Here is one worth thinking about. Ann and I have had a lot of problems with mast breakage issues, lately we have reinvested in RDM's as they are said to be bullet proof although double the cost and also you need a skinny extension now to fit but fortunatley the booms have a shim adapter so that saves a bit. So far (three years) no issues with RDM's yet! Also on breaking a mast I have given this a lot of thought and most of our masts would break just above or just below the boom so what I have thought I would try (again I have not had to do this yet) is to fist lower the boom onto the bottom or unbroken mast part ( take extreme care with the broken carbon ends the shards can sliced you up easily), then slip the top portion of the mast out of the sail flip it over and jam it into the mast bottom so you now have one mast that may have been a 460 now possibly a 400 but one piece. Take the extra 1 foot long piece of spare downhaul rope that you always carry with you for emergencies and tie the sail head (strap) to the top of the mast, this would not be very efficient but it may just get you back to shore.