Everything you need to know about surfboard design and performance

Surfboards are objects of design. They could easily be in the heart of a proper museum. Surfboards are a complicated equation with still many secrets to unveil. Learn what's right and what's wrong in a magnificent surfboard.

You don't have to be a surfboard shaper to be an accomplished surfer, but information and knowledge are never too much.

In this particular case - surfboard science, surfboard art - you might make the difference if you add up awareness and comprehension to your physical and natural water skills.

A surfboard is a hub between water, waves, and people. A surfboard without a surfer is nothing. A surfer without a surfboard is never a surfer.

To understand better how surfboards work, we have to learn about the forces that act on them, the variables of surfboard shape, the general construction types and techniques, the core materials, and the types of surfboards.

For a more in-depth look at what's inside a surfboard, get "The Surfboard Book," a fundamental perspective on design, shaping, and performance by Simon Anderson, Dick Brewer, Steve Lis, Bob McTavish, and more.

These are a few rules of thumb that you will find useful when buying a new board or when picking one from your quiver:

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 an 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 curves 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 the 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. Pintail surfboards have an 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 in leaning on the 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 a 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 molding a foam blank from polyurethane beads, hand shaping the pre-molded foam blank, and applying fiberglass and resin by squeegee;
4. Shaping machines cut foam to a predetermined shape designed in 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 increased 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, and weight, but epoxy is more impact-resistant;

The Types of Surfboards

1. Longboards offer easy paddling and wave catching, and stability but are harder to turn;
2. Shortboards require more effort to paddle, but they trim and turn without having to move feet;
3. Fish boards plane well, side-slip on steep, fast waves, and can keep the speed over slow sections;
4. Twin fin surfboards have less fin drag than a thruster on rail, are relatively easy to turn on medium waves, but tend to side-slip on waves of consequence;
5. Thruster boards have more drive and hold than a twin fin, are looser than a single fin, but manage to perform well on bigger vertical waves;
6. Quads have less fin drag than a thruster on rail, offer a stiffer rotation compared to a twin fin, but won't side-slip on bigger waves;
7. Guns are easy to paddle for catching big waves, and they're not easy to turn but hold the wave face in steeper drops;
8. Tow-in surfboards are short, narrow, and heavy and come equipped with small thruster/quad setups designed to reduce drag;

Discover the surfboard volume calculator, and take a look at the effects of surfboard design on wave performance.