mast construction

would anybody be able to either assist me with the specs for constructing a fiberglass mast or point me to some reference material where i could figure it out myself.

i have the height, and i have the sail area on the mast.
these will be freestanding masts( un-stayed).
additionally, does anybody have any input with regards to what % of bury i should allow for with the unstayed masts.i have read that a minimum of 10% and 15% being ideal.
the masts will be buried in fiberglass tube sockets that will run from keel to deck


i plan to use a foam mandrel and use the woven fiberglass tubes, which i would pull onto the mast like a sock, and then wet it out.
using a good laminating epoxy for the resin.

i think i would rather use the fiberglass than the carbon- only due to durability of the glass,
but i do undertsand that the glass mast will be heavier, due to the extra laminations to obtain the same degree of stiffness.

many thanks

 

It should be fairly straight forward. There is lots of design and empirical data for wood and aluminium free standing masts. You need to keep EI constant. And you know the E value for wood, aluminium and glass. And the I for the wood/ali masts. So finding I for your grp mast is trivial
There are lots of boats with unstayed masts, from Laser and Sunfish to Freedoms, so again you can find some empirical data for mast bury
Richard Woods of Woods Designs

 

Hi Wayne,

Out of interest, here in Australia Ben Lexens Revolution 38 Cat Ketch had free standing fiberglass masts.
These were constructed to halves split fore and aft then riveted together on the join.
The only one that I know that failed was lost when spept under the very low Fremantle traffic bridge.

 

many thanks for that, i will do a search

 

rig design hints http://www.aes.net.nz/info.html

Scroll down to home made carbon masts. You’ll have to calculate the substitution but the principles should apply.

 

many thanks- an interesting read all round!