The energy from the wave enters at the rear of the board and creates lift. The fin adds direction and the weight of the surfer in front of this lift creates the surfboard’s forward motion. When the board traverses on the face of the wave, the fin traps the upward force of the wave. The weight of the surfer in front of this force provides the forward motion. Surfboards with hard rails in the tail area also gain some lift from this feature. You can pump the rail, driving the edge more parallel to the wave’s face and the speed increases because you are no longer moving just towards the beach, but somewhat parallel to it. The tighter the line that is drawn to the face of the wave, the faster you go. On long boards, the speed of the board will increase as the surfer moves forward on the board, until his weight overcomes the volume of board beneath his feet. The place of maximum speed, which is about 1/3 from the nose, is sometimes referred to as the [full] trim spot. Conversely, the closer one places his weight to the fin area, the lift action will begin reducing, stalling the board.
A surfboard turns because the surfer initially tips the board on one rail. The amount of curve in the part of the outline that is in the water creates drag, forcing the board to begin to change direction. More weight is usually applied to the rear foot as the surfer twists his body. The upper torso remains in the direction of the turn, and in the uncoiling of the legs from this twisting motion, the board is forced to follow. During all of this the fin, or fins offer a pivot point while it grips the wave’s surface.
Stability is the first thing we strive for, and board width, nose width, length, and weight will produce this. Action on the wave is gained from more tail rocker and less nose rocker. A 50/50 rail design finds a higher slot on the wave’s surface, and some form of scooped out bottom of the nose will add lift and possibly slow it down adding stability. One or more of these design concepts, when properly applied, will enhance the nose ridding.
Paddling, Floatation And Buoyancy
Some long time surfers suffer from back and neck problems due to that constant arching of the back that prone paddling requires. Knee paddling, also has its drawbacks. You put both arms in the water when you take a stroke. Therefore, you must rely on the board’s coasting ability to keep up the momentum before the next stroke. Thus, any board that floats less than nose and tail out of the water will not be effective at knee paddling. Clearly, a board of these proportions will restrict the turning characteristics.
Most surfers want to maximize maneuverability. The shorter the board is, the less swing weight will be in front of you; so it turns easier. However s shorter length typically reduces volume. You will always give up something in order to get more floatation.
You should make the decision about how much maneuverability you are willing to sacrifice in order to paddle well. In general, consider how much paddling or floatation you need. More volume will help floatation, and a little less rocker, length and width will also help. Because egg shaped, or 50/50 rails usually have a rounder bottom, boards with these rails usually paddle better. The side bite fins on 2+1 set ups are towed in and cause drag. If paddling is an issue, consider not buying a 2+1 setup.
Catching waves easily seems to be one of the more frequent design requests. A narrow nose will be more efficient and especially in offshore winds. I don’t believe any type of nose concave will have a major effect on dropping in. Too much bend at the point of water entry will push water. Typically, the bigger the board, the easier it catches waves. A wider tail will capture more of the wave’s energy than a narrow one.
The size charts we provide on the Surfboard page are here to suggest what we feel will get the optimum performance for a board’s length. This means a total package: turn, nose ride, cut back, wave connect, drive, and wave catching. For example, if you go smaller, the paddling and tip time will not deliver the board’s potential. If you go longer you will lose some of the turning characteristics. Nothing is etched in stone, and you may make your own choices.