Monthly Archives: July 2015

Constructing the Hebridean days 9 to 11

I have taken a bit more time off work to try to complete the Hebridean wind vane self steering gear that I started last week. I’ve also had quite a few visitors to Tammy Norie, and have been doing other work on her, so days 9 to 11 aren’t days of solid workshop, as they have been up to now.  However, quite a few important things have been done.

Firstly, I’ve made the mount.  I started off by making a template while aboard, based on the position I found for the pivot pin using my foot a few days ago.

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Using this I shaped an offcut from the oak planks to make two sides for the mount, that clamp in the socket for the pivot pin.

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The pendulum is held down in the water by friction between these blocks, so that if it hits an obstacle in the water it will swing up and save itself.

Having made the mount, I took it and the Hebridean (sans pendulum) to Tammy Norie yesterday. It’s amazing how many people stopped me to ask what it was! It’s quite an unusual contraption. One guy said “If you just told me it was a sculpture I would have believed you.”

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I marked up the transom for mounting bolts, took a deep breath, and drilled holes.

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Here’s the mount on the transom. You can see that it needs a bit more fitting to make it snug, but this is good enough for a bit of testing.

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With that, I was able to attach the Hebridean. Quite a moment.

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Of course it’s not rigged up, and so I spend some time that day checking the various angles and lengths.  I have not yet cut down the outriggers to get the rudder turn angle correct with respect to the Hebridean’s tilt.  I just attached lines to the end of the current outriggers to get an idea.

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You can see that I’ve tilted the outriggers down slightly.  This is to avoid a potential clash with the anchor light.  It will reduce their effective length, but I don’t think it will affect operation.  Tammy Norie’s pushpit is very low and so the extra clearance will help.

Then I rigged up some string and blocks to test connection to the tiller.

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I realise I haven’t crossed over the lines yet.  I was just checking the rudder turn angle, so which way it turned was irrelevant.  I decided to re-use the tiller pilot’s pin as the tiller attachment.  I should be able to find a clip or chain that will sit nicely on it.  I really need to take a protractor to the boat to get a clear idea, but from my measurements the rudder is probably turning about twice as far as it should, and so my outriggers need to be considerably shorter!  I will test this under way with a jury rig before I make any cuts.

I’m now back at the workshop to work on the pendulum, counterweights, and a few other details.

A couple of days ago I was planing the pendulum to get the curved profile and realised it was going to take me a very long time.  So I did an experiment with a router.  By setting it up with a fence and carefully controlling the depth I was able to make a good approximation to the profile curve.

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A small amount of planing and sanding then made for a perfect fit.

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So I think I’ll extend this technique along the whole length (and the other side) to save a huge amount of work.  That’s what I’ll mainly be doing today.

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Constructing the Hebridean day 8

The title of this post is a bit inaccurate, since I did no construction today at all. But I did bring the Hebridean frame, vane, and mount bearing to Tammy Norie and worked out how they will fit.

The first job was simply to locate a good position for the Hebridean on the stern.  This was quite easy.  As you can see from this picture, the Hebridean looks made for the boat, with its trunk angle nicely matching the top angle of the transom.

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There’s plenty of clearance all around, but the end of the pivot pin (resting on my toes) is just outside the boat. The mount bearing will sit here.

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It will be sandwiched between two planks which will be fastened to the boat. After a bit of thought, it’s clear that I should cut planks that are bolted down to the top of the transom, on the 80mm-wide flat part of the deck, but then are shaped to rest on the top slope of the transom to bear load.  This will keep the mount clear of the stern lockers and anything else going on in the cockpit.  I’ll make a proper diagram later and share it.

I also checked how the Hebridean will act when it swings.  I have yet to determine the correct length for the outriggers, and it’s not clear how I can do that before mounting and rigging the whole thing. There will be pulleys suspended from the stern rail taking lines from the outriggers to the tiller.  At the angle shown in the photo below the outrigger is exceeding the height of the rail, and that means the gear will stop working.  I wonder if it will have enough movement.

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One possible refinement is that the Coromandel’s tiller could be adapted to be reversible.

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Here you can see the tiller when vertical.  By making the bottom bolt removable (using an anchor pin, for example) the reinforcing the top link, the tiller will swing back over the stern lockers.  This would allow the Hebridean to connect without the usual cross-over of its lines, and also mean that the cockpit is clear then using the self-steering.

Anyway, I now have enough measurements to determine the correct length for the pendulum.

The rest of the day was taken up with a wonderful sail from Warsash to Fareham with my friend Gareth and his nephew and niece, Kyle (12) and Cara (10), neither of whom had been sailing before.  I’ll let the Met Office tell you about the weather:

Selsey Bill to Lyme Regis – Strong winds are forecast

24 hour forecast: West or southwest 6 to gale 8, occasionally 5 later. Moderate or rough. Mainly fair. Good.

We came out of the Hamble and messed around in Southampton Water for a while. The winds were strong, but it was also sunny and warm. The others weren’t due back until the late afternoon so we decided to take Tammy home to Fareham. It was a delightful run before a force 7 in 1m seas, and once again we had the Solent to ourselves.

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I also got to measure the distance from Tammy’s stern deck to the stern wave (about 310mm) while doing 6 knots in front of a force 7. That’s probably a good working figure for the Hebridean.

I will be sailing again tomorrow, and then I will need to return to work for a few days, so construction may be suspended for a short while.

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Constructing the Hebridean day 7

I only did ten hours today on my project to build the Hebridean wind vane self steering gear.  For most of the previous six days I’ve been working 12-14 hours each day.  It’s Sunday and I felt like a bit of a lie in.

As on previous days, there are more photos in the Flickr album than I’ve shown here, with details in the descriptions.

I started today by making the vane itself.  This is the “sail” that gets pushed by the wind, twists the pendulum, rotates the trunk, pulls the tiller, and thus steers the boat.  It’s a framework of three carbon fibre tubes, filled with some kind of cloth, that attaches to the vane attachment I made yesterday.

The tubes are clamped in to something I’m calling the “vane end”.  John Fleming’s method for making this seems a bit complicated, involving blind drilling at strange angles and then starting again if you get it wrong.  I decided to cut grooves to hold the tubes instead, using a chisel and a round file.

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I had a short debate with friends on Facebook about why woodworkers avoid files, but I decided that a rasp is just a file in disguise and used one anyway.

One mystery is why the vane end isn’t arched like the vane attachment.  When you fix the vane at an angle it’s going to clash with the counterweight flange, like this.

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I’ve asked John about this, but he’s very sensibly not answering email on a Sunday.

Rather than start the pendulum as planned, I decided to work on the mount. This is the bearing that will attach the whole gear to the back of the boat. I started by making the bearing, which is three boxes bolted together with a large hole down the middle to take the pivot pin.

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Making the large hole took a long time and a lot of tallow.

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But I was pleased when it fit perfectly first time!

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That’s as far as I got with the mount today.  Before going further I plan to take the frame to the boat and make detailed plans about how I’m going to attach the bearing.

This evening I started on the pendulum. This is a kind of reverse rudder that twists, steering the gear and thus pulling on the tiller.  It’s basically a plank that you must plane into a wing-like profile.  The plans come with a computer-generated profile to copy. To do this, I copied the profile to a piece of thin plywood.

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This was done by first photocopying the page, cutting a groove through the copy with a knife, using a jigsaw to get it roughly right, then filing and sanding until I matched the line of the original.  This template will be used when planing the pendulum to get the shape right all the way along.

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I’ve started the planing just to get a feel for it, but haven’t got very far yet.

One other thing, at dinner we happened to come to the end of a wine box. Dad took out the bag to get the last of the wine. It’s a very nice strong mylar bag, and it’s just the right size to fill in the vane!

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So that’s that problem solved.

Tomorrow I’m sailing (with children!) in the morning, but hope to get some more construction done later in the day.

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Constructing the Hebridean day 6

We’re into the sixth day of construction of the Hebridean wind vane self steering gear, since I started on Monday.  It’s getting close to complete assembly, with only the pendulum, vane, and mount to make.

This morning was taken up with building the vane base. This is a large block that clamps to the turret tube. You turn it in order to change course, because it controls the angle of the vane that is pushed by the wind.  In spite of being more or less a cube, it’s quite complicated, being made of four plys of wood and three of metal. John Fleming tells me this is to ensure that it copes well with wear.

As before, there are quite a few photos in the Flickr album with descriptions containing tips.

Once again, I deviated from John’s instructions. Having a drill press, I’m able to make accurate holes through quite long distances. That means I was able to cut and drill all the holes in all the layers of wood and metal in one go.

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It also meant I could make these long holes without needing to saw and chisel as instructed.

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One thing that does puzzle me is that John’s instructions for cutting the base in half involved separating all the pieces and cutting them individually.  I just cut the whole thing with a hacksaw in a couple of minutes.

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Here’s what the vane base looked like assembled.  Twisting the block around the turret tube is what will change the course of the boat.

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I also made the vane attachment.  This is a bracket which will hold the wind vane itself (the “sail” that gets pushed by the wind to keep a course).  Its main feature is a flange that will hold a counterweight, so that the vane is balanced.  It hinges on the vane base.  Here’s what it looks like when assembled with the vane on the frame.

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And here’s the frame almost completely assembled, with the vane attachment, vane base, and push rod linkages all put together at the end of the day.

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Once again, I have quite a few smaller tips in Flickr album that might help someone else building, or interest the very curious!

I’m writing this entry at the beginning of day 7, so now it’s time to get to work on the pendulum and vane.

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Constructing the Hebridean day 5

It’s day five of my project to construct a Hebridean wind-vane self steering gear, and things are literally coming together.

I was somewhat stuck at the end of yesterday, not knowing how I should align the extension — the piece of the frame that has the vane at the top. I had quite a bit of back and forth with John Fleming, but he gave me a key bit of information: the carbon fibre push rod that comes down from the vane to the pivot is 30mm left of the line DE on the frame diagram.  Since it passes through the centre of the turret tube, I was able to use it to line everything up.

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This allowed me to mark up and cut the cross lap join that’s so critical.  I wasn’t all that confident about this bit of woodworking.  The last time I made a cross lap joint was during ‘O’-level Design Technology at school. But it turns out to be much easier than I remember, as long as you sharpen your chisel until it’s like a razor. (The chisels at school were always blunt.)

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I made another deviation from John’s plans.  Since you need a 20mm hole saw to make the bearing for the pivot pin, why not use it to cut the groove for the same pin?  This saves a lot of delicate chisel-work.  It helps if you have a drill press.  Here’s the work in progress.  (More details in the Flickr album.)

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Finally, I assembled the outrigger hinges. This was straightforward, and it’s great to see the fiddly stainless-steel parts I’ve been making start to make sense in context. Here’s what I have at the end of today.

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There are more photos with details of the steps in the Flickr album, including multiple checking steps.

But now it’s time for strawberries and bed.

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Constructing the Hebridean day 4

I started construction of a Hebridean on Monday. I didn’t get very much construction done on Thursday for two reasons. Firstly, I went to a meeting of the Small Sailboat Club at Ashlett Creek and met (amongst others) Jim Hall on his amazing Paradox micro-cruiser, Faith. More about that later!

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The second reason was that I got stuck.  John Fleming’s plans for the Hebridean are sometimes quite tricky to follow.  At this stage, I should be joining the “extension” (upper arm that goes to the vane) to the “trunk” (main frame strut).  The instructions go in to great detail about the joint, but don’t tell you where to put it.  There is a serious lack of dimensions in the diagrams.  I even resorted to tracing to try to figure it out.

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I wrote to John and he seemed a bit baffled by my bafflement!  But he did include a very important dimension in his reply.  The vertical push rod’s centreline is 30mm left of D on the frame 1 diagram.  Since it passes through the centre of the turret tube, this locates the extension (and the pivot later on too).

It’s now Friday morning and I can start to join the frame together.  If it stops raining this afternoon I’ll take the frame to Tammy Norie and I can start designing the mounting on the back of the boat.  That part has to be custom for each boat, and I think Tammy’s will sit on top of the transom. We’ll see!

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Constructing the Hebridean day 3

I started constructing the Hebridean self steering gear on MondayYesterday I made most of the metal parts.  Today I got started on the woodworking.

Right now I’m about to catch a train to reach Tammy Norie before she dries out, so that I can set sail at 05:00 and reach Warsash in the morning. Then I can get to Ashlett Creek on the afternoon high tide for the meeting of the Small Sailboat Club. I’ll try to get back for some more construction in-between.

But that means I’m in a hurry and can’t write much.

I have uploaded more photos to the Flickr album, with captions containing tips.  Start with this one.

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I’ll be reviewing all of this again later.

Tammy is calling!

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