How does the Streaker rig work
Printed From: Yachts and Yachting Online
Category: Dinghy classes
Forum Name: Dinghy development
Forum Discription: The latest moves in the dinghy market
URL: http://www.yachtsandyachting.com/forum/forum_posts.asp?TID=12569
Printed Date: 08 Jul 25 at 7:23am
Software Version: Web Wiz Forums 9.665y - http://www.webwizforums.com
Topic: How does the Streaker rig work
Posted By: ifoxwell
Subject: How does the Streaker rig work
Date Posted: 14 Nov 16 at 11:47am
|
Walking around the beach looking at the Streakers at our club they all seemed to have VERY slack rigging. Now I sail a Blaze so I'm used to slack rigging but in our case its to control the interaction with the spreaders. The Streaker doesn't have spreaders and so far as I could tell didn't even have any control at the mast gate so whats the idea? ------------- RS300 |
Replies:
Posted By: iGRF
Date Posted: 14 Nov 16 at 12:03pm
|
At our club the streakers have picked up on the technique I employ to get the Solution to run by the lee, by slackening the forestay which allows the boom to go further forward thanks to the slack shrouds, I guessed that must be why the Blaze guys did it after the nationals when the Rooster guy came and mopped up with slack shrouds. ------------- https://www.corekite.co.uk/snow-accessories-11-c.asp" rel="nofollow - Snow Equipment Deals https://www.corekite.co.uk" rel="nofollow - New Core Kite website |
Posted By: jeffers
Date Posted: 14 Nov 16 at 12:37pm
|
Isn't the Solo rig similar? I am always surprised by the amount of sag on the leeward shrouds they have. It may be to get the rig to try and act like an unstayed rig as much as possible but the deck/pot cannot handle the mast loads for the shrouds to be removed? ------------- Paul ---------------------- D-Zero GBR 74 |
Posted By: Ardea
Date Posted: 14 Nov 16 at 12:51pm
|
I think of it as a supported unstayed rig. The mast is stepped on the base of the hull (or the false floor if fitted) then supported at deck level which gives a basic degree of mast stiffness (similar to a laser/topper/etc.), the shrouds then further support the mast allowing it to be of a smaller section. Running slack rigging allow you to run deeper as the leward shroud goes slack allowing the sail and boom to go out further. There's a tradeoff between tighter rigging giving increased mast stiffness and upwind speed, and slacker rigging giving a more flexible mast sacrificing upwind speed, but allows you to sail deeper before the shrouds get in the way. It's a reasonable answer to the compromise of a stayed rig limiting the boom angle when going downwind. I must admit it felt really wrong the first time I sailed mine with slack rigging, but it certainly sailed much nicer. Jeffers sums it up pretty nicely, but it's not just the deck/pot strength, it also allows a smaller/lighter mast to be used.
|
Posted By: Sam.Spoons
Date Posted: 14 Nov 16 at 12:53pm
| I think Steve Cockrell probably would have mopped up with a tight rig TBH. |
Posted By: Ian99
Date Posted: 14 Nov 16 at 1:37pm
|
The idea of the rig is that the relative position of deck hole (which should be a pretty tight fit) and mast foot is used to set the rake, in a similar way to an adjustable unstayed rig in a Europe, Optimist etc.
The shrouds are then used to limit high up sideways bend in a similar way to cap shrouds, and the forestay used in conjunction with the mainsheet/kicker to get a reasonable degree of mainsail leech tension without needing to pull the boom onto the back deck laser style. However, many boats do in my opinion have the rigging set too slack for any amount of breeze. The general guidance is that the shrouds and forestay should be put in the furthest hole down you can get it into by yourself, doing the shrouds first. When done like this, the shrouds don't really flop around, but obviously are significantly less tight than a boat which has a mechanical means of tensioning the rig. Any less rig tension than this in breezy conditions, and the boat turns into a complete animal downwind, as the mast flicks around all over the place in gusts and shifts. |
Posted By: ifoxwell
Date Posted: 14 Nov 16 at 1:46pm
|
Thanks guys, all good stuff. Do the class rules govern the position of the hounds? ------------- RS300 |
Posted By: RS400atC
Date Posted: 14 Nov 16 at 4:07pm
| Don't most Solos have slack in the shrouds these days? |
Posted By: PaulPoshW
Date Posted: 14 Nov 16 at 4:53pm
| Slacks also describes the trousers worn by most Solo sailors... |
Posted By: zippyRN
Date Posted: 14 Nov 16 at 10:07pm
makes sense - i think the #problem' is cognitive dissonance brought about by ever higher rig tensions etc in 2 ( or 3) sail boats ... which to some extent follows from jib luff sag prevention
|
Posted By: Sam.Spoons
Date Posted: 14 Nov 16 at 11:16pm
I'm beginning to wish I'd bought a Europe after all.......  |
Posted By: JimC
Date Posted: 15 Nov 16 at 10:26am
|
Rig tension is needed with spreaders, because if there's none they do nothing.
Trapeze boats with spreaders tend to need ultra high rig tension, because weight on the trapeze unloads the windward shroud, reducing the effectiveness of the spreaders. In a spinnaker boat there will also be considerations about spinnaker induced mast bend, and especially inversion if the hoist is significantly above the hounds. Double spreader rigs march to a bit of a different drummer, especially those where the caps are brought back to the mast so are effectively sort of diamonds. (double diamonds?). So a single sail boat without spreaders has a lot more options for how tight or loose the rigging is. |
Posted By: ifoxwell
Date Posted: 15 Nov 16 at 10:47am
|
Hi Jim. I get your whole post and that understanding was the driving force behind the question. In a normal stayed/spreader rig the tension can affect this interaction and thus give you control over whats happening. So although you say
on one hand that makes sense but my question is really to what end? Ian99's reply has come closest so far to something I follow but I still wonder if I'm missing something. Ian ------------- RS300 |
Posted By: JimC
Date Posted: 15 Nov 16 at 10:58am
| TBH I've seen so many theories about tighter or slacker rigging on single sail boats over the years, many contradictory and all seemingly backed by race results that I hesitate to offer any conclusions or even suggestions. |
Posted By: iGRF
Date Posted: 15 Nov 16 at 11:38am
Some questions
I'd always assumed that shrouds and spreaders other than the obvious task of holding the sticky up pole up were another necessity of aluminium masts which tend not to return too well if bent, unlike Carbon so largely an historic and unnecessary feature of modern una rig boats and a positive disadvantage as witnessed by my Solution which I'm convinced would perform so much better with an EPS style carbon set up as indeed would the Streaker. All that Gubbins was also required because the mast bend/ luff curve mismatch means of creating twist could never fully be employed using aluminium so you guys buggered about with various settings to alter the mast bend and top twist as best you could, then along comes a spinnaker and creates lots of other issues, but Streakers don't have kites, so surely don't need spreaders? ------------- https://www.corekite.co.uk/snow-accessories-11-c.asp" rel="nofollow - Snow Equipment Deals https://www.corekite.co.uk" rel="nofollow - New Core Kite website |
Posted By: Noah
Date Posted: 15 Nov 16 at 11:49am
Showing your age there, Mr.C 😀 ------------- Nick D-Zero 316 |
Posted By: JimC
Date Posted: 15 Nov 16 at 12:00pm
|
Don't forget the wires permit a lighter and thinner mast and the ability to alter the bend characteristics without gluing on or shaving off carbon. The reduced weight in particular makes the boat more user friendly to sail and rig.
Spreaders are a very effective way to control mid mast bend - cheap, light and low windage compared to alternatives. |
Posted By: Sam.Spoons
Date Posted: 15 Nov 16 at 12:05pm
Interesting discussion, I noticed the extremely sloppy shrouds on the Solos on Sunday and was curious. I sort of get what Ian99 is suggesting too but I'm also curious as to why sloppy rigs work on the Blaze (which has a deck stepped mast and lowers). I'd have thought that would work differently but haven't worked out why? After 9 years of sailing the Spice with it's high tension rig setting up the Blaze rig so slack seem wrong (but I know it is supposed to be fastest). Time to watch Ian F's Blaze walk through vids again ;)
|
Posted By: Ardea
Date Posted: 15 Nov 16 at 12:50pm
| Ian99's reply is a much neater way of saying what I was attempting to get at. Also to follow on from JimC, the the wires not only allow a thinner and lighter mast, but also a lighter mast step and deck construction. Whilst strengthening the mast support or mast with today's materials and tools might be possible without adding significant weight it would have been very tricky, if not impossible to do that at the time. |
Posted By: ifoxwell
Date Posted: 15 Nov 16 at 1:13pm
On the Blaze, the Ali M7 mast is just way stiffer than most people need. So when you run the rig loose the spreaders have much less influence, it lets the middle of the mast move forward and to windward in the gusts which in turn depowers the middle of the sail and lets the top twist off to leeward, spilling wind. Crude but effective and one of the many reasons that I prefer a mast with spreaders, it just gives you more tuning options. In an unstayed rig the only person who has control of the stiffness of the mast is the builder.... And
now we get to the real reason for posing the question, how much control does
the sailor really have over the stiffness of the mast and how much is just down
to the builder. And yes yes I know we can influence it with kicker and Cunningham
etc but its not the same thing. Ian ------------- RS300 |
Posted By: iGRF
Date Posted: 15 Nov 16 at 2:00pm
|
What would definitely make more sense would be on single sail setups, the spreaders raked forwards, not only to permit the boom to go forward, but to control and vary the effect of the kicker. ------------- https://www.corekite.co.uk/snow-accessories-11-c.asp" rel="nofollow - Snow Equipment Deals https://www.corekite.co.uk" rel="nofollow - New Core Kite website |
Posted By: Cirrus
Date Posted: 15 Nov 16 at 2:22pm
|
Slack Blaze rigging ? No great secret ... the M7 is/was a great mast .... and particularly for the 470 and Fireball. For the Blaze and I suspect a number of other single-handers it is/was way too stiff. Slacker rigging can help as does slacker lowers and later on we also adopted articulated (swiveling) spreaders. It is an advantage in terms of sailing by the lee ... the Blaze main is a high aspect design with 3 adjustable full width battens up the top. So you do want to sail by the lee ? Just ease the kicker offwind a tad and the top of the sail goes a long way forward - articulating the spreaders in addition means the leeward one can also 'go forward' and this helps further still. The M7 is usefully light for an alloy mast btw. All this has been known since Noah was a spotty squaddie ... The real advantage of a stayed mast is you can set it up very easily for a very wide range of helm weight.... using just the one standard suplied mast - and they can be both light and low drag as support triangulation is naturally so much better than for an unstayed rig. The diameter can be less, the wall thickness less and so on. In unstayed classes that allow it it really really helps to have the mast stiffness and therefore construction 'matched' to the helms weight and height - ie tailor made for 'you'. This really is one instance where one size does and cannot really be made to fit all optimally ! Stayed masts can also very easily be adjusted to suit - unstayed have the stiffness characteristics built into the mast walls - so are bloody difficult to then change if made of alloy/carbon. Though there are some devious methods if you have the right 'facilities' if not strictly legal in 'off-the-shelf' classes. (As teenagers we used to plane and sand wooden OK masts down to 'suit' - and even sometimes too far- even if it was allowed !) Modifying one-design unstayed carbon masts once made is much more difficult of course ;-) |
Posted By: Sam.Spoons
Date Posted: 15 Nov 16 at 2:45pm
|
Thanks guys, better understanding now. I too remember gluing bits of wood to my OK mast one weekend and planing it off the next according to what my dad's rudimentary mast bend measurement rig told us.......
|