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Hi,
I have heard many times about nose heavy guns and i would like to share some thoughts on the issue.The designers of the major brands are well aware of Archimedes laws and one would wander how it came that most of the spearguns are slightly nose heavy and so became hard on the wrist to hold.
The reason is that no speargun is designed for the specific conditions of Denmark: fishing typically in shallow waters with long swims of several hours and, when fishing at night, with the gun pointing 45 degree down most of the times…
In the Med, that is where 90% of the EU brands test their guns, the minimum fishing depth to be able to find any fish of decent size is 10m (and in many places 20m) so that means that the surface movements are not relevant for the hunting action: the speargun is then hold pointing up and sustained by the water friction. Only on the vertical of the fishing spot is the gun put into position before the dive. Also in rocky places where people fish from the surface for seabass and mullets, the gun is seldom hold in a fix position but moved to follow the rocks contour and so relieving the strain to the wrist.
The reason of the designers for the choice of having a speargun slightly nose-heavy is to enhance precision: a speargun too light, especially on sizes over 90 cm, will rise as soon as the spear is released and will very likely touch the tail of the spear before it manage to go out of the muzzle and so direct the shot low. Try with a standard 130-140 gun and you will see how lower it goes compared to the aiming point.
Here the situation is completely different and the average speargun is a 75-85cm with very few longer ones and generally used for mullets hunting. A 75 will feel the rise of the barrel very little and so is possible to try to lighten the gun.
At this point there are two options:
1) Add positive volume (larger barrel ~30mm, shaped PU floats, wine corks, etc.)
2) Reduce the diameter of the spearPersonally i would prefer the second solutions, changing the spear from a 6,5mm to a 6,25mm (earning 23 g) and changing the rubbers with two 14,5mm of the new generation that increase the floating volume of another 20g.
I say “I would” because with demultiplied guns the spear is so fast that the barrel have no time to rise at all… 😉
I was so pissed-off with the sore wrist all the time ( i’m not a teenager so save any funny comments 😛 ) that at the end I built my speargun so that it can float with the spear on!! Is a Demo1Speed so 100% precise and, with a 6,25mm spear is super fast.
Last thoughts about the spear size…. a thinner spear 6,25 will lose 50-70cm range compared to the 6,5 on a traditional gun but will cover that distance much faster if properly powered (mean with moderation) and will not have the same impact on the stones behind the fish either so saving precious centimetres of steel every season 😉
Cheers!
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nice, what about salinity? our waters is 2-3 times less salty than e.g. most of the mediterranean sea, I just feel my gun is less noseheavy in saltier waters, but i’m not able to prove the amount of effect in an equation with Dr. Archimedes and Mr. Salinity. And I do’t know if the effect actually might just be “all around” on the gun and not lifting the front part in particular, so it just feels a bit lighter but is still nose heavy.
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Jeg har haft meget held med at skære forskellige størrelser flamingo ud. Tape dem på harpunen også måle hvor meget flamingo der skal til at gøre den neutral, og derefter veje mængden. Så skære et nyt stykke ud i samme vægt (i den form som indersiden af dit alu rør har) og putte det ind i alu røret. Så slipper man for at smide kork eller flamingo udenpå ens harpun.
Har gjort det her med min gamle seac sting 75’er og en kammerat’s 90’er. Det er de fleste harpuner du kan skille ad ved håndtaget også tage alu røret af.
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Surely it has an effect and that increase the heaviness even more making it harder to drive around.
The salinity (Med vs Øresund) will influence around 1,25% but you can’t calculate it straight because the positive vector will be applied at the metacentre (volumetric centre of the submerged part) while the spear negative vector will be forward respect to the fulcrum that is your wrist…. in short, one gram on the gun total weight will influence less than one gram on the spear and even less than one gram of “floating force” from the cork inserted in the second rubber hole.
The salinity conditions are very different between various areas in Denmark so it is difficult to give a number.
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Jeg har haft meget held med at skære forskellige størrelser flamingo ud. Tape dem på harpunen også måle hvor meget flamingo der skal til at gøre den neutral, og derefter veje mængden. Så skære et nyt stykke ud i samme vægt (i den form som indersiden af dit alu rør har) og putte det ind i alu røret. Så slipper man for at smide kork eller flamingo udenpå ens harpun.
Men normalt kommer der da ikke vand ind i røret. Det er tætnet med o-ringe i enderne, og dermed får man intet ud af at komme flamingo indeni røret.
Har jeg overset noget?
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Jeg har limet et stykke rør-isolering til mit løb, og det afhjælper gevaldigt på håndledssmerterne. Jeg har set en p åFB som istedet brugte fuge-stop, som han satte på bungeen. Fugestop er beregnet til døre/vinduer som isolering og “bagvæg” til den silicone fuge man tætner vinduer med. Den er oftest med en hul-kerne, så den direkte kan anvendes. Kan købes i de fleste byggemarkeder i str. fra 8mm-40mm
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[quote=”Groenn” post=21509]Jeg har haft meget held med at skære forskellige størrelser flamingo ud. Tape dem på harpunen også måle hvor meget flamingo der skal til at gøre den neutral, og derefter veje mængden. Så skære et nyt stykke ud i samme vægt (i den form som indersiden af dit alu rør har) og putte det ind i alu røret. Så slipper man for at smide kork eller flamingo udenpå ens harpun.
Men normalt kommer der da ikke vand ind i røret. Det er tætnet med o-ringe i enderne, og dermed får man intet ud af at komme flamingo indeni røret.
Har jeg overset noget?[/quote]
nej det har du ikke, det får man absolut ikke noget ud af medmindre harpunen er piv utæt, så er det nok smartere at få den tætnet. Der var også én på facebook, der ville sætte ventil i og pumpe luft ind i harpunen, her vil jeg foreslå at man benytter skrævgas.
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Yes, to add stuff inside the gun is actually making it worst… whatever it is is still heavier than air 🙂
Additions outside the guns are used for airguns that are already desperately clumsy 😛 but one of the most important features in shallow water is the mobility of the gun: whatever is added outside will just increase water drag and possibly vibrations.
If I where forced to add something outside i would use one of the floats in rigid polyurethane used in fishing nets: carved and painted to seal the cells.
Soft materials will be compressed when diving deep and would not work well for one all-round gun.
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En beuchat Marlin carbon den flyder i Dansk vandet… syd på svæver den måske :woohoo: :silly: :blink:
Det minder mig om min morfar. Min morfar han var fisker, og dengang i 1940 da Danmark blev besat, pakkede min morfar familien sammen og sejlede den, sig selv, og sin kutter til England, hvor han meldte sig hos Roayl Navy. Efter endt uddannelse tjente han som antiluftskytte på en destroyer, og deres opgave gik ud på at holde den engelske kanal fri for tyske U-både. Til denne opgave havde de ved hver ny patrulje alle vandrette flader stuvet fulde af tønder med grøn oliemaling, dækket, taget på kanontårnene, på åben bro osv. havde de tønder med maling.
Når de så fik en sonarkontakt, altså spottede en neddykket U-båd, begyndte de at sejle i en stadigt større og større spiral rundt om det sted hvor de havde fået kontakt, mens de hældte maling i havet hvorefter de slukkede motorerne.
Når tyskerne så steg op for at se hvor de var blevet af, og eventuelt lige stikke dem en torpedo, så lagde malingen sig som en film over linsen i periskopet, så når tyskerne kiggede igennem det kunne de kun se grønt, og troede derfor at de stadig var neddykket, og fortsatte med at stige. Når U-båden havde nået op til en højde på omkring 150 meter, skød de den ned med antiluftskyts.Yes, to add stuff inside the gun is actually making it worst… whatever it is is still heavier than air 🙂
I’m sitting here with Helium, and it doesn’t like being called fat.:)
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I tried this one time and it was great:
http://sportsbutikken.dk/catalog/product_info.php?products_id=5002
Unfortunately the glue is NOT strong enough so i lost it. hence – should be fastened with some MS-adhesive.
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