Fin Keel? Long Keel? Jeff?

[Hiracer]

Originally Posted by Jeff H

In the period since the book was written, a huge amount has been learned about hull and keel forms, weight and bouyancy distribution, dampening and so on, and much of that research has been incorporated into newer designs that are more seaworthy and offer better motion comfort than the boats than the IOR era. In the case of the better of these new designs, proper hull shape, keel formsm and weight distribution pretty much invalidate the advantages of a full keel in terms of seakeeping, or motion comfort in extreme conditions.

In the period since the book was written, the physics that determine seaworthiness and seakindliness have not changed one iota.

Light hulls that disproportionately rely on form stabilty pose the same problems today as they did then.

Which is not so say that nothing has been learned about boat design, or that IOR boats were good or bad designs. All I'm saying is that just because a design is new doesn't mean it's a good cruising design. That's the argument made in favor of IOR boats thirty years ago. It wasn't valid then and it's not valid today.

Cruising boats thirty years ago had a disproportionate tendency to mimic racing designs. In that respect, not much has changed. People still think what's good in a racer must be good for a cruiser.

In a race boat, the crew looks after the boat--period. For cruisers sailing shorthanded, it's only a matter of time before the boat had better be able to look after an incapacitated crew. The latter is a design objective you'll never see in a race boat. Apples/oranges.

A lot of seaworthiness and seakindliness can be forfeited by a design aiming for an incremental increase in speed. There's the rub. In that respect not much has changed in thirty years at all. The tension among design objectives still there.

[Wainui]

I have spent time driving a Andrews 68' ULDB sled which could turn within its own length when motoring around a marina. It could almost throw somebody off the bow.
My own boat (a Cal 48) has a large and long fin with a spade rudder but is slow to turn at at low docking speeds. It does track well and has a comfortable ride which is a tribute to William Lapworth and his pre computer design skills
Mark
Ventura

[Jeff H]

It is imortant to understand that Marchaj was looking at the test results of designs that existed in that era and was correctly drawing conclusions about their short comings. The work was pivotal in shinning a light on the vital issue that racing rules can produce boats that are totally at odds with seaworthiness. It was also clearly critical of race boats of that era that depended on form stability and crew weight on the rail to keep them on their feet. Many readers overlook that the book is also very critical of what was happening with more traditional designs of that era, just less so than with the IOR era race boats.

In the years after the book was written, several things happened. First of all grand prix level racing boats moved from using rating rules to using VPP (Velocity Prediction Program) based rating systems, in other words, a way of handicapping a boat that is not measurement sensitive. If you are able to fairly handicap a boat based on its real performance and the rule can't be tricked as was the case with CCA era and IOR era boats, then the most successful boats on the race course will be the boats that sail well in a wide range of conditions. Instead of getting boats that were distorted to meet some rule, the rating system resulted in boats that simply designed to be good boats. That meant a lot of ballast stability, less dependance on form stability, easily driven hulls, and generous sail plans that were easy to shift gears as wind speeds changed.

To some extent these VPP driven rules (the IMS typeforms and Volvo 60's for example) produced boats that were 'type formed' to the rules, but it is a very important distiction that they did not produce boats that were distorted to beat a rule. And these VPP generated designs produced some very good sea boats, boats that performed well across a very wide range of wind and sea conditions, were very seaworthy and easy to handle, and yes, these boats look somewhat dinghy like, but they were not flat bottomed like dinghies or the earlier IOR boats for that matter. (And for the record I am not referring to Open Class Boats or the current Volvo 70's, which are heavily distorted to achieve tremendous reaching speeds at the price of being pretty mediocre models in many ways).

Which brings us to motion comfort and tracking. In the period after Marchaj's book came out, and with the advent of VPP generated rating systems, researchers and designers began to look more seriously at motion and seakeeping. I must admit that the reasoning behind the concerns about motion and seakeeping had little to do with crew comfort. Designers had long known that a boat with a quick motion or which hared large amounts of movement, lost foil (sails, keel, and rudder) efficiency and had more drag as the flow across the foils changed, separated and created drag. Since under VPP generated rating systems designers could create hull forms free of distortion, they were free to develop hull forms that were designed to produce hulls that were intended to produce gentle motions. When you look at these hulls, and rigs, they are carefully modeled to minimize quick motion, being moderately narrow at the waterline and progressively increasing dampening and form stability with roll and pitch. While this is good for performance, it is great for the comfort of the crews that have to sail these boats.

Similarly, designers understood that large helm loads, and lots of steering corrections were not good for performance since each turn of the rudder means more drag. And so through carefully developed designs, these new boats track exceptionally well and have very light helm loadings. They also worked hard to develop hull forms that would not change helm loads with heeling as was the case with boat old rating rule designs and the tradition water craft that proceeded them.

And while the above primarily focused on racing boats, many of the lessons learned in designing race boats to these VPP generated rules, and about motion comfort are filtering out into the world of modern cruising boats. The grand result is that there are a bunch of really super cruising boats out there compared to what was available 20-30 years ago, which is not to say that all modern boats have benefitted from these breakthroughs.

From my perspective, there is still a problem in what gets offered to the public. In the marketplace of ideas, these VPP generated type forms produce really great boats, but they compete with boats that are being derived from other thought processes and type forms (such as open class type forms) which are far less ideal in terms of motion comfort, over dependance on form stability, all around ease of handling and performance. And these other type forms do produce the fairly flat bottom, overly beamy designs that are propular for coastal cruisers because they offer a shallower draft and much more generous volumes for accommodations. The reason that I use the term better of these new design is to distinguish between the boats which have evolved from the VPP derived race boats vs. the less motion comfort and tracking sensitive modern boats which derive from Open Class type rules.

Lastly, I keep hearing the old saw that fin keel/spade rudder boats can't hove to in a blow. I have not found that to be the case at all and from my readings it appears that fin keel/spade rudder boats routinely hove-to in tough conditions.

Respectfully,
Jeff

[Jim Cate]

Jeff,

Well done, mate! BEst job of debunking the "traditional is the only way to go if ya wanna be seaworthy" school tthat has appeared in these columns yet. We've had one of these more modern hull shapes for the past 6 years now, and can attest to its comfortable motion at sea. Heaving to is a bit problematical, though, primarily due to the forward windage of the two roller sails on our "Solent" rig. Oh well, there is no free lunch at sea!
Cheers,
Jim

[Amgine]

But VPP models are as easy to diddle as a set of racing rules. They attempt to handicap a design before it's ever been in the water. If the formulae weights beam more than length designers will churn out skinny hulls, but in fact it's vice-versa so we see all these wide transoms with imbalanced waterlines. The VPP school of thought would seem to value speed as the primary consideration rather than safety or crew comfort.

I again reiterate that modern designs appear in mean, to me, to be no more seaworthy (and no less) than prior to Machaj. The over-all average tends to focus on what sailors will buy (shiny, cheap, fast) rather than what the tiny minority of blue water cruisers need (safe, easy, comfortable.) I would say in the past decade the design market has been driven by the charter trade, which in turn is driven by their retirement sales departments. And they don't seem to care much about seaworthiness.

[Hiracer]

Originally Posted by Amgine

I again reiterate that modern designs appear in mean, to me, to be no more seaworthy (and no less) than prior to Machaj. The over-all average tends to focus on what sailors will buy (shiny, cheap, fast) rather than what the tiny minority of blue water cruisers need (safe, easy, comfortable.)

What has changed in the last thirty years is economics. Most cruising boats essentially are sold by the pound. The industry's dirty little secret. Further, most sailboats are oil derivative products, i.e., fiberglass and dacron. The price of oil relative to salaries has soared in the past thirty years.

There is a strong economic push to make boats affordable by making them light, and then selling that concept as fast. Coupled with the drive for large accomodations for any given DWL, this inevitably leads to light fat boats that rely heavily on form stability. This kind of boat can be seaworthing but physics makes it impossible to be seakindly. Oh, such a boat can be balanced and sail without large rudder angles. But F=MA, or in this instance A=F/M. No exceptions. It will not be a seakindly boat if it is light and fat. High B/D ratios to provide RM for high SA/D ratios only compounds the seakindly problem.

I have nothing against fin keeled boats. Own one myself. But that's not the issue because a keel is not a boat and a boat is not a keel.

Let's not fool ourselves into thinking that we are at some kind of pinnacle in cruising design. We have the ability to optimize cruising designs, but other objectives inevitably muddy the waters and the end results all too often are something other than optimal designs for cruising.

The emphasis today is on cost, speed, and large accomodations. That is, IMO, an incomplete list. Seakindliness is vital to the cruiser, albeit not to the racer. Seakindliness is practically a forgotten design objective these days, because, among all the sailing attributes, it is just about the most expensive. You can't come about it cheaply. A=F/M.

None of the above, it should be noted, is an argument that older designs are anything special either. They have their other, different, design shortcomings.

[Pathfinder]

What are some examples of "IOR Racing Rules" yachts? In what years were they built?

[cal40john]

Originally Posted by Pathfinder

What are some examples of "IOR Racing Rules" yachts? In what years were they built?

San Juan 24 is an example.

They are boats that tried to use bloopers to keep from falling over while sailing downwind.

John

[Hiracer]

Originally Posted by Jeff H

From my perspective, there is still a problem in what gets offered to the public. In the marketplace of ideas, these VPP generated type forms produce really great boats, but they compete with boats that are being derived from other thought processes and type forms (such as open class type forms) which are far less ideal in terms of motion comfort, over dependance on form stability, all around ease of handling and performance.

We agree more than we disagree.

For boats under 40' I like displacement, to a degree, which is where I part company with many modern 'cruising' designs.

[Pathfinder]

So, is the Cal40 one of them also?

[cal40john]

Originally Posted by Pathfinder

So, is the Cal40 one of them also?

The Cal 40 was designed to the CCA rule, but it was a break from other boats designed to that rule. Some credit the demise of the CCA rule bringing IOR into play due to the Cal 40s success. Some of its drawbacks, is that it is a narrow boat by todays standards, at 11 feet, and has a lot less interior room. It steers easily enough that it has a tiller, but if it heels excessively, >20 degrees, it gets unhappy. It is known for pounding upwind with its too flat and wide bow. I haven't been in conditions with this boat to compare yet, but with a Cal 34 I have sailed back from Hawaii with the same rep, we just headed off 5-15 degrees until the pounding stopped.

I can't find the article right now, but it was about a Cal 40 and a Yankee 38 in near proximity on Swiftsure. The Yankee 38, an IOR boat was working hard to minimize the number of broaches, while the woman steering the Cal 40 was steering calm and easy.

I have friends that have bought IOR designs for cruising and for the most part if they don't push them hard, steering is not an issue, but recently a friend with a San Juan 28 was describing how he was under control with a main and jib in some wind, but was pretty much using the full range of steering to keep the boat under control.

So far I've been happy with my boat. The compromise is, my friends with their Morgan OI 41, Gulfstar 39, CT 41, all have more room, but I get to sail when they're motoring, which is important to me.

Intro by Robert Perry on the Cal 40
Welcome to Cal40.com

Some history
Welcome to Cal40.com

[Jeff H]

I had written this for a similar question about the history of various offshore racing rules,

I did not get a chance to research precise dates but in a general sense here is an approximate time line: (some of this was cut and pasted from other posts or articles that I had written)

1928 Bermuda Rule (Early small boat offshore racing rule, produced reasonably seaworthy designs compared to inshore ratingg rules of the era.)

1937 RORC (English offshore rating rule. Like the Bermuda rule produced more wholesome designs than inshore rules of the era.)

1948 CCA (this was loosely based on the Bermuda Rule but increased penalty for waterline length and mainsail area.)

Early 1950's to this day Portsmouth Rule
(This is a rating rule for small dinghies and I think may include multihulls. There may have been a pre WW II version as well)

1952 MORC (Midget Offshore Racing Conference- Started out as a rule aimed at boats less than 30 feet and was intended to encourage seaworthy offshore designs. The big difference was that it handicapped waterline length more fairly and so encouraged proportionately longer water waterline lengths. MORC also included accommodation requirements which made early MORC boats pretty comfortable for their size. Eventually evolved into a grand prix development rule by the late 1980's. Early MORC boats looked like the Tartan 27, middle period MORC boats look like the J-24, Kirby 25, J-30 and S2 9.1, Late period boats were very expensive one offs or limited production boats)

1970 IOR Rule
(This rule started out looking at the shortcomings of the RORC and CCA rule and attempted to produce better offshore boats than produced under both prior rules. IOR came in three main flavors IOR-1, IOR-II and IOR-III. That said the rule changed fairly significantly nearly every year and so there is a spectrum of designs that fall in the category of IOR boats.

In its original form IOR-1 (starting around 1970) produced pretty good boats. The poster children for IOR-1 would be boats like the Tartan 41, Catalina 38, Ranger 37, and Morgan 1 ton. The defining features of these early IOR boats were their pinched ends, and topsides often characterized by a lot of tumblehome. (This tumblehome was there to increase the mid-ship girth since part of the formula was the different in girth between the point of maximum beam and the transom girth.) They typically had shark fin like fin keels and skeg hung rudders.

Their rigs were characterized by huge Genoa jibs and spinackers combined with small high aspect ratio mainsails that carried over from late CCA boats. Because of that they often carried huge foresail inventories with 12 to 15 jibs and spinackers not being all that unusual for a 40 or so footer. (My 25 foot IOR-1 quarter tonner carried 8 or so headsails) They were pretty good boats upwind but were really wild off the wind rolling wildly under their huge chutes and bloopers. These were big boats to sail that took a really big and strong crew to race these boats and big heavy gear would routinely blow up with major consequences.

IOR-1 boats often had comparably high freeboard and low deck structures. Halyards were often organized around a control ‘island’ that would consist of a ring of winches around the base of the mast since stoppers and low friction blocks had not really showed up on the scene.

Later IOR-1 boats would include the Holland designed Imp,
Then came IOR-II. The IOR hull form evolved to have a deeper canoe body, more of a raked stem and reversed transom, a wider entry angle, more flare, and narrower run. They also developed a very distinct section that resulted from the measurement points used in IOR. This ‘three plane’ section had a relative flat area on the bottom that radiused into relatively flat sections on either side that sloped up toward a point just above the waterline. These are then radiused into a hard turn of the bilge at or above the waterline that proceed to fair into fairly straight flared topside. This profile tends to have mediocre initial form stability but quickly develops more stability as the turns in the bilge at the water line become immersed.

This shape was solely IOR-2 rule driven because of the IOR location for measurement points and the big penalty for initial stability. It was not fast and as a type did a lot to foster the common impression that that all light boats automatically have unbearably quick motions. Poster children IOR-2 boats would include the Peterson 34, Contessa 35, Holland designed Ericsons and the Fastnet Disaster boats.

IOR III had a very wide range of variations, changing frequently during its lifespan. In reaction to the Fastnet Disaster, IOR III's ballast ratios increased and with it so did sail area. Fractional riugs began to appear as designers began to see the advantage in of more rapid gear shifting that was also encouraged by low stretch sail cloth and bendier spars. Good examples are boats like the Garratt 40, Dickerson 37, Soverel 39. As the IOR began to drop in popularity, and were raced in fewer offshore venues, these boats became specialized grand prix only, fragile, and short lived.)

Early 1970's PHRF
Strictly speaking this is not a measurement rule like the rest on this list. It was a handicapping rule that looked at the performance of actual boats in the average conditions in that venue and made a somewhat subjective call as to the best rating for that boat. Ratings are cheap and there really are no ideal PHRF typeforms like there are under measurement rules. It does reward well rounded designs and in long distance racing, oddly enough boats that are rarely raced because they are percieved as slow and so are likely to have artificially low ratings and their slow speeds have less of a tactical disadvantage).

1980 Open Classes
(This is really a series of rules that do not rate boats at all, but establishes maximum length and sometimes max beam, mast heights, and stability standards and little else. The boats race boat for boat as if one design. It produces the beamy huge rigged race long distance race boats that you think of for round the world single-handed racing. When cruising boats are influenced by the design of Open Class boats I personally don't like what it does to these boats in terms of encouraging extreme beam and full ends, high form stability and poor motion comfort.)

1983 MHS Rule (This was an early attempt to develop a VPP [velocity prdiction program] based rating system. The rule was intended to fairly rate boats off all types one against another and so did not generate specific typeforms. It was expensive to measure a boat for MHS and since there were individual ratings for different windspeeds it was a hard rule for race committees who had to guess at the wind conditions on the course. The true advantage as well as the shortcoming of MHS was that if all boats were fairly rated as to their relative speed, a faster boat and a boat that sailed well in a wide range of conditions had a real advantage over the course of a season. This tended to produce boats that were very well rounded...Good news! but it quickly resulted in obsolescence of earlier CCA and IOR designs. MHS also included minimum interior accomodation standards and so they tended to have more headroom and more useable interiors than the IOR and CCA boats that came before them. This rule was unique in that it offered two versions, time on time and time on distance, as well as a rating for various courses and windspeeds. As a result every boat had a series of ratings and it was impossible for a competitor to know where he stood out on the race course. )

Late 1980's IMS
(The MHS evolved into the IMS which took advantage of improvements in technology to measure boats and also the results of refined VPP's to produce a rule that again tried to rate fairly for speed. With the introduction of IMS a typeform began to develop which looked at various unrated aspects such as the ability to shift gears quickly, carry fewer crew members, and motions impact on performance. Early IMS boats carried over the interior requirements of MHS. Good examples of these might be the Beneteau First 40.7, 36.7, Tripp 36 and Tripp 40. Later the IMS shifted to more agressive designs as the acommodations requirements were eased. Ultimatedly the IMS produced grand prix level no holds barred race boats that lost many of the virtues that IMS was intended to produce.

Like the MHS, performance cruisers based on the IMS were good all around boats, fast across a wide wind range, easy to handle, seaworthy and offering excellent motion comfort as compared to boats out of earlier rules. but also like MHS measurement was expensive, every boat had a lot of ratings and it was a race committee's nightmare.)

2002 IRC
(The IRC is a simplified version of the IMS. It encourages simplier, more cruising oriented rigs and heavier displacements. It is apparently popular in Europe but is just showing up over here. It seems to produce some wonderful boats though.)

Jeff

[Wainui]

John. My 48 has a more pronounced V shape in the hull forward of the keel than the Cal 40. It does not pound at all but won't get up and surf as easly as your 40. The fastest was 17 knts down a large wave during a race. The interior is as large as most modern 40' boats but it works.
Mark
Ventura

[Jeff H]

Originally Posted by Amgine
I again reiterate that modern designs appear in mean, to me, to be no more seaworthy (and no less) than prior to Machaj. The over-all average tends to focus on what sailors will buy (shiny, cheap, fast) rather than what the tiny minority of blue water cruisers need (safe, easy, comfortable.)

I think you are way oversimplifying things if you talk about modern boats in terms of 'on the mean' or 'on overall average'. As I see it, in the years after Marchaj's book was published boats became increasingly specialized with niche designs attempting to reflect the apparent tastes of the sailboat buying marketplace. If sales number are any indication, the largest segment of that marketplace are people who are coastal cruisers and budget oriented (and charter companies which have similar needs) and so we have seen a very large number of boats built that have been optimized for that market.

I would agree that if we include these boats in your averaging of modern boats, I would agree in principal with your staetment that modern boats on average are not all that much more seaworthy than the boats that were common in the late 1970's. (although I would argue that for coastal cruising their lower VCG's, more easily depowered rigs, and higher initial form stability probably make them more seaworthy for the conditions that they are likely to be sailed in (coastal cruising), even if they are not any more seaworthy in the kinds of extreme conditions that they might encounter if taken offshore.)

But as I tried to clarify, when we look at boats that are intended as dual purpose boats that are suitable to being taken offshore, and which have been benefitted from the lessons learned since Marchaj's pivotal book, we see a huge leap in seaworthiness, ease of handling and motion comfort. If you look at a range of boats such as the Morris 45, Hylas 46, Hallberg Rassey 40 or 48, Dehler 39 or even something as mondane as the Beneteau First 40.7, you can find that the lessons learned in the years since Marchaj, many of them filtering down from IMS/V60 research) have payed off big in terms of lower VCG's, hull forms that have gentler motions, and so on which all add to the inherent seaworthiness of these boats, especially as compared to the standard fare of that era.

Respectfully,
Jeff

[Bash]

Originally Posted by Curtis

The thing I've learned about the bulb keel is that it stalls very easily at low speeds. In light air, going to windward, I'm much better footing off until I get boat speed up in the 2-3 knot range before I try to point much higher than 60 degrees to apparent wind. Once boatspeed is above 2+ knots, the boat will point right up to 40-45 degrees of apparent.

My previous boat had a bulb keel, and in light air it always seemed to have a bit of lee helm until I got the boatspeed above two or three knots. Could solve that problem by footing off, as you've described.

Bulb keels make a lot of sense until you ground one in soft San Francisco Bay mud. For my part, I'm happy to have gone back to a boat with a fin keel.