Came across this. Nothing ground breaking, but thought it was interesting, for various reasons: https://www.surfertoday.com/surfing/everything-you-need-to-know-about-surfboard-design-and-performance
The Forces
1. More buoyancy means easier paddling above water;
2. The more area of the surfboard is in contact with the water, the more friction drag will exist and, the slower the surfboard will be;
3. The greater the rocker, the greater the drag force;
4. The greater the velocity or speed, the greater the lift;
5. Bottom shapes with concaves and channels produce an upward force or lift;
6. Wave faces flow and move in orbital fashion and create lift;
The Variables of Surfboard Shaping
1. More surfboard area means more planing potential, less sinking and bogging;
2. The elements of a template are total and half length, nose shape and width, outline curve, location of the wide point relative to the center, width, tail shape and width;
3. More curve in the outline means easier turning;
4. Longer boards provide faster paddling, greater risk of nose diving and more effort required in turning;
5. Wider surfboards plane better in dead or slow wave spots;
6. Wider boards turn easier at slow speeds but have poorer rail-to-rail transitions;
7. Wider templates have poor hold in the wave face at high speeds on rail;
8. Wider surfboards are stiffer;
9. Rounder noses provide more lift and buoyancy, but create form drag;
10. Pointed noses suffer less "baseball bat effect" and are easier to hold in rail turns;
11. Pin tail surfboards have extremely low surface area and high holding power;
12. Square tail surfboards have high planing area and looseness;
13. Thicker boards have greater buoyancy and have easier paddling;
14. More thickness in the middle of the board means difficulty to lean on rail;
15. Thicker tails are looser at slow speeds;
16. More rocker means easier turning, harder paddling, and slow speeds in a straight line;
17. More rocker means less nose diving;
18. Vee bottoms create less lift and are slower than flat bottoms in neutral position;
19. Vee bottoms allow for easier rail-to-rail transitions;
20. Single concaves create more lift and speed and are harder to turn;
21. Double concaves keep the rails free and are looser and faster;
22. Harder rails plane very well but have a stiff, less smooth response to turning;
23. Soft rails are slower but provide better hold in subtle turns;
24. Tucked under edge rails balance the characteristics of hard rails and soft rails;
25. Greater fin area means better holding power;
26. Streamlined fin foils have higher holding power;
27. Asymmetrical side fin foils provide better directional holding power;
28. Greater fin base length/rake resists lateral turning;
29. Greater fin height creates greater resistance to rail-to-rail turning;
30. Further forward fin placement will loosen up the board;
31. Further back fin placement will create more holding power and drive;
32. More space between the front and rear fins means more torque required for weaving;
33. Toed-in fins create more drag and are easier to turn;
34. Bigger fin cant/camber means looser turns;
The Construction Types and Techniques
1. Traditional construction includes solid timber and hollow wood. They are strong, but they are heavy;
2. Sandwich construction puts strength only where it is needed, and offers high strength relative to weight;
3. Conventional manufacturing is all about moulding a foam blank from polyurethane beads, hand shaping the pre-moulded foam blank, and applying fiberglass and resin by squeegee;
4. Shaping machines cut foam to a predetermined shape designed in a computer software;
The Core Materials
1. More weight means more force needed to accelerate and turn;
2. Greater density cores add more strength but are less flexible;
3. Foam core is roughly half the weight of a surfboard;
4. Balsa is five times heavier than foam;
5. Doubling core stiffness is doubling the strength, but the flex remains the same;
6. Increasing foam core density means increasing strength and weight;
7. Carbon fiber is two times stiffer, two times stronger, and only 1.1 heavier than glass;
8. S-glass and E-glass are three times more flexible than carbon fiber;
9. Extra layers of glass can triple the load capacity of a board;
10. Choosing epoxy over polyester resin has negligible impact on strength, stiffness, weight, but epoxy is more impact resistant;
The Forces
1. More buoyancy means easier paddling above water;
2. The more area of the surfboard is in contact with the water, the more friction drag will exist and, the slower the surfboard will be;
3. The greater the rocker, the greater the drag force;
4. The greater the velocity or speed, the greater the lift;
5. Bottom shapes with concaves and channels produce an upward force or lift;
6. Wave faces flow and move in orbital fashion and create lift;
The Variables of Surfboard Shaping
1. More surfboard area means more planing potential, less sinking and bogging;
2. The elements of a template are total and half length, nose shape and width, outline curve, location of the wide point relative to the center, width, tail shape and width;
3. More curve in the outline means easier turning;
4. Longer boards provide faster paddling, greater risk of nose diving and more effort required in turning;
5. Wider surfboards plane better in dead or slow wave spots;
6. Wider boards turn easier at slow speeds but have poorer rail-to-rail transitions;
7. Wider templates have poor hold in the wave face at high speeds on rail;
8. Wider surfboards are stiffer;
9. Rounder noses provide more lift and buoyancy, but create form drag;
10. Pointed noses suffer less "baseball bat effect" and are easier to hold in rail turns;
11. Pin tail surfboards have extremely low surface area and high holding power;
12. Square tail surfboards have high planing area and looseness;
13. Thicker boards have greater buoyancy and have easier paddling;
14. More thickness in the middle of the board means difficulty to lean on rail;
15. Thicker tails are looser at slow speeds;
16. More rocker means easier turning, harder paddling, and slow speeds in a straight line;
17. More rocker means less nose diving;
18. Vee bottoms create less lift and are slower than flat bottoms in neutral position;
19. Vee bottoms allow for easier rail-to-rail transitions;
20. Single concaves create more lift and speed and are harder to turn;
21. Double concaves keep the rails free and are looser and faster;
22. Harder rails plane very well but have a stiff, less smooth response to turning;
23. Soft rails are slower but provide better hold in subtle turns;
24. Tucked under edge rails balance the characteristics of hard rails and soft rails;
25. Greater fin area means better holding power;
26. Streamlined fin foils have higher holding power;
27. Asymmetrical side fin foils provide better directional holding power;
28. Greater fin base length/rake resists lateral turning;
29. Greater fin height creates greater resistance to rail-to-rail turning;
30. Further forward fin placement will loosen up the board;
31. Further back fin placement will create more holding power and drive;
32. More space between the front and rear fins means more torque required for weaving;
33. Toed-in fins create more drag and are easier to turn;
34. Bigger fin cant/camber means looser turns;
The Construction Types and Techniques
1. Traditional construction includes solid timber and hollow wood. They are strong, but they are heavy;
2. Sandwich construction puts strength only where it is needed, and offers high strength relative to weight;
3. Conventional manufacturing is all about moulding a foam blank from polyurethane beads, hand shaping the pre-moulded foam blank, and applying fiberglass and resin by squeegee;
4. Shaping machines cut foam to a predetermined shape designed in a computer software;
The Core Materials
1. More weight means more force needed to accelerate and turn;
2. Greater density cores add more strength but are less flexible;
3. Foam core is roughly half the weight of a surfboard;
4. Balsa is five times heavier than foam;
5. Doubling core stiffness is doubling the strength, but the flex remains the same;
6. Increasing foam core density means increasing strength and weight;
7. Carbon fiber is two times stiffer, two times stronger, and only 1.1 heavier than glass;
8. S-glass and E-glass are three times more flexible than carbon fiber;
9. Extra layers of glass can triple the load capacity of a board;
10. Choosing epoxy over polyester resin has negligible impact on strength, stiffness, weight, but epoxy is more impact resistant;
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