Posts by Don Paul

  • Speargun designs I can't stand

    Quote from Wishihadgills;

    Im sure Don can explain better as he is an expert when it comes to speargun rubber.



    I'll come back to this when I'm feeling better as now I'm sleep deprived and pumped up on sore throat and cold meds.


    LR ( natural rubber) is a amazing product just like grapes, and like fine wine, fine rubber needs to be blended, cured, and aged properly.


    I have spent hundreds of hrs testing rubber 20 years ago on stock specimens and custom rubber blends by a few gun builders that tried to push the edge. A new thread will be need to be started.


    Short version....right now one of my guns has Dan's small id hole 5/8's @ 300% elongation. (Specimen length X 3) One gun has Mori's 5/8's at the same percentage elongation.


    For optimum performance all rubber needs to be matched to the individual gun length, it's wt, along with shaft length,and dia. All this has to be finally factored into what a individual shooter can successfully cock.



    Cheers, Don

  • The Adventures of Thumper

    Here are some shots showing my rear aluminum deck panel, and 1 of the brackets the will support the 12 ply 7/8'' radar platform plate/ filet table which will have a raised 2'' border to contain fishy water before in dumps off the stern through a drain.I used up some old west systems epoxie as a base to seal the wood before the black epoxie to be done later.
    Next images show mock up of one of the 2 Ti struts that will triangulate the 2 stainless arch loops to the transom.( yellow rod for mock up).
    The transom U-bolts will have L-bracket to tie in to the transom.
    The little deck will have a port and starboard rod port in case my boy wants to troll a jig when the water is dirty.


    Cheers, Don

  • Speargun designs I can't stand

    Quote from ladvr

    The only scientific way to prove this is to have someone from spearbored fire both guns straight up in the air and see which shaft goes higher...



    <img src= " class="smiley" srcset="https://spearfishing.world/forum/images/smilies/emojione/1f606@2x.png 2x" height="23" width="23" loading="eager" data-tooltip="biggrin" aria-label="biggrin"> <img src= " class="smiley" srcset="https://spearfishing.world/forum/images/smilies/emojione/1f606@2x.png 2x" height="23" width="23" loading="eager" data-tooltip="biggrin" aria-label="biggrin">:toast::toast:.


    D

  • Speargun designs I can't stand

    Dan, I have had guys tell me that their skinny 6mil shaft is hitting as hard as my 5/16, because of increased speed of the light shaft with the same power.


    Aviation people distinguish air resistance as parasitic and induced drag, but the importent thing to understand is that drag increases as the square of speed. While power increases in a linear fashion, drag increases exponentially with speed, in a parabolic function. Lets think of a car for example but leave out rolling resistance. If 100 horsepower would push a certain vehicle 100 miles per hour through the air, doubling the speed to 200 would require two-squared or 400 horsepower to overcome air resistance, while 300 miles per hour would require 900 horsepower.


    High shaft speed (7-8 meters per second) from a light/thin shaft has it's limitations when we want 2O foot shots to penetrate.


    Shite:@ what am I doing here.......I have a kitten to play with.;)^^


    Cheers, Don

  • Speargun designs I can't stand

    Roller guns are a great tool to demonstrate how unnecessary ET's are on shafts with balanced rubber power.
    A roller is pulling the shaft right down to the last couple inch's of barrel, OMG:@what is supporting the overhanging shaft and having it hold it's spline cycle during band pull. The shaft is still trying to push it's nose through a medium that is 784 times denser than air @ sea level.


    I hunt in a fluid environment, I am moving, the sea is moving, the fish can move in a split second. There is a millisecond when my brain sends a signal to my trigger finger that all is alined for a shaft launch. I want a shaft that leaves the ''moving'' launch platform as fast as possible, at that moment in time that my brain connected the dots. I don't want a platform ( barrel) influencing/ touching the shaft tail any longer than necessary. Hold a long column of wood out in front of you, have a friend touch the end with a cigarette, very little force will steer the column your grasping....leverage.


    Euro guys love rollers because they have been hunting with 1 band guns most of their life, as they used their stalking skills to get close to fish, and make head shots. The extra power stroke of the roller gives them a bit more range on fish that ''know'' how long a gun is.


    Rollers are fun to Flect around with, I have three, 2 are ancient, 1 has had it's roller removed, as I shoot it with 2 bands the last 25 years.


    Cheers, Don

  • The Adventures of Thumper

    Centered,mounted, and drilled the transom for mounting the motor.Need to remove it prep and paint the rusty mount sleeve and detail the motor. Received my hypalon rub strake for the side of the tube, waiting for more expensive two part glue. Finally worked out the design of the radar arch/ gun rack. The challenge was building something that could articulate down to a height the would fit under the garage door when the boat is on the trailer. More on that when I get the remaining bits.


    Yesterday I drove to Julian to pick up my newest crew mate, Kauai, a 3 month old Bengal hybrid. She will be in charge of fish processing this summer.


    Cheers, Don

  • Tendonitis cures?

    Hank, I think time heals most wounds.
    I have had a busted right hand take 4 years to finally heal to 75% because I kept using it as best I could.
    Last week I nailed the heavy bag with a hard right showing off to my son, and was instantly reminded that it
    still needs more time.:( I'll be using feet, elbows and chokes if shite goes down.



    Cheers, Don