Homemade Carbon spear shaft

[Jonny250]

After some discussion last year about using lightweight shafts versus traditional steel shafts i have recently made my first carbon fibre hybrid spear shaft.

i have only had the chance to test it on one trip, where it 'seemed' to launch super-fast, and reached the end of the line. however i will have to do some more technical tests when time permits.

i dont suppose that a carbon spear will ever be too popular as it is unlikely to have 'stopping power', but i am interested to see how it affects accuracy/spear drop and recoil [or lack of]...

the steel spear weighs 232g and the carbon/steel spear weighs 97g, altho i could get that down to about 80g i think.

It all just a bit of interest and fun for me

Here are a couple of piccies:

 

[azapa]

great stuff, love spearing DIY. Is that an arrow shaft? How did you bond it? Have you hit a fish with it yet?

 

[foxfish]

Interesting experiment......

 

[Jonny250]

great stuff, love spearing DIY. Is that an arrow shaft? How did you bond it? Have you hit a fish with it yet?

yes its an arrow shaft with just sufficient inner diameter to fit the steel shaft inside. I just used 'wet-grab' to hold it.
I dont plan to shoot fish with it until i have tested it a bit more... [but you never know what might swim up...]

 

[Jaca]

I was thinking about light weight shafts but my conclusion was: the shaft will be faster but because of low weight it will not have enough momentum to penetrate the fish... Especially scaly one... But it was just the theory... Have you filmed or can you film and upload the shots to the target? I am very interested... Great job though!!!

 

[Pav]

P=M * V
But carbon always looks the dogs 8 .

 

[Jonny250]

P = m x v true and the drag is a function of the speed squared. If A lightweight shaft leaves the gun significantly faster than a heavy one then over a short distance there may be a gain. I doubt it, but i tried calculating the numbers and didnt beleive them! Lol.
One thing has shown already, the complete lack of recoil.
I havent had a chance to do anything technical yet, but hope to next week...
A carbon arrow costs 4 quid. A steel spear shaft is 20 ish...

 

[azapa]

another great plus: it must be quieter than a steel shaft, both from the guide (especially metal ones, you know, not covered) and less clank of the metal wishbone on top too..

 

[Jaca]

Over a short distance there would be no mater of the noise I suspect... I haven't noticed that fish run away far after a shot but I can be wrong. I am not good at science... Can anyone calculate the speed of the shaft at leaveing the muzzle or should it be done experimentaly???

 

[azapa]

Jaca, most shafts are quite noisy when they leave the gun; the wishbone (if it is metal) scrapes along the shaft above, and bellow, the shaft scrapes along the guide. sensitive fish can hear that for miles I seem to notice.

 

[Jaca]

thx azapa. But does it scare them or attracts??? what about other noises like boat propelers for instance??? I was spearfishing in Norway, UK and polish lakes only. I have noticed that air guns are louder than rubber and it is the reason why I use rubber ones with dyneema wishbone (I am afraid of my fingers :blackeye ). But when I dive after I put the fish on the string in few minutes there are sea basses and mullets around me again. So I thought that it may attracts them... maby it is the reason I cannot find bream around here... hehe

 

[Jonny250]

i suspect this will become a winter project; its just tooooo fishy at the moment to be doing tests if i get a calm day i want to be huntin' ...
however i will keep you posted when i do finally get in the water with it for some side by side tests...

 

[margus014]

A carbon arrow costs 4 quid. A steel spear shaft is 20 ish...

Where can I buy carbon arrow with that low price?

 

[Adammoore]

K = mv2 k is the kinetic energy refers to the penetrating power so if the v increase and mass decrease the k will increase the square of the v so a little Los in the mass but huge increase in the v2 that's what. Think it is

 

[Jaca]

but... the grater velocity, the grater resistance is... loss of shaft's mass will give us grater resistance force and the shaft will loose it's velocity much quicker... then if you want to have a shaft which is fast but on short range then use lighter shafts... but i think it bill bounce from the fish... better to test it

 

[Adammoore]

Great info . Well I have a question that can be asked here too how does long carbon spearguns which is very light in weight shoots very still and accurate with no recoil while in building a wooden speargun though the wood is already heavy we still need to ballast with lead I really wonder how do they got it balanced and no recoil like this ???

 

[Jaca]

that is due to heavy muzzle... there are special weights put in the muzzle (depends on make) or underneath. But it is located at the front of the gun.

 

[Jonny250]

Where can I buy carbon arrow with that low price?

Here:
Carbon Express - One Stop Archery

I hope to do the test sometime soon - just need some calm weather for a few days...

 

[Adammoore]

Ok java great info I they hide all the weigh in the muzzle that makes it perfectly accurate and still great info thanks dude

 

[margus014]

have you done any testing?