Mast Diameter Choice     There is much discussion about the pros & cons of standard and reduced diameter masts... RDM's generally use a similar amount of material as SDM's, as a result they feature an increased wall structure making the mast more durable. Smaller diameter tubes naturally flex more so will often bend further before failing. Some sailors prefer sails with a softer and more forgiving feel resulting from the RDM's extra 'suspension' like properties. The ease of grabbing hold of the mast is also popular. The thicker wall structure and smaller diameter reduces the speed of the reflex cycle. Extra flex compromises the potential power output and ultimate stability when fully loaded. Some of the inherent flexibility can be reduced by increasing the carbon content or wall thickness, but those factors have their own consequential issues. RDM's sink as the volume of air within is insufficient for them to remain afloat.   In Summary SDM's naturally remain in shape when loaded and have a faster response because of the reduced wall structure. For those reasons they offer the most superior performance in terms of wind range and power, but with the trade-off of reduced durability and sometimes a less forgiving feel - but that often results from mast:sail compatibility issues and/or poor tuning. For those specifically sailing in surf conditions where durability is the concern above all others, and bearing in mind that so often a sail is being run like this in a lower relative wind range anyway when compared to bump & jump or freeride mode, for sure reduced diameter masts are worth serious consideration.     Equipment Failure - Faulty Or Fair Game?     Modern carbon fibre masts are generally highly reliable pieces of equipment. Failure normally results either from impact damage or excessive loading. If a rig goes down in surf conditions it can quickly be swamped by a huge weight of water - remember that 1litre of water weighs 1kg - with that in mind go and hang a 1litre bottle off the top of a rig and walk just a short distance with it...you will quickly get an understanding of the load/leverage effect of even just a small mass let alone a wave! Any weakness resulting from an impact will only heighten the odds of load failure. Increased strength achieved by using a reduced diameter mast can have an effect on some other part of your equipment. If the mast survives a massive load it is likely the force will be transmitted onto something else instead. I've seen more extensions, booms, battens and sails fail as a result of rigs featuring RDM's going down in the surf!   Very often when I hear of mast failure I am told 'I was just sailing along and it snapped' or 'I was rigging and it simply went off like a gun shot'... The simple fact of the matter is that a mast is instantly exposed to a huge load when tensioned during the rigging process. Most masts with any weakness, caused either by bad manufacture or subsequent transit/impact damage, will fail before even getting to or on the water. Additionally as a mast is deflected in use an even greater degree of strain is exerted upon it, as a result any weakness that doesn't initially cause failure will be extremely likely to shortly thereafter.   So a faulty mast (even from new) will often break within the first few hours of use, if it doesn't then it should be assumed that there is no issue with the mast. Impact damage can cause the structure of even a durable mast to delaminate (break apart). I always rig and deflect my new masts on the shore before heading out, that way i can be certain the mast is going to be okay. Any used mast coming in as an exchange goes through the same test so we are then confident to re-sell without issue.