Weather helm on half tonner

[nemo]

Hello, I have a Farr 31 half tonner, and it suffers heavy weather helm, of course increasing with the wind speed. The rig is fractional 7/8 (even less), and I surprisingly found that the mast have been shifted forward by the previous owner, so one would expect that the boat should have lost the weather helm.
At first, I thought that the reduction of the forward triangle, following the shift of the mast, lead to the movement of the centre of effort aft, but after some calculations I found out that this was unlikely.
I am now concentrated on the rudder: like other IOR boats, it has a big bustle in front of it, and I am thinking of removing it, as the boat is now out of the water, and maybe re-designing and balancing it.
Any consideration/advice?

[Gary Baigent]

Your bustle will be helping to keep the centre of lateral resistance aft, which is what you want - removing bustle, you'll have to increase the rudder size to compensate (or put in a balancing daggerboard in the cockpit to take some of the weather helm load off the rudder). Maybe having the mast weight further forward where there is less buoyancy, the boat is heeling more and digging in the bow ... which will make the boat hard helmed. Are you carrying extra weight forward below deck? That won't help your helm balance either. This is iust guessing on my part, could be completely wrong.

[PAR]

There are a number of things that could be called "weather helm". What is the actual angle of incidence of the rudder, close hauled in 10 knots? What is the condition of the sails? What is the current mast rake and how far forward has the mast been moved? Have you talked with other Farr 31 owners?

[waikikin]

Hi Nemo, before I started changing the boat I'd try some diferent trimming techniques paticularily in regards to the main, the boat I used to sail on in the eighties- a Swarbrick the main trimmer would realy drive the boat in harmony with the helmsman, pretty much playing the traveller to the helm b est from Jef. All the

[daiquiri]

My two cents worth:
In a main-jib (or genoa) combination, the jib carries the biggest part of the aerodynamic load. By moving the mast forward (and therefore decreasing the jib area) the contribution of the jib to the total load decreases, while the main's increases... This could move the total aerodynamic center of the rig aft, contrary to the first-thought logic and contrary to the initial intention behind the modification.
In addition, by having the main sail working more (and has the main's area been increased too, to compensate the decrease of jib's?), the aerodynamic center travels up, increasing the heel lever. The heel is the fundamental origin of the weather helm. More heel, more weather helm.
It is a general consideration, don't take it for granted. Too many things could play a role there, maybe you have some other issues which still need to be reckoned.
As Waikikin correctly pointed out - before spending tons of bucks on modifying the rig, you should play a lot with trims and try to resolve it in that way. Your goals should be: lower the aerodynamic center of the mainsail and increase the load of the jib/genoa (or decrease the load of the main).

[Garry Hartshorn]

In the old IOR boat's it was typical when going to windward that the main was feathered for the most part. As mentioned in an earlier post it is how the class was sailed. This is due to the IOR measurement formula, and in my belief one of the many reasons why in the end the system was left behind.

[Omeron]

Moving the mast from its original position is not something you can do easily and quickly, as it would require several other modifications. If the previous owner went into that much trouble, it is also likely that, the mast itself may have been lengthened to compansate loss of fore triangle area. This would definately increase the mainsail area and destroy the balance. It is worth checking.

[gonzo]

How much rail meat do you carry? Those boats were designed with a fairly large crew in mind. They always get weather helm when they heel. It was one of the reasons the formula died. They also tend to nose dive and pitchpole in heavy weather because of the pinched ends.

[nemo]

Thank you for your replies!
First of all, the rudder angle in close haul at 10 knots is about 5 degrees. The crew onboard can vary from 4 to 7 people.
The mast has been moved forward by 0,2 metres. I have the original sail plan, so I will make some calculations comparing the actual centre of effort with the one marked on the plan, but I have the feeling that the overall centre of effort hasn't changed much. What is difficult to calculate is the effective power reduction of the foresail, due to the different shape.
Unfortunately, I don't know any other owner of the Farr 31..

[gonzo]

5 degrees is good. That means the rudder is providing lift

[Charly Setter]

Hello Nemo

Is it really Weather Helm (strong forces) or is the boat simply loosing stearing due to the fact that the rudder is lifted out of the water with increasing heel.

I experience similar problems with my own 1/2ton. Not a Farr design, but "homebrewed"(red cedar strip planked, 1,9t overall weight, 1t lead keel). Due to formula changes resulting from Fastnet 79 during build time we had to cut sail area as a result of penalties for light displacement designs

We increased boom length by roughly 30% on our boat 15 years ago (increasing mainsail from 21m² to the original planned 28m²) and were surprised to find no change in boat handling / weather helm, but only huge increase in downwind and reaching performance.

Based on this experience I doubt that moving the rig has any significant influence on boat handling. The changes made on the boat by the previous owner are more and less fruitless efforts to reduce the "weather helm problem".

Our measures to handle the problem are as follows:
- We increased the rudder length (high aspect rudder, only 10cm shorter than the keel, 1,6m length, 0,35m cord length). Optimum solution would be a twin rudder design ;-)
- place crew weight as far aft as possible on the rail (sometimes a bit difficult, when sailing double handed on a boat planned for crew weight nearly 50% of boat weight... ;-) )
- reduce heel as far as possible by mainsail trim (traveller)
- if ruder forces are too strong, balance the rudder, but don´t over balance....
- tight reaching: Move the sheeting point of the jib forward/out and depower the main ( tight vang / loose main sheet

[Paul B]

Thank you for your replies!
First of all, the rudder angle in close haul at 10 knots is about 5 degrees.

When you are sailing upwind you should have 3 to 5 degrees of helm. Your situations is not excessive.

Have you had your sailmaker out to have a look at your sails and setup?


The mast has been moved forward by 0,2 metres. I have the original sail plan, so I will make some calculations comparing the actual centre of effort with the one marked on the plan, but I have the feeling that the overall centre of effort hasn't changed much. What is difficult to calculate is the effective power reduction of the foresail, due to the different shape.
Unfortunately, I don't know any other owner of the Farr 31..

What Design Number is your boat? I have sailed on an early production Farr Half Tonner. I sailed on it with the stock rig and after the rig height was increased by about 10%. It sailed fine both ways.

I have sailed on many old IOR boats where the rigs have been changed a bit, adding up to 20% to the boom length in some instances. All the boats were easy to balance after the mods. Moving the mast on a Farr HT forward by 200mm would not be a significant change, and would definitely not increase weather helm.

[Paul B]

In the old IOR boat's it was typical when going to windward that the main was feathered for the most part. As mentioned in an earlier post it is how the class was sailed. This is due to the IOR measurement formula, and in my belief one of the many reasons why in the end the system was left behind.

Why would you post nonsense like this? It does no one any good to have things that are not true posted on the internet. If you don't know what you are talking about you should not say anything.

[Garry Hartshorn]

That all depends one ones experiance. In my experiance most IOR boats carried bucket loads of weatherhelm when sailed to windward with the main sheeted in and driving. The mainsheet trimmer would be working in tandem with the helmsman and be continously feathering. It was also common practice on deliveries and when cruising to reef the main even in very light conditions to balance the boat. That was my experiance and observation and thats a FACT. In the latter years of IOR many boats were designed to take advantage of the rule not primarily designed to be seakindly and fast boats, that is my opinion. There are many that have the same opinion and many that don't, it's not nonsense.

[Paul B]

That all depends one ones experiance.

Then please, tell us of all your experience with top level IOR racing.



In my experiance most IOR boats carried bucket loads of weatherhelm when sailed to windward with the main sheeted in and driving.

What designs were these? Who set up the boats, who was sailing them, and in what regattas?



It was also common practice on deliveries and when cruising to reef the main even in very light conditions to balance the boat. That was my experiance and observation and thats a FACT.

Because you don't know how to sail does not make something FACT. I have raced on IOR boats of every era at the top level and I have never seen one that needed to be reefed in light air to make it balance.



In the latter years of IOR many boats were designed to take advantage of the rule not primarily and designed to be seakindly and fast boats, that is my opinion.

Uh, no. As the years went on IOR designers pushed the limits of the rule MORE, not less. Please list these successful IOR designs that were designed to be seakindly and not push the limits of the rule.

Your opinion is worth nothing. It is clear you don't know what you are talking about. I guess it makes you feel special to post nonsense "in your opinion".

[Charly Setter]

The mainsheet trimmer would be working in tandem with the helmsman and be continously feathering. It was also common practice on deliveries and when cruising to reef the main even in very light conditions to balance the boat.

I think this is also common practice on modern boats. Especially taking the huge sail areas into account

This has nothing to do with IOR....

You are right, there are a lot of unfavorable effects of IOR on boat design, but in the end this happens to every formula driven development.

Or do You think IRC and ORC have no influence on boat design ?

[Crag Cay.]

The 'IOR era' spanned quite a long period of time and covered many varied sailing waters. It also incorporated the work of many designers who in turn responded to three major versions of the rule. The generalisations about the IOR are as tiresome as they are often misinformed.

However, that won't stop me making another one! I've sailed tens of thousands of miles on many IOR boats and two in particular; an S&S 1/2 tonner from the early seventies and a Ron Holland 2 tonner from the late 70s that made a national team for the '79 Admirals Cup. Now, although they were as different as chalk and cheese, they, and all the others I sailed, were a joy to steer to windward.

[Garry Hartshorn]

I think this is also common practice on modern boats. Especially taking the huge sail areas into account

This has nothing to do with IOR....

You are right, there are a lot of unfavorable effects of IOR on boat design, but in the end this happens to every formula driven development.

Or do You think IRC and ORC have no influence on boat design ?

Yes it is common practice on many modern boats, though I tend to think they are not as unforgiving as the later IOR boats. And yes every rating formular will tend to drive designers to come up with extreme developements, some good and some bad. It is the nature of the game.

Paul

With all due respect, I have well over 250 000 miles at sea under sail in many kinds of boats, cruising, racing and deliveries. I make quite a nice living out of sailing so go shove it where the sun don't shine.

[Paul B]

Paul

With all due respect, I have well over 250 000 miles at sea under sail in many kinds of boats, cruising, racing and deliveries. I make quite a nice living out of sailing so go shove it where the sun don't shine.

So you have proven that sea miles under power does not correlate to sail trim ability.

Of course this is something we already know.

[gonzo]

Paul B: you have an opinion like all of us. However, it doesn't give you the right to be rude and obnoxious. That attitude is what really causes a disservice to the forum. If you have facts and can refute someone else, go ahead and post them. Calling people names only shows lack of respect and not knowledge.

[Paul B]

Calling people names only shows lack of respect and not knowledge.

I did not call anyone "names".

Of course you are one of the people who likes to regurgitate "facts" on these forums, and have also become irritated when your nonsense was pointed out.

If you don't like what I write don't read it.

[Garry Hartshorn]

Paul

Under sail means under sail not under power and yes I have many miles under power as well. But then unlike you I am not a sailing GOD and I never would never suggest that anyones opinion or experiance was invalid and not worthy of listening to.

Now before I start make judgements and misinformed statements about you and your abilities I would suggest that we both be polite and respectful of each other and everyone else on this forum.

[Paul B]

Now before I start make judgements and misinformed statements about you and your abilities I would suggest that we both be polite and respectful of each other and everyone else on this forum.


By "be polite" you mean don't say anything when you post something utterly ridiculous.

Guys like you post something fundamentally incorrect, then expect the world to accept it as another potentially correct point of view. That's like me going on an auto racing forum and posting that, in my experience, it is faster to go around the track in reverse. That would be invalid and not worth listening to.

Utter gibberish, like saying one needs to reef an IOR boat's main in light air to make it balance, shows a lack of understanding of how things actually work. If you had any real-life experience you would know that on most boats, including pretty much every IOR boat I've ever seen, you would add rake in light air. That has a similar effect as INCREASING mainsail area, not decreasing (as in reefing).

I don't post on a vast majority of the forums on this site, because I have no knowledge of powerboats and their systems, etc. What good would it do for me to log in and repeat some incorrect info that I read on some other board, or post something I simply made up. It would do no good for anyone reading the thread. I have enough respect for the people reading the threads that I don't do things like that.

[Garry Hartshorn]

By polite I mean don't make it a personal attack or infer that anyone who has different ideas to you are idiots, lyers and generally inept morons. By all means you may disagree and put forward an opinion that is exactly the opposite and the other members of the forum can make up their own mind.

[PAR]

Paul you seem to value you opinion considerably more then any one else's. This isn't the first time you've become confrontational and insulting in your posts, with adversarial moments and dialog in many of the threads you participate on. You're not the only experienced poster and your view isn't the only one, nor any more valid then others. Most of what you have said has already been said or acknowledged to some degree without the derogatory retorts. Consider similar and play nice or go and tinker with the Sailing Anarchy kids, who seem to thrive on your personality type.

[Gary Baigent]

Not trying to be antagonistic, Paul, me fellow historical nutter, but *********, when she won at Poole? impressed Jack Knights because the big kiwi dinghy was actually sailed like that, meaning the main was eased on the traveller with mainsail actually pumping at times, headsail flat of course. Laurie or Tony Bouzaid remarked that the boat was faster sailed like that way, staying upright was very important - and Laurie added if the wind had been stronger, ********* would have blitzed the fleet by even a greater margin.

[Gary Baigent]

What, that is very weird!! The ********* bogey hits again, that is meant to be Wave-rider - but her name was bever spelt with a hyphen.

[Paul B]

Paul you seem to value you opinion considerably more then any one else's.

Imagine hearing from you, another guy whose BS I've pointed out on this forum.

Yes, I do value my opinion in areas where I have expertise. Guys like you and GH spout nonsense, then your pride gets all wound up when it is shown that you are poseurs. Hell, your ego seems to still be smarting from when I called your BS, what a year ago?

[Paul B]

Not trying to be antagonistic, Paul, me fellow historical nutter, but *********, when she won at Poole? impressed Jack Knights because the big kiwi dinghy was actually sailed like that, meaning the main was eased on the traveller with mainsail actually pumping at times, headsail flat of course. Laurie or Tony Bouzaid remarked that the boat was faster sailed like that way, staying upright was very important - and Laurie added if the wind had been stronger, ********* would have blitzed the fleet by even a greater margin.

Sheet on and trav down is a good way to depower and keep it flat. No doubt about it. Works in everything from your Davo HT to J24s to masthead two tonners, etc.

But when you're not overpowered the trav comes up. You won't hold a lane without the boom up as high to CL as you can hold it with the correct amount of heel on. At Poole they weren't doing it because of weather helm (the original point of contention here). I'll bet they weren't reefing in light air either.

Boats with more stability than the Davo would be able to keep the boom on CL longer, and make gains upwind. You don't get something for nothing in Physics or sail trim.

[PAR]

Paul you clearly you don't see how your words are being interpreted by others here. This blatant arrogance and disdain has obliterated this thread into your personal assault blog and proven a disservice to the original poster. There are avenues where you can pursue this course of action, but this isn't one of them. Again please find a more suitable manner to express yourself or leave. Unless I'm completely miss reading the tone of your posts, I suspect the majority on this thread feel the same, if not now turned off and ignoring the thread completely as a result of your lack of elegance.

[daiquiri]

You won't hold a lane without the boom up as high to CL as you can hold it with the correct amount of heel on. At Poole they weren't doing it because of weather helm (the original point of contention here). I'll bet they weren't reefing in light air either.

Hello,
Don't want to enter the dispute between you guys, but Paul, what you just said sounds to me like a confirmation of G.H.'s and G.B.'s words about easing the main (up until pinching, but not up to luffing - that's useless drag) as a mean of preventing the weather helm. Or was it something else that you are disputing here? Sounds more to me like there is a missing episode in this movie....

[booster]

Regarding Wave-rider. At the World's in Australia (won by the Farr design Gunboat Rangiriri) the year before Poole Wave-rider had balance problems. Still it ended about 4th. Does Gary B. know what was modified to Wave-rider? So far the posts have been focused on the main. A common probelm is that one moves the traveller of the genoa backwards (or depower the barber-hauler). If one instead move it slightly forward and depower the sheet a little the lower part of the genoa gets fuller and the aerodynamic center moves forward and down. As a result the boat gets less weatherhelm ("lovgirig" in Swedish) and less heel. Note that the adjusments are small. By the way, in Swedish we have a word for the opposite to wheterhelm: "fallgirig". An translation could be: "nonwetherhelmgreedy".
Regards,
Booster

[Charly Setter]

("lovgirig" in Swedish)... "fallgirig". .

In German it´s "luvgierig" and "leegierig" :)

[Paul B]

This blatant arrogance and disdain has obliterated this thread into your personal assault blog and proven a disservice to the original poster.

Look who is talking. You posted NOTHING on this thread about the topic. You simply came here to try and start a fight. I guess you're still bitter that your nonsense in the past was pointed out for what it was.

[Paul B]

In German it´s "luvgierig" and "leegierig" :)

In English, Lee helm.

[nemo]

Hello Nemo
...
Our measures to handle the problem are as follows:
- We increased the rudder length (high aspect rudder, only 10cm shorter than the keel, 1,6m length, 0,35m cord length). Optimum solution would be a twin rudder design ;-)
- place crew weight as far aft as possible on the rail (sometimes a bit difficult, when sailing double handed on a boat planned for crew weight nearly 50% of boat weight... ;-) )
- reduce heel as far as possible by mainsail trim (traveller)
- if ruder forces are too strong, balance the rudder, but don´t over balance....
- tight reaching: Move the sheeting point of the jib forward/out and depower the main ( tight vang / loose main sheet

Modifying the rudder sounds a good idea, although I have a large bustle fwd of the rudder, so I cannot balance the rudder without removing the bustle. But definitely I can increase the length. Did you keep the original maximum cord length or did you decrease that?

[nemo]

When you are sailing upwind you should have 3 to 5 degrees of helm. Your situations is not excessive.

Have you had your sailmaker out to have a look at your sails and setup?




What Design Number is your boat? I have sailed on an early production Farr Half Tonner. I sailed on it with the stock rig and after the rig height was increased by about 10%. It sailed fine both ways.

I have sailed on many old IOR boats where the rigs have been changed a bit, adding up to 20% to the boom length in some instances. All the boats were easy to balance after the mods. Moving the mast on a Farr HT forward by 200mm would not be a significant change, and would definitely not increase weather helm.

The design number of the boat is #65, same as Rangiriri mentioned above.
I made some calculations on the original and actual theoretical centres of effort, and I agree that the mast movement didn't do a significant change, even though the foresail was slightly bigger in the original version.

[Paul B]

Hello,
what you just said sounds to me like a confirmation of G.H.'s and G.B.'s words

Nope, not even close.

The claim by GH was IOR boats had "buckets" of weather helm due to some design requirement in the rule, to the point that the boats needed to be reefed even in light air to make them balance, and that led to the demise of the rule. This is total nonsense.

IOR boats had no more "buckets" of weather helm than any other tye of boat. All the competitive ones I sailed on and against were set up to sail with 3 to 5 degrees of helm, so the rudder was also providing lift along with the keel.


In fact, most earlier IOR boats and even later masthead ones had less than optimal aspect ratio on the mainsail. So after their IOR days were over many had 10 to 20% of "E" added to the boom length, with no changes to the rig or keel position. Even this did not add the weather helm issues claimed by GH.

Before the practice was outlawed by the rule we would fit hydraulic cylinders to the headstay and backstay, so we could rake the rig for the desired amount of helm. In light air we would rake back, as the breeze came on we would stand the rig up. After the practice was outlawed we would look at the weather report for the day and set the rig to what we thought the prevailing conditions would be. Even if we were caught out with our light air setting and the breeze built we still did not encounter "buckets" of helm as described.

[Paul B]

Modifying the rudder sounds a good idea, although I have a large bustle fwd of the rudder, so I cannot balance the rudder without removing the bustle. But definitely I can increase the length. Did you keep the original maximum cord length or did you decrease that?

Your rudder should have some counterbalance below the skeglet, if it is the original rudder for the boat.

Increasing the span of the rudder would be good, since the rudders back in the old days were a bit stubby due to the available rudder stock materials. If you go with a carbon construction you should be able to have a much nicer rudder.

[Charly Setter]

Your rudder should have some counterbalance below the skeglet, if it is the original rudder for the boat.

Increasing the span of the rudder would be good, since the rudders back in the old days were a bit stubby due to the available rudder stock materials. If you go with a carbon construction you should be able to have a much nicer rudder.

There´s no need of a carbon rudder stock....

Just take a 35mm stainless steel shaft, weld four strips of 30x4mm stainless steel to the shaft (2 on each side) and put a 35mm oak-plank between these strips on the front and the backside of the shaft. Cover the oak plank between the strips with 6 mm wood and give this design a hydrodynamic profile. You will get a rigid rudder design with good hydrodynamic properties and reduced drag, compared to the "light weigth" designs with large hollow shafts and acc. wide rudder profiles. The larger weighht of the shaft doesn´t matter as you need weight aft ;-).

But never take plywood, this will break after some years (app. 5), the oak plank last 20+ years ;-).

No, we didn´t change the chord length, there was no need. The "skeglet" is only a 50x30x300mm triangle shaped wood glued to the underside of the hull. It bears no load from the rudder bearings.

[Paul B]

No, we didn´t change the chord length, there was no need. The "skeglet" is only a 50x30x300mm triangle shaped wood glued to the underside of the hull. It bears no load from the rudder bearings.

Hi Charley,

I wasn't referring to your boat, but to Nemo's Farr.

Using a rectangular carbon shaft would allow a thinner rudder profile than the original, thereby allowing a shorter top chord for the same % thickness. This is a good thing.

The original rudder does have counterbalance (shown in detail below), but possibly could use more.

In the end the original seemed to work pretty well for Gunboat, and 2269, at the '77 Worlds. So maybe no change should be made.

Nemo, do you know why the rig was moved forward? Was it an attempt to get the rating back down to HT after the rule changes of '78?

The attached photos are from the Bruce Farr Catalog of his Designs.

[Gary Baigent]

Booster
26. a class above
IN EARLY 1977 Davidson designed a Half Ton yacht ********* that followed the theme established in Quarter Ton Fun. Farr, seeing his Half Ton Cotton Blossom outclassed by Whiting’s Newspaper Taxi, drew Gunboat Rangiriri – but Whiting and Ross decided to vacate the Half Ton series, sold Newspaper Taxi to Australia (where the new crew sunk it) and concentrated on the larger Smackwater Jack.
Davidson’s approach with ********* was different to Farr and Whiting. Like Fun, all ballast was carried internally in lead bricks bolted to the floor like a chocolate bar but the major difference was his hull design which was narrower with less depth forward than the others. By having less beam Davidson believed his boats had less inclination to get out of balance during fresh sailing conditions and would not lift its stern or bury its bow when overpowered – which he felt was possible with the more asymmetric hull plan forms of Farr and Whiting. ********* looked small and narrow with low freeboard, shorter than Gunboat Rangiriri but had more sail. *********’s low hull made the coach roof appear prominent; it was there to satisfy the Rule’s high headroom requirement but in spite of this, ********* was a beautiful yacht and set an aesthetic standard and appearance that was to be emulated by a number of successful French designers. And like Fun, it was expertly built by John Rea in exceptionally light timber construction: two veneers that totaled 9mm over many stringers and frames. The stern was wide and low to provide power upwind and easy surfing downwind while topsides were slightly flared to get crew weight outboard. The deck was plywood on wooden beams and the rudder was fully retractable, like it was on Fun.
Gunboat Rangiriri was similar to One Ton Red Lion but proportionately was beamier, heavier and carried more sail to be competitive in the light winds of Sydney. Ron Holland’s first daggerboard yacht, a tiger striped Silver Shamrock 111 skippered by Harold Cudmore, was similar to his fixed keelers – which turned out to be a disadvantage. *********, skippered by Tony Bouzaid with Helmer Pedersen alongside, was fastest, especially across and downwind – but in a long distance race the leaders, the Farr Swuzzlebubble and ********* fell into a hole; Gunboat Rangiriri (Peter Walker) won with a consistent 5,1,2,2,2 series.

AFTER SYDNEY and new penalties ********* was prepared for 1978 by Davidson deepening the amidships area and fairing it out fore and aft. Bouzaid and Pedersen set up a new rig and sail combination and honed ********* before shipping to England. In a fleet of 50 yachts, 11 were centerboard designs but only three were considered in contention: ********* and two French designs, Anke from Michel Joubert and Jaunac by Jean Berret. Two British fixed keel boats were also considered but once racing began ********* was the fastest, upwind and down. While beating the main was sheeted down to leeward so the sail pumped. Although contrary to accepted sail trim, ********* was exceptionally fast in this mode, sailing freer than masthead designs but moving faster through the water which created lift for the daggerboard. The wind never rose above 12 knots, a strength some European journalists thought would lay the New Zealand boat on its side but in response Davidson growled, “If there had been a decent blow, ********* would have stamped even more her superiority over the fleet. Really the ORC has over-reacted to the results of the 1977-78 Southern Hemisphere results where centerboard boats cleaned up. But this was not the case at Poole where racing from a variety of designs was very close. There has been no conclusive evidence found that ultra-light will alter the trend of IOR racing – indeed at one stage the fixed keel Jones designed Indulgence looked certain to take the Half Ton Cup.”
In spite of penalties being introduced to further slow the New Zealand lightweights, Davidson was in demand. The French were particularly impressed with ********* and picked up on the design continuing their own development so that later French designs gained a stranglehold on Cup Championships. US dinghy sailor John McClaurin wanted a flat hulled New Zealand daggerboard yacht and asked Davidson for a Three Quarter Ton version. The reply was Pendragon which naturally was a development of *********, again built lightly in wood by Tim Gurr and when it was finished in Auckland, shipped to the States. Pendragon won the Three Quarter Ton Cup held in the light airs of British Columbia, beating special designs from Chance, Holland and others in conditions the light boat was not expected to excel. Again the IOR was angered and unimpressed and the next list of penalties increased Pendragon’s rating by a full two feet - so much for Davidson’s attempt at diplomatic reality after winning the Half Ton Cup.

[Gary Baigent]

Merde! ********* read Wave-rider.

[nemo]

Hi Charley,

I wasn't referring to your boat, but to Nemo's Farr.

Using a rectangular carbon shaft would allow a thinner rudder profile than the original, thereby allowing a shorter top chord for the same % thickness. This is a good thing.

The original rudder does have counterbalance (shown in detail below), but possibly could use more.

In the end the original seemed to work pretty well for Gunboat, and 2269, at the '77 Worlds. So maybe no change should be made.

Nemo, do you know why the rig was moved forward? Was it an attempt to get the rating back down to HT after the rule changes of '78?

The attached photos are from the Bruce Farr Catalog of his Designs.

I'm not sure that my rudder is exactly as shown in the picture. However, the skeglet wraps around the leading edge so maybe it just looks like the counterbalance is below it.. anyway I'll take some pictures in the weekend.
What was the reason behind those skeglets anyway? Were they done in order to "cheat" IOR measurements?
I believe increasing the aspect ratio would be good, even if maybe in light airs the boat would feel the additional drag caused by the increased area.
Charly, have you got any feedback on this?

[Paul Kotzebue]

What was the reason behind those skeglets anyway? Were they done in order to "cheat" IOR measurements?

If memory serves, the idea was to have the AIGS station in the skeg and the AGS station aft of the skeg. The IOR included dimensions to establish whether or not the boat had a skeg. The net result was the boats had just enough skeg to qualify as one under the IOR.

This is all from memory for what it's worth. My copy of the IOR rule is long gone and I haven't worked on an IOR design since 1984.

[Paul B]

The IOR included dimensions to establish whether or not the boat had a skeg. The net result was the boats had just enough skeg to qualify as one under the IOR.

This is all from memory for what it's worth. My copy of the IOR rule is long gone and I haven't worked on an IOR design since 1984.

Ha Ha, my dogeared copy of the rule went into the bin in 1988. Now I wish I had kept it, with all the revised sections neatly glued in over the old text.

Yes, the Rule did make designers jump through hoops, hoops the designers caused the rulemakers to put in because they would push everything to the limit.

The skegs had to be measured in every dimension, a joy for the measurers. Even the radii of the edges of the skeg had to be measured to ensure they were legal skegs.

People who never had to deal with designing or measuring to the IOR Rule have no idea just how technical little details like skegs and P brakets could be. The designer had to get it ALL right, every little detail. So did the builders.

[Paul B]

However, the skeglet wraps around the leading edge so maybe it just looks like the counterbalance is below it.. anyway I'll take some pictures in the weekend.

The dashed line in the detail picture I posted is the CL of the rudder post. All the area in front of that is counterbalance.


I believe increasing the aspect ratio would be good, even if maybe in light airs the boat would feel the additional drag caused by the increased area.

If you are able to make a thinner post and rudder you can shorten the chord length along the entire rudder, so a deeper rudder should not have any more wetted area than the existing one.

[booster]

Gary B!
Thanks for the Wave-rider analysis. So they stepped a new mast. Yes, those holes are irritating, especially on the long offshore race. How to come out of those in decent shape... By the way I have been struggeling with those "merde" ******** as well.
Regards,
Booster

[Charly Setter]

Is this the Wave-rider you are talking about ? http://tinyurl.com/ygveh2n

Second place IRC 1/2ton Championship 2009 in Belgium.:)

[Paul B]

If you are able to make a thinner post and rudder you can shorten the chord length along the entire rudder, so a deeper rudder should not have any more wetted area than the existing one.

This is a crude outline (MS Paint over the existing Farr drawing) of what I was trying to say.

[Paul B]

Is this the Wave-rider you are talking about ? http://tinyurl.com/ygveh2n

Second place IRC 1/2ton Championship 2009 in Belgium.:)

Yes, that is the boat.

Note in the photo the boom is sheeted pretty much on CL, going upwind nicely.

Note the angle of the tiller. Hmmm, looks like pretty neutral helm. No sign of "buckets" of weather helm on this IOR boat.

Doesn't look like they need to "feather" the main.

Doesn't look like they've had to reef in this light air to balance the boat.

[waikikin]

Nice picture, looks like a nice day out in light conditions. All the best from Jeff.

[Perm Stress]

"No sign of "buckets" of weather helm on this IOR boat"

There is just barely any wind.... what weather helm in conditions this light ?!

As to the "loads" weather helm...

Good example is old Carter 30 halftoner, if not superchampion in class, but produced in great numbers in Poland some decades ago. For many dacades it was the only real alternative for ex Olympic sailors of Soviet part of the world. They were raced no less aggressively, as dingy classes their crews were originating from. Masthead rig with large genoas. Full depth skeg forward of her rudder. Stern lines somewhat similar to sailbag stuffed full, and open end then pulled tight with rope. Her tiller is ~80x80mm in cross section for good reason: two hands are not always sufficient to helm her in stronger conditions, no regards to the heading relative to wind! And yes, at least when cruising, they often reef the main deliberately and early. (all these developments made before introduction of full battens, really stiff sailcloth, etc.. I do not talk here about top budget world lewel racing; on our side of Iron Wall many technical advances in sailing were not physically present for long time, except only for state-supported-top-level-Olympic sailors.) At one occasion I even noticed a cruising oriented boat of this type with brand new suit of sails, with main 1-1.5m short on the mast, when fully set.
That is one part: there WERE IOR boats with excessive helm.

Then one more half penny:

In Lithuania there is an RS280 racing monotype -~28ft long keelboat -a Toy used by ex-Olympic sailors to prove once again they arte still string and fast under sail. Why I mention it is because all of them have pretty normal weather helm upwind, except one -which have sails from different supplier this one, with appearently same mast rake and sail trim has definite lee helm...

That is part two: sails could make HUGE difference.

[Brent Swain]

Much of the weather helm common in so many racing boats comes from grossly unblanced hull shapes which tend to go down in the bow , and rise in the stern when well heeled, due to excessively wide sterns and excessively lean bows. A bustle tends to help by moving the centre of gravity further aft. Twin rudders well angled outward may give you more control.

[ancient kayaker]

One would expect excess sail carried too high to press the bow down, too. Not a racer or sailor myself (yet - but I'm working on the sailor part) but when I watch videos of ocean racers they seem to spend an awful lot of time with water hosing over the cockpit from forward. I suppose that is all part of the life of a racing sailor, but it would use up energy to do that.

[barrynelson]

Hello

I sail a 1980 model 3/4 tonner (albin stratus/Norlin36). Phenominal boat all things considered. Over the past 10 years, through many subtle changes she has gone from beast to well-mannered greyhound. Sail design, rudder design & weight distribution worked the magic. After spending the previous 25 years racing E-scows & Star Boats I had experienced the power of tuning.

The first improvement was to remove everything from the bow. I tore out the water tank, got rid of the chain & big anchor, moved the batteries back etc. This made a huge differency in the tendancy to wipe out.

The second, was a new rudder. The old shaft was slightly bent & bound-up in the bearings. The replacement, is a fully devleloped, carefully designed lifting surface with gimballed bearings. The new rudder provides two finger steering in ALL conditions with no back-lash & nice feed back. I rarely move the wheel more than an inch when things are in the groove. Very subtle & precise.

The final big improvement was the new mainsail built by Chris Nielson Of Nielson sailmakers. Very flat, draft forward & dead flat in the leech area. Two top battens, just like the Star. One super stiff & streched tight for heavy air & a soft tapered one for light-medium. The previous main was soft, with draft way back & deep camber ... blown out, just like a worn out Star main.

The difference between two identical Stars: one, with old, soft, blown out main & the other, a new firm, well shaped one is the difference between two completely different boats. One cranky, the other .. close to perfection. I am not aware of any boat which demonstrates the relationships of steering, sail shape & tune-ability like the Star. For those who haven't experienced the magic of Star boats, I sugest you try it. A friend of mine who is a world class Lightning sailor, spent a couple of years playing with an old Star just to learn about sail shaping.

Hope this wasn't too long winded

Barry