need advice on my Apnea Carbon 95 Speargun

[omerblue]

Hello everyone,

I have looked for some older posts about this, thanks to all of you there are so many informations available that I can put into use, yet couldn't find an exact answer for my query, sorry if missed.

I am using an Apnea Carbon speargun (95cm) for a long time, a guy I know (also spearfishing himself, having his own brand) suggested 2x16mm rubbers for it, the shaft im using is 6.5 130cm. The dimensions from head to fins of the shaft (elongation distance that is i guess) are 100cm and 92cm. So, he suggested 66cm & 69cm rubbers (16mm).


I just had two dives with this combination, got some fish but ended up missing some close shots feeling like the recoil is too much that the gun vibrates when I shoot, guessing that's what causes the misses.

About my spearfishing; I have been doing this for some years,yet only in summers most of the time, diving at real clear waters, doing shallow water hunts usually around 0-5 meters. From time to time I go for big blues when it's season, however most of the time it is seabream and seabass, not real big fish.

My question here is; should I change my shaft? To a thicker or longer one?
Or should I change the bands? If so what would you suggest? Single 18,20? Double 14's? Lengths etc. since they are too expensive to execute a "trial-and-error" method
You can also suggest a completely new combination, would be much appreciated.

Thank you

 

[Mr. X]

I have a 95cm Apnea but mine is a roller-gun, so very little kick. 6.5mm diameter spear sounds a little thin for twin 16mm; I think RA normally use 7mm for their 2x16mm Tuna model. What band does it come with?? Anything wrong with sticking to that?

If it were me and for the UK I might try using a single 16, 18 or 19mm bulk rubber or perhaps 2x14mm bulk rubber if your spear has 2 notches (but takes longer to load 2 bands, which is often important for me). I use Dyneema wishbones with bulk rubber. But if the factory config works well, I'd probably just stick with that - why wouldn't you?!

Re. Rubber length, I normally use the Rob Allen guide table value as my starting point. A bit longer for easier loading and to allow worn ends to be cut off later. Or a bit shorter for more power ( but that's not usually an issue for me).

 

[rollerGR]

2x16mm with a 6.5mm shaft on a simple carbon tube has a lot of recoil. 2x14,5mm is far better recoil-wise. (2x16mm + 6.5mm is good if the gun has mass to absorb the recoil.) A 16mm single roller with the same shaft would perform even better - I have literally tried all these combos (2x14 + 6.5, 2x16 + 6.5, 1x16 roller + 6.5) with a 96cm speargun.

If you change the shaft to a heavier one, the recoil will just go up.

Go for a stretch of 340% or so. Just get the number you counted for each sharkfin, remove wishbone + tie length, something like 4-6cm, divide by 3.4, double the result by 2 and then add 1-2cm of rubber to account for the hole's width in the muzzle.

You could also try 1x14,5mm + 1x16mm with the same shaft. Or 2x14,5mm with a 6,75 shaft (same length).

I'd personally switch to either an invert roller (polyspast)* or a fusion** with the same shaft. This gun length works great for a demultiplied fusion system as well but that's too complicated.

*: 1x19mm + 1x17,5mm, both @ 340% or so stretch.
**: either fusion 1 (1x19mm or 1x17,5mm on top & bottom) or fusion 2 (a common combination is 1x17,5mm or 1x19mm, and 2x14,5mm at the bottom. Bit complicated though).

P.S.: fusion k 2, "k" standing for fixed top rubber band length (with an inner dyneema cord to stop it from overstretch once it's fully loaded on the first load) would probably be simpler than a fusion 2. 1x16mm (top) + 2x16mm (bottom).

 

[rollerGR]

Just get the number you counted for each sharkfin, remove wishbone + tie length, something like 4-6cm, divide by 3.4, double the result by 2 and then add 1-2cm of rubber to account for the hole's width in the muzzle.

Forgot to add, this is the "clean" (active) rubber length. There will be an extra 0,5cm or so on each side (so 1cm for a single piece of rubber) for the wishbone knots to be tied.