Unstayed masts: why aren't they more common?

Poignard

Poignard

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I saw an unusual yacht in Brittany recently, a wishbone schooner, British-registered; an attractive boat.

It's masts were unstayed. Presumably it sails alright, (not much point in owning it otherwise).

This got me wondering why unstayed masts are not more widely used. Is there some overwhelming disadvantage to them or is it just unwilingness to innovate?
 
parsifal said:
This got me wondering why unstayed masts are not more widely used. Is there some overwhelming disadvantage to them or is it just unwilingness to innovate?
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Mostly the latter in my opinion.

Not sure how the pricing compares - fewer bits needed, but the bits you do need are special. There must be a lot of volume efficiency in Selden aluminium extrusion.

Pete
 
parsifal said:
This got me wondering why unstayed masts are not more widely used. Is there some overwhelming disadvantage to them or is it just unwilingness to innovate?
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Probably the same as multihulls. Theoretically unarguable but in practice ... blech.

Confession: We have two unstayed masts in the family.
 
parsifal said:
Presumably it sails alright, (not much point in owning it otherwise).
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There are an awful lot of popular designs over the years that would argue that point!

As to why there aren't more unstayed masts, it's a mix of conservatism, the cost of being an early adopter and a lack of any perceived need to deviate from what works well for 99% of sailors for some pretty marginal gains.
 
Unstayed masts have to be a lot bigger or heavier or made of stronger materials.
It's a weigh up of the drag of a fat mast against the drag of standing rigging.

They are hardly new. They've been tried many times through history.
And used a fair bit all over the globe.
 
lw395 said:
They are hardly new. They've been tried many times through history.
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Throughout most of history the best material available was bits of dead tree, though. A lot changes with modern materials, so you can't just write it off as "tried, didn't work".

Pete
 
Cost as usually made of carbon fibre to keep weight down plus cost of building boat strong enough to cope with stress at deck level. The major british manufacturer went bust trying to get the concept established, but only custom built boats experimented with them, apart from the (relatively) large scale production of freedom boats.

like many innovations with some perceived advantages they never caught on and for the mass market have to offer real advantages to gain acceptance. Bit like in mast vs in boom - the former has gained acceptance, but the latter, despite its theoretical advantages has only really made an impression on larger boats, primarily because its benefits of controlling raising and lowering of the mainsail is more obvious in that application.
 
prv said:
Throughout most of history the best material available was bits of dead tree, though. A lot changes with modern materials, so you can't just write it off as "tried, didn't work".

Pete
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True, as materials change, so does the optimum design.
I never said it didn't work.
200,000 Lasers can't be that wrong.
There is a long history of unstayed rigs in the US.
 
DanTribe said:
Standing rigging is a bit old technology. Not many aeroplane wings are held on with bits of wire nowadays.
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The drag of wires would be a downside at mach 2.
If you are designing a microlight, you are in a different set of compromises and rigging wires are still the norm.
Which is the newer concept, the microlight or the delta wing jet?

There was a French Admirals Cup Boat, Krazy Koyote 2, around 1999. Looked quick in some conditions, disappeared in due course IIRC.
 
I might argue Tranonas point of the cost of stresses at deck level. Compared to the high tension of rigging and the loads produced in the structure, the loads from an unstayed mast are relatively mild.

Plenty of lug rigged boats with unstayed masts, mostly small, but fishing boats used have quite big lugs. The halyard was usually tied off to windward, so might be considered a stay.
We have a model of a Chinese War Junk from the 1800s, while lug rigged, the masts are multi stayed laterally, but not fore & aft.

One of the problems with an unstayed mast, is that if you set a jib, it is difficult to get any tension in the luff, so it loses efficiency.
 
lw395 said:
The drag of wires would be a downside at mach 2.
If you are designing a microlight, you are in a different set of compromises and rigging wires are still the norm.
Which is the newer concept, the microlight or the delta wing jet?

There was a French Admirals Cup Boat, Krazy Koyote 2, around 1999. Looked quick in some conditions, disappeared in due course IIRC.
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Built one microlite, no wires in sight. Cruise at 80kts (wires for rudder and elevators, ailerons by torque tube)

Boats designed to racing rules are not good examples. Hoyt raced an early freedom, his success quickly changed the rules :o)
 
You want unstayed masts? Howzabout these? I'm told they worked really well - perhaps too well!

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With low-aspect-ratio rigs they work quite well and don't even have to be that high-tech. American traditional New England catboats have used them for about 150 years... originally just a tapered wooden mast; now mostly tapered aluminum with a round section. Gaff or Gunter rig keeps the center of effort low, which reduces the strain. Not the best arrangement for super windward performance, but a real tiger on a reach or run, especially with a long boom.

Works for me on my catboat.
 
All good arguments for and against. I am no engineer but I reckon instinctively that a stayed mast is a better way to go for sail boats. More strength for less weight. I imagine for aircraft a similar question the change over in value for reduced drag comes at over 100knots so with that comparison no problem with sail boat. olewill
 
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