View Full Version : Spar making for IO Caledonia Yawl

01-14-2012, 06:28 AM
Does anyone know of any good blogs or maybe can describe how spars have been made?

The timber for mine arrived yesterday and I am looking at the spars plan and drawing what I think I should be doing but am just getting myself in knots!. I'm sure its a lot simpler than I am making it but want to make sure I'm on the right path before I attack the timber.

I'm doing solid Douglas Fir spars glued fron 2 lengths back to back. Thought it best to keep it simple.


01-14-2012, 10:10 AM
Solid Douglas Fir spars are going to be awfully heavy. Solid fir will work but over the lifetime of the boat you're probably going to wish they were hollow. Never done it myself but I understand that birdsmouth construction of hollow spars is fairly straightforward. Simple is good but lighter is better – and don't ask me how I know this.

Charles B
01-14-2012, 11:10 AM
Have a look at Woodboatbuilder.com. It is the website of the Workshop on the Water at the Independence Seaport Museum in Philadelphia (where I happen to volunteer.) If you poke around, you will see several videos and also some good descriptions and photos of spar building. Look particularly at sections on building the rig for Elf, and the Silent Maid sections. By the way, I agree with kenjamin that the weight of the mast may be an issue. WOW uses Sitka spruce (which is, unfortunately, MUCH more expensive,) but lighter. Also, a hollow mast is not such a tough job, although it does require planning, calculating, and machining, especially if you want to use birdsmouth. A simpler hollow solution is to start by gluing up a hollow 4 sided tapered form, and rounding that.

Good luck.

01-14-2012, 11:23 AM
If you have access to a good table saw and router table bird mouthing is not that tough, and it sure makes a nice stick.
Lee Valley tools sells the router bits. I bought the 8 sided bit for my Coquina main mast.

01-14-2012, 03:28 PM
FWIW: I just got the 8-sided bit from Lee Valley, just under $50 with shipping. They do sell bits for other-sided spars too. I figured $50 was a pretty small capital investment in the long run.


01-14-2012, 03:51 PM
I built a solid stick for a 10-foot mast for my 12-foot skiff. Its relatively heavy; but relatively small. The CY rig is bigger. Posts 40 or so on from this thread detail how I did it. Next time I'm going BM. Just not that much harder and a lighter stick.


01-14-2012, 04:06 PM
Search the WB online index (http://woodenboat.com/wbmag/idx/) for birdsmouth spar. Then buy the downloadable pdf for a couple bucks. All will be revealed.

01-14-2012, 04:57 PM
Here is the thread from last summer when Chris broke his CY mast just before the Small Reach Regatta:


Clinton B Chase
01-14-2012, 06:01 PM
Definitely go Birdsmouth on mast. Also see Duckworks for info on making these.

01-14-2012, 06:10 PM
I know I should have gone birds mouth...however I got a load of 4" x 4" x 16' old red spruce (30+ rings per inch) I couldn'b bare to gut it up and epoxy it back together

01-15-2012, 03:07 AM
Thanks for all the advice here. My original thought was to keep it simple and make solid spars. I'll have a good read through the threads and sites above.

Bob Smalser
01-15-2012, 07:38 AM
No need to waste 50 bucks on router bits useless fo anything else. Make a pair of finger boards instead, and your TS will cut those birdsmouths just fine.



01-15-2012, 12:17 PM
The Duckworks tutorial is superb. I am definitely going to do a birdsmouth mast; I think for any trailerable boat they are desirable.

01-15-2012, 12:49 PM
I agree with Bob about the router bits. There are a few special applications when they are handy but for a regular birdsmouth mast the tablesaw is fine.