Friday, January 29, 2016

Getting Shippy Part Two

In my last post I was musing on the idea that being dis-masted in a box barge might be preferable to capsizing.  In that regard having some redundancy with multiple masts could be an advantage.

Multiple masts allow me to have a lower rig, with lower center of effort, and smaller lighter poles that are easier to take down.  Plus, I think I would have more control of the boat.


In this latest iteration we have three sails identical in shape and proportion but varying in size with the largest aft and the smallest forward.  They are straight out of Hasler/McLeod.  The sizes are 218 s.f. with a pole rising 20 feet from the tabernacle, 124 s.f with a 14 foot mast above the tabernacle, and 92 s.f. with 12.5 feet above the tabernacle for a total sail area 434 s.f.  A little on the under-powered side I'll admit.

But here are the advantages:

All three masts can be straight aluminum schedule 40 pipe.  They are short enough not to be too ugly without a taper.  All three masts are light enough to raise and lower with ease.  The sails are all small enough and light enough that everything can be managed by hand and without a winch.  These things are important to us as we get older.


Supporting structure for the tabernacles is not going to be a problem.  I'll probably get a metal tabernacle welded up for the fore mast since it is out on the bow and traditional 'bury' won't be accommodated.  But spreading the torsional loads will be a cinch with a welded fabrication.  It's not a big sail out there anyway.


Tabernacles are off center

I haven't worked out the center of effort for this rig but I imagine it would put my lee boards a bit further aft, or increase the size of my rudder.

Anyway, I think it looks cool.  Still thinking on it...

7 comments:

  1. Really beautiful. Low aspect just looks like it would do so much better. Perhaps a spinnaker when in super light winds and ghosting. In TColvins sailmaking book he describes taking a client out on a junk he just built for the guy. Colvin tied off the wheel and proceeded to show the guy how to sail with the three masted rig only, 15 degrees at a time, all the way around the do-able rose (which was facilitated as well by the deep forefoot and long straight keel). In classic dry Colvin fashion he stepped away from the helm and said "The vessel is now yours" to which the guy replied "You got me out here... you get me back!" Anyway: great tweaking ability for balance. Colvin used euphroed sails so had more ability to shape the top of the sail as well. What else do you have to do, often, than play with sail trim? Also: I used a steel pipe for my mainmast on one rig and it didn't look weird at all. Painted it gloss white. Even had shrouds and a forestay for a regular jib. All masthead fittings were welded right on the top and quite strong. Got the mast scantlings from a forum where Colvin was instructing some guy on how to construct steel tabernacles and sized pipe for various sail areas. You are approaching standard chinese junk array if moving the sails about. Good video of Alan Farrell sailing his 40 or so junk on youtube with standard rig. Engineless. Same long straight keel as Colvin but shallower with bilge keels. Best wishes from the high mexican desert.

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  2. Thanks Robert. There is still lots of time to make a final decision on the rig, but I'm trying to vet and thoroughly consider every idea and possibility. I need to find the right combination of sailing ability and performance, along with ability to drop the rig for the bridges. It's not easy. Oh yeah. I also want it to be cool :-)

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  3. In the past I sailed a junk rigged Gazelle some 8,000nm, v.large aft main, modest foresail and jib out on a sprit. In my experience the only sail we ever used much was the foresail, which we found incredibly useful, roughly 2/3 fwd it was great on all points of sail, lots of deck to work it and easily reefed. In fact junk sails are so easily reefed I would have left the main behind and increased the foresail a wee bit and called it done. One thing anyone who hasn't built/rigged a junk sail doesn't contemplate fully is just how much of everything it takes to put a junk sail into the air. Further this is the sail you use when the wind increases. Good luck with your Junk, in my opinion it is one of the best live-aboard/ cruising sail ever invented. (using my wife's google account)
    cheers,
    jim

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  4. Thanks for your input Jim. I'm leaning towards making the main sail as large as I can within practicality and then smaller mizzen and fore sails. Those two may even be lugs as drawn in a previous post.

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  5. When a squall (or williwaw) comes up nice to drop that center main in a instant and continue on with the fore and aft sails. Only one mast to drop when dealing with a bridge. I take it that Jim (above comment) basically advocates a sloop junk rig of sorts and he should know. IMHO a excellent starting point for a rig design keeping in mind the increased resistance of a barge hull. We ran with a single marconi sail on a little 15' sharpie daysailer-beach camper and it was my favorite boat of all time to sail and use. If it had had a small mizzen on the stern it would have been perfect. Like Chris Morejohns drawings of his simple single mast lugsailed box boats with sprit mizzen for balance, heaving to, and raising sail easily. Jeez.... this rig design stuff is so awful to contemplate...... hee hee hee.

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  6. I'd suggest taking a look at the common Chinese Junk configuration for larger vessels - small fore and mizzen for maneuvering and a big main for power. It can't have survived for so long if it didn't work well. A split rig like that makes it much easier to handle the boat.

    Caveat: I'm used to square rig, not junk, but the principles are similar.

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  7. Thanks Bryce and Robert. I think I'm leaning that way again along the lines of a previous post. Larger junk main and fore and aft lugs. I just like the look of it too.

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