The "demultiplied" spearguns from Roisub
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- Опубліковано 3 лют 2017
- UPDATE: Ragnarok Sub has stopped the commercial activity in 2019 and is not selling spearguns anymore... but you can DIY.
Handle: Sigalsub Nemesis
Tube: carbon Ø26/30mm
Head: Roisub (Prisma) Crystal with dyneema stoppers
Blocks: Harken 16mm
Rubbers: kit Roisub pre-assembled for the speargun length
Spear: 6.5mm medium length, brand Hunt/Sigalsub
Line: 2/3 passes of monoline Asso Supersoft in 0.9mm, followed by a good quality reel Hunt or LG Sub dressed with 1-1.5 mm nylon line.
The connection line/spear is made with a short loop of 1mm braided dyneema SK99 and angling uni knot (no sleeves)
Enjoy!
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Do not confuse this system with rollers, invert-whatever and others... the demultiplied is another story altogether...
Different variations of the same concept make it extremely customizable: Pure Demo, Volcan, FKD2...
My preference, not needing extreme power, goes for the FKD2 which, in my opinion, represent the best compromise between high-power, flexibility and ease of loading.
In Divecenter we build the speargun according to your needs and wishes: The carbon model starts from a Pathos Laser Carbon chassis, while the Gungnir (Gungnir is the infallible spear of Odin in the Nordic mythology) is a custom speargun in laminated bamboos
Interested in purchasing one carbon Fusion or FKD2 speargun? We custom-made them in Denmark... check it out here: divecenter.dk/roisub-spearguns... - Навчання та стиль
That gun is a beauty in it’s efficient simplicity. The way the under rubbers are hooked in that little groove, just so smart. Thank you so much for these explanations, it really demystify a lot of things.
This guy is so kind and he has the best videos
My son loves his 60. For us rock hunters in NZ, it's perfect.
Ur videos are so nice keep it up
ممتاز
great video thank you!
Cool mate!!... I'm pretty excited about this concept!...can't wait to get one!! Cheers
I know!.. I've emailed you already ...haha
Buddy.. It seems like your contact form at your website doesn't work.. I've already texted you twice on it about purchasing a Demo 2K...cheers Tilo
Greetings from Galicia, I currently use a common speargun "Omer Cayman 75" to hunt in rocky shores and from the coast. I would like to add some power to my gun to win some more power and distance with velocity. Would you recomend me getting the Roisub Whitefish 85, or maybe its too much gun and money for a shore and rocky fisherman like me?
Respect!
Parabéns meu amigo um abraço do Brasil 🇧🇷
great gun
Hi was looking at items tyo buy on your web site but it simply refuses to list prices in £££ and online converters wont work.
Hello buddy, you have done a good job, I like it very much! TOP.
I have an old speargun and I want to transform it in fusion KD2 system, but i'm not sure about what rubbers should i use. I know that i need to use progressive rubbers, but i need a suggestion about some specific brands that u may have tested. Also what pretension coefficient should I use?
Thanks!
Divecenter.dk - The Spearfishing Specialists
What pretension should i use, i heard that roy use 200% pretension now on the fusion kd2 systems
Divecenter.dk - The Spearfishing Specialists
Thank you very much for your info.
hey! wouldn't it be better if there was no slacking rubber at all?i have an idea how to do it,but basically both rubbers preloading and loading components would be under the gggun -and on top would be only rope peeking over the rollers!!??????
The small rubbers at the top are necessary to achieve the preload necessary on the lower rubbers.. otherwise there is simply no geometric option to achieve that: this is why the top rubbers are filled with dyneema to transfer the initial energy from the lower rubbers to the spear... the top rubbers come into action later.
They are also very useful for easy loading.
I think the setup you mention is called "invert" in Italy and as far as I heard (I never tried it myself) from friends, it is not as brilliant.
top
Show de arpones👏👏👏🐠🐟
Hellooo.Nice videos. Can you tell me how do you meassure upper rubber,and lower rubbers.thank you so much...
Thank you thank you thank you....
Can you make a video how to make rubbers for FKD2 spergan? good chanel keep it that whay ;)
Could you explain the reason for having a small rubber pair on the top instead of having three pairs on the bottom?
I don't quite understand why it is there.... is it for just helping to arm the gun?
Thanks in advance.
The small rubber on top has a kevlar core that limit it's stretch. The meaning of the rubber is to accelerate the spear already in the first instant of the shot. The difference between the Demo2-3 (without small rubber) and FKD2-3 (with small rubber) is really big in power of the shot and speed of the spear.
@@ragnaroksub1442 But you loose the main advantage of roller systems - accelerating length (I think for at least 150 mm). Does your solution compensate this effect?
The link isn't working. Can't I just convert the roller speargun into that, since it only adds an extra rubber on the top pulley?
Yes you can... easy way to upgrade a roller
what is the price of this 75cm gun?
Can you please show a video on calibration? How much pre-load is in the first and second bands? How much notch load (sharkfin load) is there applied by each band? As you know, the energy given to the spear for launch is the sum of (notch load + pre-load) / 2 times the length of travel (launch) distance. If you are using an 8mm shaft, does that not make it nose-heavy in the water?
Calibration depends on the geometry of the speargun... There are too many variables to draw an algorithm to simulate the finished product... It's easier to do it time by time. The preload can be increased by adding a dyneema line inside a pair of top rubbers to limit the stretch... So you decide the min-max load below and adjust on the top.
Yes, an 8mm shaft is heavy... That is why the barrel is a carbon tube 26/30 and sometimes 30/32 with the two ends double-walled with a 26/30 reduction.
Basically you increase the volume of the barrel to match the spear weight.
Personally, in a demultiplexed system, I prefer to use a spear 7mm powered to the upper limit to maximize the speed... 8mm are slower and I don't need that added range here.
For me, the ultimate speargun for the Scandinavian waters is a FusionK1 90cm with 6.5mm spear, 2 passes of monoline Asso Supersoft 0.9 followed by a good quality reel.... In other waters you'll need to find your balanced range/speed/power
@@ragnaroksub1442 The geometry of the speargun is simple. It’s a 90cm carbon Fusion inverted roller gun. The preload is the amount of pretension in the rubber bands (each) with the wishbone at the end of its travel. The notch load is the load at the shark fin when fully tensioned, per band. What is complicated about that? Energy imparted to spear launch is the average of these values x travel from notch at trigger to where it stops at the roller head
It is not complicated at all... and the empirical method is straightforward.
And by the way, if you like to be accurate, the energy is not calculated by an "average" but by the equation K=1/2*m*v^2. You can see the graphical demonstration of two systems with the draft of the integral of the function (pretty much linear) of load and distance between the two extreme wishbone positions.... But it is pretty much a scholarly discussion without real application.
Ha... I forgot... The "Invert roller" is a completely different system... composed by two pair of sheaves: a pair of wire sheaves on the muzzle and a pair of round rope sheaves on the proximity of the handle where the rubbers go around... I guess the confusion in terminology comes because of the rushed translation of the spearfishing tradition in English when the social media brought the many different rubber-systems to the other side of the ocean a few years ago.... rollers, invert, invert roller, Demo(s), Fusion(s), Vela, Volcan, Mach... and a few more like G-roll etcetera nowadays disappeared.... No wonder that the internet is full of misunderstanding.
Thanks very much for your replies. Yes, I agree that the energy (of the spear leaving the muzzle) is 1/2 mv^2 I.e. kinetic energy equation but you have to know the terminal velocity to calculate that as well as mass of the spear. I am intrigued by your reference to the spear accelerating faster than the wishbone due impulse loading rather than a simple linear imparting of rubber bungee energy from notch load to the end of the travel at the muzzle. This invalidates the assumption of the average energy summation and is more driven by the impulse at notch load. This is good news because it removes the requirement for preload at the muzzle. Could you please comment on this?
Hello, your video are very instructive and well done. I have a 115cm roisub Michelangelo F1 and I'd like to update it as the one that you showed in your video, can you please tell me the size and the diameter of the 2 couples of rubber? If you could also make a video on how to claculate the size of this kind of gun it would be great ! Thanks a lot for what you do that's give me a lot of usefull informations. Ludo
Thanks for the answer, but the kit is extremly expansive.... I change my rubbers by myself and I use a very good greek brand for my F1 and you can't see the différence with the original. Thanks a lot for your advices and continue to post your good videos ! Ludo.
The link to divecenter.dk in the description did not open (using Mozilla/Firefox)
Divecenter was closed one year ago... check instead www.roisub.net/
好枪，想买一把
That Gungnir speargun looks awsome! I think i want one!! Please let me know how to reach or contact !
Gungnir is out of production... from now on, only carbon spearguns.
If you live outside Scandinavia then email to la@divecenter.dk
Inside Scandinavia instead you can buy from kingfish.dk
How can i get one of this?
Tienici aggiornati !
Ciao
Yo estoy en poli
Beauti fulHow much.. 120cm.. 🙏👌💪❤️
Not for sale anymore... Sorry
Im sorry but that gun looks like trash. Too many things cool break or go wrong. I rather the simple rob allen two band railgun. Theres so much on this gun that looks like it could break. Its a no from me.
We will survive... enjoy your Rob Allen