Dock Mounted 2-Sided Kayak/SUP Rack. No more lugging around your heavy kayak or paddleboard after a long day on the water. With Magma's new Kayak/SUP Storage Rack System your problems are solved.. Building the rack system is simple; start with the base rack, R10-1002-64, and purchase the specific arms separately that best fit your needs. Rack arms are constructed from 304 Mirror Polished Marine Grade Stainless Steel tubing and are available in either straight, 30" x 1-1/2" Dia., R10-1010-30, or