Rig parts and opinions

Discussion in 'Sailboats' started by bntii, Jul 9, 2012.

  1. bntii
    Joined: Jun 2006
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    bntii Senior Member

    I was mussing about with a couple of rigging straps I used to make up a few inches of length on my fore-stay.
    A rigger walked by (some young guy- the *******) & pointed out how wrong my setup was and how I should change out parts to get it squared away.

    He might be correct but one of the details he suggested was changing out from my old bronze toggle to the stainless strap style.

    So from these:

    [​IMG]

    To these:

    [​IMG]


    Well I like my old bronze toggles & they have been rock solid for over 50 years on the boat. Further- I distrust stainless gear in such critical spots.

    His reply was "well those bronze toggles are just cast" & didn't seem to mind that as he was rummaging though a box of old stainless strap toggles to show me the set up, a number were blown up where crevice corrosion cracked the straps over the pin..

    Whats the deal?

    Is the strap toggle designed to be simply replaced wholesale when one re-rigs the boat.
    I think the shops are now saying to replace wire every 8 years or so now...

    On my boat, coming on 60 years the original screws,turnbuckles and toggles are still in service and will stay there even if I replace the wire.

    Is this what happens to old sailors.
    They disappear at sea when their "they don't make it like they used to" boat or gear finally gives up the ghost?
     
  2. Stumble
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    Stumble Senior Member

    Warning shameless plug incoming....

    Bntii,

    I think the rigger you spoke to is full of it. There is nothing at all wrong with cast parts. They can suffer from inclusions in the metal that make the part weaker, but after 60 years the part either doesn't have them, or we're designed around, or the part would have broken. While its true that casting results in a weaker part than forging, it isn't a huge difference absent a large inclusion (air bubble in the casting).

    That being said, at 60 years old the problem you could have is fatigue cycles. Metals can only handle being cycle loaded a given number of times before the metal wears out, and looses its strength. Good bronze like steel and titanium has a logarithmic flattening of the cycle fatigue curve somewhere aroun the 10^7 cycles, so at low stress levels the number of cycles it can absorbe are pretty high, but not infinite, and at that age who knows how many it has left in it.

    This brings up you second question... Why don't they make it like they used to...

    The reality is they do, but "the way they used to" parts are very expensive. So much more expensive that people often balk at the higher prices and go with cheap crap that isn't nearly as good, and then complain when it breaks. So for instance....

    A 1/2" turnbuckle in different alloys...

    Siliconized aluminium bronze (the way they used to make it alloy) is $265
    http://www.greenboatstuff.com/dacobrrisc.html
    In 316 stainless $89
    http://www.westmarine.com/webapp/wc...toreNum=50045&subdeptNum=50088&classNum=50095
    In Grade 5 titanium..... $77.78
    http://www.alliedtitanium.com/products/vupdc_Detail.php?UPDCID=9216

    So ya you can get siliconized aluminium bronze, but compared to the alternatives it is outrageously expensive.

    Honestly of the three metals, I would choose titanium every time. It is stronger, more corrosion resistant, doesn't suffer from crevice corrosion, has a better cycle fatigue limit, and is half the weight of bronze or stainless. But it doesn't have the traditional look....
     
  3. alan white
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    alan white Senior Member

    The real question is what is the cross-sectional area of the two arrangements. The strap style appears to have a small area in comparison to the bronze.
    Once you've measured the cross-section of the two "legs" of the toggles, look up the tensile strength of the metal used. While the stainless can be assumed to have the highest tensile strength, the additional 'meat" of the cast bronze will probably more than make up for the metallurgical difference.
    I've made my own forestay toggles out of marine grade aluminum, using a table saw and a file and drill press. They cost me almost nothing and I was able to calculate an improvement in tensile strength due to the beefier dimensions. so there are a few ways to go and there is no single answer to the question of which metal is superior.
     
  4. Stumble
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    Stumble Senior Member

    I would be very hesitant to use aluminium Alan. Aluminium has a very short fatigue life, even at low loads when compared to bronze, stainless, or titanium. It obviously can be made strong enough, but it may not last as long.
     
  5. Petros
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    Petros Senior Member

    There is no one type of rigging one "needs" to have, anything and everything has been used on rigging. That guy was just trying to sell you something you do not own now, "his" hardware.

    It is about sizing the part to the required loads, no matter what material is is made from. Aluminum does have a limited fatigue life, but that too can be compensated with heavier cross section.

    If you have any question about the integrity of any fitting or fixture, especially if it is a critical one, it should be replaced or load tested to about 90 percent of the design load.
    If it suffers no physical deformation or damage, it is good to use.
     
  6. bntii
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    bntii Senior Member

    So I chatted up the riggers again today & was told that
    "it's the new way of doing things"
    "all of the gear is replaced with every wire change"

    So I am guessing that he doesn't expect to see corrosion failures in the parts during the limited service life they see and one has to bear the cost of all new toggles, turnbuckles and screws at each wire renewal.

    I still prefer my beefy old bronze gear to the light stamped and bent strap toggles
     
  7. alan white
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    alan white Senior Member

    No reason not to use the old bronze parts. They haven't likely deteriorated since new and they are already paid for. People who install new rigging need to make money and at the same time reduce liability. Those are their needs but your needs are different. It may be better money spent to do something else like add a few new charts or something.
    Aluminum, if sized right, won't deform and therefore shouldn't suffer fatigue. I mentioned aluminum because it is so easily worked and is so cheap. I like the idea of building a boat from shop-made parts. I think we are pretty much made to feel we're being held hostage by the industries who are in it for profit. I recently priced a 4" long 1/4" carriage bolt in bronze. Five bucks after the salesman spent a few minutes on the computor. You'd think he was pricing a new car. No thanks.
     
  8. sean9c
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    sean9c Senior Member

    Anyone care that these 2 toggles aren't interchangeable?
     
  9. Stumble
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    Stumble Senior Member

    Not really. I thought we were talking about the difference in metal and creation method, and just assumed the pictures were examples. But yes those toggles are defiantly not interchangeable.
     
  10. bntii
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    bntii Senior Member

    Yes- just examples
     
  11. sean9c
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    sean9c Senior Member

    Looked for bronze turnbuckle, technically bronze body with s/s studs. $100 for 1/2" at Fisheries Supply, my local distributor. http://www.fisheriessupply.com/productgroupdetail.aspx?cid=142689&keywords=turnbuckle
    All s/s turnbuckle, which is a really dumb idea since the galling will drive you crazy, is about $85.
    The Ti link you enclosed is for a body only (no studs) at $90. From what I can gather from the site studs are about $90ea, so a Ti turnbuckle complete looks to be around $300
     
  12. bntii
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    bntii Senior Member

    Stumble- am I remembering correctly:
    You have something to do with custom fabrication of TI parts??

    Thanks
     
  13. PAR
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    PAR Yacht Designer/Builder

    Petros has it right (typical) and rigging bits and pieces are sized. Their type and utilization are commonly application specific, meaning you have to use the appropriate fittings for the selections made. Stamped parts, cast bits, forged what ever, really doesn't matter, so long as they're sized accordingly and most importantly appropriate for the application.
     
  14. Stumble
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    Stumble Senior Member

    Sean,

    I sell titanium parts so yes I am biased. But that doesn't mean I am wrong.

    Bronze alloys are highly variable, probably more so than any other alloy class, and can have significantly different properties depending on exacally what alloy is being used. So unless you know exacally what alloy you have, saying a part is bronze is like saying you drive a vehicle... It's true, but it doesn't tell anyone much.

    For instance

    Commercially Pure Bronze is 90% copper, and 10% zinc. Though technically it isn't bronze at all since it uses zinc as an alloying material.

    Architectural bronze is 57% Copper, 3% Lead, 40% Zinc.

    Bismuth bronze is 52% copper, 30% nickel, 12% zinc, 5% lead, 1% bismuth

    Aluminium bronze has six different typical alloys that range from 4-11.5% aluminium, .5-6% iron, .6-8% Nickle, .5-2% magnesium, .5 magnesium, .4 arsenic


    Each of these alloys is commonly found, and is properly listed as Bronze. But if you put a 40% zinc fitting on a boat, you have just added a very expensive, and likely important sacrificial anode to the hull.

    The traditional standard for marine use is siliconized bronze, which is a far better alloy than the rest for marine use because it doesn't corrode in th emarine environment. But it is a very expensive metal. This is exacally what I was talking about earlier when I mentioned people not wanting to pay for "the don't build it like they used to" parts. Yes Home Depo sells bronze pipe fittings, and other bronze parts, but they really are not even close to the same as siliconized bronze.

    And don't trust the prices on our website too far. They are based on full MSRP, not retail pricing. And anyone who orders from BD.net will get better prices than retail price. Probably wholesale if not warehouse pricing, which would be significantly lower than the online quotes.
     

  15. bntii
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    bntii Senior Member

    Stumble- Hope I didn't seem to imply that.
    I just have a question...

    I have this plate of Titanium kicking around in my scrap bin and I was wondering if you could give me an ideal of the suitable use for this alloy.

    It is stamped

    TY.A-RM1-COND.5-TY.A-RM1-COND.5-TY.A-RM1-COND.5

    and:

    AL4VH295477GR6AL4VH295477GR6AL4VH295477GR6

    The stampings are continuous so I don't know how the series starts
    The piece is a cast off from the navy research lab & I have no ideal of what it is...

    Thanks
     
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