rope backstay/flicker

 

Home Forums General Olson 30 Discussions rope backstay/flicker

This topic contains 36 replies, has 10 voices, and was last updated by  Zeke Wolfskehl 4 years, 9 months ago.

Viewing 30 posts - 1 through 30 (of 37 total)
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  • #1850
    Bruce Hubble
    Bruce Hubble
    Participant

    I’m thinking of getting rid of the rod backstay finally. Thinking of dyneema 75 or 90 uncovered with sailmaker thimbles. If you went rope, did you use a turnbuckle to attach at the top block? I want to keep some adjustment there for rope length error I might make.

    Anyone using a flicker? M24 flickers are reasonable.

    Thinking spring launch already!

    #2424
    Bruce Hubble
    Bruce Hubble
    Participant

    forgot: 3/16 or 1/4??

    #2425

    Old School
    Participant

    I went with 7mm Dux, 16500# breaking strength. The rigger suggested that the line should have a minimum of 300% (others say 400%) of the of the rod BS in order to minimize stretch. The rod that I took off my boat was -4, around 5600#.

    Any measurement error you make (or creep that might enter) can easily be taken up in your backstay purchase. As such, I did a brummel around a stainless thimble for the masthead. At the bottom, I used another brummel through a ferrule. Pics are at http://www.olson30.org/the-boat/tips-and-tweaks/backstays

    No flicker for me. I have done everything I can to get weight out of the rig, so I sure as heck am not going to add something? Granted, it can be a real pain on light wind days… On those days, I just carry the main a bit lower on the mast.

    #2426

    Jim Saylor
    Participant

    Fast Company used 1/4 amsteel blue w/ Closed thimbles & no turnbuckles. We also lead all the purchases below deck and it exits just aft of the traveler on each side (48-1).

    #2427

    Jason Adamson
    Participant

    Jim,
    Would you mind describing your under deck set-up or if possible to post pics? I am curious about doing a below deck install on my boat. Thanks

    #2432

    Jim Saylor
    Participant

    Jason,

    I’ll try to get photo’s.
    We split the backstay w/ a block 6′ from deck, ran split through deck just ahead of transom to large cheek blocks on inside lower transom, up to standoff blocks half way up transom. from there I added a 3-1 purchase toward/along side of cockpit (below/inside) to which I added a 5-1 that exits cockpit wall just aft of Traveler. Easy. I’ll work on photos.

    #2433

    Jason Adamson
    Participant

    Thanks Jim, Sounds simple enough but I’ll wait for pics to really wrap my head around it.

    #2471
    Bruce Hubble
    Bruce Hubble
    Participant

    Bought 39 feet of Amsteel 1/4″ for $17 on ebay. I rough measured the rod @ 31 ft (for the records). I’m going to use a single block on the bottom and replace the wire with Amsteel.

    #2476

    Jim Saylor
    Participant

    don’t forget to pre-stretch the Amsteel. A truck and tree…

    #2482

    Curt Rodgers
    Participant

    Do class rules allow for other than rod or wire standing rigging?

    #2483

    Jim Saylor
    Participant

    Yes, but only for the backstay.

    #2484
    Bruce Hubble
    Bruce Hubble
    Participant

    Actually Jim..I didn’t see any such rule. I only saw minimum weight, including shrouds and running rigging. Rope is not even mentioned for the backstay.

    #2485

    Old School
    Participant

    8) Sail plan dimensions are as follows: J=11.75; P=31.50 feet; E=10.75; I=36.00 feet. The rig shall be masthead; the original chainplate dimension shall not be modified; the location of the points of attachment of the standing rigging to the hull and deck shall not be moved nor modified. The baby stay is not considered standing rigging. Running backstays shall not be allowed for class racing.”

    Thus, the babystay is considered running rigging, and is not subject to measurement. It is only mentioned in the mast weighing section so that you may not run it up the mast in order to raise the CG of the mast.

    There is NO restriction on materials of any rigging. As Bruce indicates, only minimum mast weight and lowest CG is specified.

    #2486

    Curt Rodgers
    Participant

    Thanks for the clarification. Good to know. The only thing I would worry about with a Amsteel/Dyneema back stay would be chaff at the top where the leach normally hits. I suppose you could put a cover on it up there however.

    #2487

    Old School
    Participant

    I don’t have anything covering my dux backstay. It is showing a very minimal amount of chafe at the top batten after two years of use. Not nearly enough to be concerned about in my opinion.

    #2488

    Old School
    Participant

    I should have included the text for the mast weighing so people don’t have to go searching for it:

    i) The mast shall be weighed at the center of gravity and shall weigh no less than 128 pounds. The center of gravity shall be no closer than 19 feet, 3 inches from the base of the mast.

    #2489
    Bruce Hubble
    Bruce Hubble
    Participant

    Amsteel is very wear/abrasive resistant. It is also very slippery. I had a 3/16 robline dyneema lifeline rub on a post for a day…barely a mark.

    #2490

    Jim Saylor
    Participant

    What a great group! I’m not sure where I heard no fiber stays??? Might have made it up…Our 1/4″ Amsteel blue has held up great and shows minimal wear at the top batten point. It’s been up for 2.5 years and I’ll probably replace it next year, just to be on the safe side. We’ve never had a baby stay either.

    #3086

    Derek Lay
    Participant

    Gents,
    I’m currently looking at using Amsteel blue to replace the backstay this year. I notice that the 1/4″ shows only 8600lbs breaking strength. Have any of you noticed an issue with it that would convince me to pay 60% more for 5/16 (13,700 lbs), or 100% more for 3/8″ (19,600 lbs)?
    Is there another product I should look at? Thanks
    Derek

    #3087

    Jim Saylor
    Participant

    We sail in big seas and lots of wind and feel totally comfortable w/ our 1/4″ Amsteel. Pre-stretch it.

    #3088

    Old School
    Participant

    The riggers suggest you should have greater breaking strength in order to minimize stretch. This is why I went with Dux.

    #3089
    Bruce Hubble
    Bruce Hubble
    Participant

    “only 8600 lbs”…that’s double the weight of your boat.

    Max..I bet you are not putting 2000 lbs pressure on it. Go with 1/4 and replace every couple years. I bought a Melges 32 flicker for $25..but shipping was another $25. Forget trying a batten…looks right..doesn’t work.

    Key is doing the prestretch. Tie your truck to a tree with it. Put it in reverse…then park it overnight with a ton of pressure. It doesn’t stretch, it just ‘adjusts’ the fibers into alignment. The rope will be stiff when ready..almost like wire.

    #3090

    Ken
    Participant

    My forestay is Pre stretched Dux and backstay is dyneema , there is a few feet of adjustment with the ratio , and backstay is constantly adjusted so I wouldn’t imagine tight tolerance on length would be necessary …? Has anyone gone to solid carbon or pbo rigging yet ?

    #3091

    Old School
    Participant

    From my post a year ago:

    “I went with 7mm Dux, 16500# breaking strength. The rigger suggested that the line should have a minimum of 300% (others say 400%) of the of the rod BS in order to minimize stretch. The rod that I took off my boat was -4, around 5600#.”

    The 300% was to minimize stretch. As you know, stretch in any line is dependant upon the % of BS. Lower %, lower stretch. Once you have your backstay dialed in, it is very nice to not have it move! If you use 1/4
    amsteel BLUE (not gray), at 20% BS (1720#, well within reach with most 48:1 purchases) you have 0.7% stretch. Does not sound like much, does it? Well, .7% over 30 feet is (30*12*.007) 2.5 inches. Two and a half inches is HUGE variation! And this does not take into consideration the shock loads pounding upwind into waves.

    My Dux would be operating at a bit less than 10% BS, with significantly less stretch. I am sorry, but I could not find the % stretch, but it will be much less.

    If you would be okay with a few inches stretch, then go for the less expensive amsteel. It is a third the cost of dux. I figured that the extra $80 was a small price to pay.

    #3093
    Bruce Hubble
    Bruce Hubble
    Participant

    I think the rod on the Olson’s are -4..the smallest.

    To compensate for the initial creep, I have one section of the back stay adjuster that can be shortened to take up the inevitable creep. I used 5/16 (7mm?) gray Robline 3000 I think. I know I used it for lifelines (3/16). Once the creep is out..I don’t think I had ANY stretch. I’m on my second season and it looks new. (we don’t have intense sun and heat to deal with) Heat is the enemy..this stuff has a temperature level that the tropics might not like.

    #3095

    Old School
    Participant

    Dyneema (amsteel or dux, etc) has very good UV tolerance and a high melting point, so neither sun nor heat should factor into your decisions.

    #3096

    Derek Lay
    Participant

    Thanks gents. The biggest takeaway for me is to pre-stretch the line. I probably would have wound up with a bit more than I needed otherwise. How much creep did you get during the stretch, and how much did you use during the splices? just trying to figure out how much to order . . .

    #3097
    Bruce Hubble
    Bruce Hubble
    Participant

    I did long splices…no need to scrimp. About 18″. This stuff is slippery and I wanted to not have a worry. I used SS thimbles and seized with thread at the thimble.

    Overall..about 6″ of creep is my best guess. I didn’t pre-stretch, but recommend it.

    #3098

    Derek Lay
    Participant

    Thanks Bruce. Time to splice!

    #3109

    Gene Perkins
    Participant

    Guys. After reading this I am looking at replacing my wire with Amsteel. I have a roll that came with the boat. Looks like 1/4 but it is the grey color. What is the difference between the grey and blue if any? The tag on the roll is half missing but says amsteel and it looks like a number 8700?? Any help would be appeciated.

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