All Seldén dinghy mast sections have been designed to give the best stiffness to weight ratio available in an alloy extrusion. Material, section shape and size, and wall thickness all have a major effect on both the static and dynamic bend characteristics of a tube. These details are studied in the design of every section and are carefully checked on every piece of spar tube we use. Selecting the correct section to suit your class and your specific crew weight and sail cut is vital. Please dont hesitate to refer to your class data sheet on www.seldenmast.com for further details, or contact your local dealer for advice