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I've got no advice for you, but would like to exclaim: wow! that's a lot of work for a mockup! It looks lovely, and I trust you'll find a use for it somewhere when you're done.

Hopefully someone here will have something more useful to say - if not, I'd suggest trying over at the woodenboat forums, since they deal more often with this sort of thing - I think.

Good luck, and thanks for the pictures!

That sure is some serious mock up! Well, if nothing else you have proven to yourself you have the skills to do it well. You might even find that your mock up works just fine as the real thing. I am guessing that by heart pine you mean Southern Yellow Pine? True heart pine is almost impossible to find these days as the trees are never allowed to mature enough to even have heart wood. Southern Yellow Pine is actually a fairly good choice for this application. Sitka Spruce is one of the best for weight to strength ratio, but the total weight difference between the 2 would only be significant to the serious racer.

Northstar wrote:.......... and it appears the pole should be about 2 11/16” in the middle in order to fit into the 1 ¾” pole ends I have.

I don't understand that logic at all. You can adapt your design to make the needed center diameter work. The diameter of the pole and the taper are engineering decisions based on the need for strength. The pole ends are built to accommodate the fittings. The fittings are chosen to meet the needs of the pole. All of this is effected by the choice of wood, or even better the choice of wood was part of the original parameters for the design. If you build the pole to aesthetically meet the fittings then you end up with a beautiful pole that may or may not meet the needs of your boat.

Off hand I would think the dimensions you chose would be quite sufficient for a Triton. I would be tempted to varnish your mock up and go sailing :>)

Glenn,

Wow! Great mockup. I was also tracking those pole end fittings. Nice to see that they found a good home.

When I finally get to making a spinnaker or whisker pole I will definitely be back looking at this post. Thanks for all the great photo and please keep us posted.

Here is the page from Skene's that I think you are referencing for pole size and taper (just to add as a reference for this thread).



I would definitely agree with the idea of some varnish and some sailing on that beautiful mockup.

Cheers,
Bill

Heart Pine is sold for a pretty price by recyclers of old building parts. I bought some of mine from a fellow in Doylestown PA and some other from Good Olde Things in Scranton, PA. Sold for flooring and cabinetry. I doubt I'd use it for spars since it's heavier and perhaps not all that happily gluable. I use it for flooring (to match the rest of the house), and for countertops. I have glued it with epoxy, coated some with epoxy and Urethane. I think that the bond is adequate for house service but iffy for boat service; the wood is very resinous. The spring wood is softer and collapses under impact; the epoxy would rather chip than follow the wood.

A favored spar wood for performance and light weight is Sitka Spruce. Gluable, holds a finish. A favored spar wood for stiffness and strength is Douglas Fir. Ditto re gluable and holding a finish. I think that pines with the strongly contrasting summer and spring wood, like your yellow pine mockup would be less suitable for glue and finish.

Once you've jigged and cut the birds' mouth, the fun will be in thinking up an easy way to shape the curve on the square edge.

You're on the right track for size and shape; a pretty curve will be much nicer than the tapers usually seen.

NICE project.

The birdsmouth section is stronger than the square upon which that table is based. I think your scantlings are fine, particularly if you do NOT rig the pole as shown in that "spin.gif" image. That "rings lashed to the pole" method is very tidy and convenient for the foredeck crew, but imparts a lot of strain on the pole when sailing a puffy reach. The traditional bridle method keeps things in simple compression.

Curving the taper, when divided between the eight staves, will be a VERY exacting piece of work. Draw the lines with a razor blade instead of a pencil for that one. I'd be inclined to just straight-taper it and soften the look of it on the exterior only.

I just finished a wood pole for MUSKRAT and cheated- with advice from a local spar maker pawed throught the pile at the local lumber yard for 3 clear (fairly) spruce 2 x 6's. It called for a hollow pole so I cut out the middle of the inner plank and then west systemed them together. The plans from alden called for 3.5" in the middle tapering to 2" at the ends with a total length of 14' 3".

I power planed it to a tapered square and then was flumuxed as to how to create a tapered octogon. On the internet found the plans for a spar gauge which actually uses that greek guy's-pythagurus sp?- theorm sp?. Very slick rig and with that I could draw lines on all four and then plane down to an octogon. After that it was planing until i quit trying to make it perfectly round. 12 coats of varnish and it's all done- Probably will self destruct the first set!

I'll try and post some pix.

That's my spinnaker pole in the first photo you posted. It's the same as John describes with a lot of camber in the taper from 3+" to 2" on the ends.

I have seen it with an alarming bend once or twice but it has survived. I could see during those bends, the taper was well thought out.

The compression from a symmetrical spinnaker can be substantial. If you do intend to use it more as a whisker pole, you will not likely see the same loads.

The photo doesn't show the taper which in fact is quite visible.

Northstar wrote: Figment: I’m with you on the “The traditional bridle method” or possibly just a topping lift on the outboard end? So what do you think…a 1/8”-3/16” piece of line or a small diameter coated piece of 7x19…like life line material to tie the two triggers together??

Having an "outboard end" of the pole means you're planning to dip the pole during gybes, not go end-for-end? It's only a Triton, man. As far as spinnaker loads go it's about equal to a J24. End for end is the way to go.

Topping lift isn't really what imparts the strain on the pole, it's the downhaul/foreguy/whateveryoucallit.
The topping lift primarily supports the weight of the pole on a deep run. I've never heard of a pole failing on a run.
On a reach in a puffy breeze, the uplift on the end of the pole is significant, and the compression is significantly more as well. All is fine until you try to carry the sail a bit too high (or the wind shifts forward), the spin collapses (unloads) then suddenly refills and tries to yank the pole tip skyward.

There is a hybrid rig that's worth considering: Have a D-ring lashed (or webstrapped) to the midpoint of the pole for the topping lift, and a bridle for the foreguy which you clip on when the breeze warrants. It's just SO much easier to keep lines sorted out during and after gybes without that damn topping lift bridle in the way.

For the tripline, use whatever low stretch light line you have. I wouldn't use the coated wire because you want it to have some grip and some slack so that you can have the ability to open only one jaw at a time. You don't always want to trip both ends of the pole at the same time.

You do great work on the mock-up!

I realise you want to make a birdsmouth spar, but here is a spinaker pole I made a few years ago for my Bristol 24. It has seen a lot of use in all kinds of wind. I've even used it to push the boat off a sandbar. It is nice and light, and easy to handle. Maybe not all that strong, but I haven't broke it yet.

I made it from 2, 12' western red cedar 2x4's I picked out at the local lumberyard. Before gluing them together; I routed out a 1" x 1/2" slot down the middle of each board, to about 1 foot from each end. . I glued them with Titebond 2. I sawed them tapered from about 2 1/2" at the middle to 1 1/2" at the ends. I then rounded the pole with a drawknife and plane. I finnished with 8 coats of spar varnish.

SWEET! Excellent work!

Very nice. Looks more like a piece of furniture than a pole you stick on a mast every once in a while.

Right.

Now to the question of stowing it. It won't do to simply lay it on the deck like some common aluminum fencepost. What's the plan?

Figment wrote:Right.
What's the plan?

Plan? He's been having way too much fun building the thing to have a plan.

Man that is some fine joinery. I am impressed. Bamboo fly rods use a flat face joint that tapers from butt to tip over 6-12 feet. Obviously a different engineering concept but interesting in that they are designed to bend, not break. I do think using the electric plane is cheating. You should be using a piece of obsidian while sitting at the fireplace telling your kids/grandkids about seafaring adventures.

In all honesty, very nice job.

Dave.

Using a birdsmouth joint between staves adds little if any strength to the spar. It does add a little surface area to the glue joint, which helps, although not really necessary. What the birdsmouth joint does do is make aligning the staves during assembly a whole lot easier. When you are trying to assemble 6 or 8 pieces all slobbered up with epoxy and otherwise sliding around, having a joint that brings all the pieces into alignment for you is a really big deal.

I bet Glenn was wearing plenty of the epoxy as it was by the time he walked away from the glue up ;-)