Thanks Thanks:  1
Likes Likes:  12
Page 2 of 2 FirstFirst 12
Results 11 to 20 of 20
  1. #11
    Join Date
    Nov 2010
    Location
    Highlands
    Posts
    5,695

    Default Re: Are there any mechanical engineers out ther?

    You should not be holding the rod at arms length, I keep my arm tucked in, far less tiring the only time I lift the rod is when I lift the line, but for casting I prefer to keep the rod down, the old timers recommended tucking a book between the elbow and side, and their rods weighed ounces not grams, you may be surprised, easker1

  2. #12
    Join Date
    Oct 2019
    Location
    Hampshire UK
    Posts
    392

    Default Re: Are there any mechanical engineers out ther?

    Quote Originally Posted by running bear View Post
    Not a mech eng, but an applied mathematician by trade....It gets very complicated very quickly....
    Me too and it sure does.

    I reckon the whole thing is a leg pull

  3. #13

    Default Re: Are there any mechanical engineers out ther?

    Quote Originally Posted by running bear View Post
    Not a mech eng, but an applied mathematician by trade.

    You need the line weights and backing added for any calcs. The model you are looking for would have the line out variable and the force on the line from curent/flies etc. youíd also need the exact weight distribution for the rod, it you could make the assumption (which is wrong but perhaps doesnít have a great impact) that the rod is of even weight throughout Its length. Itís gets very complicated very quickly and isnít just a simple balancing of the moment ( force x distance) across the fulcrum. Then as the rod bends the model changes again. You could get a model that like all models is wrong but may be useful.

    Thinking about what youíre trying to achieve is probably the most efficient outfit. Therefore using the elbow as a fulcrum (or even the shoulder) etc may not make the most sense in a fishing situation. If you are looking at the least TOTAL force through the body when holding the outfit aloft, the lighter reel obviously wins out (Iím assuming you donít have really really short forearms or arms) but that may not be the feeling after fishing as although the smaller reel may untimely have less total force, the rotational forces are more likely to impact smaller muscles (eg youíd feel 10nm across a finger much more than 100nm across your leg) So over all the best outfit for fishing is likely to balance at the rod grip or slight butt heavy for the line out variable, so Iíd definitely go with the heavier reel.

    Before you could get short butt pike dead bait rods for boats, I used to cut down standard 12í pike rods and balance them with decorative window lead wraps at the butt. Youíd think a perfectly balanced (in the horizontal) rod would be better, but a slightly butt heavy rod was better when wobbling/ float trolling with rod in hand as they were all high tip methods. Similar to fly fishing.
    Since this I've done some calculations based upon measurements. Two points to consider: my butt weight is about 14g lighter than commercial rods, so I have the option of putting 14g of lead in the butt. The other option is which reel to use. The weights quoted are for the reel plus line. Clearly there are changes in use such as how much line is out etc., but they will all be constant no matter what set up I use, so for comparisons they can be ignored. So:
    Set up A: 160g reel balances 26cm from the butt. distance from balance point to elbow: 44cm
    to the shoulder 72 cm. So calculating the total balance weight x distance, for the elbow it is 10.3, for the shoulder 16.9
    Set up B: 160g reel with 14 g at the butt: balance distances now 42.5 and 70.5 giving figures of 10.6 and 17.6 respectively
    Set up C with 140 gm reel: balance distances 48.5 and 76.5 giving figures of 10.4 and 16.4 respectively.
    Set up D: 140g reel with 14 g butt weight: balance distances now 46 and 74 giving figures of 10.5 and 16.9

    So in all cases adding the 14g weight gives better balance but more force is needed to keep the rod horizontal. For the reel comparison, from the elbow the heavier reel is better. However, from the shoulder the lighter reel is better! Thinking about what you are doing, you are briefly casting, then holding the rod at arms length while the nymph travels downstream. So except in very fast water, more time is spent holding the rod at arms length. So does that mean that the arms length is the more important criterion for tiredness? If so, then the lighter reel wins out.
    Of course, if you hold the rod with you elbow at your side, the heavier reel wins out. But I would then lose 26cm of reach. I could compensate for that by using an 11ft rod, but that then sets up a whole new set of calculations and I'd have to start building a new rod, which would be heavier!

  4. #14
    Join Date
    Feb 2009
    Location
    Scotland
    Posts
    3,983

    Default Re: Are there any mechanical engineers out ther?

    I've got a nose bleed

    Al

  5. #15

    Default Re: Are there any mechanical engineers out ther?

    Quote Originally Posted by speytime View Post
    I've got a nose bleed

    Al
    Comes from the high blood pressure you get from using a too heavy a reel!

  6. #16
    Join Date
    Oct 2019
    Location
    Hampshire UK
    Posts
    392

    Default Re: Are there any mechanical engineers out ther?

    Quote Originally Posted by kingf000 View Post
    Since this I've done some calculations based upon measurements. Two points to consider: my butt weight is about 14g lighter than commercial rods, so I have the option of putting 14g of lead in the butt. The other option is which reel to use. The weights quoted are for the reel plus line. Clearly there are changes in use such as how much line is out etc., but they will all be constant no matter what set up I use, so for comparisons they can be ignored. So:
    Set up A: 160g reel balances 26cm from the butt. distance from balance point to elbow: 44cm
    to the shoulder 72 cm. So calculating the total balance weight x distance, for the elbow it is 10.3, for the shoulder 16.9
    Set up B: 160g reel with 14 g at the butt: balance distances now 42.5 and 70.5 giving figures of 10.6 and 17.6 respectively
    Set up C with 140 gm reel: balance distances 48.5 and 76.5 giving figures of 10.4 and 16.4 respectively.
    Set up D: 140g reel with 14 g butt weight: balance distances now 46 and 74 giving figures of 10.5 and 16.9

    So in all cases adding the 14g weight gives better balance but more force is needed to keep the rod horizontal. For the reel comparison, from the elbow the heavier reel is better. However, from the shoulder the lighter reel is better! Thinking about what you are doing, you are briefly casting, then holding the rod at arms length while the nymph travels downstream. So except in very fast water, more time is spent holding the rod at arms length. So does that mean that the arms length is the more important criterion for tiredness? If so, then the lighter reel wins out.
    Of course, if you hold the rod with you elbow at your side, the heavier reel wins out. But I would then lose 26cm of reach. I could compensate for that by using an 11ft rod, but that then sets up a whole new set of calculations and I'd have to start building a new rod, which would be heavier!
    You need to get out more. And as we've bothered to reply maybe we do too

  7. #17
    Join Date
    Dec 2007
    Location
    Northumberland
    Posts
    1,657

    Default Re: Are there any mechanical engineers out ther?

    Quote Originally Posted by kingf000 View Post
    Since this I've done some calculations based upon measurements. Two points to consider: my butt weight is about 14g lighter than commercial rods, so I have the option of putting 14g of lead in the butt. The other option is which reel to use. The weights quoted are for the reel plus line. Clearly there are changes in use such as how much line is out etc., but they will all be constant no matter what set up I use, so for comparisons they can be ignored. So:
    Set up A: 160g reel balances 26cm from the butt. distance from balance point to elbow: 44cm
    to the shoulder 72 cm. So calculating the total balance weight x distance, for the elbow it is 10.3, for the shoulder 16.9
    Set up B: 160g reel with 14 g at the butt: balance distances now 42.5 and 70.5 giving figures of 10.6 and 17.6 respectively
    Set up C with 140 gm reel: balance distances 48.5 and 76.5 giving figures of 10.4 and 16.4 respectively.
    Set up D: 140g reel with 14 g butt weight: balance distances now 46 and 74 giving figures of 10.5 and 16.9

    So in all cases adding the 14g weight gives better balance but more force is needed to keep the rod horizontal. For the reel comparison, from the elbow the heavier reel is better. However, from the shoulder the lighter reel is better! Thinking about what you are doing, you are briefly casting, then holding the rod at arms length while the nymph travels downstream. So except in very fast water, more time is spent holding the rod at arms length. So does that mean that the arms length is the more important criterion for tiredness? If so, then the lighter reel wins out.
    Of course, if you hold the rod with you elbow at your side, the heavier reel wins out. But I would then lose 26cm of reach. I could compensate for that by using an 11ft rod, but that then sets up a whole new set of calculations and I'd have to start building a new rod, which would be heavier!
    You've built the rod and are therefore very capable, if such marginal differences are important to you then use the 140g reel for now and part finish your rod (or customize it so you can) fit pair of removable butt weights at (say) 20g and 14g and get out for your first few days fishing. If you prefer the heavier setup in use swap for the heavier reel and finish the rod with your planned 14g weight otherwise leave unweighted and change reel as you see fit.

    I can't see how you could be certain what's best for you otherwise.

  8. #18

    Default Re: Are there any mechanical engineers out ther?

    I should put in a patent for a dynamic active butt balance system (DABBS), it measures the force on the tip at all times and automatically compensates the butt balance (probably using a fluid system) in real time. The overall system will weigh 500g, have a battery life of 3 hours (or come with an optional battery extension back pack) and cost 3k per rod. I think itís a limited market, but didnít they say that about home computers once.
    In the mean time I think itís one thatís best tackled in the fishing situation, even just adding/removing weight until itís optimal - I think some of the Eastern European rod manufacturers have rods with removable weights to balance versus the method

  9. #19
    Join Date
    Dec 2014
    Posts
    2,868

    Default Re: Are there any mechanical engineers out ther?

    All gets very complicated if you try and calculate dynamic forces for different casting. Here's one I'm playing with that has a thread insert for removable butt that I replaced with some penny washers on a cap screw. Casts easier than a T38 and most noticeable thing from initial playing is how easy it picks line up and launches it into back cast. Far too much weight though.. about 200g in this pic. Hanging from a loop of line shows how the balance point moved from front of grip to back with too much weight.
    Are there any mechanical engineers out ther?-capture-jpg

  10. #20

    Red face Re: Are there any mechanical engineers out ther?

    Quote Originally Posted by wrongfoot View Post
    You've built the rod and are therefore very capable, if such marginal differences are important to you then use the 140g reel for now and part finish your rod (or customize it so you can) fit pair of removable butt weights at (say) 20g and 14g and get out for your first few days fishing. If you prefer the heavier setup in use swap for the heavier reel and finish the rod with your planned 14g weight otherwise leave unweighted and change reel as you see fit.

    I can't see how you could be certain what's best for you otherwise.
    Many thanks fro actually considering what I'm trying to do here. What you suggest is reasonable but I think would be too subjective and fraught with too many variables for me to be comfortable with. Also as you'll only know the difference in fatigue after a days fishing, it could take a long time and differences in fatigue could be due to other reasons. My first goal was to produce a rod that is not only lighter, but feels lighter than the other 10ft 3wt rods I have access to. So I compared these and the values I got are shown below where E is from the elbow, normal casting; S is from the shoulder for an extended arm, H is heavy reel and L is light reel:
    My rod: EH 10.3 , EL 10.4 ; SH 16.9 , SL 16.4
    Hardy Jet: EH 11.0, EL 10.8; SH 16.5, SL 17.2
    Vision Mag: EH 11.1, EL 12.3; SH 18.2; SL 17.9

    From looking into my old physics books these values are for Torque in Kg.cm
    So from this it looks as though I have succeeded in my first objective of making a lighter rod that should feel lighter. For a rod blank such as the Sage ESN, which is about 7g lighter, these values would be even lower! These torque values are dependent upon the rod weight, the weight distribution and an individual's length of forearm and upper arm. Someone with a longer arm would get different values. Interesting that whereas the heavier reel is marginally better for my rod, for the Jet the lighter reel is preferred, which is actually what I use. In contrast, for the Mag the heavier reel is better by quite a bit. Things are different for the extended arm, with the Vision Mag feeling much heavier than the rest, which is what I find just holding it.

Page 2 of 2 FirstFirst 12

Similar Threads

  1. Bargain Fast action rod? Iíd ther such a thing??
    By matt_hill in forum Tackle Talk
    Replies: 24
    Last Post: 20-01-2018, 03:04 PM
  2. Vintage Wooden Mechanical Fishing Reel with Brass Fittings
    By EbayUK in forum Vintage fly reels for sale on Ebay
    Replies: 0
    Last Post: 18-05-2017, 06:30 PM
  3. Replies: 12
    Last Post: 01-06-2014, 07:38 AM
  4. ever wondered why ther are no sea trout in Loch leven anymore?
    By zeolite in forum General Fly Fishing Discussion
    Replies: 35
    Last Post: 03-07-2013, 07:07 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •