Tag Archives: junk-rig

The Spitfire sail

I’ve spent most of my limited wakeful time in the past few days reading books by Czesław Antony Marchaj:

  • Seaworthiness: the forgotten factor
  • Sail performance: techniques to maximize sail power
  • Aero-hydrodynamics of sailing.

These are all fantastic books. Not only is Marchaj one of the few writers to present actual hard evidence for his assertions, he writes with a dry wit that implies a great deal of criticism for the rumours and fashions that dominate sailing design. (The junk rig community seems somewhat exceptional in this regard.)

He presents evidence that elliptical foils produce more lift than rectangular or triangular, especially at low aspect ratios. (I’m summarizing here.) This is rather interesting given my earlier drawing of an enlarged sail for Tammy Norie. I think this evidence gives some clues to why the top triangle on junk rig sails is important: it approximates a curved top.

With this in mind I drew this sail plan based on the elliptical Spitfire wing.

The “Spitfire Junk” sail plan, based on research by C A Marchaj, which showed that elliptical sails generate more lift, especially at low aspect ratios.

This plan is based on 4.5m battens, but has a 3.2m second batten and a yard of only 1.9m at a steep angle of 65°. The yard forms the leading edge of the approximately elliptical wingtip.

Given Marchaj’s other results showing the critical nature of the leading edge of foils, the yard shape could be quite critical, but fortunately this suggests shaping it in a way similar to that suggested by Hasler and McLeod to provide strength. In this case it would be arched to fill in the ellipse and have a thin top.

If this plan works, the centre of lift will be shifted forward considerably, hopefully correcting the Coromandel’s balance problems.

I also can’t believe it’s a coincidence that Paul McKay’s Aerojunk looks like a Spitfire wing.

Fantail even resembles it.


Filed under A New Rig, 2017-2018, sail

Tammy, Emmelène, and Amiina

I sailed Tammy Norie from Portsmouth to Poole Harbour for the August bank holiday, in tandem with Chris Boxer aboard Emmelène. It was a weekend of many meetings, but this video shows Tammy, Emmelène, and Edward Hooper’s Amiina.

Amiina has Edward’s latest version of the split junk rig, and Emmelène is using his previous version. Tammy Norie has her original flat Hasler-McLeod rig from 1983, and so this was a rare opportunity to compare rigs on two boats of the same hull.  Unfortunately we only had very light winds, and Emmelène’s sail is significantly larger than Tammy’s, so it’s by no means a thorough comparison.

Can Emmelène point higher than Tammy Norie? Not really. Tammy Norie can go very close to the wind, but gets slower and slower. The sail never seems to stop completely. Emmelène, like a Bermudan, seems to have a definite highest angle “groove”. She’s faster than Tammy up to that groove, but stalls and stops above it. This was noticeable when manoeuvering into Portsmouth Harbour entrance in a northerly F5. I wouldn’t say this is a particularly amazing advantage for Tammy, except when manoeuvering under sail.

Is Emmelène faster to windward than Tammy Norie? Definitely in light wind (up to force 4) and probably in general. Emmelène with one panel reefed was about ⅓kt faster over several hours to windward in a F3 crossing Christchurch bay. Emmelène had to drop two panels to stay with Tammy in a F4 from Beaulieu to Lee-on-Solent at about 80° off.

Is Emmelène faster downwind that Tammy Norie? Again, definitely in light wind. Since both sails are in drag mode, this is probably just due to Emmelène’s larger sail area, as seen towards the end of the video.

What is clear is that Edward literally sailed rings around Tammy in Amiina!

All this makes some sort of split more likely in a future rig for Tammy Norie, though I’m likely to go for some sort of compromise or hybrid approach. What I mainly plan to do is experiment, and you’ll read about it here on the blog.

There’s also a photo album of the weekend on Flickr. A more general account of the trip will follow.

Edit: More photos by Edward Hooper, including pictures of Tammy (which are hard to take when you’re sailing her).

Edit 2: Amiina (with the sail that’s currently on Emmelène) was featured in a side-by-side comparison of the junk and bermudan rigs in Practical Boat Owner, 2014-11-05.


2017-09-04 · 14:14

Sister Rings

When I first rigged up the Hebridean wind vane self-steering, I used some hard anodized aluminium rings instead of blocks to run the tiller control lines. These rings are mechanically simple and very slippery, and they’ve done a great job. A couple of years ago I started to think about where else I could apply them.

Tammy Norie has “sister blocks” in the main sheet to evenly distribute load across battens. These are simply two blocks attached back-to-back.


There’s nothing wrong with this, and Tammy’s are in good condition, but I wondered if something simpler and lighter could be made from anodized rings. And here it is: the “sister rings”!



This is such a simple idea that I can’t believe someone hasn’t done it before. It’s just two rings joined together with a double eye splice. In this case, two 16mm Barton “high load eyes” joined with Dyneema.

This is a simple, lightweight, cheap, strong, and easy-to-make alternative to sister blocks, with comparable friction, unlike the traditional wooden euphroe.

To form the splice using single-braided line (such as Dyneema), form two eyes like this. Note that the long end passes through the short end (the opposite to what you might expect) and this involves passing one of the eyes through the braid.


Once you have the rings in place and have tightened the eyes, trim and tuck the ends inside the braid between the rings, fixing the eyes.

I use Selma fids for this kind of splicing.

I’m experimenting with using these rings to replace blocks in other parts of the rigging. It’s easy to carry rings and line and make up or repair things that you need on board, and that very much fits with my philosophy for Tammy Norie!


Filed under Repairs and Modifications, sheet

Emmelène meets Tammy Norie

Chris Boxer has written about our recent meeting at Bembridge on the Isle of Wight. You can find his post on Emmelène’s blog.


Emmelène has a split junk rig, which means about a third of the sail area is ahead of the mast and formed of conic sections called “jiblets”. These direct airflow over the main part of the panels abaft the mast. The slot effect helps the air stick to the back of the mains and so increases the stall angle, and thus how high you can point. To make this work the luffs of the main sections need to be tight near the mast, like the luff of a Bermudan main.

It’s quite like sailing a stack of small pivoting Bermudan rigs!


It’s often said that the Coromandel’s mast is too far back. Tammy certainly suffers from weather helm, especially on a reach. But Emmelène has none at all. It’s quite spooky.

If anything she could do with moving the centre if effort aft a touch. The sheets are perhaps a little too relaxed and sometimes it was hard to persuade the sail to swing out.

This is no fault of Chris’s. He bought the rig second-hand to replace the poor “hi-power” rig that came with Emmelène. In fact it was the exact rig the Practical Boat Owner featured in their comparison of junk and Bermudan rigs (using identical Splinter 22s I think) a while ago.


I look forward to meeting Chris again and perhaps trying it all out in more varied conditions.


A full set of photos is on Flickr. And a set of photos taken by Chris.


Filed under Logs

Presenting the Tied Hybrid system: can it work?

I’ve been pondering new sails for Tammy Norie for some time. My goals are to increase performance in light winds and improve upwind performance while keeping things simple, strong, and maintainable. I believe that I’ll need to increase sail area and add camber to my sails to achieve this. I’ve briefly described various methods in my earlier post New Sails for Tammy Norie . I had more-or-less settled on an HHH system for simplicity and maintainability.

On Friday I was looking at figure 10.2 from Practical Junk Rig showing how to attach the sail to the yard.

Figure 10.2 from Practical Junk Rig

Figure 10.2 from Practical Junk Rig

Then it struck me: why not attach all the panels to the battens with string? One weekend-long brainstorm later, and I present to you the Tied Hybrid system for Junk Rigs.

Tied Hybrid sketch

Tied Hybrid sketch

The idea is simple: cut the main panels flat with reinforced seams with eyelets. Then tie the panels to the battens with loops of cord. By adjusting the lengths of the loops you can adjust the camber of the sail in pretty much any way you like. Sprung cord locks allow you to do this easily, but you can of course use stopper knots. If the battens are smooth stainless steel tubes then the loops will slip round easily when tacking, flipping the sail camber to the other side.

In addition, it’s a simple matter to make split panels and get a split junk rig with jiblets. It wouldn’t even be very hard to carry both split and full-length panels on a voyage for different conditions. Since all the panels are the same you can get a lot of flexibility.

This is so simple that I have trouble believing that it hasn’t been tried and somehow failed. I’ll be interested in feedback from the members of the Junk Rig Association about that. If it hasn’t been done then I’ll definitely be giving it a go. It should be easy and cheap to construct, and allow for a lot of research into sail trim.


Filed under Plans, Repairs and Modifications, sail

New sails for Tammy Norie: background

Tammy Norie has her original sail from 1982 in almost pristine condition. It’s been admired by many people, and more than one person has described it as a textbook example of a Haslar-McLeod rig. That’s all very well, but it’s quite out-of-date with modern junk rig thinking.

The junk rig.  At the top is the halyard (which hauls the yard up) and the yard parrel (which holds it near the mast).  The battens are held close to the mast by fixed parrels.  Then the zig-zag line is a luff hauling parrel that can move the sail forward

The main problem is that the sail is flat. There is no curve in the sail cloth. The battens may bend a tiny bit, and a little bit of curvature is developed by a small amount of slope in the battens, but it’s essentially a “barn door wing” and aerodynamically inefficient. It’s fine when used as drag downwind, when Tammy Norie leaps and surfs as well or better than any boat I’ve sailed, but it just doesn’t drive well to windward.


Ash Woods (of the Junk Rig Association) told me

The Coromandel / Corribee underwater hull is very sweet but fairly full
forrd […] Corribees  were  built full in the bow to stop diving when running.

One consequence of that is that she gets slapped off the wind by waves, making it even harder to make progress to windward in a chop.

For these reasons, I want to completely replace the sail. I don’t want to modify the existing sail at all — it’s in beautiful condition and it’s a piece of history — so I’ll start from scratch. This gives me a lot of freedom in deciding what to do.

Another issue is Tammy’s mast position. Robin Blain (a very experienced rig developer) told me that the Coromandels’ masts are too far back, and that makes them difficult to tack. I’ve not had trouble with tacking except in a chop, but I think shifting the centre of effort of the sail forward might help. However, I really don’t want to move the mast. It’s in an otherwise well-designed position supported by a reinforced arched coach roof.

Comparing the Coromandel with Annie Hill’s Fantail, a much more recent boat, it doesn’t seem that the partners are far back, but there’s about a 4.5° difference in mast rake.

Fantail Coromandel 2

I believe I can adjust Tammy Norie’s rake and even make it adjustable while sailing but I’ll discuss that in another post.

I also think that Tammy could do with a larger sail area. She doesn’t really get going in anything less than a force 4, and I’ve found that a bit frustrating while cruising around the east coast in summer.  I’d like to carry a larger sail area. Junk rigs are so easy to handle and reef that this really shouldn’t be a problem. The only question would be whether the sail efficiency is compromised if I’m reefed in typical conditions.  The current sail area (according to the brochure) is 18.3m². (For comparison, Roger Taylor as 26m² on his Achilles 24, Mingming II, and Annie Hill has 29.5m² on her Raven 26, seen above.)

Building a junk rig sail is quite straightforward and I intend to do it myself and learn all about it.

What kind of sail? There are several competing sail plans. I think David Tyler’s “fan tail” looks right, and is supposedly a good cruising compromise. On the other hand, Slieve McGalliard’s split rig (a junk rig with a slot) is very intriguing and makes great claims for upwind and light wind performance. Roger Taylor, on the other hand, has stuck with a simple Haslar-McLeod layout for Mingming II, but with a clever system for introducing curves into the panels that I’ll come to.

Various methods of introducing curves into junk rigs have been tried since the 1980s. I’ll give a very brief summary of them.

  • flexible battens seem obvious, but the sail curves more in strong winds and less in light winds, and that’s the opposite of what’s needed. Nobody uses these.
  • pre-curved battens that flip inside wide pockets were tried, I believe, but there’s too much friction to allow them to flip over easily.
  • jointed battens are a clever method using metal tubes with a clever joint that limits the maximum angle. These are still quite popular, but I don’t like the complexity and the need for special parts.
  • barrel cuts are simply a way to cut belly into each panel in a similar way to normal sail making. These are probably the most common these days, but people seem to worry a lot about wrinkles.
  • Roger Taylor devised a unique “HHH” system that (as far as I know) only exists on Mingming II. Separate panels hang off the battens by tapes so that the result resembles a piano hinge, and the sail has gaps.

I have to say that I’m very keen on Roger’s method. It has a very simple construction and could be tweaked quite easily while cruising. Tinkering with things is one of the reasons I like the junk rig, and I’m pretty sure it would be easy to adjust the hinges at sea to try out various sail trim ideas. And carry or make spare panels.

So, what I fancy at the moment is a large fan tail sail with curved panels hanging off hinges attached to a mast with adjustable rake.

Sailcoth? Dunno. Batten material? Not sure. Sheeting system? Erm…

Probably all wrong. We shall see.


Filed under Repairs and Modifications

Fan-tailed Tammy Norie?

I made this post on the Junk Rig Association technical forums. I’m quoting it here for the record, and so that anyone interested can follow the discussion.

I’m inexperienced with junk rig but (I hope) learning fast. So far I find the flat-sailed HR rig on Tammy Norie lacking drive below F4 and unable to make progress to windward in light airs in a chop. This may just be poor technique on my part, but when I bought her I was definitely thinking about making a more up-to-date sail. I have offshore ambitions. The fantail rig just looks right.

I admit that I have not done any homework yet, but I made this crude overlay by matching the waterlines of Tammy Norie and this fantail, just to get an idea if it’s at all feasible.

It quickly raises one question: does the mast position of the Coromandel rule out the fantail (at least, the standard one). If so, what can be done? But also, what homework should I be doing?

Coromandel on fantail overlay

Coromandel on fantail overlay


Filed under Repairs and Modifications, sail