Posted by John Nichols on March 12, 2003 at 20:07:14 from 165.91.199.202 user Mcneacail.
In Reply to: Re: The design of the Swallow. posted by Jonathan Labaree on March 10, 2003 at 22:43:28:
Dear Dave, Andrew, Ed and Jonathan,
Thank you for all the information on this site and also in the direct emails. I will try and summarize where the project is up to at the moment.
Mast Traveller,
I am going to make the rig as absolutely true to the sketches in the AR books as I can. The rig is not a dipping lug rather it is a standing lug (which was my mistake), I have read all the stuff I can and it appears to be a variant of the lug rig that is progressing towards the modern gaff and bermuda rig. The pictures of the Swallow at the Boat Show given in the article by Dave Jenkins in about 1974 show the arrangement for the mast traveller. It is described in the Ransome SA on about page 14 but I have not found a sketch of the mast traveller in any of the AR pictures. But Jenkins gives a sketch of one. I will have to make one, or if Mike Field knows someone in England maybe I can buy one, when I get a minute I need to send Mike an email.
The strop that goes with the traveller is about 6 inches long. I will have to design that myself. AR tends to show the halyard still attached to the yard when it is down, which is impossible as far as I can see. See the picture of the sail falling in PM with the D's, this is just not possible as sketched. It is possible but the traveller would still be attached to the mast.
(Ed in PM does AR talk about the first time the D's try and rig the Scarab?)
AR does not show an arrangement for the main sheet, even the very detailed sketch of the SCARAB when the D's landed the GA does not show a sheet arrangement except for a single hand held line hung from the boom. The sail will generate a load of about 300 lbs resolved which requires quite a decent set of pulleys for the force to be reasonable on a 12 year old person. The two problems are :
1. Avoiding a twist in the sail to improve the windward characteristics which means that there has to be a traveller somewhere on the main sheet. The obvious place is the transom, but that then gets in the road of the tiller and sculling. A raised traveller would work, but then controlling the location of the sheets on the traveller is a hassle fro fine control to windward.
2. I would really like to put a rachet pulley on the keel to provide a sound point to hold the main sail or alternatively recess the traveller into the thwart so the boat can still be rowed. This is the current issue to solve.
The boom has a set of jaws as shown for scarab. I think I will just go with a more modern fitting here. I do not think I can make a set of timber jaws.
Timber
To: info@whitecedar.com
Subject: White Cedar
Dear Sir,
I was looking for some white cedar planks for a boat. I need 16 feet planks
at least an inch thick and I would need ten planks each 6 inches wide.
Do you have such stock
From: "Klaas Armster" So I have a white cedar stock. I will be able to get green white oak from Paxtons (I hope) Rig, Jonathan sent me the following links: Here are a few web pages with what might prove useful illustrations of dipping lugs: ------------------------------ As I noted earlier it is my mistake and it is a standing lug rig. The interesting issues are how big to make the rig as I have discussed in previous emails. The book on sail design gave me enough info to evaluate the design. I have just got a book on hydro dynamics which means I can have a shot at working out the hull resistance. The main issue is the displacment and the volume. Assuming a density of 310 kg/m3 or about 20 lbs/ft3 the planks will weigh about 150 to 180 pounds, so I should be able to get the whole lot including your truly in under abotu 550 lbs. AS Jonathan noted The wood shop has a planer that will do a 2 foot wide board so this should be no problem. Yes I saw where Gardner said in his book to do it that way and if you consider the residual stress issue it is a good idea. These size boards are cheaper to buy (a bit). Sail size. At 147 sq feet and on a angle to the wind of about 35 degrees the sail force is about 30 % higher than an equivalent Bermuda rig, if I accept the books curves. I reckon in a stiff breeze on the 3/4 run (135 degrees to wind) I will get this little girl to plane if I sail her one up. The worst that can happen is I capsize or break the mast. Or I am wrong but I will have a lot of fun trying it out. To all who have sent notes, thanks. I am learning a lot. Finally what is the Dog's house the name rings a bell but I have forgotten the exact reference. Andrew gave me several good sites to look at and it appears that the Swallow was a Lune boat. According to the OED Lune means one of the following things: Lune 1 A leash for a hawk. Lunes 2 Lune 3 Geom. The figure formed on a sphere or on a plane by two arcs of circles that enclose a space. Lune 4 I gather Dave is putting the plans on the web site. So I am still having fun. John
To: "John Nichols"
Subject: RE: White Cedar
Date: Mon, 10 Mar 2003 17:17:46 -0500
X-Mailer: Microsoft Outlook IMO, Build 9.0.2416 (9.0.2910.0)
Importance: Normal
Yes, we have the rough lumber to make these in stock. We have rough 1x6x16
clear and dry Atlantic white cedar. The price is $44.00 per piece or $2.75
per linear foot.
If you are interested we could see what we could do about shipping. If you
could take 8-footers we could ship via UPS.
Sincerely,
Klaas Armster
whitecedar.com
203-214-9705
http://www.friend.ly.net/~dadadata/tiphys/Practical_4.html
http://www.friend.ly.net/~dadadata/oddsails.html
http://www.gartsideboats.com/catsail2.php
On this page, the famous EF Knight comments on the dipping lug.
http://www.arthur-ransome.org/ar/literary/knight5.htm
From what I've heard (and Knight seems to concur), the dipping lug is quite a handful and not easy to sail by yourself. The standing lug may be a bit easier. I like the spritsail or just the old fashioned gaff.
Anyway I hope these links are useful.
John,
I should mention that when you split planks in half with a table saw, it's very handy to have a planer as well. You need to have plenty of extra thickness on your initial plank. If you want to end up with 3/8", you will probably want a board that's 1" or maybe a bit thicker. The reason is the width of the table saw blade (of course), but also because it's very hard to get it exactly right.
What we ended up doing was making two passes with the table saw, cutting both the top and bottom edges and making sure that the same side was against the table saw fence. On a plank with any width or curvature, you will also need to take out a hand saw and finish the job because you might not make it all the way through the plank. Once that's done, it's very helpful to have a planer to allow you to get the plank down to the proper thickness.
You probably already know this from reading Gardner, but I just thought I'd mention it.
- Jonathan
So the issue at the moment is the design of the main sheet. If I go for one central sheet then I need to design a thicker boom and I introduce a possible sail twist going to windward.
1470-85 MALORY Arthur VI. xvi, Thenne was he ware of a Faucon..and longe lunys aboute her feete. 1486 Bk. St. Albans Bvb, The lewnes shulde be fastened to theym, with a payre of tyrettis. 1580 H. GIFFORD Gilloflowers (1875) 90 In fancie's lune I fast was cought. 1593 GREENE Mamillia I. E3, The closer shee couered the sparke, the more it kindled: yea, in seeking to vnlose the Lunes, the more she was intangled. 1611 COTGR., Longe,..a hawkes lune or leash. 1895 QUILLER-COUCH Wandering Heath 230 A gerfalcon lying with long lunes tangled about his feet.
pl. Fits of frenzy or lunacy; mad freaks or tantrums. (Cf. LINE n.2 29.)
1611 SHAKES. Wint. T. II. ii. 30 These dangerous, vnsafe Lunes i' th' King,beshrew them. 1778 JOHNSON Let. to Mrs. Thrale 14 Nov., My master is in his old lunes and so am I. 1799 LAMB John Woodvil III, Let him alone. I have seen him in these lunes before. 1867 J. H. STIRLING in Fortn. Rev. Oct. 381 This is the central weak point, the special lunes of the De Quincey nature. 1883 SYMONDS Renaiss. It., Ital. Lit. II. II. x. 97 Their tales for the most part are the lunes of wanton love.
1704 HARRIS Lex. Techn., Lunes or Lunulæ. 1839 in Penny Cycl. XIV. 199. 1854 MOSELEY Astron. xxxiv. (ed. 4) 119 Her [the moon's] crescent..now presents the appearance of a lune. 1891 CAYLEY in Coll. Papers (1897) XIII. 205 The two lunes ACB and ABD of figure 6.
2. Anything in the shape of a crescent or half-moon.
1706-9 WATTS Lyric Poems II. Vict. Poles over Osman 149 Faithful Janizaries..Fall'n in just Ranks or Wedges, Lunes or Squares. 1805 W. HERSCHEL in Phil. Trans. XCV. 36 This made them [the globules] gradually assume the shape of half moons..The dark part of these little lunes..did not appear sensibly less than the enlightened part.
anglicized f. LUNA.
So I am not sure where the full boat type name comes from. Maybe Andrew could answer that question.