The concept of surfboard volume is of increasingly popular interest; despite the fact that it has been used in windsurfing for a long time. Buoyancy is, in fact, a critical factor when it comes paddling and gliding.For several decades, shapers wrote three main specs on the back of their surfboards. These were the length, width and thickness of the board. Volume, in liters, was never a consideration.
Recently, former pro surfer John Whitney Guild proposed the inclusion of the volume ratio to rider weight in our surfboard spec list, so that surfers could better choose the best surfboards for themselves.
Knowing that two surfers with the same weight, but differing experience levels will paddle for a wave differently, it follows that the floatation needs for each situation should be adapted accordingly.
The intermediate/advanced surfer on a shortboard will require between 33-35% of his body weight in board volume. For example, a surfer weighing 154 lbs (70 kilograms) should be looking for a 24-liter surfboard.
Beginners in the art of surfing can easily learn how to pop up on a surfboard that has higher flotation ratios. This means that the most suitable surfboards for learning how to surf will have more volume in liters, and be bigger overall.
One liter floats one kilogram of weight, and based on this knowledge, Whitney Guild has created a volumetric table system named the "Guild Factor." This surfing scale allows surfers to pick the right surfboard for his or her skill levels; and accounts for wave conditions.
It can also be used for selecting longboards and stand up paddleboards. So, what are the most common "Guild Factor" ratios?
Formula: Surfer's Weight in Kilograms (Kg) X Guild Factor (GF) for Skill Level = Liters of Surfboard Volume
Advanced/Pro Surfers: 0.34-0.36 (GF)
Intermediate/Advanced Surfers: 0.36-0.38 (GF)
Intermediate/Older Surfers: 0.38-0.42 (GF)
Weekend Warriors/Casual Surfers: 0.43-0.49+ (GF)
Beginner Surfers: 0.50+ (GF)