 60 has the now common deck spreaders and wing shection mast. The spreaders are to get a wide shroud base, to minize the compression on the spar so it can be a but lighter. Many many Excel spreadsheet Cells were sacrificed in figuring out the cost benefit of this arrangemebt.

This latest generation IMOCA 60 has the, now common, deck spreaders and wing section mast. The spreaders are there to get a wide shroud base, to minimize the compression on the spar so it can be a bit lighter. Many, many Excel spreadsheet Cells were sacrificed in figuring out the cost benefit of this arrangement.

The benefits of reducing drag are even more visible on big trimarans. This picture is courtesy of Spindrift Racing.

Spindrift stb tack