Mast Building 101

[oldriverat]

I moved this to B&R in order not to take up anymore of mmd's space on the Mahone Bay Thread.
Thanks for the responses ao far. smile.gif

Thanks mmd. I'm almost to the point of installing the fore and aft decks on mine. This gives me different and possibly better alternative. Also, if you don't mind, could you get me the mast dimensions at the base. The plans state 2 to 2/12 inches square. That seems a little weak to me.

[oldriverat]

mmd
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Member # 1908

posted 08-02-2003 02:26 AM
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Jeeze, Memphis! Ya gotta let me answer one question afore ya asks the next one!

Mrs. MMD brought your question about mast foot thickness to me while I was kibbutzing with the Small Wooden Boat Assoc. of Nova Scotia (SWBANS) members at our permanently-reserved table (actually, we never leave - there is always somebody there to hold the fort!) at the Mug 'n' Anchor Pub, so I posed it to the assembled members. These included four Windsprint owners, including two of the owners of the decked boats, and the winner of the daily race today. Amidst the roar of bragging, lies, and heart-felt toasts to each others' health, their duly considered reply was, "Yeah. Well.. Sort of. I think. Maybe. What was the question?" Keith's beer has that effect on some, ya know.

Bottom line is, I think so. I didn't measure the mast when I took the pic below, and wasn't about to leave my beer unattended around that pack of sea dogs to go back to the boat ramp to do so, but I think that the pic shows that 2-1/2" is a reasonable size.

[oldriverat]

Memphis Mike
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Member # 6715

posted 08-02-2003 09:58 AM
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Thanks mmd. Next question is the mast looks thicker at the partner and tapers off to 2 1/2 inches at the foot. Is that true? I've never built a mast before and will probably wear out the moaning chair over this. I guess what I'm asking is what are the overall dimensions of the unfinished stock used in the construction of the mast. The plans state 2 1/2 inches square by 15ft 6inches long. The masts in the pictures look thicker than that above the partner.
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From: Memphis,Tn. | IP: Logged

mmd
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Member # 1908

posted 08-02-2003 11:53 AM
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I am not familiar with the scantlings of the design; I have not built one nor even looked closely at the plans so I can't speak authoritatively on them. And of course, now I am ten miles from the fleet so I can't measure the mast. It does seem, however that the masts are in the order of 3" to 3-1/2" in diameter at the partners. If you are not misinterpeting the plans and it really does spec a 2-1/2" square mast, I agree that it seems a bit small.

Just to toss a further wrench in the works, most of the SWBANS Windsprint owners are going to replace their solid spars with 3-1/2" diameter bird's-mouthed hollow ones. Same strength, half the weight aloft. WB issue 149 had an article on how to build them.
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From: Bridgewater NS Canada | IP: Logged

Art Read
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Member # 994

posted 08-02-2003 01:04 PM
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Mike, is that ALL the plans specify for the mast? It seems for a tapered spar, and virtually ALL are, they would need to provide information to determine the tapers. My plans gave dimensions and location for the widest part, (at the gaff) and also for the bottom and top ends. Three different numbers. You sure they don't have something marked on the drawing itself? Perhaps on another "view"? 2 2/2" seems a bit small for a fifteen foot long spar. My 22' mast is four inches at it's widest. About 3 1/2" at the heel and 2 1/2 at it's top.
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From: Seattle, WA | IP: Logged

Memphis Mike
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Member # 6715

posted 08-02-2003 03:49 PM
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In Payson's book, it gives all the information for a couple of the other boats concerning construction of the mast but very little on the Windsprint. For the other boats it shows the length, degree in taper at 2ft. intervals...ect.
It could be the information is there and I'm missing it. If it is, it sure is not provided in the same manner as the other two boats.

It could be he intends for me to refer back to the plans for another boat { he mentions doing this sometimes} but if so, that would mean starting off with a 2 1/2 in. sq. 15ft. 6in. long piece of unfinished stock for the mast. It doesn't make sense to me because the masts in mmd's pictures are clearly heavier than that.
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From: Memphis,Tn. | IP: Logged

holzbt
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Member # 1528

posted 08-02-2003 08:07 PM
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MM- It looks like you are supposed to measure the mast taper from the full sized plans. I looked through the book quickly and didn't find the dimensions for the mast that you need. I used proportional dividers and came up with a heavy 3" for the mast at the partners. I'm sure that my method is not the most accurate as I worked off the small drawings in the book but 3" or a bit more seems about right.
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From: Babylon, N.Y. USA | IP: Logged

Memphis Mike
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Member # 6715

posted 08-02-2003 08:35 PM
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Thanks Holzbt. I noticed on the plan just now where is says "transverse scale full size" and I measured at the partner and it is 3 inches. According to another forumite, this tapers off to 2 inches at the step. Now if I can just figure out the taper from the partner to the masthead. Sorry for the thread hijack mmd. I'll try to move this to B&R.
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From: Memphis,Tn. | IP: Logged

[ 08-02-2003, 08:48 PM: Message edited by: Memphis Mike ]