Hi!

I meassured the maximum possible spreader rake within the second hole of just being 25 mm. I would like to achieve much more 45 to 65 mm. Is it possible to drill open the rivels and place the spreader arms more behind? has anyone ever done this before? I just try to avoid having to buy the proctor spreaders...

Thanks for any help!

Regards

Dirk

Which type of spreaders are they? and what is the mast section that they are on and what type of cat is it? A little more information is needed I think?

sorry, you are right!

i talk about the white gfk spreaders on a aproximately 6-8 years old taipan 4.9 superwing section...

each of the spreader is hold by four rivets, two on each side. the spreader is formed that both fronts touch each other in front of the mast.

Just curious--why do you want as much as 65mm rake? Are you trying to achieve lots of prebend with little diamond tension?

following the guidelines given by [color:"green"] Glenn (Ashby) :

Mast set up:

0 to 10kts 40mm rake, 15 to 25 mm pre bend

10 to 15kts 50mm rake, 25 to 35mm pre bend

15 to 20kts 60 to 70mm rake and 35 to 40mm pre bend.
[/color]


I think 25 mm are far of the pace. Furthermore,

[color:"black"] [/color] I sail singlehanded with a sloopsail, so the sail is much to full in profile, and saying this, after sailing the boat twice, I am totally unhappy with the current shape and behaviour of the sail.

I strongly believe, setting much spreader rake as a default and changing the diamond tension even out of the trapeze which became quite used by several sailors in the A-cat again is a good thing, specially if you sail with a much to bulbous sail on a mast which is to stiff...

you all use the adjustable proctor spreaders?

I assume that you have tried pulling the "[censored]" out of the luff tension?
If your cat has been sailed as a sloop you may find it necessary to have some of the luff round cut out of the main to be able to sail it efficiently as cat rigged, so that you tune the sail to the mast which is always a better result than tuning the mast to the sail (within reason) To "prebend" a mast to flatten a main is OK within reason, when it requires that "major" prebend is necessary the better option is to reduce the luff round in the sail cut.

I have about 35mm prebend and diamond tension is about 33 on loos. I've fiddled with Ashby's settings and currently use an Ashby main for uni rig. I have proctors but I haven't adjusted them from the stock settings of 50-55mm of rake. So you're right, 25mm is not much. But 65mm seems excessive. In fact, I was actually thinking about decreasing the rake and prebend a bit but tightening the diamonds slightly to compesate for less rake.

I'm no lightweight, but I've found the superwing to be the bendiest alum mast I've used and more flexible than the Stealth F16 carbon mast. When a gust hits, I can lean further in the trap and get the top to spill air. Also, I can bend the heck out of it in the other axis with the downhaul alone. (My only complaint about the Taipan mast set up is that the diamonds cannot be adjusted on the water or even between races.)

If you rake the spreaders more, you'll have to decrease the diamond tension to prevent overdoing the prebend, and then the guts of the sail will only get more full in the gusts.

Can't you get enough on-the-water adjustment with the downhaul alone? It sounds like you want more adjustability--are you going to change the way the diamond wires are rigged? If so, let us know how you do it because that would be a great modification to the standard Taipan rig.

Sounds like the root of your problem, though, is the sail itself. Although I don't think my Ashby F16 main is faster per se than my Goodall standard 4.9 main, it behaves much better; i.e. it twists off to gust nicely, making it alot easier to keep sheet tension even without getting overpowered. I can take it from full to flat as a board with luff tension alone, without having to fiddle with the diamonds (full to flat take 4.5 Ronstan numbers). Also, Glen puts these little mini battens at the top of the sail, which give the sail a very streamline profile and never any fluttering. Photo attached--note that this was Glenn's first F16 sail and the fat top is only slightly bigger than a standard 4.9 sail.

I have about 35mm prebend and diamond tension is about 33 on loos. I've fiddled with Ashby's settings and currently use an Ashby main for uni rig. I have proctors but I haven't adjusted them from the stock settings of 50-55mm of rake. So you're right, 25mm is not much. But 65mm seems excessive. In fact, I was actually thinking about decreasing the rake and prebend a bit but tightening the diamonds slightly to compesate for less rake.

I'm no lightweight, but I've found the superwing to be the bendiest alum mast I've used and more flexible than the Stealth F16 carbon mast. When a gust hits, I can lean further in the trap and get the top to spill air. Also, I can bend the heck out of it in the other axis with the downhaul alone. (My only complaint about the Taipan mast set up is that the diamonds cannot be adjusted on the water or even between races.)

If you rake the spreaders more, you'll have to decrease the diamond tension to prevent overdoing the prebend, and then the guts of the sail will only get more full in the gusts.

Can't you get enough on-the-water adjustment with the downhaul alone? It sounds like you want more adjustability--are you going to change the way the diamond wires are rigged? If so, let us know how you do it because that would be a great modification to the standard Taipan rig.

Sounds like the root of your problem, though, is the sail itself. Although I don't think my Ashby F16 main is faster per se than my Goodall standard 4.9 main, it behaves much better; i.e. it twists off to gust nicely, making it alot easier to keep sheet tension even without getting overpowered. Also, Ashby puts these little mini battens at the top of the sail, which give the sail a very streamline profile and never any fluttering. Photo attached of the Ashby main--note that this was his first F16 sail and the fat top is only slightly bigger than a standard 4.9 sail.

Here's an action photo of the sail--a bit blurry but you can see the mast bend and leech opening even though I'm sheeted pretty hard (I think it was about 13-14knts, I'm 84 kg).

I got proctor spreader arms (fully adjustable) and have 50 mm spreader rake and 20 mm prebend. I've set it up for doublehanded sailing so I may be sailing with to little prebend for singlehanding however I seem to get it close enough to where I want it by using the downhaul and mainsheet together. I can go from full mainsail to totally flat by setting the right tensions on both the downhaul and mainsheet. In this respect I have no issues with the mast being either "too stiff" or "too flexible". Of course the right mast rotation setting plays a role in this as well.

With regard to adjustable diamond wires tension. This is allowed under the F16 rules, you may build yourself a system that allows you to finetune the diamond wire tension WHILE sailing. When we first drafted the class rules I felt that such an allowance would be a welcome one later on. That was 5 years ago.

Personally I feel no need for it as I'm finding that I win far more by getting my head out of the boat and concentrate on sailing. I'm not adjusting the outhaul and stuff during racing anymore. It is just too much work and you gain alot more by just nailing that mark rounding, hook on quickly and get on your way on the new heading as soon as possible. even if the such secondary settings are slight off the optimal. After a few months experimenting I've found a decent prebend and diamond tension setting and I'm running with that now. Dirk, maybe you should do the same, invest soem time in finding a good average setting and then run with that.

Wouter

Eric,

In the following post you can see a solution that will meet your wishes partly.

Turnbuckles in the diamond wires

The turnbuckles can be tightend and slackened with the boat upright and the sail hoisted. The modification is actually a really simple one. Just have your diamond shorten and a threaded terminal pressed to the ends. Place a turnbuckle between the new threaded ends and a "clawed end" that you lead through the small hole in the mast base plate.

Actually AHPC is using this setup now on their Capricorn F18's ! Another thing that jumped from my Formula 16 setup to a Taipan product. The first was of course the 3-staged internal cascading downhaul system (over the old 2 staged system)

The setup really works.

You can also make the proctor arms adjustable with the mainsail up. You can by special turnbuckles with proctor to replace the current ones. These new ones can be adjusted without having to take out the pins.


Wouter

thanks for all the feedback,

unfortunately we drift slightly away from the main question.

actually i did not so much wanted to discuss how usefull is spreader rake (i let Greg Godall talk for me:
[color:"green"]
Spreader rake

Spreader rake is the method of tuning the fore aft stiffness of the mast below the hounds. The ideal amount of spreader rake is dependent on the fore-aft stiffness of the mast and to a lesser extent, the amount of luff curve cut into the sail. Stiff masts require more rake to make the mast bend sufficiently, soft masts require less rake.

Crew weight effects the required amount of spreader rake as it has a significant effect on the amount power developed by the rig.

The spreader rake is measured by placing a straight edge or string-line between the diamond wires at the spreaders and measure the distance to the back of the mast. We are currently using 40 - 65mm of spreader rake.

To answer how much is sufficient rake can only be determined by sailing the boat and knowing what to look for.

If you have excellent height, but lack boat speed up wind and the boat does not want to accelerate in the wind gusts, then you need more rake. This helps the mast bend fore and aft which allows the sail to flatten and the leech to open in the wind gusts. ( See also notes on diamond tension.)

If you are lacking height and "grunt" in light to medium weather, then you have too much spreader rake.

Diamond Tension

This primarily controls the side bends of your mast. Loose diamonds allow the middle of the mast to bend to leeward and the top of the mast to hook to windward. If the diamonds are too loose the mast will bow into the jib slot in the wind gusts. When beating this makes the boat feel bound up and it does not want to accelerate in the wind gusts,. This also tends to cause the boat to heel very easily in wind gusts. Very tight diamonds do the opposite.

Downwind, tight diamonds keep the mast bent reducing camber and power. On our boats the diamond tension is set at 42 on the Loose gauge. )[/color]

but what I asked for if someone knows (or knows someone) who achieved more than 25mm spreader rake with the old glassfibre spreaders?

recutting the sails is not an option! furthermore I strongly believe in much spreader rake and to adjust diamond tension regarding wind conditions.

I think the most all aspects describing article for the relation of spreader rake, diamond tension and mast rotation angle comes from Andrew Landenberger:

[color:"green"]
Landenberger One Design


Tuning Tips - Mast setup


Over the past few seasons it has become quite clear that many people who have been experiencing speed or

power problems have had little basic knowledge of what they can do with the mast settings. It is clear what do

with the cunningham, simply pull on it to get the pressure out of the sail as you need, but often the mast is left

unattended to, as a last priority. In fact it is one of the most important speed controls on the boat. It is important

to understand how to use it, and what you want to have in the sail shape for different conditions. It is not so easy

to just come up with numbers and angles that will suit every mast and sail so I will try to make some key points

to help understand this correctly.



1.The more pre bend set in the mast the more effect mast rotation has on the sail shape.



2.The effect of the spreaders means that the more the mast is rotated backwards, the more the lower mast

section can bend forward (in the direction of the boat) and the stiffer the top section becomes. Leaving the

cunningham tension out of the discussion at the moment, the result would be that the sail becomes flatter in the

bottom and fuller in the top.



3.Rotating the mast more forward allows the spreader to start to work and the lower

mast section becomes stiffer

in the forward direction and the top becomes softer backwards. The result is the sail will become deeper in the

bottom and flatter in the top.



4.Cunningham pressure flattens the sail and will tend to flatten the top more than the bottom since the top of the

mast is unsupported and more free to bend.


Understanding the sail shape that works best in the differing conditions is then very important. For example in

Flat water you would like to have a very even profile through the sail from top to bottom with good power in the

top and the possibility to pull the mainsheet quite hard without stalling the back of the sail. On flat water you can

sheet hard and point higher. By wave conditions you would want good power down low in the sail and have the

top more open and twisted. This gives you power and the twisted top allows the boat to accelerate easily letting

you steer around more and power the boat through the waves easier. Generally you can’t point as high as the

boat on flat water but because of the waves you can achieve a much better VMG (velocity made good).


The typical example is that with increasing wind the sailor will pull the Cunningham hard but not adjust the mast

rotation to go with it. The effect of the Cunningham is flattening the sail, but more in the top. This allows the leech

to open. The boat may feel ok but often the leech is to open and you can’t point high enough. This setup can be

good in big waves but on flat water the sailor would like to have the leech standing much straighter so they

should rotate the mast further back. If you go back to our original points you can see that the mast becomes

stiffer in the top and can bend more in the bottom. This is therefore powering up the top and flattening the

bottom of the sail. With the Cunningham pressure you can sheet on hard and point high with good speed.


The other typical mistake which occurs, is that the sailor by strong wind, simply pulls the mast back in line with

the boom and pulls full Cunningham pressure. Because the mast rotation is too far back the sail becomes

too full in the top and too open in the bottom. The sail will have a lot of twist which some sailors think is good for

strong wind, but because of the top of the mast reaching its maximum stiffness in the aft direction of the boat the

sail will remain too full in the top. The end result is a sail which is twisted to far and with too much profile for the

strong wind. The twist causes you to loose pointing ability and the depth is causing excessive drag, just slowing

you down. You are in effect going slower and lower than the correctly trimmed boats.


Spreader rake is also another significant factor in setting up you rig. It also plays a part in how much the rotation

angle affects the depth of the sail. That can be a whole subject of its own, so for now I make just a few

comments. Try to think of pre-bend as controlling the position the mast takes its bend. The more pre-bend you

make in the mast the lower the mast likes to bend. The lower the mast tries to bend the straighter the top

section becomes. The flatter the pre-bend the more the top section tries to bend. The normal reaction of sailors

is to increase the pre-bend for strong wind to flatten the sail and reduce it in light wind to increase power.

Principally that is correct, but it must be incorporated with the rotation to get the right balance in the sail. Like

most things, too much or too little can be harmful. It is a great failure made by many sailors to flatten the

spreader angle to far reducing the pre-bend in the mast to almost straight. For light wind this is doing more

harm than good. The heavier sailors also often request more luff curve because they are looking for power.

With more luff curve and flatter spreaders light wind speed can quickly come to an end. The sail will become

very full down low with a deep entry angle from the mast and a very closed leech section. When you get the first

wind in the sail you may get a feeling of power, but you may also experience the boat just wanting to fly a hull

but not wanting to go easily forward. The boat will not point and will not accelerate.


In many cases it is actually better to go the other way. By very light wind you can increase the pre-bend to open

the lower part of the sail and reduce the entry angle of the sail behind the mast. With the rotation angle set

correctly to get the head standing up just the right amount you can be very fast. Just remember flat is fast and

deep is slow. It has a lot more to do with entry and exit angles of the sail to achieve height and power.


Amongst sail makers there are many different ideas, and history has proven that there are many ways to build

fast sails. The most important thing is that the sailor can understand how the sail should work and manage it

well. Also restrictions on materials and designs in the boats themselves change the way the sail has to work to

achieve the best results. We design our A class sails to allow the mast to be rotated well back. The reason

being, that the mast itself creates a lot of profile over the rig and therefore it is very important to be able to

reduce the wind age over the mast by rotating back as the wind increases. At the same time the sail must

flatten rather than get fuller. That is the secret to success.




Good sailing.


Landy

Dirk,

To answer your original question, you can not sucessfully adjust the spreader arms that you have. I too have a set of these arms & they only fit in one position ( I guess if you re-fair the end fitting, you could reposition the spreader & hence the rake). The only adjustment from there is the position of the wire at the tip of the arm ( up to 20mm max).

The only way to achieve more adjustment is with a proctor style arms.

Marcus

Interesting that we tried to steer away from the Proctor arms on Agent Orange and the Rhino Grey Taipan as well for a few reasons 1. expense 2. simplicity 3. style. Attached are the photos of the epoxy arms we made to fit the Goodall Wing.

In our local fleet most sailors aren't too concerned with varying the rake on the arms. We opted for simplicity in that the 'ezi-tune' system is just 3 slots cut into the outer end of the arm which allow the rake to be varied.

Could this have a relation with the expected light weight asian sailors ? :-)
Is it the heavier sailor, the more rake you need ? Or the other way round ?

What is the spreader rake you have designed into these Carbon/Epoxy arms ?

Personally I believe that such a set-up can work well as long as the basic amount of spreader rake is sufficient and when at least you have some 30 mm adjustment range, preferably with 5 holes. (or more as long as it is an odd number)

Once you've found a good setting with the proctor arms you don't adjust them much anyway. So it all comes down to wether the designed of the boat has spend significant time to find the optimal setting for the sails that are sold with the boat. Sadly this is something that often gets cut in the race to get the product on the market quickly.

I'm still very happy with the Proctor arms and they weren't too expensive.

How much would these Epoxy arms go for ? Is there much saving in money ?

Having watched the rake of the spreaders change over the last few years, we took the decision to make mast setup an easier proposition for all. We benefited by having Daniel Van Kirkhof race here a while ago and from his mast setup spec's we designed the spreader arms around what was working for us here.

The right combination even for a heavy weight sailor is substantial and I believ the new sails are all cut to account for the correct mast setup. Although we are in Asia, 70% of our sailors are Europeans working in the region. As such we have a variety of weights on the Taipan platforms here.

Generally we have run 60mm (+ - of spreader rake) and use about 42 on the Loos Gauge on the diamonds. We did discover a year ago that the correct anoumt of twist in the mainsail is the single biggest boost to boat speed - apart from just good sailing! Get the twist happening right and the boat is a rocket that will sail higher and faster...

We have close to 30mm of basic adjustment (roughly 30 - 60mm of rake) in 3 slots our composite spreaders. Adjustment is just a matter of popping the wire out and moving it to another slot. This saves heaps of time on the initial mast tuning process.

The arms are made of Epoxy with Uni-directional fibres. We are currently working on a 'mark 2' set that will see the trailing edge moved further aft to account for the extreme loads on the arm with such an' amount of rake.

At the moment the spreaders cost us Singapore Dollars $180/(approx. AUD 150 or thereabouts) pair which compares favourably with the AUD 280 for the imported Proctors. So every little bit in reducing the cost helps local sailors get into the sport - a good thing.

sjon,

read the landenberger tuning guides i posted here. should answer all hidden secrets.

just to answer your questions:

as lighter you are, so more spreader rake you need.

so lighter you are, so more diamond tension you need.

still i know really have guys who sailed quite a lot of spreader rake with very loose diamonds. i think that is a general development taking place.

more spreader rake can help you a lot to enable the top to twist much more controlled with nowadays sails. just pulling cunningham to the max without paying attention to a reasonable spreader rake is simply not comparable in what comes out of it, specially in terms of the desired autodepowering twist.

hi SkunkWORX ,

that are great news! how are those spreaders fixed to the mast?

can they be shiped to china? where can I order them?

I owned 3 marstroem carbon spars in the A-cat the last 6 years and I believe your spreaders are quite simular to theirs, although the marstroem ones are only fixed by one screw in the middle of the mast where you can (within a certain range) can move the arms back or fore on the mastprofile. I furthermore (to lazy sometimes to change the mast to suit a different sail) also added a second rail for the diamond at the end. that allowed perfectly (like you described) changing settings easily by just pulling on the wires with your foot pushing against the mastprofile even with the diamons under tension (which anyhow was much nicer solved and more easily adjustable than on the saarber/ahpc/fibrefoam spars). i strongly believe two different settings are o.k. and three are realy enough. for example 30/45/60 would cover most of nowadays needs?

regards

dirk

Skunkworks.
Nice set of spreaders.
I hope you have a means of holding the wire in the slot on the sreaders.
If not make sure you tape it well with electrical tape to hold it in. A number of masts have broken when the wire pops out of the AHPS composite spreaders. It usualy happens on down wind legs. In very strong conditions the lee wire goes really slack and falls out. You don't find out until you jibe and then it is too late.
Thankfully it hasn't happenned to me. I tape mine in. I was lucky enough to learn from the mistakes of others.
Regards,
Phill