Mast tube source

[davidpm]

Where is a good place to get the 2" and 1.75" mast tube.

Is this the stuff?

http://www.onlinemetals.com/merchant.cfm?pid=4368&step=4&showunits=inches&id=71&top_cat=0

Seems expensive.

The plans seem to mention a full wood mast.

Can I just epoxy some 1 / 4 clear fir flooring and make a mast?

It would look nicer. how do you do a joint to make it 3 piece.

Would it be too heavy?

[Charlie Jones]

That's where I get aluminum tubing. I use aluminum lower sections and birdsmouth wood upper sections. And the tubing isn't THAT costly considering what you are putting into the boat overall.

If you choose to use two sizes, one inside the other, you'll need to ream the larger one so the smaller will fit. I built a reamer like this to do the job. The short narrow strips are used to pack out under the flap part to increase the bite as it reams out. That's sections of floor sanding paper stapled on to each flat of the wooden part. I used a chunk of all thread rod with nuts each end as a shaft. You'll need to double nut as the pressure will spin the nuts loose otherwise

[Greg Luckett]

That is a good question about building an all wooden mast.  I have wondered about doing that for the Spindrift 12 being built currently.

I have an Oday 10 with a wooden mast and boom, and I like it that way.  Easy to maintain, repair, or replace, and not too heavy for me to handle easily.  While I use Aluminum for mast on other boats, I like the look of wooden spars much better.  AL just always looks ugly to me when contrasted with a wood boat.  Years ago, my first boat, was a Lightening with all wooden spars and Egyptian cotten sails.  At the ripe old age of 13 I learned to sew repairs in my sails and maintain my wooden boat and spars.  I would still prefer the Egyptian cotten sails on the small boats like we build, but it is darn hard to find any cloth.  The mills that made it in England have all shut down, though I heard one might start up again.  If it does I plan to buy as many bolts of the cloth as I can afford.

[Charlie Jones]

Greg- I've built birdsmouth masts as small as 8 feet, for a dinghy for a guy out in Arizona. Turned out really well. In fact, it was tapered to about 1 inch or maybe a tad more- I forget those things. But it was really pretty light.

[Greg Luckett]

Charlie,

I have been thinking about the birdsmouth spars for several years now and bought a couple of the router bits then.  I need to talk with Graham about the mast possiblities for the S12 sloop rigged.

[Designer]

Greg,

Because you are doing a sloop, you need a mast with a luff groove. You are probably better off doing a birdsmouth mast.

[Greg Luckett]

Greg,

Because you are doing a sloop, you need a mast with a luff groove. You are probably better off doing a birdsmouth mast.

Good!  

Thanks Graham.

[Cricket]

Hi Folks,

I built birdsmouth spars for my Windward sharpie http://www.jimluton.com/boatsand while it produced beautiful, light. sticks, I found it very time consuming. I ran the vee groove on my shaper with a stock feeder. I used 5/8" stainless sail track from Defender to good result. One thing I would say, is be sure to use vertical grain or at least quarter sawn fir for the staves. Flat sawn stock is hard to plane and sand smooth w/o waves due to soft grain/hard grain. Bendiness is another issue. My mast is very stiff, maybe stiffer than is good for spilling air, but I erred on the side of heavier rather than lighter scantlings. A good website for birdsmouth spars is http://www.duckworksmagazine.com/03/r/articles/birdsmouth/mast.htm

Cheers,

Jim Luton

[Greg Luckett]

Jim,

Thanks for those links.  I have just enjoyed looking at your pictures.  Very nicely done boat.

I am printing out the other birdsmouth information.  One question is, are booms made using the birdsmouth method?  I am thinking a boom for our size of boat would be too small.

Greg.

[Charlie Jones]

Curious as to exactly what you found so time consuming?

I timed myself once building a birdsmouth bowsprit for a boat- took me exactly 3 hours from the time I walked to the saw to cut the rough board to length, until I had it sanded round and ready to apply finish. Not counting glue curing time of course. And I do all my cutting using a table saw. I can't imagine building one another way any quicker, unless you could buy a round piece the correct size.

But then I've built 12 or so spars with Birdsmouth so I'm used to the technique. Maybe that makes a difference.

I think the uses for the technique have just barely been scratched. I can picture ovals, rough rectangular spars, doubled tapered, tapered toward the center ( can't think why though ;D) Just immense variations possible. I intend to explore the use more in the future.

Sure agree on the vertical or quarter grain stock though.

[Greg Luckett]

Heck, Charlie, it takes me three hours to dig out the lumber and set up the shop just to rip the strips....based on my past performance ripping the lumber for this Spindrift.  I expect to get faster and certainly would be buidling the spars faster after doing a couple...I hope.  At this point, it would take me a while to figure my way through the process.  Maybe Jim was the same way, though the  pics of his shop make me think he would be faster than me right out of the chute too.

[Charlie Jones]

Greg- when you get down here in June, maybe we can scrounge the time to run through a set up and cut of some staves. Show you exactly what's involved. 

[Cricket]

The time consuming part for me was the tapering of all the strips, and once I popped it together dry I found I wasn't happy with the shape, so I re-tapered all the strips before gluing. I've built several solid spars where you glue up two pieces, then saw out the profile and 8 side, etc. and I found this to be quicker. But I have heard many people say the birdsmouth is fast. It pays to be fastidious about the cleanup of glue while wet. Its pretty brutal to powerplane all the gobs of epoxy.

I did build the boom this way too, and though fairly robust in section, its wicked light. I too, think that there are worlds of possibility for building structures this way. You could build in some bend, for example, or multihull cross beams. Ovals are no problem. I'd build porch columns this way too.

It could be I'll be faster next time around, now that I know some of the design pitfalls.

One question though. Why (besides the storage issues) are people building multi section alu sticks. Are the lower and upper sections independently engineered for controlled bend like in a Laser mast? If sails are being purchased off the shelf, I would be careful to match the mast bend to the luff curve. This might be harder to do with a wood stick. You won't know till its all done! I once had a racing sail for a C Class sailing canoe made, and the sailmaker used a heavier stick to bend for checking the curve than what I used for the boat. Consequently, my mast was too soft, and in light air just halyard tension made the sail too flat. This was a full batten sail.

Here is another duckworks article on staved spars.

http://www.duckworksmagazine.com/04/s/articles/birdsmouth/index.cfm

After all this, I meant to say that I really like the CS17. Its definitely in the running for my next project. I might just squeeze it into my freight elevator.

Jim

[Cricket]

Sorry, I forgot to say that I was trying to build a nice parabolic taper in the mast, and it was difficult to figure, and to cut the curve for each teeny, whippy 22 foot long stave, so that the net effect was the parabolic curve I was after.

Jim

[Greg Luckett]

Charlie, thanks for that offer.  I expect you will be pretty tired from the Texas 200 and then the Mess About to find the time that weekend, but maybe some good timing will work out.  I have never been to a mess about and have no real idea how much time is used or in what way.  Seeing how a pro makes a birdsmouth would be wonderful.

Jim, thanks for those links on building the birdsmouth.  I have not taken time to read them yet but will do so this weekend.  Yard work, building the Spindrift, and drinking coffee seem to take most of my time lately.  I will read while drinking.....coffee that is.

One question, probably answered when reading the links, but how do you get 20 some feet long staves?  Are lumber planks scarfed, then ripped, or is each stave scarfed to make it longer, or??

Thanks.

[Cricket]

Greg,

I glued up 1x6 planks w/ a scarf, trued an edge, then ripped out the staves. Then thicknessed, vee grooved 1 edge, then tapered.

Jim