CS 20 masts

[GeneB]

Received my set of CS 20 plans in Friday's mail.  Been studying the masts.  The aluminum tubing seems to be very thin walled.  This is my first free standing mast boat.  Wondering about anyone's experience with these masts.

 

Thanks,

Gene

[PAR]

Free standing mast design is a function of several factors. As an example wall thickness can be pretty thin, if you can live with a bigger diameter. On the other hand, materials can also make a big impact, but I'm sure Graham is specing 6061, which is a strong and stiff alloy, permitting this seemingly thin wall. My experience with the CS series is the masts are well sized and yep, you can break them, but you'll have had some considerable warning, long before they do. As to the specifics of your question, I've seen several bending way past what I'd feel comfortable with, but they held up, though it does seem the spec's for the wooden version is a tad on the light side. These could use another 1/4" - 3/8" of diameter to be more robust, but more importantly, less bendy in the typical wind strengths most sail these puppies in.

[Joe Anderson]

I think the masts perform very well. Just be aware that you can not make any substitution for the alloy specified in the plans.  If it says 6061 T-6 that is what you have to have or you are asking for trouble. I would not recommend altering the size or alloy unless you really know what you are doing.

[Designer]

Gene,

 

The masts on the Core Sounds have been well tried and tested. The only masts that I am aware of that have broken on a Core Sound have used the wrong metal or have hit something with their masts.

 

Core Sound 20 Dawn Patrol was the most prominent recent dismasting. She has raced for many years in various adventure races without mishap until she got her spinnaker halyard caught on a day marker in the dark doing about 6 knots hard on the wind. The boat rotated about 90 degrees around the piling before the mast came down. They tided up and stowed the rig on board and carried on racing with just the mizzen. They went on to win the Everglades Challenge and set a course record. We have since sized the wall section on the lower masts up one size to allow for extra abuse.