In “Notes on Sailing-Yacht Hullforms” (Professional BoatBuilder No. 196, page 32) naval architect Jay Paris, citing drawings and photographs of his own designs as well as the lines of other designers, detailed some characteristics, attributes, and design methods used to develop monohull sailboat hullforms. Because of space constraints in the print magazine, we are publishing Paris’s additional notes and reference material on Proboat.com. In addition to his sections on fin-keel variants and parent hullforms, Paris includes a reference list of hullforms worthy of note for a number of reasons—aesthetics, excellence as examples of their type, historic significance, or design methodology. All but one of the hullforms in this Part 2 are round bottomed, and all the yachts cited, which were built during the past century, are wooden boat designs. The lengths for the hullforms in this article are length of hull (LOH) since length overall (LOA) includes extensions to the hull such as bowsprits and boomkins and length on deck (LOD) is often less than the hull due to bulwarks and reverse transoms. —Ed.
Twin-Keel and Retracting-Foil Variants
A variant of the fin-keel design is the twin-keel. Most common on coastal cruisers intended to take the ground when the tide is out, they reflect an empirical approach to their design. A few are serious offshore passagemakers, including the noteworthy Bluebird of Thorne.
A more current fin-keel variation is the use of canting keels, with or without lift-generating sections, employed on offshore racers to shift the ballast bulb to weather to increase their righting moments.
Parent Sailing-Yacht Hullforms and Evolution
Historically, designers have used specific earlier boats as the basis for follow-on designs, in some cases very closely but with changes in the overall size and proportions. For example, Nathanael Greene Herreshoff had noticeable success using his 26’ (7.92m) Alerion III NGH 718 of 1912 as the parent for designs as large as the 33.42’ (10.19m) Newport 29 of 1914 and the 43.25’ (13.18m) Fishers Island 31, designed by his son Sidney using NGH’s offsets.
Maynard Bray, in his book Aida, includes a photograph of Herreshoff’s offset booklet pages used in the mathematical expansion to create the 33.67’ (10.26m) Aida of 1926. The Buzzards Bay 25 of 1914 looks perhaps to be the least likely of being an Alerion derivative.
Another famous parent hullform is the Pilot S&S 539, 32.92’ (10.03m) wooden stock class sloop of 1945. Olin Stephens wrote in Lines 2002 that the Pilot was “drawn in the Boston office by K. Aage Nielsen, who was, in theory, working under my supervision.” The later S&S 1727 fiberglass version from the New York office was lengthened to 36.07’ (10.99m).
The beautiful Anitra S&S 1358 48.42‘ (14.76m) yawl of 1958, the largest of the Pilot family, was the overall winner of the 1959 Fastnet Race.
In my own practice, The Paris Design P-32 (9.75m) Petrel is the parent of the later P-37, G-37, and OCC-47 designs.
Those using state-of-the-art yacht design software often morph parents to the extent that their design “DNA” is no longer apparent.
Hullform evolution is similar but less slavishly derivative than the use of parent hullforms. The Viking ships of a thousand years ago are candidates for the most elegant hullforms of all time. The Scandinavian preference for double-enders has followed this fashion in some degree to modern times. Colin Archer’s Redningsskoite (rescue boats), which evolved from them, have inspired designers to this day. William Atkin’s 38’ (11.58m) ketch Ingrid, his highly refined granddaughter of this type, is considered to be one of his best designs.
Knud Reimers’s Cohoe is a 1932, 32’ enlargement of his famous and beautiful 27’ (8.23m) Tumlare of 1927. These designs introduced lighter displacement and finer lines than earlier Scandinavian double-enders. Many consider the Tumlares to have the most beautiful hullforms of all time.
A small Danish fishing boat type with very full sterns typical of the sound north of Copenhagen was the parent of the Spidsgatter classes of sailing yachts. Aage Nielsen, a Dane, was familiar with the type. Some of his smaller designs from 15’ to 26’ (4.57m to 7.92m) were referred to as Nielsenized Spidsgatters. Their full sterns were models for that of Holger Danske, his 42.5’ (12.95m) cruising ketch that won the 1980 Newport-to-Bermuda Race by a large margin.
Over time, many working craft have served as models for sailing yachts. The danger, at times, has been designers ignoring the original function, loading, and the wind and sea conditions for which working craft were developed.
Design evolution can also be seen amongst ocean racers. Olin Stephens’s Stormy Weather came seven years after the famous Dorade of 1929, which had introduced the forms of his earlier inshore Six-Meter designs to the offshore world. These two sisters established a trend for blended-body ocean racers for some four decades.
Sources From My Library
Starting before high school with the original five Uffa Fox books of 1934/1938, my office library has grown to almost a thousand books on sailing and sailing yachts with most containing technical material as well as numerous technical reports. I also have some 100 volumes addressing hydrodynamics, aerodynamics, and aerospace design containing material applicable to sailing yachts not addressed in yachting publications.
Lines drawings from my library that I consider worthy of note and reference but not embedded in the text are shown below with captions and sources. Note: Lines in the early five Uffa Fox books were redrawn by Fox.
Starling Burgess. Nina, 59’ Staysail Schooner, 1928.
Howard I. Chapelle. Clipper-Bowed Centerboarder, 1936
Frederick A. Fenger. Diablesse, 38’ Wishbone Ketch, 1935
William Garden. Oceanus, 60’ Narrow Doubled-Ended Sloop, 1954
N.G. Herreshoff. Aida, 33.67’ Keel/Centerboard Yawl, 1926
L. Francis Herreshoff. Rozinante, 24’ Canoe Yawl (Ketch Rig), 1956
George Holmes. Trent, 25’ Canoe Yawl, 1910
Robert Perry. Amati, 40’ High-Aspect-Ratio Fin-Keel, Spade-Rudder, Wood-Foam-Wood Composite, Fast Cruising Sloop, 1999
Knud Riemers. Moose, 43.0’ 30-Square-Meter Sloop, 1934
Sparkman & Stephens. Babe, 30.5’ Fractional Sloop, 1935
Sparkman & Stephens. 1834 Intrepid, 64.25’ 12-Meter Sloop, 1967
E.G. van de Stadt. Zeevalk, 41’ V-Bottom Plywood, Fin-Keel, Spade-Rudder, Fractional Sloop, 1949
Joel White. Dragonera, JW Design 49 74’ Fin-Keel Ketch, 1993
Jay Paris Designs:
No. 10 Aeromarine 50, 50’ Tall Mizzen Ketch 1968
No. 24 Lone Star, 54’ LOH Clipper Bow Ketch 1976
No. 27 Freedom 33, 33’ Cat Ketch for Gary Hoyt 1977
No. 33 P-32, 32’ Keel/Centerboard Sloop 1982
No. 40 P-45/Y-45, 45’ Ketch for YW/CW Contests 1988
No. 43 OCC/Sail, 43’ Sloop for Sail Article 1992 (An Ocean Cruising Club member survey design)
No. 48 P-37, Yawl for IBEX and METS Lectures 2007
No. 51 G-37, Keel/CB Yawl for a CCA Lecture 2014
No. 53 OCC-47, Keel/Centerboard Ketch 2018 (A rethink of the 1992 OCC member survey requirements)
Lines Drawings Reading List
In the following books, design examples illustrate the step-by-step creation of the lines reflecting the hullforms in fashion when the texts were written:
Chapelle, Howard I. Yacht Designing and Planning, 1936.
Clipper Bow 33.33’ DWL Shoal-Draft Centerboarder.
Kinney, Francis. Skene’s Elements of Yacht Design, 8th Ed., 1973.
Pipe Dream 25.42’ DWL Cruising Yacht.
Phillips-Birt, Douglas. Sailing Yacht Design, 3rd Ed., 1966 and 1976.
Full Keel 30’ DWL Fast Cruiser Including design using Diagonals.
Larsson, Lars and Rolf Eliasson. Principals of Yacht Design. 3rd/4th Eds., 2007 and 2014.
YD-40 39.5’ 2007 and YD-41 41’ 2014 Fin Keel Fast Cruising Yachts.
These books discuss various technical design details and parameters used by yacht designers:
Brewer, Ted. Ted Brewer Explains Sailboat Design, 1985.
Killing, Steve. Yacht Design Explained, 1998.
Perry, Robert H. Yacht Design According to Perry, 2008.
For a more theoretical explanation of the factors influencing sailing yacht design, I recommend:
Marchaj, C.A. Sailing Theory and Practice, 2nd Ed., 1982.
Marchaj, C.A. Seaworthiness: The Forgotten Factor, 1996.
Fossati, Fabio. Aero-Hydrodynamics and the Performance of Sailing Yachts, 2007.
Slooff, J.W. The Aero- and Hydrodynamics of Keel Yachts, 2015.
Bruce, Peter. Heavy Weather Sailing, 7th Ed., 2016.
About the Author: While attending Webb Institute Jay Paris worked two winters and one summer at Sparkman & Stephens. His graduate studies at MIT focused mostly on oceanography and research-vessel design. He also managed the MIT towing tank and operations of the yacht-testing program and participated in the international investigations into the 1979 Fastnet Race disaster. After MIT he was involved in the design of winches for the America’s Cup and high-end racing yachts, the design and construction of various sailboats, and the writing and editing of articles on sailing yachts for a number of different journals.