Mast scantlings for BCC

[Tom Chapman]

Looking for mast scantlings for BCC 28ft OD, 36'OA....from the Morse mold. Mast to be glued up
Doug fir. 5 1/2" x 7 1/2 x 3/4"? I dunno....any guesstimates?

Tom
St. Helens

[Meerkat]

Hmmm... why not call the Sam L. Morse company or write them an email?

Sam L. Morse Company (http://www.samlmorse.com/)

[Thaddeus J. Van Gilder]

My 27 foot Bristol channel cutter has a solid longleaf mast 8 inches in diameter tapering to 4 inches at the truck.

Thad

[cherokee]

tom, if you can't get an input from morse on your mast scant's you can figure it out using the gerr or kenney/skene's 'by guess and by gosh' method to obtain a guesstimate roll time,then with your all-up disp get a max righting moment at 30 dgr heel(RM30) ,then with the fomulas from skenes you can deduce various section stregths(moments of inertia-'I')for wood spars-hollow box.hlw oval,round,solid box,oval,rnd etc,then you take your panel distance-typically the deck to lower shroud tangs- this # with 'I'is inserted into 'euler's formula' with the spar material strength-'E'to get a compression strength for your sample spar.add safety/unknown/idiot factor of 3-6X depending on your bias and you get a section.......whew!the telling of it is harder than the doing!! thad's cutter w/ the solid stick seems a better choice than the hollow box if your bcc is a high ballast ratio/deep as that up-top mass helps dampen a quick roll. if your going tall marconi rig then a thich wall box may be good. you gotta know your boats personality before you can decide. herreshoffs book 'sensible cruising designs' has great examples of strong box spars. if you can't easily obtain the various methods and/or formulas i'll send up the method which others may want as well-it took me a long time and alot of used book purchases to get all the parts to figure a wood(unaluminum)spar. also in your neckothewoods a nice solid d.fir stick should be a easy find. and working that solid wood beats glueing and a thousand clamping devices any day....take care-and on to the horn with ya in that bcc!! john