Re: Cal 33 Lapworth

Jerry, the reverse transom and other features were not driven by appearance (or wanting to mimic the AC racers); like almost every part of sailboat design over the years, it was dictated by handicapping rules. In this case, I believe it was the IOR One Ton rule that was responsible. (The Cal 33 would have been in the Half Ton class, I believe.) As I understand it, it favored boats with broad beams and pinched ends for and aft. The designs never appealed to me much, either for looks or for stability downwind in a quartering sea. From a Wikipedia entry: "The IOR rule encouraged wide short boats with limited stability. A narrow waterline and large beam on deck, combined with a high centre of gravity, meant that crew weight provided a significant proportion of stability at small heel angles, and boats had a relatively low angle of vanishing stability. This developed into the situation about 1977 when the boats winning in most smaller IOR categories (up to the half tonners - about 10m LOA) had all internal ballast, often with an unballasted daggerboard. The managers of the rule realised that this was not a suitable direction for seaworthy yachts, and heavily penalised boats with lifting keels. "Apart from the girth measurements, all measurements were basically point measurements. This meant that the hull was often locally distorted to maximise or minimise a measurement locally, with minimal effect to the surrounding hull. This gave a characteristic bumped look to many boats, particularly at the point of maximum beam and in the stern. Also, as stability was only measured at very low heel angles (less than 5 degrees), boats were designed with a very narrow waterline and low stability in measurement trim, but a hull form that gained stability with the weight of the crew and other equipment, and with increasing angles of heel. Interestingly, low stability was encouraged (up to a point) because the initial assumption was that low stability indicated a well fitted out interior, and so more of a cruising boat than a stripped out racer." So don't go blaming the designers; they were just trying to take the greatest advantage possible from the handicapping rules. (Note that the CCA - Cruising Club of America - handicapping rules were largely responsible for the classic narrow boats with long overhangs at the bow and stern that so many of us find so lovely.) If you're interested in reading more about how handicapping rules affect boat design, Ted Brewer wrote an excellent explainer for Good Old Boat magazine: http://www.goodoldboat.com/reader_services/articles/ratingrules.php Alfred Poor 1973 Tartan 34C #288 "Jambalaya"

Alfred, That reminds me of sailing on a Santana 30-30 and 35. Boats were very over powered and unstable without crew weight on the rail. So you're saying that the overhangs on, say, the Cal 34 and 40 were caused by the CCA rule? Thankfully, they aren't that much, and my Cal 24 has a nice, sexy wineglass stern. I wonder how olde the CCA rule is? I guess Google knows? Jerry of Shpritz On Tuesday, May 8, 2018, 6:20:27 AM PDT, 'Alfred Poor' ap… [at] verizon.net [Cal_Boats] <Ca… [at] yahoogroups.com> wrote: Jerry, the reverse transom and other features were not driven by appearance (or wanting to mimic the AC racers); like almost every part of sailboat design over the years, it was dictated by handicapping rules. In this case, I believe it was the IOR One Ton rule that was responsible. (The Cal 33 would have been in the Half Ton class, I believe.) As I understand it, it favored boats with broad beams and pinched ends for and aft. The designs never appealed to me much, either for looks or for stability downwind in a quartering sea. From a Wikipedia entry: “The IOR rule encouraged wide short boats with limited stability. A narrow waterline and large beam on deck, combined with a high centre of gravity, meant that crew weight provided a significant proportion of stability at small heel angles, and boats had a relatively low angle of vanishing stability. This developed into the situation about 1977 when the boats winning in most smaller IOR categories (up to the half tonners - about 10m LOA) had all internal ballast, often with an unballasted daggerboard. The managers of the rule realised that this was not a suitable direction for seaworthy yachts, and heavily penalised boats with lifting keels. “Apart from the girth measurements, all measurements were basically point measurements. This meant that the hull was often locally distorted to maximise or minimise a measurement locally, with minimal effect to the surrounding hull. This gave a characteristic bumped look to many boats, particularly at the point of maximum beam and in the stern. Also, as stability was only measured at very low heel angles (less than 5 degrees), boats were designed with a very narrow waterline and low stability in measurement trim, but a hull form that gained stability with the weight of the crew and other equipment, and with increasing angles of heel. Interestingly, low stability was encouraged (up to a point) because the initial assumption was that low stability indicated a well fitted out interior, and so more of a cruising boat than a stripped out racer.” So don’t go blaming the designers; they were just trying to take the greatest advantage possible from the handicapping rules. (Note that the CCA – Cruising Club of America – handicapping rules were largely responsible for the classic narrow boats with long overhangs at the bow and stern that so many of us find so lovely.) If you’re interested in reading more about how handicapping rules affect boat design, Ted Brewer wrote an excellent explainer for Good Old Boat magazine: http://www.goodoldboat.com/reader_services/articles/ratingrules.php Alfred Poor 1973 Tartan 34C #288 “Jambalaya”

The Ted Brewer article covers the CCA pretty well. I’m sure I’ve got this a bit sideways, but as I understand it, the old rules measured waterline when floating upright. As you probably know, hull speed (the speed at which it takes exponentially more power to make the boat go faster) for displacement hulls is a factor of waterline. You take those beautiful boats and lay them over on their rails, and you nearly double their waterline and they go a lot faster. Modern racing rules must penalize extra waterline length when heeling, which is why you now have plumb (or reversed) bows and sterns; there’s nothing to be gained from the overhang. This is also why most modern boats sail fastest when “standing up straight”; that’s what they’re designed to do, encouraged by the handicapping rules. In the early days of the IOR One Ton rules, some people actually went out and had “bubbles” added to the midships of their topsides in an effort to get a more favorable rating. It made for ugly and potentially unsafe boats. Alfred From: Gerald Sobel <so… [at] yahoo.com> Sent: Tuesday, May 08, 2018 11:06 AM To: Ca… [at] yahoogroups.com; Alfred Poor <ap… [at] verizon.net> Subject: Re: [Cal_Boats] Re: Cal 33 Lapworth Alfred, That reminds me of sailing on a Santana 30-30 and 35. Boats were very over powered and unstable without crew weight on the rail. So you're saying that the overhangs on, say, the Cal 34 and 40 were caused by the CCA rule? Thankfully, they aren't that much, and my Cal 24 has a nice, sexy wineglass stern. I wonder how olde the CCA rule is? I guess Google knows? Jerry of Shpritz On Tuesday, May 8, 2018, 6:20:27 AM PDT, 'Alfred Poor' ap… [at] verizon.net <mailto:ap… [at] verizon.net> [Cal_Boats] <Ca… [at] yahoogroups.com <mailto:Ca… [at] yahoogroups.com> > wrote: Jerry, the reverse transom and other features were not driven by appearance (or wanting to mimic the AC racers); like almost every part of sailboat design over the years, it was dictated by handicapping rules. In this case, I believe it was the IOR One Ton rule that was responsible. (The Cal 33 would have been in the Half Ton class, I believe.) As I understand it, it favored boats with broad beams and pinched ends for and aft. The designs never appealed to me much, either for looks or for stability downwind in a quartering sea. From a Wikipedia entry: “The IOR rule encouraged wide short boats with limited stability. A narrow waterline and large beam on deck, combined with a high centre of gravity, meant that crew weight provided a significant proportion of stability at small heel angles, and boats had a relatively low angle of vanishing stability. This developed into the situation about 1977 when the boats winning in most smaller IOR categories (up to the half tonners - about 10m LOA) had all internal ballast, often with an unballasted daggerboard. The managers of the rule realised that this was not a suitable direction for seaworthy yachts, and heavily penalised boats with lifting keels. “Apart from the girth measurements, all measurements were basically point measurements. This meant that the hull was often locally distorted to maximise or minimise a measurement locally, with minimal effect to the surrounding hull. This gave a characteristic bumped look to many boats, particularly at the point of maximum beam and in the stern. Also, as stability was only measured at very low heel angles (less than 5 degrees), boats were designed with a very narrow waterline and low stability in measurement trim, but a hull form that gained stability with the weight of the crew and other equipment, and with increasing angles of heel. Interestingly, low stability was encouraged (up to a point) because the initial assumption was that low stability indicated a well fitted out interior, and so more of a cruising boat than a stripped out racer.” So don’t go blaming the designers; they were just trying to take the greatest advantage possible from the handicapping rules. (Note that the CCA – Cruising Club of America – handicapping rules were largely responsible for the classic narrow boats with long overhangs at the bow and stern that so many of us find so lovely.) If you’re interested in reading more about how handicapping rules affect boat design, Ted Brewer wrote an excellent explainer for Good Old Boat magazine: http://www.goodoldboat.com/reader_services/articles/ratingrules.php Alfred Poor 1973 Tartan 34C #288 “Jambalaya”

On 5/8/2018 11:21 AM, 'Alfred Poor' ap… [at] verizon.net [Cal_Boats] wrote: > > > The Ted Brewer article covers the CCA pretty well. > > I’m sure I’ve got this a bit sideways, but as I understand it, the old > rules measured waterline when floating upright. As you probably know, > hull speed (the speed at which it takes exponentially more power to > make the boat go faster) for displacement hulls is a factor of > waterline. You take those beautiful boats and lay them over on their > rails, and you nearly double their waterline and they go a lot faster. > Modern racing rules must penalize extra waterline length when heeling, > which is why you now have plumb (or reversed) bows and sterns; there’s > nothing to be gained from the overhang. This is also why most modern > boats sail fastest when “standing up straight”; that’s what they’re > designed to do, encouraged by the handicapping rules. > I've never been quite convinced about the purported waterline-length benefit of CCA boats when heeling. Maybe it works. But CCA-era boats were often kinder to their crews in a blow than newer designs created to go fast. There is something to be said for comfort and security. The current fad for a bulb ballast way, way down on a skinny fin keel holding a flat planing hull upright may make sense on a race course, but for most sailing it's impractical. There are the engineering questions that arise when the keels fall off, but also the simple question about extreme draft when sailing in coastal waters. Not very practical. For most of us, the best design will balance speed against comfort and practicality. CCA boats did not disappear just because the rule changed. They were skinny and cramped below by current standards. I recall the first time I went aboard a Concordia yawl. Whoa, not much space below. Newer broad-beamed boats usually have a lot more living space. Nothing wrong with that. (Well, not unless they turn into floating condos that never go sailing). Let's note that the IOR rule produced some of the least attractive boats of the fiberglass era. All those bulges, concavities, pinched sterns... anything would have been a relief after that. I haven't sailed much on such vessels but apparently the behavior could be squirrely, at least in the extreme interpretations. I expect my boats to have good manners when sailing. Chris Campbell > >