Re: [bolger] Re: micro video
- Thanks. The "e" is important!On Jan 31, 2010, at 11:09 PM, eric14850 wrote:
Here is a link to a LOTS of pictures of boats sporting junk rigs. http://images. google.com/ images?hl= en&um=1&q= junk+rig& sa=N&start= 0&ndsp=21
http://www.kastenma rine.com/ junk_rig. htm
shows his take off on the junk rig A euphroe would replace the fiddle block. Because a euphroe is just a slat of wood with holes the lines pass through it has a lot of resistance. the sheet can be adjusted to pull more on one batten than another. From Kasten: "Sail shape is controlled by the sheets mainly. Each "sheetlet" runs through a "euphroe" which acts as friction block to keep the tension set as intended. In my drawing, I've made use of a simpler arrangement using a fiddle block and separate "lizard" eyes in order to allow the sail to self adjust when it is reefed."
From Wikipedia: "On a
traditional Chinese junk rig, the sail is controlled by
sheetlets -- small sheet lines running from the battens to
blocks that in turn are on lines running through a
euphroe, a long piece of wood with holes in it. This helps
maintain uniform tension in each panel of the sail." Sheetlets are the line loops from one batten down to the next.
And here is what I was looking for halfway down the page:
http://www.dragonvo yage.com/ ship/rig. shtml
Western designers starting with Hastler and then Colvin followed by others have made modifications of the Junk rig. Bolger took some aspects of the junk rig and created a modern multi-yard gaff rig. Some on this forum have been (I think) referring to this as Bolger's Chinese Junk rig. It is not. The junk rig is a lug rig, and though Bolger liked the lug rig, he did not like the Chinese lug rig very much, though he respected Hastler and others who did like it. Bolger did design at least one boat that I am aware of that had the option of a Chinese Junk rig. 35'+- barge hull if I remember correctly.
--- In bolger@yahoogroups. com, Bill Howard <billh39@... > wrote:
> Google never heard of euphros. What are they?
> On Jan 31, 2010, at 7:59 PM, eric14850 wrote:
> > The nice thing about a small and not too serious boat is one can experiment with it without it costing too much, or anyone taking the experiment too seriously.
> > Even to windward the plastic tarp is pulling quite well. :-)
> > And there are several things wrong with this set up.
> > He uses battens which are not nearly stiff enough. The wind is not blowing very hard and the battens are curved. They should be stiff enough to be straight. The mainsheet is probably not led far enough aft. The designer Tom Colvin typically uses two sheets to each junk sail with the sheets attached about a fifth of the way forward of the leech on each side of the sail to deal with this problem. It does mean using a lot of line and handling two lines to control one sail. Colvin also states emphatically to resist the urge to use blocks in place of euphros. One wants the resistance a euphro provides and a block does not in order to set the sail properly. A properly set junk sail will have each batten in a line virtually parallel to the mast, or just the slightest twist at the top where the wind is stronger. Only the bottom three battens of the blue tarp are set correctly.
> > Fun to experiment with, the junk sail is best suited to situations where safety requires all sail handling to be done from the cockpit or control station (Jester), to safely/easily handle a large sail (especially reefing), or to make inadequate sailmaterial adequate to the job of motivating a boat in all sailing weather, including the ability to sail to windward.
> > On a small boat with the possibility of good sail cloth, the balanced lug will set far better than this junk sail was setting, and will, in my experience (using an old mainsail (too flat a cut to be ideal) with a yard taking the place of the top third of the sail) a well set balanced lug sail is capable of pointing just as high and motivating a boat just as fast as modern fin keel high masted sloops of similar size. In 25mph gusting to 35mph winds (finally winds strong enough to fill the eight oz sailcloth!) ROGUE outsailed the few other boats of similar size, and most that were larger on the lake, and kept up with a well sailed racer/cruiser that club races twice a week and is a few feet longer than ROGUE. That boat was crewed, I sailed alone. Once tacked, ROGUE was capable of sailing itself, so, as with the other boats, I strolled up to the mainmast to enjoy the scenery including the other boat's attempts to trim sails more effectively, while Rogue sailed itself. So much for the innate superiority of the modern sloop. Furthermore, at the time ROGUE's leeboards were only partially lowered. My guess is we could easily have sailed in three feet of water. None of the other boats could have followed us into such shallow water. Raising the leeboards would have allowed me to sail in these winds in even shallower water.
> > Eric
> > --- In bolger@yahoogroups. com, "steve" <stevepallen@ > wrote:
> > >
> > > I came across this on a meander,
> > >
> > > http://www.keepturn ingleft.co. uk/keepturningle ft.php?type= scuttlebutt# IKprDvV7- po
> > >
> > > hopefully its of interest to someone
> > >
> > > steve
> > >
- On Sun, Feb 7, 2010 at 7:51 AM, etap28 <dave.irland@...> wrote:
around here (Western MA) Home Depot rules, unfortunately. To the detriment of any serious lumber outfit.
A la Junebug, even 15 years ago I bet BC pine was better than it is now.. and when I think WAY back, AC ply was perfectly good for boats, even "serious" ones (if you didn't mind that it does't finish very well, and checks like crazy). Cut off those ends, make a Tortoise out of it!!
My son and I went to Menards today and picked up four sheets of 3/4" A/C Arauco on sale for $24 a sheet, plus there was an additional 10% discount for using a Menards card. My son said the C side of the panels looked more like a B side. The radiata pine plantations use fixed tree spacings and prune all the trees so the plies that are peeled off are very regular with few knot holes.
Above the Arauco was a bunch of treated southern pine plywood. My son said, what is that ugly stuff. I said treated plywood is always ugly, but difference with the two panels side by side was quite dramatic.
Regarding my deceased Junebug, it's the middle that rotted and the ends are OK. I've been thinking of putting in an 8 foot long Tortoise section in the middle and joining it to the ends. Maybe I should make it bolt together in three pieces, so I could have one long boat or two shorter ones.