Tag Archives: rig

Raking the mast

The idea of raking Tammy Norie’s mast forward first came up when I compared Tammy to Fantail several years ago. As far as I can make out, raking Tammy’s mast will have three advantages:

  1. It will help the sail stay out in very light winds — particularly useful when becalmed.
  2. It will cause me to rebuild Tammy’s mast step, which is a known weak point.
  3. It will shift the centre of effort of the sail forward, improving the balance of the boat and reducing weather helm.

I believe I can achieve about 5° forward rake by moving the mast step aft, pivoting the mast within the cone that forms the partners.

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arctan(10cm/118cm) = 4.8° I believe.

This should being the centre of effort of the sail (shown below) forward by about 3.5m × 10cm/118cm = 30cm.

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Because nobody has done this on a Coromandel and the future sail plan is unclear, I’ve come up with a scheme to make the rake adjustable.

Firstly, here’s s picture of the existing step. I hope you can see why this is inadequate. It’s been replaced on every other Coromandel I’ve seen!

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Here’s a drawing of the mast step that will make raking possible. I’m afraid I’m writing blog articles on my phone recently and so I don’t have my nice diagram software. You will have to make do with a photo of my pencil drawing.

This is basically a rectangular box made of aluminium angle, into which the mast is wedged using hard rubber chocks, and further secured with a retaining pin (to stop the mast wandering or jumping out).

The box is screwed to the laminated wood block that’s already glassed into Tammy’s hull, using large coach screws (hex heads and wood threads).

The mast base can be chocked and pinned at various positions in the box, allowing various angles of rake. Of course this means adjusting the blocks in the mast cone, so it’s not something to do at sea. I tried that (accidentally) once.

To allow for this I need to enlarge the hole in the berth that the mast passes through, making it into a round-ended slot.

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The box could be strengthened in various ways, but I already have 6mm gauge aluminium angle — double the gauge of the mast itself — so it ought to be fine.

Incidentally, the reason that the angle turns inwards is that it’s very hard to get tool access to this area of the boat. I don’t think I will be able to make pilot holes for the coach screws except through the slot for the mast. Having the screws inside also makes them possible to inspect through that same slot.

I hope this will all become a lot clearer when I start doing the work and have some photographs.

In the meantime, is be very interested in criticism or ideas for improvement.

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Filed under A New Rig, 2017-2018, mast, Repairs and Modifications

A New Rig

It’s been three years since I first wrote about making new sails for Tammy Norie. Since then I’ve been delayed by illness and injury, and have been getting along quite well with her existing sail, but now I’m planning to make a move.

Seeing Emmelène with a split junk rig was inspiring, because of improved light wind performance and especially the significant improvement in boat balance.

There has also been some very interesting (and sometimes fierce) debate about sail position and balance on the Junk Rig Association forums. This prompted me to experiment with my own sail position and geometry, with some very encouraging results.

But mostly, of course, I want to play around with the rigging.

Currently I’m doing several things simultaneously, as my health allows:

  • Designing a new mast step that will allow me to adjust the rake of the mast up to about 5° forward.
  • Making sketches of sail plans to see how they might fit.
  • Sailing Tammy with the sail tied in various odd positions to see what happens.
  • Experimenting with materials for making short-lived experimental sails and sail battens.
  • Shoving Tammy around with a boathook to discover her centre of lateral resistance.
  • Reading about Roger Taylor’s experience with his “Triple H TB” rig on Mingming II.

I hope to write more about all these activities and cover the actual construction and testing of a new rig, so I’m starting a new blog series called “A New Rig”.

Be warned that what I do is going to be experimental. This won’t be a step-by-step guide on how to build a junk rig written by an experienced constructor. (You can find that information at the Junk Rig Association.) As usual this will be me trying out ideas, making mistakes, and possibly discovering some new and useful stuff.

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Filed under A New Rig, 2017-2018, mast, Plans, sail

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.

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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!

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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.

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

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

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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.

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Filed under Plans, Repairs and Modifications, sail

Autumn plans

The summer was fantastic. I have gained so many experiences in the past few months that it surprises me to look back on them. Did I really do all that?

And now everything must seem very quiet to regular followers of this blog. This is something of an illusion. Two things are happening. I’m having to get on with some work. But also I’m quietly planning all the things I want to do with Tammy Norie before spring.

The next goal on my long term plan is the Jester Baltimore Challenge 2015: solo sailing from Plymouth to Baltimore in June. While not yet a true ocean crossing, it’s a significant bit of offshore solo sailing, and I need to prepare.

The most important item on the list is mechanical self-steering gear. Tammy Norie’s electronic tiller pilot has done well over the summer, but it sometimes plays up, fails to keep a course in some conditions, and I’ve managed to break it once already. I want a reliable wind vane, and I’ll keep the tiller pilot as backup.

I plan to build a Hebridean. Building my own self-steering will not only be interesting, it’ll give me a thorough understanding, and a much better chance of being able to repair or adapt the gear. It’s also a cheap option. If the Hebridean doesn’t work out, I will have lost only a little money and learned a great deal.

The second item on my list is to either make Tammy Norie unsinkable or repair the liferaft. My plans for making her unsinkable involve lining her with foam and that includes fixing up the headlining, so it might be a good move in any case.

I would like to have a Jordan series drogue ready. I’ve had various opinions on this. Most people think I’m unlikely to need one for the Baltimore challenge, but several have also said that I really should have one in general, given Tammy’s small size. So I’m going to see if I can get this done too.

I would also like to build a new sail, so that I have more flexibility in adverse conditions. This is quite a big job, probably involving re-engineering the mast step, so it may not get done this winter. The current sail is good enough, and it’s not a safety issue.

There are, of course, various bits of kit I need: a simple reliable GPS, an SSB radio receiver, a distress beacon (though I may just rent an EPIRB for the Baltimore challenge). I have a much longer list of things I’d like to have, but those are the only ones I think I ought to have before going offshore.

And of course, sailing! I’ll get Tammy on a mooring in Portsmouth Harbour as soon as I can for some autumn and winter sailing.

I’ll be writing about each of these projects in time, so watch this space!

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Filed under drogue, Plans, sail