Square rig surprise

bilbobaggins

bilbobaggins

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I share a few extracts from comment by Colin Mudie RDI, which may interest peeps. These snippets are necessarily 'out of context' but remain true to the original....

[ QUOTE ]
.....I can appreciate the development of the modern Bermuda rig as a bright branch of wind propulsion but it has a long way to go to match the overall sophistication of square rig developed over some thousands of years by the top technical brains of their periods..... notice how square rig uses a turbine-like wind flow to maximise that power development.... sails operate as efficiently sideways on as they do vertically and were commonly 'kited' to reduce heeling for the benefit of the hull hydrofoil.

The horizontal slots between the sails of square rig are as important as the vertical slots between genoa and mainsail.... the fore-and-aft sails on square riggers were principally used for balance, manoeuvring or anti-rolling, rather than being an early attempt to improve windward ability.

The ignorance of the use of wind power outside our rating rule yacht rigs is fairly universal and perhaps it needs to be explored.... To be helpful I attach the polar diagram for a 200 tonne brigantine which illustrates a modern use of square rig.

[/ QUOTE ]


SquareRig2.jpg



These notes are taken from a recent issue of the Journal of the Amateur Yacht Research Society. Perhaps peeps would enjoy visiting the AYRS stand at LIBS, in January....



/forums/images/graemlins/wink.gif


Should you care to dispute these views, kindly dispute them with Colin Moodie, for I have enuff trouble getting the spelling right, never mind the calculus.



/forums/images/graemlins/grin.gif
 
And for more excellent info on square rig, have a look at Colin's website at www.colinmudie.com

Before anybody starts to shoot down the royals (usually the highest square sails on the masts), first ask yourself 'Have I been sailing on a tall ship yet?'

If you havent, just do it.

A Donf!

If you are a 'conventional' fore and aft sailor, you will find this experience to be quite an eye opener, and invariably many of your stereo-typical views about square rig will be blown away.
 
7kts running boatspeed in 12kts of true wind seems pretty good to me. (assuming plot is true wind???)
Still doesn't point though!, but this could be said of a lot of ketches.
Also shows the benefit of size doesn't it!
 
Even BIGGER Square rig surprise

Young Endeavour whose polar diagram you give operates in Australia and we came across her a couple of times. BUT each time she was under power with no sails set.

Perhaps the engine gives an even better polar diagram /forums/images/graemlins/grin.gif

I would also venture to mention that she has far more sail area in fore and aft sails than in square ones /forums/images/graemlins/smile.gif.

But, she was built in the UK as bicentenary gift to Australia so she can't be all bad I suppose.
 
Re: Even BIGGER Square rig surprise

I tried a square sail on a 1930's Hillyard schooner on a trainning course early this year. I was so immpressed by both the ease or use and power of the sail I have rigged on on my own boat (cutter rig) Beats a spinaker or cruising shoot on all counts and as the spar is hoisted when required rather than left aloft no problems with stability. Apparently this used to be a recognised cruising set up. Not sure if it went because it was not allowed under racing rules, the blight of much good cruising design, or because with a full crew it was quicker to set a spinacker (again when racing) Havent tried it out yet as I only got the hardware set at the end of the season and wont have the sail till next sping. The square sail will be about 20% bigger than the main but because all of it sets to catch the wind, unlike a spinacker where the head is not doing much, and because the spar gives a wider top it sets more projected area than a conventional spinacker and can be set over a wider range. It dosen't have the reaching ability of a cruising shoot
 
I wonder if Colin Mudie is quite as well versed in square rig as he might be. I have sailed several times on the Lord Nelson which he designed. It had such bad weather helm that an extra length of bowsprit and jib had to be added and still the mizzen upper spanker and gaff topsail are only ever set for photographs.

He's not alone in getting it wrong though. The second Jubilee Trust ship Tenacious, designed by Tony Castro, was so tender that she rolled to 50° (great for wheelchairs!) until they added huge amounts of additional ballast.
 
Theres lots of stories about square riggers becoming "embayed" ie sailing back and forth between two headlands for days waiting for a wind shift to allow them out of the bay.Or being blown ashore and wrecked first.
 
That was mostly before the peak of square rigger development in the last half of the 19th century when very efficient rigs were developed for merchant ships. In particular, warships of Nelson's era were far less weatherly than the likes of Cutty Sark. You can see from the vector diagram above that ships like these could sail themselves off a lee shore in almost any weather.
 
The first brig (Stavros) owned by the Tall Ships Youth Trust also had very extreme weather helm when she was first launched - the main mast should have been further forward - the only realistic 'fix' they could do then was to shift quite a lot of ballast (I think over 100 tonnes?) further aft, in order to trim her down more at the stern.
On both ships now they rarely use the spanker as a conventional sail for propulsion, as it does generate a lot of weather helm - but it can be useful for helping them to manoeuvre.
Similarly the main course is rarely used, although the reason here is partially due to visibility from the helm when the course is set.
 
Colin Mudie designed the brig "Royalist" in which I had the pleasure to sail when I was in the Sea Cadets (many moons ago). Properly handled, she sails like a witch, and won the Tall Ships Race in both the 1982 and 83. I crewed her in the 83 race and can say that, with tack-bowlines rigged, she could point just as high as a similarly sized ketch or schooner. Over three days, with points of sail from close-hauled to broad reaching, in conditions from flat calm to F7, she beat most of the bermudan rigged boats (with spinnakers) on the water without needing to claim any handicap. Even when pushed hard (ever sailed with 32 people on the windward rail?) her helm was never too heavy for the average 16 year-old to handle.
So yes, Colin Mudie does know how to design a square rigger.
As I remember, the problems with the Lord Nelson came because JST wanted changes to his original design. The bowsprit was made shorter (to allow full wheelchair access), the courses (lowest sails) reduced in size to make them easier to handle, with the loss of sail area compensated by making the rig made taller by the addition of royals: any of these will induce weather helm - having all 3 together would, as you have found, make it nigh-on unmanageable. When she was built, however, this was not a major consideration for the Trust - after all, the frustration of sailing a vessel which performs poorly would rarely be felt by those whom the Trust are aiming to help, who have never had the opportunity to sail before. The key was to have a ship fully accessible by her full crew, taking them safely to sea, which is what she has done so successfully.
 
People often make the assumption that because all the sheets and braces are normally lead aft, the square sail is just for use in winds abaft the beam.
But with the yards swung right round into a nearly fore and aft direction, and the bottom of the sail tensioned forwards rather than aft, it becomes in effect a fore and aft sail, and the ship can tack into the wind.

This was best demonstrated on a replica Viking vessel, where the crew discovered that by swinging the yard right round and dipping it, it became virtually a lug sail, with surprisingly good windward performance.
 
The only thing that surprises me about rig design is that most people consider the bermudan rig to be the be-all and end-all after just 50 years of development.

Most other rigs have been used for hundreds of years, and bring with them the experience learnt by generations of sailors who used their boats to earn a living and didn't have an engine to rely on.....
 
[ QUOTE ]
The only thing that surprises me about rig design is that most people consider the bermudan rig to be the be-all and end-all after just 50 years of development.

Most other rigs have been used for hundreds of years, and bring with them the experience learnt by generations of sailors who used their boats to earn a living and didn't have an engine to rely on.....

[/ QUOTE ]
Quite agree. Thats why I never fly or travel in cars.

Horses and carts have been used for hundreds of years, and bring with them the experience learnt by generations of travellers and carriers who used their horses and carts to earn a living and didn't have an engine to rely on..... /forums/images/graemlins/grin.gif
 
He didn't get the Royallist quite right either - the sailmaker who made her first suit told me that he drew stays going right through the middle of some of the squares!
 
bilbobaggins said:
I share a few extracts from comment by Colin Mudie RDI, which may interest peeps. These snippets are necessarily 'out of context' but remain true to the original....

[ QUOTE ]
.....I can appreciate the development of the modern Bermuda rig as a bright branch of wind propulsion but it has a long way to go to match the overall sophistication of square rig developed over some thousands of years by the top technical brains of their periods..... notice how square rig uses a turbine-like wind flow to maximise that power development.... sails operate as efficiently sideways on as they do vertically and were commonly 'kited' to reduce heeling for the benefit of the hull hydrofoil.

The horizontal slots between the sails of square rig are as important as the vertical slots between genoa and mainsail.... the fore-and-aft sails on square riggers were principally used for balance, manoeuvring or anti-rolling, rather than being an early attempt to improve windward ability.

The ignorance of the use of wind power outside our rating rule yacht rigs is fairly universal and perhaps it needs to be explored.... To be helpful I attach the polar diagram for a 200 tonne brigantine which illustrates a modern use of square rig.

[/ QUOTE ]


SquareRig2.jpg



These notes are taken from a recent issue of the Journal of the Amateur Yacht Research Society. Perhaps peeps would enjoy visiting the AYRS stand at LIBS, in January....



/forums/images/graemlins/wink.gif


Should you care to dispute these views, kindly dispute them with Colin Moodie, for I have enuff trouble getting the spelling right, never mind the calculus.



/forums/images/graemlins/grin.gif
Click to expand...
Hello, i'm reading this thread with interest. Any chance to have the polar diagram of the brigantine?
 
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