17 March 2011

Mystery of the Blue Moon

For my entire 2000 mile cruise around Florida and up the east coast of the US, I was never satisfied with the way the Blue Moon's sails were rigged. The staysail, for instance, didn't self-tack without adjustment. The mainsheet was awkward to use. And the mizzen was downright dangerous!

Blue Moon
Sails, from left to right: mizzen, main, staysail, jib
topsail above the main
drawing Tom Gilmer
Being new to gaffers and wooden boats, I blamed myself. I figured I just didn't know how to use the gear properly. But gradually I began to suspect the problem went deeper than that.

And now I'm convinced the Blue Moon was rigged all wrong!

For example, let's just look at the worst offender: the mizzen. Referring to the drawing above, the mizzen is the left-most sail -- the one hanging 8' off the Blue Moon's stern.

It looks pretty small, right? Just one of the cute little sails that give the Blue Moon it's character.

The sail itself is 50 square feet, about the same size as Vintage's mainsail. The mast is about 14' tall, the boom 8' long, and the yard 11'.

This type of sail is called a standing lug sail, which has a reputation for being powerful and easy to use.

So what's the problem? Check out the mizzen spars, which I have taken off the boat for painting.

Mizzen spars
From right to left: Mast (14'), Boom (8'), Yard (11')
photo jalmberg
Notice anything odd? There are virtually no fittings on these spars, except for a couple of small, plastic blocks that have obviously been added fairly recently. There is a 1.5" cheek block at the top of the mast, and a turning block hanging from the boom (not visible in photo.)

Otherwise, the only fittings are the 'shoulders' at the top of the mast, and holes drilled at each end of the boom and yard.

I believe the Blue Moon was built by a builder named Randy Hill down in NC. I've never met Mr. Hill, though I would love to. I haven't been able to track him down, so far. But Mr. Hill knew a thing or two about wooden boats. He knew how to build them strong, and he knew how to rig them simply, without a lot of shiny geegaws screwed into the spars.

But somehow his knowledge was not passed down through all the Blue Moon's owners.

Blue Moon's Mizzen - click for closer look
drawing Tom Gilmer
Someone, at some point, looked at this set of mizzen spars and asked, "How the heck do you hoist up the sail?" and "Where does the dangburn sheet go???"

Let's look at the halyard first. The halyard is the rope used to pull the sail to the top of the mast. To do this, the halyard is led from the cockpit, up through some sort of block at the top of the mast, and down to the top of the sail, where it is tied off. To hoist, you just pull on the loose end of the halyard.

But how was this done before the plastic cheek block was installed?

A mystery.

Next, lets look at the mizzen sheet. You can see from the diagram above that the Blue Moon's mizzen sheet is a simple affair. Just a rope attached to the end of the boom, led through a turning block on the boomkin, back up through another turning block on the boom, and into the cockpit. Could not be simpler.

But again, there is no hardware on the boom. No place to tie off the sheet. No turning block. How was the sheet set up before someone screwed a tiny plastic turning block into the boom?

Another mystery.

What is my problem with these small plastic blocks? Simply put, they are unsafe. The two 1.5" screws holding the cheekblock to the top of the mast pulled out in a fairly light wind. That's how much power this 'small' sail can generate.

And thank King Neptune that they pulled out when they did. Even in a light breeze, it was a heck of a job to pull the yard, sail, and boom, plus a bunch of tangled rope, out of the water and back into the cockpit. I'd hate to think what would have happened if it pulled out on a dark night, offshore.

I screwed the cheekblock back into the mast after the first disaster, but never had the nerve to try it again.

There are other problems. Suppose the halyard was set up more securely. What happens when you let the sail down?

Think about it. The only thing holding up the yard, sail, and boom is the halyard. When you slack off on the halyard, the boom drops down onto the boomkin, the sail comes down behind it and starts to drag in the water. Finally the 11' yard comes down, swinging around, uncontrolled, threatening to drag the sail, you, and whoever happens to be hanging onto your feet, down to Davy Jones' locker.

Supposing you don't get dragged overboard, how do you get sail ties around all that stuff when it's hanging off the back of the boat, out of reach?

Another mystery.

I have some clues: four small holes drilled into the bottom of the boom, and two small footprints in the paint.

Mystery holes drilled into the bottom of the boom
photo jalmberg
What were these holes for? I believe there were two pad eyes attached to the bottom of the boom, roughly dividing the boom into thirds.

Pad eyes
photo Jamestown Distributors

My first thought was that they were for attaching the end of the sheet and the turning block, but they are in the wrong place for that. The plans show the end of the sheet tied off to the end of the boom, with the turning block close to the middle. But these pad eyes were installed 1/3rd of the distance from either end.

Mizzen boom setup
diagram jalmberg
More importantly, I can't see the conservative Mr. Hill depending on four short screws to control all the force generated by the mizzen sail. If he did attach the mizzen sheet to the boom with pad eyes, they would also tend to pull out just when you needed them most. Not the kind of strong and simple construction that he seemed to favor.

So what were those pad eyes for? And how did he hoist and sheet the mizzen without any hardware?

That's what puzzled me and at least one other Blue Moon owner. But I think I've finally solved the mystery...

To be continued

>>> Next Episode: Mystery solved!

Helena standing at the bottom of an inlet in Cornwall.
The ocean comes back and floats the boats half-hidden behind her.
photo jalmberg


  1. "rope"! Dang John, ain't no such thing as a rope on a boat. They are lines John, lines. But I am not about to get involved in your analysis of how it was all intended to be used. Not sure why the sheet would have to go out to the end of the boom though. Not to be picky, but I don't think it is quite correct to say the halyard is tied to the top of the sail either. BTW, what on earth is a "burn sheet? Why on earth did I come back here? John will either make a fool out of me or never let me visit his blog again...

  2. Hi John.

    I suspect that fitting some kind of parrell arrangement would help by holding the yard(gaff) against the mast both under sail, and when raising and lowering. It also helps pass the drive forces to the mast, and reduces the force on the halyard under sail. You can't do that with that fabulous sail the Dipping Lug, the sail o f choice where I come from (Cornwall), but that one is a whole new ball game!


  3. Ralph: well, not quite to the end, but almost, as you can see from Tom Gilmer's drawing. I guess because it give more mechanical advantage, and helps hold the boom down?

    I say 'rope' when I'm explaining things to readers (like my mom) who don't know what a halyard or a line are.

    Ain't you ever heard the expression 'dang burn'? As in, where the heck are my dang burn glasses?

    Hey, it was a long day.

  4. Jim, you're getting ahead of me, but we're thinking on the same track.

    I miss Cornwall! Check out the picture of Helena in Cornwall (I'm behind the camera, where I belong.)

  5. I'm wondering if those pad eyes were on top of the boom rather than below - on our gaff yawl we had a wire strop around the boom shackled to a block which took the sheet. The pad eye on top of the boom just stopped the wire strop from moving fore and aft so didn't take much load.

    We had similar arrangement for the kicking strap on the main boom.

    Wire strops were leather covered (latter;y replaced with plastic tube) to prevent chafe and damage to the spars.

    Hope it helps. drop me an email if you need more details.

  6. My first thought about those pad eyes was that they were attachment points on the bottom. As I researched this more and learned how traditional boats were rigged, my second thought was what you suggest -- retainers for rope strops.

    If that was their purpose (and I admit the chances of that are over 50%), then the builder changed the location of the sheet attachment points for some reason. See my diagram, above.

    But I have another theory that fits my plans, better, whether it's true or not :-)

    I'll get into that, next time.

  7. I thought there was one rope on some sailboats: a boltrope. Fun blog, thanks!

  8. How about lazy jacks? maybe a sail gasket?( something to hold the sail onto the boom). lazy jacks would be very useful on this sail as it is hanging out over the water, and it was methined that the sail had a tendancy to go in the water when lowered. Just a thought.

  9. Lovely yawl.
    Porlock's in Somerset though.


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