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Thread: Raked spreaders

  1. #1
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    Default Raked spreaders

    Is there any advantage or disadvantage to having raked spreaders?

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    Default Re: Raked spreaders

    Context, we need some context.
    It really is quite difficult to build an ugly wooden boat.

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    Default Re: Raked spreaders

    I think that what's best is what the Star class does, where they are raked back while upwind and move forward with the mast while running.

    Mickey Lake
    'A disciple of the Norse god of aesthetically pleasing boats, Johan Anker'

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    Default Re: Raked spreaders

    Quote Originally Posted by bamamick View Post
    I think that what's best is what the Star class does, where they are raked back while upwind and move forward with the mast while running.

    Mickey Lake
    I assume that is to bend the mast to remove fullness upwind and restore fullness downwind?
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    Default Re: Raked spreaders

    Exactly so.

    Mickey Lake
    'A disciple of the Norse god of aesthetically pleasing boats, Johan Anker'

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    Default Re: Raked spreaders

    I don’t like them on anything bigger than a dinghy. Taint natural!
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    Default Re: Raked spreaders

    Oops, I meant to post this above decks. That being said, Not sure of what info would be pertinent. I'll try.
    50' wooden mast with two sets. No significant bend. Normal ketch rake. Boat was designed like that. I don't have any plans to change them.
    Just curious as to why. I'll be glad to answer any questions.

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    Default Re: Raked spreaders

    I've sailed FDs, and a couple of other classes with 3/4 rigs and bendy masts. That kind of rig requires raked spreaders to control that bend.

    John Welsford.
    An expert is but a beginner with experience.

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    Default Re: Raked spreaders

    Quote Originally Posted by Andrew Craig-Bennett View Post
    I don’t like them on anything bigger than a dinghy. Taint natural!
    I must confess that on some small boats (505s, Dutchmen, etc.) a bendy mast can work quite well. However, I've seen some of those Stars and I wonder sometimes why that mast doesn't break? They bend the heck out of them!
    "Where you live in the world should not determine whether you live in the world." - Bono

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    Default Re: Raked spreaders

    Yep the Kestrel mast I'm using for Blue Moon has raked spreaders and a bendy mast. Of course most dinghies have a hinged arrangement at the mast end so as the rake changes with the bendy mast the spreader angle changes between mast and shrouds.
    I'm considering whether to fit a second set as my hull is only 4ft wide against a Kestrels 5ft 5 inches.. a 37.5 % difference
    Some things bigger than a dinghy need more spreaders..

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  11. #11
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    Default Re: Raked spreaders

    Quote Originally Posted by Andrew Craig-Bennett View Post
    I don’t like them on anything bigger than a dinghy. Taint natural!

    A lot of the last couple of generations of quarter tonners had 3/4 bendy rigs, I really liked sailing those, the rig, if set up properly works extremely well in gusty or variable conditions as it self adjusts for changes in windstrengths unlike the stiffer masthead rigs which to a certain extent are set and forget.

    But much bigger than those little racers, or for cruisers, I think that the masthead rig is less prone to failure.

    John Welsford
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    Default Re: Raked spreaders

    Needed if there is no backstay.
    I'd much rather lay in my bunk all freakin day lookin at Youtube videos .

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    Default Re: Raked spreaders

    It's clearly not a bendy rig on a 50 ft mast on a classic looking ketch and its unlikely they will be flexible to move forward to any great degree.
    The cap shrouds or intermediates that use those swept spreaders will be set behind the mast rather than in line. Common practise.

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    Default Re: Raked spreaders

    Spreaders are compression struts, they can be hinged both ends. So unless they are big chunky spars, capable of taking bending loads and socketed at the mast, they have to lay in the plane of the shroud. Raking aft if the shroud chain plate is aft of the mast, and square to the boats CL if the shroud is in line with the mast.

    That said, what is this thread about?
    It really is quite difficult to build an ugly wooden boat.

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    Default Re: Raked spreaders

    Fractional rigged yachts where the mast bend is controlled by the backstay will tend to have swept-back spreaders as it is the shrouds and the forestay that keep the mast up. The backstay is really just a line to control the mast shape. as an example the photo below shows the setup for a J99 backstay. It's the little red line that snakes across the cockpit floor culminating at each end in a small cam cleat - not something you would rely on to hold the mast up:

    J99a.jpg

    Basically a dinghy rig, forestay and swept-back shrouds with a mast bender attached to the transom.

    Masthead rigged boats may have adjustable backstays, but the adjustment is there to control sag on the forestay. The backstay is always under tension and so acts as a support to the mast along with the shrouds and forestay. As such you neither need nor want swept-back spreaders as the mast is prevented from falling forwards by the backstay.

    You mention that your boat is a ketch. If so then I assume that this is the mainmast. Does it have a backstay that attaches to the deck somewhere near the base of the mizzen mast or is there a triatic stay that runs to the top of the mizzen - or perhaps neither?

    I'm not sure that you'd need swept back spreaders if you have a backstay, but perhaps if you have a triatic stay instead then it would provide some extra support to the mainmast should you to ever have an issue with the mizzen mast rigging?

    Obviously if you have neither backstay nor triatic stay then there's your answer.

    As perhaps another thought: if your boat originally had running backstays/checkstays but, in the interests of convenience these were ditched at some point, then I guess it may be possible that someone opted for a swept-back spreader rig instead. I'm not entirely convinced by this train of thought, I should probably think it through a little more first...

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    Default Re: Raked spreaders

    Quote Originally Posted by AndanteEd View Post
    Fractional rigged yachts where the mast bend is controlled by the backstay will tend to have swept-back spreaders as it is the shrouds and the forestay that keep the mast up. The backstay is really just a line to control the mast shape. as an example the photo below shows the setup for a J99 backstay. It's the little red line that snakes across the cockpit floor culminating at each end in a small cam cleat - not something you would rely on to hold the mast up:

    J99a.jpg

    Basically a dinghy rig, forestay and swept-back shrouds with a mast bender attached to the transom.

    Masthead rigged boats may have adjustable backstays, but the adjustment is there to control sag on the forestay. The backstay is always under tension and so acts as a support to the mast along with the shrouds and forestay. As such you neither need nor want swept-back spreaders as the mast is prevented from falling forwards by the backstay.

    You mention that your boat is a ketch. If so then I assume that this is the mainmast. Does it have a backstay that attaches to the deck somewhere near the base of the mizzen mast or is there a triatic stay that runs to the top of the mizzen - or perhaps neither?

    I'm not sure that you'd need swept back spreaders if you have a backstay, but perhaps if you have a triatic stay instead then it would provide some extra support to the mainmast should you to ever have an issue with the mizzen mast rigging?

    Obviously if you have neither backstay nor triatic stay then there's your answer.

    As perhaps another thought: if your boat originally had running backstays/checkstays but, in the interests of convenience these were ditched at some point, then I guess it may be possible that someone opted for a swept-back spreader rig instead. I'm not entirely convinced by this train of thought, I should probably think it through a little more first...
    She actually has two back stays. I was thinking that they could assist in headsail/genoa pressure somehow.

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    Default Re: Raked spreaders

    Quote Originally Posted by mariner2k View Post
    Is there any advantage or disadvantage to having raked spreaders?
    The advantage is that drift aft in a shroud, and the swept spreaders that go with it adds some extra bracing in that the shroud acts partly like a stay.
    The disadvantage is that the sail will lay against them on a flat run. Not a biggy , you just don't ease as much as you might with an inline rig.
    20190418_145314.jpg
    I have both myself. The mizzen is independently rigged and there isn't a permanent backstay for it due to room. So the shrouds are set back to act both as shroud and stay. I do have runners for heavy weather or when running an extra, but 9 times out of 10 they don't get used . The shrouds set back and the swept spreaders are enough for rig integrity.

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    Default Re: Raked spreaders

    Quote Originally Posted by Peerie Maa View Post
    Spreaders are compression struts, they can be hinged both ends. So unless they are big chunky spars, capable of taking bending loads and socketed at the mast, they have to lay in the plane of the shroud. Raking aft if the shroud chain plate is aft of the mast, and square to the boats CL if the shroud is in line with the mast.

    That said, what is this thread about?
    Raked spreaders.

    https://www.goodalldesign.net/index....-spreader-rake
    Last edited by Chippie; 07-30-2021 at 01:57 AM.

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    Default Re: Raked spreaders

    Quote Originally Posted by Chippie View Post
    These?
    Diamonds and jumpers

    Diamond shrouds or stays are used to support and stiffen the upper section (or panel, to use the engineering term) of a fractionally rigged mast. Viewed from forward or aft, they form a diamond shape and are held forward and athwartships by a triangular spreader, called a jumper strut, fitted just above the headstay attachment point. The diamond stays lead from just below the masthead, over the jumper strut, and back to the mast just above the upper spreaders.
    Diamond stays are sometimes seen supporting the upper panels of the masts on older masthead rigs. In this application they are in line with the shrouds so as not to interfere with the headstay and headsail. Few sailboat rigs are built this way today.
    It really is quite difficult to build an ugly wooden boat.

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    Default Re: Raked spreaders

    Quote Originally Posted by johnw View Post
    Is this a masthead rig?
    yes, with a detachable inner forestay also.

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    Default Re: Raked spreaders

    Quote Originally Posted by mariner2k View Post
    yes, with a detachable inner forestay also.
    Raked spreaders have become popular on fractional rigs, especially those without backstays.

  23. #23
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    Default Re: Raked spreaders

    Look at the Bergstrom rig to get some idea of how spreaders can work.https://en.wikipedia.org/wiki/B%26R_rig

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    Default Re: Raked spreaders

    It's hard to look away from that J99. So, I looked it up. At $220k, it is out of my price range by about $200k.

    I guess a 60-year old Thistle is still in my budget.
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    Default Re: Raked spreaders

    it all depends on the rig. On a mast head rig, I do not see Raked spreaders doing much. On a fractional, they could be used to induce some rake on the mast. My old SeaSprite 23 had a Fractional Rig, raked spreaders, and jumper spreaders above and forward of them. My Currant Montgomery 17 has a mast head rig and straight spreaders. My gp14 with it's fractional rig, has no spreaders at all.
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    Default Re: Raked spreaders

    Go find yourself a copy of "The Riggers Apprentice" by the late Brion Toss. All kinds of good stuff in there, along with pictures, something I find very helpful once the jargon gets flowing.
    Steve

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    Default Re: Raked spreaders

    Bought that many moons ago. Also had the great privelege of corresponding with Mr. Toss over some rigging questions. Nice man, who is missed.

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    Default Re: Raked spreaders

    Quote Originally Posted by CWSmith View Post
    It's hard to look away from that J99. So, I looked it up. At $220k, it is out of my price range by about $200K
    It's a fine looking bit of kit. Well out of my budget too sadly.

    I comfort myself with the thought that I might be able to afford one in 20 years time after it's already had a lifetime or two of hard racing. I try to ignore the fact that by then I'll either be too old or too dead to be able to do it justice

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    Default Re: Raked spreaders

    Quote Originally Posted by mariner2k View Post
    Bought that many moons ago. Also had the great privelege of corresponding with Mr. Toss over some rigging questions. Nice man, who is missed.
    Reading this thread the other day led me to remember briefly meeting Brion here in NZ. I thought that was quite topical given the remembrance ceremony that just took place. It must have been 2013 because I had a nice conversation with him about the all in line rig I had climbed and inspected in Noumea before we delivered the boat to Australia.
    A really nice man, very witty ,and ready to have a laugh.

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