Sailboats with Free Standing Masts

[Greatketch33]

Originally Posted by Steady Hand

I am enjoying reading your remarks about your boat. It sounds like a nice boat to sail. Post some more photos of it when you get a chance. Interior? Cockpit? Sail/boom/mast (closeup). Layout of winches? etc. I would like to see, and others here might find it interesting too.

Hi SteadyHand,

I appreciate your support and encouragement.

Greatketch.blogspot.com has pictures of my boat and other related resources about free standing masts. My intention is to not direct folks away from this site; rather, to not duplicate resources already available.

I do enjoy the reading the information and comments posted.

On a side note: I recall listening to a online podcast with Eric Sponberg as the guest; he mentioned that he prefers to design elliptical shaped mast over circular shaped; he mentioned that elliptical is easier to calculate load and related structural consideration and that elliptical provided better air flow around the mast; that circular masts disrupted the air flow more.

Any engineers out there who can educate us on the above?

[dannc]

Originally Posted by micah719

Here are some interesting pics I found on this site:
index

...

"The Storm" is an interesting collection of pictures, imho. Pass me my spare lifejackets and the brown corduroy trousers, please......

Was that a "survival storm?" Photos of waves make the waves look smaller than reality. THOSE waves looked big...

Amazing that the ship survived. I don't think life jackets would have helped...

Really, the most disturbing photos where the hair "styles" of the crew.

Later,
Dan

[micah719]

The 70's shall return! Sideburns like a Yeti! Flares! Afros! Collars that carry the risk of takeoff in anything over Beaufort 3! Carpet pattern that you can't visually tell if the cat and two dozen of its friends puked on or not! Avocado washroom suites! Women with hairy legs! Mustaches like mine!

These two pics are from capngeoff on Boat Design Forums....the boat itself is 50ft, and the first pic especially shows how he gets the luff right back to the mast....this doesn't rule out camber in the belly, but does address the "bad tack" myth, which Arne Kerveland demolishes anyway over at the JRA site. Lots of good stuff over there...

From this post:
Chinese Junk Rig - Page 2 - Boat Design Forums




p.s. I also like how much room and vision he has over the bow...

[solarbri]

Originally Posted by alansmith

Free standing mast sailors....ok, spill the beans of your secret knowledge. What happens when you are on a dw leg and a squall pops up behind you and comes barreling down upon you? I know I have heard they are easy to depower. But if the wind is pressed against the sails and you slack the main halyard I assume the sail just doesn't drop. Also very curious what you do in a real blow for a trysail. How to you keep the boat crabbing into the wind when lying ahull? Please share with us...

I, for one, just keep on barreling downwind and after sheeting out to the max, completely unhook the sheet from the deck and let the sail weathercock downwind, then drop the mainsail, reef, whatever. Then I'll repeat the process with my other sail.




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[Greatketch33]

Originally Posted by solarbri

I, for one, just keep on barreling downwind and after sheeting out to the max, completely unhook the sheet from the deck and let the sail weathercock downwind, then drop the mainsail, reef, whatever. Then I'll repeat the process with my other sail. Sent from my iPad using Cruisers Sailing Forum

I have been fortunate enough to not test my skills in DW leg with a squall coming up from behind.

I do know that there are no shrouds to entangle the sails. I would release the sheets and and let the sails spill wind while working to pull them down. -- if I had to to this.

I would rather be facing bow into wind.

[micah719]

One idea I haven't yet seen tried is copying a bird's or bat's wing directly; and there is a lot to learn by biomimetics that can benefit us. The materials, structures, sensors, processing power, actuators and systems engineering are spectacular. If one wants the ultimate in variable geometry, one may as well emulate the best! We're in a bit of a bind, however, as there aren't really many critters that sail, and those that do aren't all that good at it. The Velella just goes downwind like Thor Heyerdal, while the Portugeuse Man'o'War has a little lateen rig and tacks. I believe there's a spider that dangles a line off the stern like a kite, have to research a little more...

So, since this is a thread about wings, er, I mean, masts and the stuff hanging off them, I thought a foray into the master class for a little cribbing might be inspirational.

A collection of vids about bird tech (skeleton, muscles and feathers would be the most relevant, though murmurations might be useful particularly for those crowded anchorages ):

https://www.youtube.com/watch?v=11fZ...ature=youtu.be

You've done it by hand, you've done it with rollers, it's perhaps even done or undone it all by itself, but here's how the eagle does it:

Collapsible wings help birds cope with turbulence | University of Oxford

Reefing: somewhat a problem for the marconis, bragging rights for junkies, and the Jamaicans are no slouches either; here's how the humble pigeon does it. Can we steal their software?

Study shows one reason why pigeons so rarely crash

We're trying...knowing what the code has to achieve, is a step on the way to writing it:

Aerial Acrobats: Pigeons Whoosh Through Tight Space | Science/AAAS | News

Here's a development that might help us finally settle the laminar/turbulent flow conundrum in sail aerodynamics; you have to know what to plagiarise, so here it the first step.....measuring tools:

https://news.stanford.edu/pr/2015/pr...ft-011515.html

Why aren't birds bigger? Their feathers can't grow fast enough:

What limits the size of birds?

Even a certain fish is no slouch in flying:

FLYING FISH GLIDE AS WELL AS BIRDS

How about a wing that can feel the wind? The bat can:

Sense of touch turns bats into acrobats | Science/AAAS | News

And if a bat can feel the air, it can also do amazing stuff with that knowledge:

Bats Best Birds at Slow Flight | Science/AAAS | News

Any inventors out there willing to tinker? There is no excuse for boredom, especially if you have a laboratory just over the other side of the rail....

[Steadman Uhlich]

Hi Micah,

Thanks for posting the numerous links to some interesting WING sites/info.

The other night I looked at a few of the links you posted earlier and saw a few Junk Rig pages with designs that varied in shape, materials, and appeal (to me).

On one boat it appears the homebuilder is making something that looks "too small" and "too heavy" to my inexpert eyes.

In another, (showing real Chinese Junks) the sails looked very much like a wing of a bird to me.

[micah719]

That's why I find the Reddish style sail so appealing; it reminds me of an owl's wing, which has mighty interesting aerodynamic properties:

Leading edge spikes to create lots of small vortices; fluffy down over the surface to keep the turbulence attached; and a fuzzy fringe for a clean detach. That's the latest theory anyway, for why the things are so silent. We spend so much time as sailors trying to control airflow, might as well learn from the masters.

There are many variations of junk sails in China, the Reddish is similar to the one called Audemard on the following link, near the bottom:

Junk Sails: A Tutorial

The rig you found too small and heavy....was that the one on the Glasshouse Chebacco?

Got it! I was looking for this before the edit clock ran out for this post. Here's one I looked at a long time ago, but the micah-files are extensive and I haven't been very good at filing, or consolidating as I migrate files from comp to comp.

Have a look at the cloth on this sail.....(the rest of the boat is intriguing too..):

http://thomashoppe.net/junks/luemeimao.php

[Greatketch33]

It is true that there appears to be more room on deck and an open view without all the shrouds and standing rigging.

For those who love irony: I make up for the lack of standing rigging cluttering the view by having lines and such hanging from the life lines. Haha.

[NevisDog]

Originally Posted by Greatketch33

... I make up for the lack of standing rigging cluttering the view by having lines and such hanging from the life lines. Haha.

With all those ropes, looks as though you've just come through a tornado! Nice view though.

[Steadman Uhlich]

Originally Posted by solarbri

I, for one, just keep on barreling downwind and after sheeting out to the max, completely unhook the sheet from the deck and let the sail weathercock downwind, then drop the mainsail, reef, whatever. Then I'll repeat the process with my other sail.

Attachment 107083


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Hi Solarbri.

That is an interesting catamaran I have not seen before. Thanks for adding it to the mix of FSM boats here in the thread.

[micah719]

A bit of info about Freedom masts from the musty CF archives:

http://www.cruisersforum.com/forums/...irs-93598.html

[Greatketch33]

Originally Posted by micah719

A bit of info about Freedom masts from the musty CF archives: http://www.cruisersforum.com/forums/...irs-93598.html

Thank you, Micah. That is good information at the link. I suspect masts built by CKY were built differently although E. Sponberg was involved with that design as well.

[findrichard]

Anyone know what it would cost to have a Freedom 33's masts repaired in such a manner?

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[HankOnthewater]

I think it has been described that one of the advantages for free standing (?and rotating) masts that one can let out the boom or wishbone passed 90 degrees and even forward towards the bow, and that way be able to reef the sail with a following wind.

Pardon my ignorance, but the mainsheet then needs to be awfully long, ie with a 4:1 blocks, and a 4 mt boom/wishbone (just arbitrary figures), that could about 35 metres or more of mainsheet. If the reduction is 5:1 much longer still. Am I missing something?
Or is the reduction a lot less and then a winch used?