View Full Version : Wood for a new mast
SV Papillon
12-24-2006, 01:48 PM
Would Silverbali be suitable for building a spar out of?
Silverbali (http://www.deepwaterventures.com/woods_silverballi.html)
I'm asking as I need to replace a mast on my 50' schooner. I'm in the PNW and going off of other posts and advice from our architech consultant Sitka Spruce and Douglas Fir seem to be the ideal choice. I'm buying a bunch of silverbali for the boat refit and thought I should throw it out there.
Thanks
Jake
Raggi_Thor
12-25-2006, 06:49 PM
Spruce is stronger in the outer fibres than close to the center, ttat may be an important detail in mast building,
see http://cat.inist.fr/?aModele=afficheN&cpsidt=16908566
"The stiffness modulus in the longitudinal direction for Norway spruce grown at a medium-fertility site increased with distance from the pith from 6±1 to 8.5±1 GPa."
Density of silverbaly seem to vary a lot.
Maybe you should check the properties of the batch you are buying.
If it's a hollow mast you can probably adjust wall thickness in a linear relation to the stiffnes ratio.
Hav you asked the architect?
BOATMIK
12-25-2006, 07:28 PM
I agree - ask your architect.
The critical factors are usually
1/ How well the timber glues - timbers can appear to glue OK but sometimes it is not as good as it seems. One of the reasons we generally stick to Fir and Spruce is because their properties and quality are pretty well understood with the result that we can predict the behaviour of structures made out of them.
2/ Its density - as strength and stiffness vary in line with density for most timbers.
3/ Its grain pattern - you want long straight grain - not grain wandering in and out of the sides of the boards.
SV Papillon
12-25-2006, 07:49 PM
Thanks for the input. I have not run it by the architect yet. I would assume a similar response. I'm rather naive in this, just looking for different alternatives. Getting a suitable length for a solid spar would be cost prohibitive, I guess spruce or fir it is.
Thanks,
Jake
View Full Version : Wood for a new mast