Composite Mast - foam core

[Eric Sponberg]

Theoretically, you could just duplicate the size thickness of an aluminum section with a carbon fiber section, and achieve a suitable result. This is the poor man's way to make a carbon fiber mast. It will not be optimized for strength, stiffness, and weight, and you still need to know about having enough unidirectional and off-axis fiber to make the laminate work. Attachments are another thing, too. You have to be able to make the spreader bases and the halyard sheaves and all the attachment and running rigging stuff, reinforcing the mast laminate wall accordingly. So overall, it really is a lot more complicated than you might think. Remember, too, that if you mess up on the design and building of the mast, the mast could fall down, and that puts the crew in danger of getting injured and/or getting stranded at sea. It's a big safety issue. Therefore, it is really prudent to consider buying a professionally built mast.

Eric

[sabahcat]

Originally Posted by scotdomergue

I plan to leave the foam in the mast. For the small boat and mast I'm planning the weight will not be such a big issue, I think. And the foam will provide buoyancy even if the mast could otherwise fill with water - a possible help with self-righting.

Solid foam?
And you run your halyards how?

[scotdomergue]

The foam core I have in mind is pipe insulation (see my first post to this thread) which has a hole running through the center. The boat is very small and light (18 ft LOA, 48 inch beam, less than 200 lbs including all sailing and rowing gear). The mast will be less than 20 feet high. Halyard for the single sail of about 100 sqft will run over or through the top of the mast and down the front side. Think long, narrow sailing dinghy and it may make more sense. It would probably be possible to run the halyard down the center of the mast, but that probably doesn't make sense. I have thought about running wiring for a masthead light up through the center of the mast.

I may decide to also have spinnaker or twin headsails for downwind (probably without the normal (main) sail, which could probably be hoisted by the same halyard running backward. I can also imagine having a second halyard, which could also run over or through the top of the mast . . . I'm still focused more on boat than rigging at this point . . .

[michael pierzga]

Make or scavenge a suitable mandrel, old mast, wood plug, flag pole then follow these instructions.

http://www.devboats.co.uk/cherubweb/masts.htm#final

Laminate e glass over mandrel....cure... carefully slice and peel off mandrel...glue back together ....now you have a mold .... then laminate carbon and reinforcements over this .

It might be easier to visit the sailing boards and buy a secondhand carbon dingy mast. Mast step, spreaders, mast head, gooseneck.....cheaper and better in the end.


I just saw one for sale..Int 14....mast boom sails rigging. The boat was stolen or destroyed.

[scotdomergue]

Thanks for good thoughts and link. Very interesting. At this point I'm focused on getting the boat design finished and built; the mast seems somewhat secondary. It will be very simple, unstayed, probably with rings attached to the sail that slide up and down the circular cross-section mast. Any further suggestions, including for buying such, are welcome.