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The title of the tread looks a bit like a videogame but the idea is to collect and share pictures and construction details of the “strange” spearguns with pulleys and sheaves attached to the barrel and that give them a futuristic and somehow complicate look.
In this first post i would like to remove this common misconception: rollers and compounds are not more complicate to load than any traditional speargun… actually they are easier to load also with rubber of larger diameter.
In this picture is the last model of compound gun rigged with only one set of rubber: a second pair can be added even in the water if one wear thin summer gloves or dare to take the thicker ones off in winter :S
MAIN ADVANTAGES:
1) All available power stored in the rubber is transferred to the spear (rollergun are pre-stressed and compounds wishbone is much faster so pushing till the end). Range in longer than traditional guns.
2) In compound guns the power is released in a very progressive way and so avoiding the twist of the spear and reducing losses. Increase range and precision of the shot
3) Recoil is reduced to the minimum or completely eliminated (in compound) so providing a greater accuracy.
4) Easier to load… roller need a thinner rubber to achieve high performances while compounds are demoltiplied and need only half the force to load.
5) In compound guns the rubber is pulling parallel to the neutral axis of the barrel, that can became thinner without flexing and so greatly improve the pan and tilt of the gun and reduce the vibration of the rubbers making the movement much more silent.
If you have made one of this guns you are welcome to post pictures here and share your impressions.
Cheers!
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This gun is a 95 compound with advanced rubbers: It will be modified with a sheave behind the release mechanism and one circular primary rubber.
As all compound they are preforming great with single or double rubber. In extreme cases (not really for our seas) a third and fourth rubber pair can be added to shoot spears of 8-8,5 mm diameter to large pelagic in blue water fishing.
The barrel size is 22×30/40 mm: very easy to tilt to be a medium-long gun…
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Rollergun 65 model “G-roll Evo” built by me from indications on the blog of Luciano Garibbo.
This gun has been a classic but even if is good to pan right-left is heavy to tilt up-down.
Main advantage of this configuration is that the rubber can be loaded on both ends from the top of the gun: there are no hooks under the barrel but just notches under the spear.
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what material is this gun made of? and is it possible to get any video of these compound guns? Ie. the loading action? In advance thank
The first is teak wood and the second is “ikea” fyrretræ and the handle is oak… all impregnated with Hempel epoxy primer and steel-wool brushed.
I would like to take a video but is complicate to do it alone and, honestly, every time i get in the water my attention goes to the fish… 👿
The various videos on youtube are not really giving the idea of the simplicity of this system: i basically put together the “vela” system with the g-roll system and the result is a gun that can be loaded very easily and without turning it or unbalancing the forces acting on the barrel.
Maybe next time i go out with someone willing to wait a bit, i can ask to take some video with the go-pro…
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Inspiring and amazing guns Lamberto, they really are. I’m thinking of trying to built a small 60-70 roller gun for caves/rocks and travel at some point in the future.
However, as the devil’s advocate and as a comment directed towards the newbies on this forum, I’d like to quote our sevenfold or so national champion and newly nordic champion Johan Nielsen when he saw my Omer Cayman ET: “Omer topped with their Excalibur 2000 model” – which he obviously owned and still used himself with no modifications at all. In other words, although big guns are nice and pretty, like my own railgun, you can still be a champion (or atleast perfom very well, if your ambitions are a little lower) with a standard gun.
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Inspiring and amazing guns Lamberto, they really are. I’m thinking of trying to built a small 60-70 roller gun for caves/rocks and travel at some point in the future.
However, as the devil’s advocate and as a comment directed towards the newbies on this forum, I’d like to quote our sevenfold or so national champion and newly nordic champion Johan Nielsen when he saw my Omer Cayman ET: “Omer topped with their Excalibur 2000 model” – which he obviously owned and still used himself with no modifications at all. In other words, although big guns are nice and pretty, like my own railgun, you can still be a champion (or atleast perfom very well, if your ambitions are a little lower) with a standard gun.
True is the fact that the equipment DO NOT make the spearo… as do not make the spearo a good pair of carbon fins or all the fancy gadgets you see around. They will help and make more comfortable the hunting but surely will never replace the experience.
You can fish wiht whatever can pierce a fish, handspear, oleo, roller, arbalete and everithing else and so you can happily dive with “Rondine” rubber fins or carbon fibers ones… Still a good spearo will bring home a good prey while a beginner with full 10.000 kr gear will probably not even see the fish…
My old Seac “Polpone” i bought 25 years ago was working well also. I have been fishing with all kind of guns with more or less success depending on the day… but now i would not use anything else than a compound if given a choice: much more comfortable, lots of power when you need it and soft on head shots… all together with a lethal accuracy of the shot.
Also one should consider that, by changing gun model, the full muscle-memory and aim goes banana for a while: at the beginning with my compounds i was always shooting 3cm higher and missed almost all the shots! It took a lot of videos to understand that i was shooting hig instinctively to compensate the spear drop as in regular guns. Still today in quick instinctive shots i often shoot slightly high… 25 years on the trigger are hard to forget!
In aimed shots (eyes on tip and tail) the spear goes true to the target without deviations.Almost all my friends that fish in competitions are actually putting stickers of their sponsors on the guns that they are using since ever (many people are still using the Cressi Comanche series) because to change to the sponsor’s own gun would mean to re-train the aim and muscle-memory… and that take a long time in the water!
Ciao!
P.S.: My first gun… Tigullio Polpone (now still made by Seac). At that time it looked like a bazooka to me! 🙂
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Hey Lamberto, if it’s not too much trouble could you please post a pic of the muzzle on the gun from your first post?
You see, when I ordered the carbon fiber for my roller, I got two lengths of 1 meter each, so I’ve still got one left and it looks like something that needs to be turned into a compound gun over the winter, if time permits.
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Hey Lamberto, if it’s not too much trouble could you please post a pic of the muzzle on the gun from your first post?
You see, when I ordered the carbon fiber for my roller, I got two lengths of 1 meter each, so I’ve still got one left and it looks like something that needs to be turned into a compound gun over the winter, if time permits.
You have carbon fabric or sock? I have been thinking to bulid a mold for lightRtm and i look for sock at affordable prices.
The pics are here but all steel parts are going to be replaced with laser cut parts next week (hopefully). Sheaves are in derlin home made with brass inlay.
Ciao
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You have carbon fabric or sock? I have been thinking to bulid a mold for lightRtm and i look for sock at affordable prices.
Unfortunately neither, what I’ve got is factory produced tube, 26mm/30mm inner/outer Ø by 1000mm.
I totally understand why you’d want carbon fabric, or preferably sock though, but I’ve been thinking that in the long run it would probably be easier and cheaper to buy tube to use as the backbone of the gun, and then add wings to improve hydrodynamics.
After all, a tube like the one I used is plenty strong for the job, and no one says that you have to build the whole body of the gun in one piece.
The wings could be cast in some sort of foam (various suitable types should be available, I’ll have to look into that) to save weight, and then coated with glass fibre fabirc and epoxy/polyester.
Granted, glass fibre is heavier than carbon fibre, but a hell of a lot easier and cheaper to come by.The pics are here but all steel parts are going to be replaced with laser cut parts next week (hopefully). Sheaves are in derlin home made with brass inlay.
Thanks a boatload!:)
From the pictures I get the impression it should be possible to use the axle rod for the sheaves, as the anchor point for the wishbone line, I haven’t thought it all the way through yet, but I reckon it could be done with the help of a lathe and a few custom made teflon shims.
If it’s doable, you could save the weight of the anchor bolt by simply not needing it, and thus get a lighter muzzle.EDIT: It looks like you’ve got a couple of bolts, or a piece of threaded rod going through the front of the muzzle, but I can’t figure out what purpose they/it serves. Is it simply balancing weights or am I blind and/or stupid?
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[quote=”Lamberto” post=10667]You have carbon fabric or sock? I have been thinking to bulid a mold for lightRtm and i look for sock at affordable prices.
Unfortunately neither, what I’ve got is factory produced tube, 26mm/30mm inner/outer Ø by 1000mm.
I totally understand why you’d want carbon fabric, or preferably sock though, but I’ve been thinking that in the long run it would probably be easier and cheaper to buy tube to use as the backbone of the gun, and then add wings to improve hydrodynamics.
After all, a tube like the one I used is plenty strong for the job, and no one says that you have to build the whole body of the gun in one piece.
The wings could be cast in some sort of foam (various suitable types should be available, I’ll have to look into that) to save weight, and then coated with glass fibre fabirc and epoxy/poyester.
Granted, glass fibre is heavier than carbon fibre, but a hell of a lot easier and cheaper to come by.The pics are here but all steel parts are going to be replaced with laser cut parts next week (hopefully). Sheaves are in derlin home made with brass inlay.
Thanks a boatload!:)
From the pictures I get the impression it should be possible to use the axle rod for the sheaves, as the anchor point for the wishbone line, I haven’t thought it all the way through yet, but I reckon it could be done with the help of a lathe and a few custom made teflon shims.
If it’s doable, you could save the weight of the anchor bolt by simply not needing it, and thus get a lighter muzzle.EDIT: It looks like you’ve got a couple of bolts, or a piece of threaded rod going through the front of the muzzle, but I can’t figure out what purpose they/it serves. Is it simply balancing weights or am I blind and/or stupid?[/quote]
If you are going to use a tube then http://www.roisub.com is for you inspiration…. google translate will help. Good guns but less flexibility of solutions compared to wood.
The rod in front is to stop the wishbone to flip forward when you unload the gun manually without spear. It will be replaced by hollow rods and cheeks from Contesub.it. I will also use a trigger Polynesia from Ermes to complete the gun.
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Quick thoughts on glass and epoxy/polyester.
Polyester is cheap but doesn’t come close to epoxy in terms of strength and pleasantness to work with. It stinks for weeks.
Get S-glass if you can. It’s stronger than the regular stuff.
And do really look into West Systems for epoxy. It’s great and very, very easy to dose and work with. You can get different hardeners for different set and curing times.
It can also be colored and used with all sorts of fillers. It’s called “System” for a reason.
Some years back when I thought I was going to be a boat builder this was the standard. I think it still is.In terms of carbon, I don’t think people used socks exclusively when moulding. I think you layer up and then finish with a sock because it looks the best. That said, if you don’t need that much thickness from the carbon, then you can get pretty thick socks and that might be enough.
Shooter & Shooter - Fotograf & Spearo
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Good observations Gecko.
I have ordered today carbon sock and resin from Germany: 22 Eur/kg is a good price and datasheet looks ok.
I have never been impressed by WS resins and actually, after Hempel’s, i think WS resins are the worst to work with. SP (Gurit i think is called now) have better results and easier to use and so are most of the laminating resins on the market. WS swet amines like a piece of flæskesteg in the oven and to have a proper finish is a pain on open surfaces. The pump kit is fine but i prefer my digital scale and syringes 😉
I will surely mold the rail but i am not sure if i will use infusion because i will have a wooden hollow core.
I will build another gun with much thinner profile and reinforced with carbon fibers…
Cheers!
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Good observations Gecko.
I have ordered today carbon sock and resin from Germany: 22 Eur/kg is a good price and datasheet looks ok.
I have never been impressed by WS resins and actually, after Hempel’s, i think WS resins are the worst to work with. SP (Gurit i think is called now) have better results and easier to use and so are most of the laminating resins on the market. WS swet amines like a piece of flæskesteg in the oven and to have a proper finish is a pain on open surfaces. The pump kit is fine but i prefer my digital scale and syringes 😉
I will surely mold the rail but i am not sure if i will use infusion because i will have a wooden hollow core.
I will build another gun with much thinner profile and reinforced with carbon fibers…
Cheers!
Ah, that’s what happened to SP. I remember there was an alternative but could never seem to recall what it was.
Maybe I was in love with the simplicity of the pump system from WS.Granted, this is about fifteen years ago, so WS may have fallen from grace since then.
Good to know.BTW, saw a great build log on Deeperblue with a guy who milled an enclosed track in a wooden gun.
First he milled a box like groove, then poured epoxy with fiber filler (I think) into it. Then he milled the enclosed track in the epoxy.
Supposedly the cutting bit is a special order but it seemed like a cool solution if one was after an enclosed track.
Others do it in Delrin.There was also a good thread on using wax as a core for a carbon gun and then after curing, melting the wax out. It may sound a bit primitive but the results were stunning.
Shooter & Shooter - Fotograf & Spearo
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For enclosed tracks the epoxy resin is not the best as it will worn our pretty fast. If you need a low-friction surface, mixing epoxy and a lot of graphite powder may be ok solution but i would use teflon or derlin tracks: you can purchase them ready made from extrusion… I’ve seen them online once.
Anyway an enclosed track is quite useless in a roller or, even less, in a compound gun: the roller need a heavier spear to achieve the desired range (and it will spin less) and a compound can use any spear without spinning problem because the energy is released softly starting from 50% at the instant of release to 100% at exit from the muzzle. The spinning on compounds is minimal and that is also why you can have longer range with spears that are relatively thin.
Resins: The pump systems are practical if you need to mix larger quantity but i would not do it for 20-50 grams as normally happen in guns construction… better a syringe and a small digital scale. Epoxy resin is quite susceptible to important changes in mechanical properties if the base-hardener ratio change over a very small limit.
Ciao!
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Hey guys!
I’m contemplating making a compound for my next project.
Got my self a 60x60x2000 mahogany plank, so i ought to get a couple of guns from that.My question is
1: Where to get the sheaves at the muzzle. I don’t have the tools/materials or the know how to make them my self.
2: It seems you don’t have anything to keep the spear on to the muzzle – doesn’t it wobble around when tracking?/Søren
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Nå, jeg lovede at komme med et indlæg om den roller jeg byggede, det kommer så her, lidt forsinket.
Jeg ved ikke helt hvor jeg skal starte, så jeg kan jo sige lidt om baggrunden for at bygge den.
Et af mine familiemedlemmer byggede en ret fed teaktræsharpun, og da jeg selv er en af de der mennesker som ikke kan lade være med at bygge ting og sager, besluttede jeg mig for at følge trop. Dog med den undtagelse at jeg valgte mere “moderne” materialer, og design.
Dels fordi jeg synes at kunstmaterialer som plastik og kulfiber kan have en vis charme, og fordi jeg ikke havde maskiner til træforarbejdning i den størrelse, stående.
Desuden er de fleste hjemmebyggede harpuner af træ, så det måtte være på tide at prøve noget andet.Valget faldt på en roller, da jeg helst ville have så meget smæk for skillingerne som muligt, og i en så lille pakke som muligt, og så ku’ jeg jo ligeså godt udnytte at teknologien eksisterede.
Det næste bliver lidt svært at forklare, men jeg skal gøre mit bedste, da der kunne sidde nogen derude som ikke kender til rollers.
Jeg bruger en SeaTec TRB 77 som sammenligningsgrundlag.Overall længden på SeaTec’en er omkring 105 cm, den har et elastik-træk på 77 cm, elastikken + wishbone er omkring de 20-25 cm alt efter smag, hvilket efterlader os i bedste fald med ca. 57 cm at tilføre spyddet energi på.
Tænk lige lidt over det… 57 cm’s energitilførsel på en 105 cm lang harpun, og så har vi ikke engang medregnet det 24 cm overhang spyddet har…
Så, på 57 cm går elastikken fra at levere 100% af den energi man har tilført ved at strække den, til at levere 0% i det øjeblik wishbon’en slipper spyddet.
100%-0%/57cm.Tager vi den roller jeg har bygget og udsætter for samme gennemgang, får vi et lidt andet resultat.
Overall er harpunen 105 cm.
Ladt op med kun 1. sæt elastikker opfører den sig som en almindelig harpun, med ca samme distance at tilføre spyddet energi over, men lader man den op med 2. sæt får den et elastik-træk på omkring 80 cm da elastikkerne trækker helt frem til muzzle’en, og stadig har energi tilbage.
Med 3. sæt får den ikke længere træk, men den får mere af det.
Det følgende er bare et overslag, da jeg ikke har testet med vægte osv, men det skulle gerne give en ide:1. sæt 100%-0%/57cm.
1.+ 2. sæt 100%-15%/80 cm.
1.+ 2.+ 3. sæt 100%-30%/80 cm.Man kan altså sige at det område elastikkerne arbejder i ligger højere – på en graf jeg ikke har tid til at tegne, ville en std. harpun gå fra 100% til 0% i energioverførsel til spyddet, på en roller ville grafen være fladere, og naturligt nok ikke ramme bunden, før spyddet var sluppet.
Der er selvfølgelig også en bunke andre faktorer der gør en forskel, og andre måder at regulere skudstyrken på (jeg regulerer på 3 sharkfins, og 2 sæt booster elastikker) men her er lidt info…
Jeg vender tilbage med mere, og lidt billeder.
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Lamberto said: The first is teak wood and the second is “ikea” fyrretræ and the handle is oak… all impregnated with Hempel epoxy primer and steel-wool brushed.
I would like to take a video but is complicate to do it alone and, honestly, every time i get in the water my attention goes to the fish… 👿
The various videos on youtube are not really giving the idea of the simplicity of this system: i basically put together the “vela” system with the g-roll system and the result is a gun that can be loaded very easily and without turning it or unbalancing the forces acting on the barrel.
Maybe next time i go out with someone willing to wait a bit, i can ask to take some video with the go-pro…
If you let me know, I would be able to bring a go-pro and shoot some short footage of the action of the guns
edits for bad quoting
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Hej Mace,
Ligger du ikke dit indlæg op som blog istedet – krydr gerne med lidt billeder så vi alle er med 🙂
Jeg skal se på det, men jeg er bange for at jeg har mistet alle de billeder jeg tog under byggeriet.
Om en uges tid får jeg nok et par måneder med lidt færre familiemæssige forpligtelser, og så kunne jeg måske få bygget en compound og tage lidt billeder af processen.Btw, vil gerne sige jatak til dit tilbud om et par rollers – 30/19 mm (dia/højde)
Bare lige for at være sikker på vi er enige, du skal bruge et sæt rollers med en ydre Ø på 30mm og en tykkelse på 19mm, right?
Hvad har du tænkt dig at kyle på af elastik-tykkelse? Jeg vil helst ikke lave sporet for smalt, eller ikke dybt nok.
Og jeg skal også lige bruge et centerhuldiameter, jeg bruger 10mm i min egen, og ingen bøsninger eller lejer. -
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Test done between longer arbalete and rollers with an aussy conversion kit… the superiority of the roller show off even without using a custom made rollergun.
Cheers!
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Fandt denne tråd om beregning af power i en roller alt efter mængden af pretension/preload og tykkelse på elastikken…
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New arrival!!
Ermes Sub “Polynesia” trigger mechanism with back-release and star line holder…. looks really nice and smooth.
Maybe at the post office is waiting also the Contesub package with the missing parts for the new compound… :woohoo:
In the next edition of the gun i will add some carbon fiber reinforcement to be able to increase buoyancy at the tip and get it even slimmer and faster to turn.
The only problem is that, with a spear 6,75×115 the gun do not achieve all the range that would be capable of. Miss penetration after few meters and with only one rubber the limit of killing shot is 3m. With two rubbers can extend that limit at 4,5-5m for normal fish (not for a tuna 😉 ). Speed is definitely there even with only one rubber and a very light spear.
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Hey Lamberto!
1. Do you have some calculations regarding compounds?
2. What does the 2:1 pulley system amount to in increased speed?
3. Does it add considerable spear flex during firing?In regards to design of gun #1
4. It seems you have nothing to hold the tip of the spear in place except the steel rods – does this cause spear wobble during tracking?
5. Do you release the pre-tensioning between hunting trips?sorry for the many questions – I have no clue about rollers/compounds and havn’t been able to find the answers on the sites you’ve linked to 🙂
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Hi.
Difficult to make serious and reliable calculations: all material that you can find online is derived from ballistic calculations and table available for projectiles in air… underwater the music change and i can’t find anywere calculations to take in account friction, displaced water wavelength and line drag. Basically all calculation are very theoretical and unreliable…
As rule of thumb, you can figure out the differences from the physics of the double pulley system: our case is case #2
In specific:
1) Speed increase is theoretically double BUT… the difference between single rubber or double rubber is a lot and that means that whit single rubber the losses to achieve that speed are high.
We have tested one 75 compound single rubber in the water together with a 2 rubber 75 railgun (same length of guns) and the difference in speed is already visible and, more of all is visible the total absence of recoil while the railgun kick like a mule. Reach of the shot with one rubber is slightly higher than the railgun with two rubbers but not much. With two rubbers the game change completely as the extra one is just providing extra power and not wasted in losses: Wednesday night i have frozen a trout at 4m from the spear tip in front of Kronborg shooting sideways to the current that was 2,5-3 knots on the beach.2) Spear flex (twist or buckling) is almost completely absent… at the beginning of the shot the power applied on the spear is 1/2 of the total energy of the rubber and it increase progressively to 100% when the spear has left the muzzle. This is the opposite of what happen in a normal gun when the energy is released all together at the beginning: at release instant (against the inertia of a spear at rest) the applicable model is of a concentric axial load of a spar/column and that means that the spear will buckle a lot. In the compound gun the maximum energy is released to a spear already in movement and the buckling is almost absent or minimal. I use spears 6,5 or 6,75mm for my guns: with the rollers that can achieve the same range i used 7 or 7,5mm spears.
3) the side steel rods (stoppers) are there to stop the wishbone in a position where it can not pinch the line that follow the spear: without it the spear will not manage to get out of the gun 😉 . My guns have a neodymium magnet 5-10 cm from the tip and that is enough to hold the spear in place even with the gun upside-down and is very easy to use… no line loops to think about.
4) pre-tensioning shouls always be release when not in action: rubbers tend to memory effect and would loose power. Also during hunt, i release the rubbers if i do not shot for 15-20 minutes (seldom happen in Denmark… is full of fish!) and every 10-15 in winter. I now got some rubber that are supposed to have a low memory but i need to verify that.
Roller and compounds have in common only the fact that there are 2 sheaves at the tip but for all other aspects they are very different: try to shoot a torsk in a hole wiht a 90 roller full loaded and with a 90 compound full loaded… the roller will very likely bend the spear while the compound will very likely make the tip flat only.
I decided to go for compounds in DK for 2 reasons:
1) needed a gun that can shoot free-swimming fish and fish in holes at the same time without damaging too much the spear (typical case in Helsingør) without sacrifice range or maneuverability
2) Needed a good shot range for trouts but also maneuverability in strong current, superior to normal guns (rollers are much harder to move in the water in up-down movement).
P.S. total absence of recoil means higher precision in distance shots 😉
Cheers!
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Lanberto, thanks, tha’ts why I am going for a compound no doubt.
I have made some drawings in google scetchup, can you view them?? I would like to have a expert view on them.
I have designed pulleys with direct connection to the insert in the rubber I also would like to have your a pinion about:
:cheer:
Claus. -
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Ermes Sub “Polynesia” trigger mechanism with back-release and star line holder…. looks really nice and smooth.
Can I ask why you chose that specific trigger?
I realize it’s a “reverse” which obviously gives you a couple of cm’s more band pull, but was there any other reasons?
I ask because I find it impractical to attempt to mod a pipe gun handle, to function as a compound system, and thus I need a stand alone trigger. Having no experience with those trigger systems I’m a bit in the dark as to which one to pick.
The gun will probably end up looking somewhat like a Daryl Wong hybrid, but built as a compound gun.
EDIT: I must be tired, it would be way easier to modify my roller, I’d need a few bits I already have, can make fairly easily, or buy cheap, if I installed the bands like the one you posted in #10642…
I wonder what I was thinking… -
[quote=”Lamberto” post=11077]Ermes Sub “Polynesia” trigger mechanism with back-release and star line holder…. looks really nice and smooth.
Can I ask why you chose that specific trigger?
I realize it’s a “reverse” which obviously gives you a couple of cm’s more band pull, but was there any other reasons?
I ask because I find it impractical to attempt to mod a pipe gun handle, to function as a compound system, and thus I need a stand alone trigger. Having no experience with those trigger systems I’m a bit in the dark as to which one to pick.
The gun will probably end up looking somewhat like a Daryl Wong hybrid, but built as a compound gun.
EDIT: I must be tired, it would be way easier to modify my roller, I’d need a few bits I already have, can make fairly easily, or buy cheap, if I installed the bands like the one you posted in #10642…
I wonder what I was thinking…[/quote]Hi. A back trigger gives you 6 to 7 cm extra: in my gun that mean 9 to 10% more rubber action… may not be a great difference but all together it helps.
If you look at the pictures of my 2 compound guns you can see that the first model (clear wood one) has the rubbers attached in front of the trigger while the second one has a sheave behind the trigger: this change is only to maximise the rubber action and the result are two guns that have the same power but 15cm shorter barrel.
The range of shot is not the same anyway: the shorter gun use spears 115cm x 6.5mm and the longet 135cm x 7mm or 6.5mm. The higher weight and lenght of the longer spear add a lot to the capacity of penetration and inertia. The short spear is faster and more handy and better for the Nordsjælland conditions while the longer is better at the Kronborg with longer shots and plenty of current to deviate the aim.
If you want to modify a normal commercial gun then look at Roi Sub guns: only the muzzle need to be rebuilt because the rubbers are attached to the spine that lock the handle in place.
Ciao
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I’ve just come across Stefano Soriano’s website and he has done a lot of ballistic tests and has a lot of ideas on prototype guns!
http://www.stefano-soriano.it/arbaffertus/index.php?option=com_content&view=category&layout=blog&id=81&Itemid=467I’m considering building this: http://www.stefano-soriano.it/arbaffertus/index.php?option=com_content&view=article&id=90:invert-vela&catid=81&Itemid=501
(use google translate) 🙂
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If you want to modify a normal commercial gun then look at Roi Sub guns: only the muzzle need to be rebuilt because the rubbers are attached to the spine that lock the handle in place.
It isn’t a commercial gun I plan on modding, it’s the roller I built.
Here’s a pic, the bands shown are the booster bands in loaded position (mains unloaded, no pressure on the spear):
Now, that is more or less the same band set-up as you have on the “Ikea 95” it seems, and that leads me to believe that I could recycle the handle/trigger assembly,
For that matter, I could probably recycle the whole gun but only make a few modifications to the way the bands are set up, by adding a pulley on either side, and scrapping the main bands.However, I think it should be possible to build a lighter muzzle, this is what it looks like now:
As I wouldn’t have to stretch the bands around the sheaves, those could be made much smaller (Ø36mm now), and the muzzle block could be trimmed down as well.
I already ordered a couple of these:
So I guess I just need to make 2 sheaves for the muzzle, as well as a new muzzle block, whishbone stoppers, and anchor point for the shooting line.
And I’d need to get a new shaft guide from Sportsbutikken. -
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Hvad hedder den dims du har bestilt nogle stykker af, og hvor har du bestilt dem henne?
Og så, hvis du altså har tid og dit blankotilbud stadig gælder, kunne jeg meget vel være interesseret i noget af dit delrin…;o)
Har du evt. en mail jeg kan skrive på, når nu beskedsystemet herinde ikke fungerer optimalt?
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[quote=”Lamberto” post=11236]If you want to modify a normal commercial gun then look at Roi Sub guns: only the muzzle need to be rebuilt because the rubbers are attached to the spine that lock the handle in place.
It isn’t a commercial gun I plan on modding, it’s the roller I built.
Here’s a pic, the bands shown are the booster bands in loaded position (mains unloaded, no pressure on the spear):
Now, that is more or less the same band set-up as you have on the “Ikea 95” it seems, and that leads me to believe that I could recycle the handle/trigger assembly,
For that matter, I could probably recycle the whole gun but only make a few modifications to the way the bands are set up, by adding a pulley on either side, and scrapping the main bands.However, I think it should be possible to build a lighter muzzle, this is what it looks like now:
As I wouldn’t have to stretch the bands around the sheaves, those could be made much smaller (Ø36mm now), and the muzzle block could be trimmed down as well.
I already ordered a couple of these:
So I guess I just need to make 2 sheaves for the muzzle, as well as a new muzzle block, whishbone stoppers, and anchor point for the shooting line.
And I’d need to get a new shaft guide from Sportsbutikken.[/quote]I might be completely off, but if I am not and your bands aren’t gonna pass through the pulley block then check out Ronstan’s kite surfing blocks. They are quite clever, very light and also what Lamberto uses.
Harken has some really nice small ones as well (maybe the 18mm series, not sure?).Shooter & Shooter - Fotograf & Spearo
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I’ve just come across Stefano Soriano’s website and he has done a lot of ballistic tests and has a lot of ideas on prototype guns!
http://www.stefano-soriano.it/arbaffertus/index.php?option=com_content&view=category&layout=blog&id=81&Itemid=467I’m considering building this: http://www.stefano-soriano.it/arbaffertus/index.php?option=com_content&view=article&id=90:invert-vela&catid=81&Itemid=501
(use google translate) 🙂
Soriano’s website is a mine of good ideas… the gun you like is a fusion of roller+compound… fish will die just looking at it! Probably will be forbidden by the authorities as it may be mistaken for an intercontinental cruise missile! 😉
Ciao!
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I might be completely off, but if I am not and your bands aren’t gonna pass through the pulley block then check out Ronstan’s kite surfing blocks. They are quite clever, very light and also what Lamberto uses.
Harken has some really nice small ones as well (maybe the 18mm series, not sure?).Ronstan kitesurf miniblocks are the best i have found till now, especially because, being plastic, they don’t scratch the wooden barrel as the metallic ones do. I also use a dyneema loop with double diamond knot instead the shackles for the same reason: no scratch and can be open in the water without tools. The blocks are available on Palby Marine catalog at 70 kr per couple. I buy them at the nautical shop in Helsingør harbour.
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Very interesting table… especially “Stiffness” (Young’ s E) and the hardness values in comparison. Yellow pine looks very interesting…
http://workshopcompanion.com/KnowHow/Design/Nature_of_Wood/3_Wood_Strength/3_Wood_Strength.htm
Does anybody know a wood supplier that have a decent choice of essences in Sjælland?
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Dammit, glemte lige den her: Sørne, hvad hedder det program du brugte til at lave de skitser med?
Og udover det, synes jeg det lyder som en go’ plan du har gang i, og tak for linket til Stefano!:)Hvad hedder den dims du har bestilt nogle stykker af, og hvor har du bestilt dem henne?
De hedder egentlig taljeblokke, eller bare taljer, men sejlerne kalder dem lidt forskelligt alt efter hvordan de ser ud. Dem jeg har bestilt kaldes “enkelt blok svirvel”, og de kan fås her.
Jeg fandt dem et andet sted men der var de dyrere, der laves også nogen i samme størrelse af Viadana, men de var også dyrere, jeg fandt dog nogen til 40,- men jeg synes de så lidt for tarvelige ud.
Og så, hvis du altså har tid og dit blankotilbud stadig gælder, kunne jeg meget vel være interesseret i noget af dit delrin…;o)
Det må vi lige få kigget på, skal du bruge hjul eller bare en stump?
Har du evt. en mail jeg kan skrive på, når nu beskedsystemet herinde ikke fungerer optimalt?
Næh, jeg glemmer altid at tjekke den fordi jeg så sjældent bruger den, men så længe vi har noget at tale om som ikke bør optage plads i det offentlige forum tjekker jeg mine beskeder herinde.
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I might be completely off, but if I am not and your bands aren’t gonna pass through the pulley block then check out Ronstan’s kite surfing blocks. They are quite clever, very light and also what Lamberto uses.
Harken has some really nice small ones as well (maybe the 18mm series, not sure?).No, you were dead on, and those Ronstan blocks does look quite nice, and the Harken T2 looks very promising as well!
Perhapse one should order a pair – surely, one could find good use for the other pair one ordered, elsewhere.I’ll keep those in mind, thanks mate.:)
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Very interesting table… especially “Stiffness” (Young’ s E) and the hardness values in comparison. Yellow pine looks very interesting…
http://workshopcompanion.com/KnowHow/Design/Nature_of_Wood/3_Wood_Strength/3_Wood_Strength.htm
Does anybody know a wood supplier that have a decent choice of essences in Sjælland?
Very nice table. Many thanks to all of you for all the interesting questions and answers. I have ordered a pair of Ronstan mini blocks 🙂
I can add this table, which include the weight properties and some general information on the different wood types. I collected the data some time ago for a tread on DB.
Jégwan
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@Mace: Programmet hedder Sketchup (http://www.sketchup.com/)
Det fungerer OK, og er det eneste gratis ordentlige 3D modellerings program jeg kender.
Det er forholdsvist simpelt at arbejde i. -
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Ser sgu rigtig godt ud RIM. Nice idé med at sætte den direkte i elastikken.
Har du overvejet at bruge et rør, som du “nitter” eller laver en opkravning på i stedet for akslen med splitten? – jeg tænker, at splitten kan rive, ridse eller komme til at fastholde en line eller lign.
Jégwan
De aksler er lidt i overstørrelse, lidt for lange, der er to muligheder, der er nu en pasning på akslen så trykker jeg den i vil den sikkert sidde fast men er ikke sikker på den bliver der så har lavet plads så jeg kan sætte en låsering på på den anden side og korte akslen af, eller gi den et par skrald af en dorn, lige nu skal jeg bare kunne skille dem ad indtil jeg tager dem i brug så gør jeg et eller andet. Nogen som ligger med noget plast som kan holde, kan evt lave dem lidt større men nu passer de til 19mm elastik.
Er sådanne en lille 5mm knast på en 3mm aksel nok til at kunne fæstne dem i elastikken ? -
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Jeg har prøvet at sende dig en besked, men jeg kan ikke få det til at virke, så jeg spammer tråden her i stedet.
Kan du lave en enkelt roller med målene 30mm i diameter og 18mm tyk (til 17mm elastik) + et sæt rollers med målene 20mm i diameter og 8-10mm tyk (til dynema)?
Jeg har ingen anelse om hvor lang tid du bruger på at lave sådan en roller, men jeg har det ikke ubetinget godt med bare at drive rovdrift på dine evner og goodwill..! Tanken om costumlavede rollers er bare ret nice…;o)
Jeg tvivler på at jeg kan tilbyde andet en ussel mammon, men jeg vil altså gerne betale, for tid og materialer, hvis du er interesseret i det? -
Jeg har prøvet at sende dig en besked, men jeg kan ikke få det til at virke, så jeg spammer tråden her i stedet.
Mon ikke det går, det har trods alt noget med emnet i tråden, at gøre.
Kan du lave en enkelt roller med målene 30mm i diameter og 18mm tyk (til 17mm elastik)
Tjoh, det skulle ikke være noget problem, det er godt nok nogle lidt tynde kanter du så får, og det gør hjulet lidt mere sårbart overfor slag, må det være 19 eller 20mm tykt? Jeg tror det ville holde bedre i længden.
+ et sæt rollers med målene 20mm i diameter og 8-10mm tyk (til dynema)?
Det er ikke noget problem, andet end at jeg skal bruge et par mål på centerhullerne til begge størrelser hjul.
De små hjul kan have mere eller mindre det størrelse hul du vil ha’, da de bare skal bores mens de sidder i drejebænken, og sporet har jeg vist et stål som passer til.
Sporet i det store hjul burde egentlig laves også på drejebænk, men da jeg ikke har et stål i den rigtige dimension er jeg nødt til at kyle hjulet på en stump gevindstang og så flytte det over i min fræser. Det betyder at det er nemmest at lave hvis centerhullet skal være af en størrelse tilsvarende hvad der findes af standard gevindstænger.
Jeg ville blive ked af at skulle investere i bor og gevindstang i et absurd tomme-mål da jeg altid regner i millimeter, så hvis vi kan blive enige om noget i retning af M8 eller M10 er det lidt lettere at have med at gøre.Jeg har ingen anelse om hvor lang tid du bruger på at lave sådan en roller, men jeg har det ikke ubetinget godt med bare at drive rovdrift på dine evner og goodwill..! Tanken om costumlavede rollers er bare ret nice…;o)
Det kommer an på hvor meget jeg kvajer mig undervejs. 😆
Men det tager som regel ikke mere end en times tid eller halvanden at lave et sæt hvis alt går efter planen, det besværlige er at lave dem ens når man ikke bare kan dreje det hele men faktisk skal tænke over hvad man laver, og samtidigt forsøge at lave et pænt stykke arbejde.
– Det bliver nemlig ikke helt så pænt et spor man laver med fræser + delehoved som man ville kunne dreje, selvom det kun er kosmetisk.Jeg tvivler på at jeg kan tilbyde andet en ussel mammon, men jeg vil altså gerne betale, for tid og materialer, hvis du er interesseret i det?
Vi kan jo se på hvad du synes det er værd når du står med stumperne i hånden, men lad os lige finde ud af det der med centerhullerne først.;)
Jeg burde have lidt overskud til at få kigget på det i løbet af ugen. -
Det lyder meget fornemt alt sammen. Og du behøver ikke skynde dig for min skyld. Hvis jeg er færdig med min gun til forårssæsonen starter, er jeg en lykkelig mand!
Det er helt fint med 19mm tykkelse på den store.
Ang. centerhuller, så er M10 glimrende til det store, hvis det også passer dig fint, og jeg tænker måske M4 til de små, er det helt off?
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Det lyder meget fornemt alt sammen. Og du behøver ikke skynde dig for min skyld. Hvis jeg er færdig med min gun til forårssæsonen starter, er jeg en lykkelig mand!
Fint nok, jeg tager det roligt.:)
Det er helt fint med 19mm tykkelse på den store.
19 it is.
Ang. centerhuller, så er M10 glimrende til det store, hvis det også passer dig fint, og jeg tænker måske M4 til de små, er det helt off?
Det passer mig fint med M10 til den store, det er det jeg bruger på min roller, og det jeg lavede i Morfars hjul.
I virkeligheden kunne man sikkert godt bruge en M8 men en M10 går aldrig hjem.
M4 til de små synes jeg dog lyder lidt klejnt, jeg ville nok lave dem i M5 eller M6, nu overdimensionerer jeg så også hellere end jeg tager chancer. Men det er op til dig, hvis vi er heldige ka’ det være nogen med erfaring ang. dimensionerne byder ind, så vi ka’ jo la’ den stå åben indtil videre. -
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Rim et elastik stræk på 250-300 %(gang med faktor 3,5-4) vil nok være fint med 19mm, du kunne også overveje en tyndere elastik, du kommer jo til at have masser af power til danske forhold 🙂
Og så er det nemmest at bore huller til trigger montering som det første, altså før man formere gunnen 🙂😛 Det er der skam også, alle huller og forarbejdning er lavet på træet, trigger hullet er bare ikke synlig.
Har også et 16mm elastik som jeg kan bruge. -
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Det er nok bare mig der misforstår, men du har da vel ikke tænkt dig at male på det lækre teaktræ? 🙁
Projektet ser brandgodt ud for øvrigt, din selvkontrol er ufattelig. Hvis det var mig, ville jeg ikke kunne modstå fristelsen til at samle hele molevitten, og hoppe i vandet sekundet efter sidste skrue var fæstnet… -
Rim et elastik stræk på 250-300 %(gang med faktor 3,5-4) vil nok være fint med 19mm, du kunne også overveje en tyndere elastik, du kommer jo til at have masser af power til danske forhold 🙂
Og så er det nemmest at bore huller til trigger montering som det første, altså før man formere gunnen 🙂Hi. The elongation factor is percentage: factor 3 means 300%, 4 means 400% and so on. In the calculation should be included the original lenght of the rubber.
I tell you this because if you pull a rubber according to the max suggested on the datasheet or by the manufacturer (generally 320 to 400%) and apply the wrong factor you risk to stretch above the limit of elastic behaviour and that will damage the rubber permanently.
Elongation below 300% is an advantage only in rollers where you are able to reduce or increase the power in the water from maximum to point-blank range: I used 200% and 250% on some roller as first step for loading and for “torsk” shot.
In a compound is not necessary so the first rubber can be stretched close to the maximum permitted by the datasheet and the second and third set of rubber can be engaged or disengaged at will.
Personally I always use 2 set of rubbers @360% (factor 3, 6) in almost all dives and only one set when the visibility is so bad that long shots are not allowed or where I know that the fish is into the holes.
Ciao
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Lanbrerto, it looks like there is no wood in that gun :ohmy: , could you give me the dimension for my next (no 2) composite, no 1 is already finish and just need some paint or lak!.
Claus.The barrel size is as small as i can get with massive teak wood. The buoyancy of the wood (barrel only) is just enough to sustain the spear weight. The other hardware add a negative buoyancy and the metacentre of the assembly is 2/5 backwards more or less.
The tip is slightly heavy for stability during shot.
Next gun is done in paulownia wood and carbon fibre skin.
Ciao
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:cheer: Nej den skal stå i natur, det bliver klar lak. Det er ikke til at lakere en våd pind , så venter tålmodigt på lakering. 😆 😆
:unsure: Ok I can find that a Cressi band G20 (19mm) on a 95-100 is 62cm long, and 60 if it is a Cressi S45 (17mm) band, if I make a calculation on that the band is taken from 62/2 = 31cm to 100cm = 1:3,2. If I use that number on my gun that is 98cm in the rubber loop, 98/3,2*2= 61,25cm rubber.
What about pretension that will also have influence if I go for 3.5 the band is 56and I can make 3cm pre tension.
I am still impressed that the teak with that small dimension can withstand the pressure from two rubber band and additional handling in water without breaking and folding together . What is the height and wide measurement on the teak in front and around the trigger??.
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[quote=”Sørne” post=11478]Rim et elastik stræk på 250-300 %(gang med faktor 3,5-4) vil nok være fint med 19mm, du kunne også overveje en tyndere elastik, du kommer jo til at have masser af power til danske forhold 🙂
Og så er det nemmest at bore huller til trigger montering som det første, altså før man formere gunnen 🙂Hi. The elongation factor is percentage: factor 3 means 300%, 4 means 400% and so on. In the calculation should be included the original lenght of the rubber.
I tell you this because if you pull a rubber according to the max suggested on the datasheet or by the manufacturer (generally 320 to 400%) and apply the wrong factor you risk to stretch above the limit of elastic behaviour and that will damage the rubber permanently.
Elongation below 300% is an advantage only in rollers where you are able to reduce or increase the power in the water from maximum to point-blank range: I used 200% and 250% on some roller as first step for loading and for “torsk” shot.
In a compound is not necessary so the first rubber can be stretched close to the maximum permitted by the datasheet and the second and third set of rubber can be engaged or disengaged at will.
Personally I always use 2 set of rubbers @360% (factor 3, 6) in almost all dives and only one set when the visibility is so bad that long shots are not allowed or where I know that the fish is into the holes.
Ciao[/quote]
And how many % pre-tension do you use on your compound?
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Ok I can find that a Cressi band G20 (19mm) on a 95-100 is 62cm long, and 60 if it is a Cressi S45 (17mm) band, if I make a calculation on that the band is taken from 62/2 = 31cm to 100cm = 1:3,2. If I use that number on my gun that is 98cm in the rubber loop, 98/3,2*2= 61,25cm rubber.
What about pretension that will also have influence if I go for 3.5 the band is 56and I can make 3cm pre tension.
The calculation of the rubber action in a roller is including:
– length spear notch to sheave center
– half circumference sheave diam. + 1 rubber diam. ( if the sheave is 30mm and rubber is 20 = ((30+20)*3.1416)/2 = 78mm)
– length from sheave center to anchor point
– subtract the double of the length from the constrictor knot on the rubber to the middle of the wishboneAfter you have the action length, divide it for the chosen factor (start with 3,2 and cut off more later if you need). remember to add the length for the knot on both sides (i add 4 cm for a 18mm rubber) and here you have your rubber total length.
Pretention: maximum you can have 50% of the total if your anchor point and spear notch are at the same distance from the sheave center. Is the best and more efficient situation but is very hard to load: add 1 or 2 intermediate anchor points to make easier to load: in my rollers i had 2 or 3 more so that the total factor was 250-300-350% or 200-250-300-350% to adapt the gun to the conditions of the moment (200-250% to shoot in a hole in a harbor pier and 300-350% for freeswimming fish).
I am still impressed that the teak with that small dimension can withstand the pressure from two rubber band and additional handling in water without breaking and folding together . What is the height and wide measurement on the teak in front and around the trigger??.
At the tip is 20x30mm tapering to 20x40mm at 50% length of the barrel.
Standard rubbers 16-18mm @ 350% are pulling between 50 and 60 Kgf so even with a double rubber is difficult to go above 120-130 Kgf that is really not much considering that we are speaking of only 20 Kg/cm2 when the wood can hold 500+ Kg before breaking. The concern should be about not to make it too slim as the force is not always concentric to the axis and that can bend it and break it and also the buoyancy volume necessary to sustain the spear in the water.Another very important factor when designing the barrel profile is that the stretched rubber(s) and the traction line should be as close as possible to the barrel surface to reduce vibration problems to be able to move it fast and silent otherwise there is no point in making it so slim. In our case (compound guns) the operation is more complicate because the mobile sheave and the need to have a second rubber for really appreciate the full power of the gun.
The actual size of my two guns is very good for handling it underwater and i am now looking to make it much lighter to be able to carry on a 7,5mm spear on a longer gun for blue water fishing: Paulownia (Kejsertræ) core and carbon skin may just make the trick.
Cheers!
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P.S.: the trigger is free on the sides. no wood, only on the sides where the pin is i have 2mm of wood to keep it in place when i set the spear. The trigger is only pushing on the front and hold with the back screw to negotiate the moment due to the spear traction that is 4-5 mm above the pushing point. The material is only where is needed… 😉
The barrel at the trigger point is 20mm whide and the trigger is 16mm whide. -
:cheer: Færdig 😉
Ja spydet er for kort, der er bestilt 130cm men de er først på lager den 12 og så et par dage hmm surt :angry:
Nå så kan jeg da bruge tiden til at lave en mere, fik 3 stykker træ så der er til et par stykker mere. Trigger er produceret i et par ekstra, og de øvrige stumper kommer ud af drejebænken en af dagene.
Det er en 95 ! Det var lige det træet kunne blive til, den næste bliver en 75 så jeg kan bruge de korte spyd jeg har.
Der er 36cm elastik som bliver til 110cm det må gi 305%, den er da mega ond at lade der skal virkelig lægges kræfter i .
Pris 150kr for 1m elastik, 198,- for 0.7l lak, resten fra lageret :cheer: -
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:cheer: Færdig 😉
Der er 36cm elastik som bliver til 110cm det må gi 305%, den er da mega ond at lade der skal virkelig lægges kræfter i .Hi RIM, the rubber seems to be a bit short for the gun and i believe it is very hard: Can you tell me the following measures taken with the rubber sheave as close as possible to the muzzle sheave?
Distance A, B and sheave diameter.
If the rubber is too short, you will have much less power out of your gun.
Ciao
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:cheer: Lanberto, as I have written the movement from the muzzle to the hatch on the spear is 88cm, with the 2:1 it makes 44cm that the rubber band can be stretched MAX. The rubber is 18cm on each side or 36cm in total. (I made it 40cm , 2 cm on each side for fixing.
The calculation on one side must be (44+18)/18 = 3.4. = 340%
The rubber is a 17mmCressi S45.
With the dimension it is not possible to stretch the rubber the full length you mention A but only from the 18cm to 18+44 = 62cm.
The sheave is a 50mm
A = 118
B = 4 (not possible to reach)Is this total wrong ??? :unsure:
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:cheer: Lanberto, as I have written the movement from the muzzle to the hatch on the spear is 88cm, with the 2:1 it makes 44cm that the rubber band can be stretched MAX. The rubber is 18cm on each side or 36cm in total. (I made it 40cm , 2 cm on each side for fixing.
The calculation on one side must be (44+18)/18 = 3.4. = 340%
The rubber is a 17mmCressi S45.
With the dimension it is not possible to stretch the rubber the full length you mention A but only from the 18cm to 18+44 = 62cm.
The sheave is a 50mm
A = 118
B = 4 (not possible to reach)Is this total wrong ??? :unsure:
The secret is called “Pretensioning” of the rubber.
To start: fit the dyneema line without rubber so that the mobile sheave stay as close as possible to the fixed one. Use bowline knots to make it easier to replace the line in the water (you can have a spare one on the buoy).
The theoretical calculation is this
And your case is this
So you can have 695mm rubber (plus ~4cm for knots?)
What happens here is that you will be using only the top part of the energy of the rubber but also the part of the movement that release the most and at a higher speed. You can try different settings to balance the rubber energy curve to your gun configuration: depend on the rubber you use.
The theoretical calculation can be used for design purposes and proportions between parts of the gun: in my gun the rubber works at 350% and is pretensioned only for 2cm each side.
The bowline knot on the dyneema line make it easier to engage/disengage the rubber when you are not fishing and so avoid that the rubber get permanently stressed or the memory effect.
Ciao!
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:cheer: OK that makes sense, going backwards to get as much rubber as possible. I have taken the other part from the 1m peace that is 64cm and mounted that instead, also the dynamee line have got a modification, instead of fixing it at the rear screw in the front I have returned it to underneath the gun an mounted two screws that I can fix them to making pretension adjustment easy, now I hope to get it tested Saturday .
Thanks for your guideline on this Lamberto.
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:cheer: Today I got the new gun in the water at Boeslum Djursland, I have not got the right spear yet so I had to try it with the short 100cm. First impression, there is not much space for 5mm gloves on the trigger, the nose is heavy floating with the handle upwards. The short spear and the 2mm dynamee line makes it difficult to get the spear fully locked in the trigger . It shoots like a dream you don’t feel that you fire the gun, with one rubber and no pretension it almost travel the full spear line of 5m. All that spear line is easy to fuck up hanging in everything making it difficult to reload fast, night time must be a nightmare!!. Not nice for low water fladfisk hunting, it is better to shoot from a distance greater then the spear length. After missing one fladfisk, I managed to get 6 skrupper on the first trip most on 1-1.5m water and my impression is that is is rather precise , even with the short spear. :cheer:
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:cheer: Today I got the new gun in the water at Boeslum Djursland, I have not got the right spear yet so I had to try it with the short 100cm. First impression, there is not much space for 5mm gloves on the trigger, the nose is heavy floating with the handle upwards. The short spear and the 2mm dynamee line makes it difficult to get the spear fully locked in the trigger . It shoots like a dream you don’t feel that you fire the gun, with one rubber and no pretension it almost travel the full spear line of 5m. All that spear line is easy to fuck up hanging in everything making it difficult to reload fast, night time must be a nightmare!!. Not nice for low water fladfisk hunting, it is better to shoot from a distance greater then the spear length. After missing one fladfisk, I managed to get 6 skrupper on the first trip most on 1-1.5m water and my impression is that is is rather precise , even with the short spear. :cheer:
Great!
The heavy nose is actually good if you don’t get tired on your wrist while swimming: a neutral nose would be positive immediately after shot and deviate the spear downward.
To check the precision try to target a sunken beer can from various distances while looking along the spear: this will give you the feeling of your gun’s straight-line shot, before the descending curve start. When you have the maximum straight-line distance then try to shoot again several times at a target 0,5-1 m closer… you will be surprised to see the spear going always on the same spot! 😉
I have been using a red laser pointer the last 3 times i went fishing and is incredible how precise this kind of gun can be: without recoil to spoil the shot it can put the spear in the spot with an error diameter of a 20kr coin… I am actually having fun playing “sharpshooter” at distance shots… :silly:As for the line… yes it is a pain especially in night dives. I think to understand from your pictures that you are using a braided dyneema (the one without sock) and this is very flexible and make it easy to get tangled on it’s self. A dyneema with sock is more rigid and has less tendency to tangle, especially in current.
Ciao!
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[quote=”RIM” post=11624]:cheer: Lanberto, as I have written the movement from the muzzle to the hatch on the spear is 88cm, with the 2:1 it makes 44cm that the rubber band can be stretched MAX. The rubber is 18cm on each side or 36cm in total. (I made it 40cm , 2 cm on each side for fixing.
The calculation on one side must be (44+18)/18 = 3.4. = 340%
The rubber is a 17mmCressi S45.
With the dimension it is not possible to stretch the rubber the full length you mention A but only from the 18cm to 18+44 = 62cm.
The sheave is a 50mm
A = 118
B = 4 (not possible to reach)Is this total wrong ??? :unsure:
The secret is called “Pretensioning” of the rubber.
To start: fit the dyneema line without rubber so that the mobile sheave stay as close as possible to the fixed one. Use bowline knots to make it easier to replace the line in the water (you can have a spare one on the buoy).
The theoretical calculation is this
And your case is this
So you can have 695mm rubber (plus ~4cm for knots?)
What happens here is that you will be using only the top part of the energy of the rubber but also the part of the movement that release the most and at a higher speed. You can try different settings to balance the rubber energy curve to your gun configuration: depend on the rubber you use.
The theoretical calculation can be used for design purposes and proportions between parts of the gun: in my gun the rubber works at 350% and is pretensioned only for 2cm each side.
The bowline knot on the dyneema line make it easier to engage/disengage the rubber when you are not fishing and so avoid that the rubber get permanently stressed or the memory effect.
Ciao![/quote]
Hi!
I must admit that I’m slightly confused with these calculations Lamberto.
The 695mm of rubber has to stretch to 2435mm to achieve a factor 3,5 stretch, an elongation of 1740mm, but the 2:1 ratio means that the max stretch achieved when loading the gun is 880mm.
That would require a 1740mm-880mm = 860mm (close to 100%) pretension in order to reach the full factor 3,5 stretch.
In an earlier post you wrote that a maximum of 50% pretensioning is recommended.
Is it just me who’s a little confused?Cheers
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😛 Sounds great with the lazer, where have you purchased that waterproof lazer device??
I used the 6 skrupper to test the precession, trying to hit the fish between the eyes and in 3 out of 7 was hit in that region+/- 2-3cm , now the water was calm and that makes everything mush easier not rolling around in the low water. I need something in the front for aiming, I have the two plates but they are not in the centre line. I will try to get a dynamee with a sock I only have a short peace that I use for the wish bone. And soon the second gun will be ready I already know where to improve.
Claus. -
Hey Lamberto.
I’m about to start building a gun, and it will definitely be a roller of some sort.
The plan is to build something like a 75′ for hunting night/caves and then hoping it would be capable of doing longer shots as well.
In your experience, what would be best for a gun that size? A compound or a classic roller (like f.ex. your G-roll evo)?Morten
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