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  1. #31
    Senior Member Old River Rat's Avatar
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    the best i can do, while scratching my head, is to say "huh?" but very entertaining . . .

  2. #32
    Senior Member Les Rust's Avatar
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    Great stuff, Professor. Have to admit that I saw the 21 minute run time and decided that I had to wait till the right time and cup of coffee to absorb the knowledge, but indeed, it was worth it. The statistical probability of being able to use either suspension was enlightening. I have had a couple of occasions where I ended up by-passing the continuous loop and larksheading the whoopie sling directly to the hammock body, but I was still able to hang with whoopies. I agree with MedicineMan on this on--no real advantage to the SRS, IMHO. But if the question comes up, I can now say with authority that Professor Hammock's thorough analysis supports that position.

  3. #33
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    I (a newbie, admittedly) seem to reside in that part of the country where the real-world tree copse density usually ranges from 100 to 750 trees - cause many times I've had to shorten or eliminate my whoopies. Or, maybe, i'm still not very good at site selection.

    This situation has left me looping whoopies back on themself, using continuous loops or dogbones several times in less than a year - non-adjustable.

    So, I'm seeing a silver-lining here with the SRS.
    • By carrying only an additional 2-rings (or perhaps something lighter as noted in the original SRS thread).
    • Then, lengthening my whoopies and using the "tail" to build the SRS system (no extra cordage to carry).

    Can I increase my odds of finding a suitable hang spot by way - more (a technical term) than 5%

    Either way it's still good to know that the SRS method can give an advantage at times.

    Copse pS pW
    100 .41 .37
    250 .73 .68
    500 .74 .63
    750 .55 .41

    So, does this mean that the probability of finding a hang spot using a SRS can be
    • 7.4% greater in a 250-tree copse,
    • upto 17.5% greater in a 500-tree copse?
    • and about 34% greater in a copse of 750 trees?


    I'm no math guy and I'm only on my first coffee for the day, so let me know if this is correct?
    - Loki,

    "Climb the mountains and get their good tidings.
    Nature's peace will flow into you as sunshine flows into trees.
    The winds will blow their own freshness into you, and the storms their energy,
    while cares will drop away from you like the leaves of Autumn."
    John Muir

  4. #34
    GrizzlyAdams's Avatar
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    Quote Originally Posted by FireInMyBones View Post
    Thanks for sharing. You bring a uniquely humorous and intelligent perspective to our hobby.

    I would like to pose the question:
    For a gathered end hammock, what is the flattest lay to lightest weight to length to width to ridgeline length ratio? I use roughly a 9'x4.5' gathered end hammock with a 90" ridgeline. Can the computer postulate the best way to manipulate these variables to maximize "flatness of lay," which is likely subjective, for the lest amount of weight/ smallest rig still marketable to the average individual? I'm not sure if you've played with that idea or not, but I'd like to see the model if you get the time.
    Thanks for the interest FIMB. Good question, we'll have to take that up in the graduate course on hammock engineering.

    Quote Originally Posted by Shewie View Post
    Excellent vid Grizz

    I used to use single rings with tubular climbing tape, but then I discovered whoopies and never looked back. There used to be a good Ray Mears vid on youtube showing the same system but I can't find it now. It's the same as the beginning of this though.

    It was a really easy system to use and a doddle in cold weather with the thick tapes, bulky to pack the two 5m lengths though. I should try it again with amsteel and see if it works, I'm not sure about the knots in amsteel though.
    Thanks Shewie. As soon as the kid wrapped the tape around his hand twice I knew were we in for a Siberian hitch. Tried that with Amsteel once, and it was really really hard to undo.

    Quote Originally Posted by Sailor View Post
    Great vid, glad to see you back in production, and I am a SRS kinda guy. Would your CS predictions change much if you varied tree trunk size as found in a s. sempervirens copse (to take a liberty)?
    hey Sailor. For this model trunk size doesn't play a role (as it would if the length of tree straps were under study). For a S. Sempervirens patch I'd bring a machete. Forget "leave no trace". This is "leave no goldenrod"...
    thanks for watching...

    Quote Originally Posted by stairguy View Post
    And that is why you are " Professor Hammock "...................
    Stairguy! Awesome peapod you've got, showcased in shug's video. I'm a fan of peapod use in winter too. My mother has a picture of me at age 5 lecturing a few neighborhood kids...they're sitting in small chairs on a patio and I'm standing up talking away. Her prescient comment on the photo, "Age 5, the Absent-minded Professor".

    Quote Originally Posted by Great White View Post
    That was an outstanding presentation! I like the field of study: Computational Hammock Science. I liked your modelling and simulation.

    There appears to be a low occurrence that one would have enough trees to choose the optimum hanging location. I infer from this information that it is best to choose a suspension system that maximizes the probability that two trees will be located within hanging distance. Something that works well at close ranges as well as long ranges. Now, of course, close and long are arbitrary terms.

    Did you perform this simulation in Octave or Matlab?
    I expect new degree programs in CHS to be springing up all over the nation, with particular concentrations in universities near major hiking trails.
    My interpretation of the model predictions are that, once the tree density is sufficiently high, your change of finding a hanging spot _somewhere_ in a large enough region is very good. Where the probabilities get low is where you get particular about where you hang. And even here, the "probability" is that a given small area has a hang with the characteristics you want. If that probability is 1 in 4, that means (on average) you end up checking out (only) four small area sites before you find what you're looking for. But yes I agree, going prepared to hang from a variety of tree separations is the way to go.

    I've looked at Octave, and run Matlab infrequently (so infrequently I always have to relearn how to use it). For these simulations the path of least resistance for me was to write the simulation in Python,
    and have the scripts pump out gnuplot data and plotting files. Given a bunch of plots (the generation of which is all scripted of course) I put them together in a program call ImageJ (free Java program, comes out of NIH) into an animated display. ImageJ will put out an animated .gif from all this, but I prefer a screen capture program SnapProX that produces .mov which is easy to introduce into the video editor.

    Quote Originally Posted by SGT Rock View Post
    I liked it. When I first pulled it up and saw it was 21 minutes I thought I would never make it to the end LOL. But it was worth watching for sure.
    Thanks SGT, I know what you mean about initial reaction to long videos. Whose got the time??? Thanks for watching anyway.

    Quote Originally Posted by craige View Post
    Great video grizz, really enjoyed that, especially the sim.

    Out of curiosity what suspension do you generally use most often?

    Thanks

    Craig
    Thanks for watching Craig. My preferred method has rings of some kind at the very ends of the hammock. I use 8' of cord that has a 3 inch fixed eye at one end. The fixed eye goes over the marlin spike hitch. The working end of the cord comes down to the ring where I tie it off using a slippery buntline line hitch, or more often a variation on sort of doubled slippery half hitches.

    Quote Originally Posted by gmcttr View Post
    ....I was ready to post the same thing...21 minutes!?!...fast forward here I come.

    In reality, I watched it all, some parts twice, and finished looking forward to the next edition of Professor Hammock.

    It's nice to have to have the "book learning" to go along with my observations.

    Very nicely done. Thanks.
    Thanks gmcttr. In my experience models tend to confirm what experience and common sense suggest. That certainly was the case for me here. My experience---I have to hunt around a bit, but not a lot, to find a pair of trees that work. The model explains why that is.

    Quote Originally Posted by JayS View Post
    Great job, Grizz! Good to see you back... and front... and flipped over.
    Hi Jay! My first thought going over the side was "Dang! Have to open up the hammock a bit more before dropping into it". My second thought was "Have to work this into the video somehow!"

    Quote Originally Posted by WV View Post
    Most enjoyable, Grizz. My only quibble is the random placement of trees. Wendell Berry would urge you to consider their distribution "random so far as we know." There are forces (real, not metaphysical) that influence the growth of trees in their environment, producing distribution patterns that may or may not be recognizable to mere mortals. As I said, it's a quibble.
    Hiya WV. Point noted. That said, I could go on and on and on and on and on about the philosophy of the level of detail in simulation models. I'm working on a paper this month written with a colleague entitled "The Dark Side of Detail What Your Mother Never Told You About Abstraction". We can take up the question sometime at a hang...

    Quote Originally Posted by Callahan View Post
    Excellent video Grizz....cleared up some questions that I've had.

    Cheers
    Great, glad for that Callahan. One of the things I try to do is anticipate the kinds of questions that might be asked that can be answered with close up visuals. I'm a visual learner myself....

    Quote Originally Posted by Shug View Post
    I sure liked all that Grizz. Hung with you on it all.
    That Miquelito is a Hunk.....
    Quant on.
    Shug
    Shug! Thanks for stopping by. Yes, one does not want to mess with "The Mexican Madman"

    Quote Originally Posted by MAD777 View Post
    That was pure fun!!!
    hope you had popcorn!

    Quote Originally Posted by hangNyak View Post
    Great work! I've experienced the same thing with the Amsteel being deformed. What is the effect if using Vectran or Spyderline?
    Vectran will squash for sure. Spyderline will resist, but there's a possibility of the core breaking, at least for the smaller diameters, if one fully load bearing strand goes on top of another. I've seen that happen to 3mm Spyderline inside of a garda hitch made with two rings. Large force concentrated on small area---not so good. I did some some experiments with a Hennessey Safari and its stock suspension. That cord is BIG and I wouldn't worry much about it.

    Quote Originally Posted by Fronkey View Post
    That was awesome and I hope you keep these coming. Galen's cameo was hilarious.


    Fronkey
    Thanks Fronkey, Galen is a natural ham.

    Quote Originally Posted by UrsaMajor1887 View Post
    Great video. I didn't look at the 21 min. time and watched the whole way through without thinking of the time. I take that as a sign that the video was both informative and entertaining. Where were you when I was taking physics?
    Ha! I was at the back of the class drawing free body diagrams of hammock suspensions.

    Quote Originally Posted by ezhiker View Post
    Great video Grizz. Very instructive as well as entertaining. Saved me some time making a new suspension. Thanks!
    "Save time"? You could put together 3 or 4 SRS suspensions in the time it takes to slog through 21 minutes of Professor Hammock! I appreciate the viewing though.

    Quote Originally Posted by scoutsnoa View Post
    Besides the sheer entertainment that this vid provided, I was totally mind blown with the education. This is what I crave for from HF, and of course you Professor....
    Glad someone gets my jokes! Teaching as I often do to large classrooms of none-native-English-speakers, my under the radar sense of humor tends not to be understood.

    Quote Originally Posted by MedicineMan View Post
    Bottom line:
    takes too long to unwind and rewind to move the ring, crushes/weakens the amsteel, and no statistical advantage over hang sites.
    SRS is pretty much a done deal dead.
    Thanks again Grizz.
    Thanks MM. Hey, I was hoping to see that secret hammock you referred to in your New Years Eve hike video... Could it be the elusive, ah, well, I better not say it in public. Leave the moment of revelation to you.



    Quote Originally Posted by Old River Rat View Post
    the best i can do, while scratching my head, is to say "huh?" but very entertaining . . .
    Thanks for watching, but more importantly, happy retirement! Saw your FB posting about New Years Eve being your last day on the force. What a night to stand down, I'm sure.

    Take thy ease, sire.
    Grizz
    (alias ProfessorHammock on youtube)

  5. #35
    Yoda's Avatar
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    Awesome video Professor, and that Lucho star, man he must have cost a pretty penny to get in.............

    I think you summed it up rather well, SRS not a better solution. WOW did that Dutch biner get destroyed wish there was a camera on that sucker when you plopped in the hammock, seeing that in slo-mo would have been fantastic, HA grizz200.
    Formerly known as "Cranky Bear"....

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  6. #36
    Shewie's Avatar
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    Quote Originally Posted by GrizzlyAdams View Post
    Thanks Shewie. As soon as the kid wrapped the tape around his hand twice I knew were we in for a Siberian hitch. Tried that with Amsteel once, and it was really really hard to undo.
    I thought that might be the case, saves me from getting in a pickle trying it

  7. #37
    GrizzlyAdams's Avatar
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    Quote Originally Posted by Les Rust View Post
    Great stuff, Professor. Have to admit that I saw the 21 minute run time and decided that I had to wait till the right time and cup of coffee to absorb the knowledge, but indeed, it was worth it. The statistical probability of being able to use either suspension was enlightening. I have had a couple of occasions where I ended up by-passing the continuous loop and larksheading the whoopie sling directly to the hammock body, but I was still able to hang with whoopies. I agree with MedicineMan on this on--no real advantage to the SRS, IMHO. But if the question comes up, I can now say with authority that Professor Hammock's thorough analysis supports that position.
    yeah, we all have to be prepared to adapt to local conditions. I'm always packing an SMC ring and a couple of Amsteel extender cords . Costs me half an ounce of not-rigorously-necessary weight, but opens up many options.


    Quote Originally Posted by Loki View Post
    I (a newbie, admittedly) seem to reside in that part of the country where the real-world tree copse density usually ranges from 100 to 750 trees - cause many times I've had to shorten or eliminate my whoopies. Or, maybe, i'm still not very good at site selection.

    This situation has left me looping whoopies back on themself, using continuous loops or dogbones several times in less than a year - non-adjustable.

    So, I'm seeing a silver-lining here with the SRS.
    • By carrying only an additional 2-rings (or perhaps something lighter as noted in the original SRS thread).
    • Then, lengthening my whoopies and using the "tail" to build the SRS system (no extra cordage to carry).

    Can I increase my odds of finding a suitable hang spot by way - more (a technical term) than 5%

    Either way it's still good to know that the SRS method can give an advantage at times.

    Copse pS pW
    100 .41 .37
    250 .73 .68
    500 .74 .63
    750 .55 .41

    So, does this mean that the probability of finding a hang spot using a SRS can be
    • 7.4% greater in a 250-tree copse,
    • upto 17.5% greater in a 500-tree copse?
    • and about 34% greater in a copse of 750 trees?

    I'm no math guy and I'm only on my first coffee for the day, so let me know if this is correct?
    A qualified yes, the qualification being the probabilities being noted here are those of finding you can hang in one given pre-selected spot. You can turn that around and estimate the average number of spots you'd (randomly!) check before finding one to your liking, and you'd find that the SRS is better from the point of view of that metric.

    My more negative conclusion is based on a less tightly quantified measure, and that is of human experience, and human perception of chance. Did you know that casinos use psychologists to figure out where to place slot machines with varying degrees of success probabilities and payoffs, with the objective of pulling players deeper into the casino and play with larger stakes with the hope of larger payoffs? Frequent wins with low payoffs are placed by the door, while deeper in the wins are bigger but less frequent. Even if the long run expected gain (expected loss, actually) is less beneficial for the player on the bigger payoff machines, that's where players are drawn. Even if the expected benefit is the same on both types of machines, one has to be able and willing to play on the lower-rate-higher-payoff machines longer to hit the wins that even up the average outcomes. Players' gut feelings about the probabilities is based on what they see happening with other players.

    If I gave you a coin that was weighted to turn up heads one out of three times on average, and another that was weighted to turn up heads one out of four times, how reliable would your guess be of which was which based on four throws of each? Yet one will turn up heads 25% more of the time than the other. You could tell the difference statistically by taking many tosses, but not with just a handful. My argument that SRS is not perceptibly better than the whoopie sling puts the emphasis on "perceptibly", because in our experience we don't have to look so hard (or gather so many "random" trials) when we're looking for a place to hang.

    And, as one perceptive reader PM'd me this morning, site selection involves a number of factors not included in this model. All models are wrong. But some of them are useful nevertheless.



    Quote Originally Posted by Cranky Bear View Post
    Awesome video Professor, and that Lucho star, man he must have cost a pretty penny to get in.............

    I think you summed it up rather well, SRS not a better solution. WOW did that Dutch biner get destroyed wish there was a camera on that sucker when you plopped in the hammock, seeing that in slo-mo would have been fantastic, HA grizz200.
    yes, I'd have liked to have dual cameras going, but just have one camera stand...
    thanks for watching!
    Last edited by GrizzlyAdams; 01-03-2013 at 16:38.
    Grizz
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  8. #38

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    I also noticed the flattening compression of the Amsteel and was a little concerned about it reducing the rating of the line. It would be nice if Dutch or somebody with the right equipment could do a stress test and find out if and how much the breaking strength is reduced. Seems like a while back somebody tested cordage and posted results. Don't know why I think it was Dutch.

  9. #39
    Senior Member Hiknhanger's Avatar
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    I'm still trying to figure out why there are so many cops in the woods. Shouldn't they be Rangers?

  10. #40
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    Quote Originally Posted by Bonepile View Post
    I also noticed the flattening compression of the Amsteel and was a little concerned about it reducing the rating of the line...
    Even substantially derated, I wouldn't expect a problem in the short term as the flattened area of the adjustable loop is only subjected to 1/2 the weight.

    Once the SRS has been used many times is when I would feel concerned. At that time, a given area of the rope may have been flattened several times and due to varying hang distances could end up between the hammock and ring where it would be subjected to the full force being applied.

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