Distance of tabs from the mech and each other

    I find that all shafts are made with tabs/pins/notches too far away for my taste. I've made shafts before with the tab almost right at the mech, and didn't have any problems. Why is everybody making the tabs so far away? The closer a tab is to the mech the more band stretch and more power the speargun has for its size. Am I missing something? Loading effort doesn't seem to be affected whether chest or hip.


    Why are tabs spaced so far apart on most shafts? I load two bands on one full size tabs, and the bands stack just fine. If I was going to do it on two tabs/notches what's the harm in them being closer?

    Good point Dan.
    I want full value on the lenght of my guns.


    Actually i would guess that the closer to the middel of the spear the notch is, the more likely it is to break or bend at that point. I would explain this with the more movement in that part of the spear, when the spear is wobbeling, just like the arrow on a bow!


    So i am, like you wondering why you would put it so far down the shaft.


    Let the eneginers do the talking here :)

    I assumed it was a lack of thought.


    Dan to saw the fins on the shaft on my ulu. They are practically at the mech. I don't understand any other configuration

    i like to spear fish

    that puzzles me too!!! what's the point?
    Another one is long wishbones.... 4 or 5" long.... the waste is equivalent in both... having the pins/fins further back but then long wishbones is just the same as pins/fins not at the back (and shorter wishbones)

    maybe it leaves room for flexing if your mech is not perfectly aligned and level with the shaft and track especially if there is wear on the track , but this is just speculation . personally i would want as much out of a gun length as possible .

    Be safe ... Happy hunting .

    For max power is there a down side to loading all bands on the furthest tab?

    A bad day at sea is better than a good day in the boatyard
    George Steele

    Only if the bands don't stack well, which is controllable, but this is only a matter of convenience. You can achieve better stacked bands on one tab by planning which band will be loaded first, and varying the lengths of the wisbhones to achieve a staggered effect.

    Here is the 1/4 bottom shaft of Double Trouble, 1 1/2 from the end of the shaft. I too believe in duration of thrust.:yaydance: Run your rubbers tight and your shaft long.:D



    Cheers, Don

    The only plausible reason in my mind is that two bands stack neatly when the two notches are a little further apart. Rob Allen can make his shafts any way he wants and still has the notches separated.


    I prefer the maximum band stretch possible, myself.

    marginatus, that's my thinking as well.


    For the bands to stack neatly the separation between the tabs/notches can be as little as 1". I've considered that with notched shafts a little more separation is required to make it easier to get the 2nd band wishbone in the notch. But this is easily circumvented by adhering to the correct sequence of loading the bands, ie 1. Furthest band under/through nearer band to 1st notch.
    2. Nearest band over the first band to the 2nd notch.
    This sequence also achieves properly stacked bands.

    Maybe the reason for the spacing between tabs is to give a wider degree of power options. I usually stack all my bands on the tab closets to my trigger mech for max penetration and range when hunting blue water, or bottom if not on or in a massive reef area where I'll be targeting smaller fish and shooting my shaft into reef. With open sand, caves, or hunting bigger fish that hang out away from shaft dulling structure I will power up. As mentioned, when I don't need the power or range and when I don't want to burry my shaft continuously into the reef, I'll load just one band on the second tab from the mech. That's the only reason I can think of: a greater difference in power loading. Otherwise all a shaft would need is one tab for a typical 3band gun, or two closely positioned tabs for a big blue water tuna gun of 4-6 bands. Especially with the thinner Kevlar/dyneema wishbones!


    And how about those obnoxious band notches so common on euro shafts?!! They weaken the shaft AND do damage to dyneema wishbones! I go with the mini shark fin tabs for my rail guns!


    Does that help


    Aloha

    HUI KOA KAI O HAMAKUA
    MAHALO KE AKUA
    E MALAMA I KE KAI

    Quote from makoa

    Maybe the reason for the spacing between tabs is to give a wider degree of power options. (...)
    And how about those obnoxious band notches so common on euro shafts?!! They weaken the shaft AND do damage to dyneema wishbones! I go with the mini shark fin tabs for my rail guns!


    Does that help


    Aloha


    that's a good point but doesn't explain why some have the first notch/pin/fin so distant from the mech


    Short answer: Cheaper to produce.

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