okay, so i've finished my first read through of the plans, and the only thing i'm not thrilled with is the idea of a re-used windsurfer mast as used in the plans. i'm thinking of a wooden mast and just tossing around ideas for the dimensions. i'm considering using a box style construction, with 1x3 stock for and aft (to take the bulk of the stress ) with 1x2 stock port and starboard making a mast approx 2 1/2 x 3"
any thoughts?
Hello Bob,Had the same thought when I started and was told by Stevensons minimum 2" diameter for wood mast,Sounds like you got that covered.
My first attempt I laminated three very nice(and expensive) close grained 1x4's and it came out severely warped.Being somewhat disgusted I went back to the wood yard and grabbed two 2x6's and laminated them,
Then cut them down to 2" octagon,They came out pretty good I think.
Good luck.
Bob.
Bob look at the birds mouth method. It will work with a small mast as well as a large one. A bit more work but they don't warp.
Having experimented with windsurfer rigs previously, I can tell you they are quite weak and easily broken. I've tried a number of different ways to attach them and none proved particularly successful. The only one that showed promise was using a stub inside the windsurfer mast, but repeatedly I found it would break just above where the stub ended.
What's the total sail area on the Super SkipJack? Masthead jib, gaff main?
117 sq ft by the plans,28 sq ft for the jib and 89 sq ft for the main.
Making all sorts of assumptions about weight RM and other attributes, a 2.5" diameter, birdsmouth mast, that gradually tapers to 2" at the masthead will be just fine for a protected waters boat. If it's white spruce it'll weigh less then 8 pounds, if Douglas fir about 10.25 pounds. This assumes it's a stayed rig.
Having just put the refurbished Super Skipjack back in the water, I'm fairly current on how it's doing. The windsurfer mast based rig is LIGHT. Nice. But it does require making plug/reinforcing pieces to insert where loads are going to be. Overall, I like it, but as I couldn't find a boom piece I just grabbed a full-round fir piece form the local lumberyard. It works fine and has the advantage of being prettier!
The very first Weekender plans used full-round fir, I think 2 1/4" maybe (I'd have to dig out an old set of plans and look). We went to the 4X4 based rig later as the full-round was getting hard to find (and probably nearly impossible now). The 4X4 is admittedly heavy, but it's strong, available, etc.
Since the SSkip is so light (I weighed mine directly after sailing, with all the gear we'd had in for the day (4pfds, bilge pump, paddle, bag of tools, cushions, etc.) and it weighed 280lbs!), the rig specs from teh original Weekender would be a fine way to go. I would very much be happy with the rig Paul has described, and if he feels like shooting one over this way I'll stick it right on! ;-)
Seriously: I have a bird's-mouth router bit sitting in the router bit box as I was considering just this concept for mine.
Mike
Routing birdsmouth staves is painful and dangerous. The router likes to spit out the staves. I use a table saw and make two 45 degree passes with a double feather board arrangement.
I think adding 10% more weight to the Super Skipjack with a 4x4 solid mast is a ridiculous waste of materials. A solid Douglas fir 4x4 will be literally 10% of the weight of the boat!
(08-11-2011, 12:39 PM)Paul Riccelli PE,NA link Wrote: [ -> ]I think adding 10% more weight to the Super Skipjack with a 4x4 solid mast is a ridiculous waste of materials. A solid Douglas fir 4x4 will be literally 10% of the weight of the boat!
To me it seems that the problem is the dimension, more than the method. How much weight does the little hole in a birthsmouth mast really save? I mean, what's the difference in weight between properly dimensioned round stick, and properly dimensioned birthsmouth?
I will probably end up building the Super Skipjack, and I have thought of making a solid spar, at least to begin with. The next winter I can spend optimizing details, like a new mast.
Well, If I recall, we do taper the mast quite a lot. And that was for simplicity's sake, to some degree. A birdsmouth mast is just too much fiddling for a lot of people to be bothered with, and I quite understand. I haven't done a laminated, tapered mast, but several builders have and that seems like a promising way to get a stiff, not-too-complicated solution.
Mike