The document summarizes the history and development of the Finnish Class A sailing yacht design and rating rules from 1936-1952. It describes the initial Class A rule from 1936-1952 that measured length, sail area, beam, and freeboard. It then outlines key trends that led to increasing sail area within the rule from 32 square meters to nearly 39 square meters. This ultimately necessitated a new rule in 1952 that added additional penalties for height and beam-to-length ratio to slow development.

1. A Finnish Classic—the Class A Design

3. They look the same !

4. Class A Rule 1936 and 1952
L + √(SA) – 0.7(B) – 0.8(F) ≤ 12.000
• Longer waterline (L)—more speed—tax
• Large sail area (SA)—more speed--tax
• Wide beam (B)—slow down--credit
• High freeboard (F)-slow down--credit
• Low h-measure (h)—tax
• High B/L measure--tax

5. Development of rating rules
• Tonnage Rule TM = ((L- B)*B*B/2)/94 1883-87
•
• Seawanhaka Rating = (L + √S)/2 1893-1903
•
• Valeur Rule Valeur = (LWL + S)/150 1887-1905
•
• Universal Rule R Class 20 ≥ (L * √S)/5 * ⁿ√D 1903-17
•
• Skerry Cruiser Rule 30 m2 = L – B – F– D– K 1908-28
•
• I Metre Rule (6 mR) 6.000 ≥ (L + 0.33√S+ B – F + 0.5G + 3d)/2 1908-19
• Int. 5 M Rule 5.000 ≥ ( L + √S - 0.5 B - F) : 2 1929-
•
• III Metre Rule (6 mR) 6.000 ≥ ( L + √S – F + 2d) / 2.37 1933-today
•
• I Finnish Class A Rule 12.000 ≥ L + √S – 0.7 B – 0.8 F 1936-1952
•
• II Finnish Class A Rule 11.000 ≥ L + √S – 0.7B – 0.8F – h – B/L 1952-

6. 6 mR 6.000 ≥ ( L + √S – F + 2d) / 2.37
Class A 12.000 ≥ L + √S – 0.7 B – 0.8 F

7. 30 m2 = L – B – F– D– K
12.000 ≥ L + √S – 0.7 B – 0.8 F

8. R Class 20 ≥ (L * √S)/5 * ⁿ√D
Class A 12.000 ≥ L + √S – 0.7 B – 0.8 F

9. Design developments
• 1. Pre-war: Skerry cruiser influence
• 2. 1940-45: Signature period
• 3. 1946-48: Time of divergence
• 4. 1949-51: Time for Optimization
• 5. 1952- : New Rule

10. Pre-war 1936-39
Skerry cruiser influence
Ingeborg (AL-1) and Lilith (AL-3)

11. 1940-45
Typical Kyntzell
Alibaba (AL-15)

12. Time of Divergence 1946-48
Slotte standard
Gunilla (AL-18)

13. “Rule Beater” Gysingen (AL-1)
Roy Scherman

14. Optimization 1948-51
K.A. Johansson’s Alouette (AL-26)

15. Key trends in Class A design
• 1. Shorter LOA—shorter L – more SA
• 2. Wider B—more SA
• 3. Higher F— more SA
• 4. D up – more stability as SA rose
• Overall SA up from 32 m2 to 36 m2 (Kyntzell),
32 m2 to 34 (Slotte), 34 m2 to near 37
m2(Lindblom), and to 39 m2 (Scherman)

16. Time for a new rule (1952)
Old rule L + √S – 0.7 B – 0.8 F ≤ 12.000
New rule L + √S – 0.7B – 0.8F – h – B/L ≤ 11.00

17. New Rule Phenomenom
Elise (AL-28)

18. Class A in 1952

19. Yacht Design
• Lord Dunraven: “ A most maddening,
complicated, and beautiful art”.
• Olin Stephens: “There is still some mystery in
sailboat design”.

20. Thank you for your attention !