Inverter roller Spearguns extensive write up.

[armandozx]

Based on build and field experience.

Well here it goes, my experience with these systems so far have been somewhat extensive and detailed. I do consider myself a builder and therefore, I will provide input and tweaks as well as some personal opinions on versions of these systems, which there are several.

First things first, inverter head (muzzle.) There are several out there, from Ermes, Sigalsub, Roisub, and others. I will be speaking of two from personal experiences in the field.

1- Ermes testeta pure inverter with ceramic bearings – A very well design muzzle from top to bottom, full derlin. The wheels on these are 26mm and came in three options, non sliding, sliding and ceramic. I originally set up two guns with these 100 & 110 one sliding and one ceramic. Everything on the sliding worked great to its design specs, the ceramic however gave plenty of issues. From getting stuck to(unable to roll freely) to semi rolling, meaning they rolled but promptly stopped after a few spins. Reason behind this was that the inner cage of the bearings were deformed, a problem my friend a very well read and studied individual (also my 3d parts design and maker, more on that later) have not yet figured out why. In practice I was unable to gauge the drop in performance prior to figuring out WTF was going on until I did a systems check. But, it goes without saying that bearings that are not rolling freely hamper performance.

2- Turkish builder (Ahmet) with stainless steel bearings inside the housing and much larger wheels, 35mm. I mean, sure, I’ll bash it because the design is almost a direct copy of the roisub muzzle with the added bonus of the mono rigging guards at the front. Meaning you can rig your speargun left or right depending on your preferences. I rig from Right to left and all my speaguns are set up this way for familiarity and muscle memory. Derlin made piece, solid CNC built, this muzzle will not let you down in any way shape or form. My only gripe was that the line guide was a piece of metal implanted into the muzzle where as the ermes it was built into the design and separated the line from the screw that holds the muzzle to the body of the gun. I will also add that the bearings/wheels on this muzzle do not spin as swiftly as the ceramic bearings alternates but with the given experience from use, I don’t mind it at all because reliability is my number 1 priority while in the water.

Shape/Body of the spearguns
This is tricky and somewhat personal on opinion but limited based on those notions. I see a lot of tubes out there, some cuddle, some standard some fully flat whether composite or wood.

I will be covering non wood spearguns due to my experience and faults that I see with cuddle shape systems.These systems when using individual pulleys vs a single block pulley from the bottom docking positions.

There are basically two main systems in which we see the majority of inverters. Double pulleys one on each side and single block pulley, both can accommodate multiple bands. Anchoring these bands goes into the design aspect of things and well, I truly believe it affects loading and performance.
Let’s speak on single pulleys on tube spearguns, meaning 1 on each side and respective anchor points. I use a standard barrel similar to a roisub system, my handle of choice is the Meandros B28, this handle is perhaps the best handle in the market for these systems, the body allows for you to run an M4 bolt from side to side and use as your main anchoring point running your initial cooked band on your pulleys. Your main load band should always be your thickest or shortest, reason being? Well, you’re using the pulleys to your loading advantage. Anything after that is linear pull (standard), non pulley assisted so the work has to be put in.

My friend and I basically designed an anchoring mount underneath the speargun, I will be brief on this but Orca spearguns and LGsub reels offer a similar concepts and basically work in the same notion. I find the Ermes avatar handle a tad compact and not enough space for me to utilize at the front for my main anchors but I have seen builds where they use the anchor points directly into the carbon body at the side of the spearguns similar to roballen's roller speargun.

Not to get too much into the topic but lets cover the same set up with cuddle shape systems, some builders like Mythicon and Soriatec have these setups and you can see the bands running the length of the barrel but getting bent where cuddle part starts. It’s up for debate and unless things (data) is measured, only speculation can ensue. So I will leave this as an opinion based statement. I feel these systems work best with a mono block running underneath the gun where they can run in a linear direction without being bent vs at the side. I believe these barrels work best with rollers vs double pulleys configurations.

On to pulleys. There are many out there PS-Dive, Ermes, MVD, Ronstan, etc ( basically I’ve experienced Ermes & Ronstan) let’s start with the obvious, Metal pulleys will scratch your barrel at the front, there are other options out there like ps-dive & Ronstan which are composite and plastic and are less likely to scratch your barrel. I basically had to shave down the band anchoring bolts on the ermes pulleys because they stick out from the back and add to the scratching, so the flatter the better. I also use Ronstan pulleys with much success, but for triple band application Ermes and PS-Dive pulleys work best on standard barrels.

Block pulleys, these are awesome with flat shaped systems, which basically is not what a carbon/aluminum pipe is. So with that said, I feel anything being ran underneath the speargun should be used with a fully flat body shaped. Seawolf, Cetma, Orca, etc (sorry if i failed to mentioned the other top builders)

Loading, and this is probably as important as function, you’ll know what I mean when you experience it. At first, things were a mess for me because, like traditional spearguns, I would rig then load. I found myself spending a lot of fking time in the process while my buddies were killing fish left and right. THESE SYSTEMS TAKE TIME TO SET UP, the more bands you add the longer it will take. Basically, I found my trick, load 1st and then rig, why? Because since it’s a tube shaped speargun, the line will get in your bands ways. You basically side step all of this when you load your rig 1st and then rig on top of your loaded bands.

The power is there, the accuracy so far has been on point. The biggest thing has been the timing from loading to firing, unloading and loading again. I have found what works for me and cut about 80% of getting ready to shoot again, to some extent what may work for many of you guys when using these systems as well.

I hope this write up helps many of you understand more about these systems. It is not simple by any means, I didn’t even cover the rigging which that in itself is technical but at least it gives you an insight on what you will be facing when making the switch.

I'm sure I didn't cover some stuff, I am open to covering them if the questions arise.

[kavachi]

great feedback there Armand! and photos to go with it
gotta love Spearboard, despite the crap you have to wade thru and the droughts between useful posts, still a bloody great place to learn so many different aspects of spearguns

still in the ranks of the roller-curious myself, havent had the time to try and channel all the knowledge on SB into a build - tho what Paul H and Franci and many others are doing in ultra-compact dogtooth guns certainly has me keen to have a go at a build when time and cash allow

re the ceramic muzzle.....have used a bunch of Mario's [Ermes Sub] hardware, and despite being a convert to his DR mechs and reels, have experienced a few cases with mechs where not enough relentless in-water testing done to ensure bulletproof construction that will stand up to heavy usage.
To be fair, the effort Mario puts into designing and constantly refining superbly effective hardware for chasing big fish in tough conditions is maaad, and thus sometimes perhaps a bit less time is given to really exhaustive in-water testing before production. But thats easily fixed by waiting for a later iteration of said piece of hardware, for example the current model 'Wings' full size DR mech.
Thus wondering if the issues experienced with the ceramic bearings in his premium roller muzzle might be a bad apple in the production run? or have you encountered in more than one of those muzzles? bloody expensive muzzle, so understand can't buy up a whole batch to test out

[armandozx]

Originally Posted by kavachi

great feedback there Armand! and photos to go with it
gotta love Spearboard, despite the crap you have to wade thru and the droughts between useful posts, still a bloody great place to learn so many different aspects of spearguns

still in the ranks of the roller-curious myself, havent had the time to try and channel all the knowledge on SB into a build - tho what Paul H and Franci and many others are doing in ultra-compact dogtooth guns certainly has me keen to have a go at a build when time and cash allow

re the ceramic muzzle.....have used a bunch of Mario's [Ermes Sub] hardware, and despite being a convert to his DR mechs and reels, have experienced a few cases with mechs where not enough relentless in-water testing done to ensure bulletproof construction that will stand up to heavy usage.
To be fair, the effort Mario puts into designing and constantly refining superbly effective hardware for chasing big fish in tough conditions is maaad, and thus sometimes perhaps a bit less time is given to really exhaustive in-water testing before production. But thats easily fixed by waiting for a later iteration of said piece of hardware, for example the current model 'Wings' full size DR mech.
Thus wondering if the issues experienced with the ceramic bearings in his premium roller muzzle might be a bad apple in the production run? or have you encountered in more than one of those muzzles? bloody expensive muzzle, so understand can't buy up a whole batch to test out

Well I kinda don't want to be that guy but yeah, I encountered issues on both his muzzles, his response was that he no longer makes that muzzle and tried to offer me the new muzzle, I humbly declined and moved away from his products as a whole.

Design should never take a back seat to function and safety.

I did have an issue once with his drop in Pathos D1 double roller mech, but to be honest the squeaky sound went away after I greased her up. I will just blame it on prob the gear not getting a better wash since I might have put an RA shaft in it vs my Sigalsub at the time of the trip.

In his defense, he doesn't make the ceramic bearings, he just adds them at a higher price point to his equipment, so technically you can't directly blame him 100% for the quality of said items (fully at least.) That's neither here or there though nor is the focus of the article.

With regard to expenses, yeah tell me about it. Made the order straight from Italy so that was a punch in the gut.

Another reason why I can no longer justify drop in mechs to existing handles. With the arrival of the Meandros B28, there is no longer a need for me to experiment and tweak handles.

R&D is very important and at the time some of that gear was experimental, according to Mario, at least that's how I understood it because he had very little knowledge of the topic. With time, you get to learn the systems based on practice and find out how and why it works the way it works. It's all in the rigging though.

[spearq8]

Thanks for all the information! That is what Spearboard should be all about. People trying out equipment and giving honest feedback on results.

I have been meaning to give the invert rollers a try and did try a few different setups, but my main issue was that although I could get good power ... I could not get good power with accurate shooting. If I would reduce the power, I do get accuracy (equal to a classic setup), but then that would be way too much sacrifice as the performance would be less than a classic setup. I do think there is a fundemental issue that needs to be looked at with inverters ... and that is that the wishbone line needs to be inline with the CG of the shaft ... it also needs to release the shaft before the wishbones impart a rotational force on the tail. During Corona lockdown I 3D scanned the front of a C4 muzzle and the plan was to do different invert roller and double invert roller setups ... and then compare that with another equivalent gun with a improved classic setup. I basically finished the design on computer and ordered parts .... and it was too nose heavy. So I then redesigned the trigger and made a DR design for the trigger and metal 3D printed in Titanium (half the weight). Trigger worked awesome but really haven't had time to put it all together as I just don't have much time these days. I did experiment a little and found that you need to elevate the propulsion wires a bit ... also you need to stop the propulsion just before the end.

Would be good to see if you can compare your results with your best invert setup with a simple classic setup. Of course by "best" I mean where power and accuracy are both factors. I will see if I can post some pix of the 3d drawings I made.

[armandozx]

Originally Posted by spearq8

Thanks for all the information! That is what Spearboard should be all about. People trying out equipment and giving honest feedback on results.

I have been meaning to give the invert rollers a try and did try a few different setups, but my main issue was that although I could get good power ... I could not get good power with accurate shooting. If I would reduce the power, I do get accuracy (equal to a classic setup), but then that would be way too much sacrifice as the performance would be less than a classic setup. I do think there is a fundemental issue that needs to be looked at with inverters ... and that is that the wishbone line needs to be inline with the CG of the shaft ... it also needs to release the shaft before the wishbones impart a rotational force on the tail. During Corona lockdown I 3D scanned the front of a C4 muzzle and the plan was to do different invert roller and double invert roller setups ... and then compare that with another equivalent gun with a improved classic setup. I basically finished the design on computer and ordered parts .... and it was too nose heavy. So I then redesigned the trigger and made a DR design for the trigger and metal 3D printed in Titanium (half the weight). Trigger worked awesome but really haven't had time to put it all together as I just don't have much time these days. I did experiment a little and found that you need to elevate the propulsion wires a bit ... also you need to stop the propulsion just before the end.

Would be good to see if you can compare your results with your best invert setup with a simple classic setup. Of course by "best" I mean where power and accuracy are both factors. I will see if I can post some pix of the 3d drawings I made.

It all sort of started with the fusion and progressed to where I am now. I found no real power in the fusion and maybe that's because how I was setting up. That top band would get stretched out by the bottom too much and therefore lack power, calibrating the system was a pain in the ass and there was always room for more power but the bottom out powered the top. I guess the trick was to run dynema to the top band and have it at a certain length, which quickly turned annoying.

SpearQ, I am currently using 7mm for my 100cm and 7.5 for 110-120 with mono, tight crimp loop close to the fin. All are Sigalsub, HRC line with 4 shark fins and I rig at the 1st sharkfin (not the resting fin) I have zero problems with wraps, tangles or unbalanced shots. I cannot say for sure how good my accuracy or power is because I have no means on pool testing like you but, I have gone 4-4 on days 100% of my shots have been on target with lack of penetration being a non factor. I unfortunately no longer use traditional guns but I will say that my real world experiences yield results.

I will also be open about it, I once took away 22-24in of extra band stretch on my rig, that was right before I had seen the light which entails correct rigging and band stretch on these systems. That's a lot of hidden potential and it showed the next time I took the speargun out. Sometimes this is the only thing that sucks about not having your gun yet dialed in due to lack of testing, but call it necessary for us to grow and come back to the drawing board.

After having gone through that, I can dial any inverter in from the get go. I will say this, it's all in the rigging but balance on both sides is a must.

I've seen a lot of your videos and the amount of time and resources you put in are far more than we deserve. Every spearo is grateful for your tests and insights. I will add that I do not cook my bands, many of my friends do (in the search for more power) and they don't seem to mind (sometimes they do) but to avoid injury since I am in the rehab world and keeping that trend up can lead you there very quick (shoulder injury). I keep my bands below 350% and keep finding success in those ranges.

Technically I have more room in them for power, I have not utilize their full potential yet and I probably wont because they are functioning in the sweet range of power and loading balance ( for me ) the yields are never lacking, and I UNDERSTAND this. We must learn when to push but also when to recognize that we have arrived and essentially stop.

Spearq, I love all my guns and find myself using them on the same trip just because, my best is prob not my fav. Best is defined as the best performing? hard to say which is but my fav is the 100cm, just the size and ease of load (2 bands pictured with the hogs) the power is there but most importantly, the ability to use it in my depths and never coming up short when the trigger gets squeezed. the 110cm is an all arounder animal which hands down slays but is a 3 band set up so when I feel I need more range and power with a heavier stronger shaft, I will bring her out.

[vstante]

Originally Posted by spearq8

Thanks for all the information! That is what Spearboard should be all about. People trying out equipment and giving honest feedback on results.

I have been meaning to give the invert rollers a try and did try a few different setups, but my main issue was that although I could get good power ... I could not get good power with accurate shooting. If I would reduce the power, I do get accuracy (equal to a classic setup), but then that would be way too much sacrifice as the performance would be less than a classic setup. I do think there is a fundemental issue that needs to be looked at with inverters ... and that is that the wishbone line needs to be inline with the CG of the shaft ... it also needs to release the shaft before the wishbones impart a rotational force on the tail. During Corona lockdown I 3D scanned the front of a C4 muzzle and the plan was to do different invert roller and double invert roller setups ... and then compare that with another equivalent gun with a improved classic setup. I basically finished the design on computer and ordered parts .... and it was too nose heavy. So I then redesigned the trigger and made a DR design for the trigger and metal 3D printed in Titanium (half the weight). Trigger worked awesome but really haven't had time to put it all together as I just don't have much time these days. I did experiment a little and found that you need to elevate the propulsion wires a bit ... also you need to stop the propulsion just before the end.

Would be good to see if you can compare your results with your best invert setup with a simple classic setup. Of course by "best" I mean where power and accuracy are both factors. I will see if I can post some pix of the 3d drawings I made.

This is great! Majd do you maybe have a video of your best classical setup with a 140/8mm shaft where I could measure the performance? (I mean the speed od shaft via sound file). I have a superb accuracy and speed data shot with a invert roller and 140/8mm so we could compare the 2 system?

[spearq8]

A 140 @ 8mm is tricky for a classic gun as it is a short shaft and thus not enough band stretch to get close to Terminal Velocity of that weight of shaft. Of course I have used a 140 @ 8mm with excellent results, but it is just that you can get better performance with a 7mm or 7.5mm shaft. With an invert roller, it makes a lot of sense to use an 8mm or even 8.5mm shaft @140 as the band energy involved works differently. The same with bands ... while small ID bands around 14 to 14.5mm might be best for classic guns ... I feel thicker bands are better for Invert Rollers.

[popgun pete]

Originally Posted by spearq8

A 140 @ 8mm is tricky for a classic gun as it is a short shaft and thus not enough band stretch to get close to Terminal Velocity of that weight of shaft. Of course I have used a 140 @ 8mm with excellent results, but it is just that you can get better performance with a 7mm or 7.5mm shaft. With an invert roller, it makes a lot of sense to use an 8mm or even 8.5mm shaft @140 as the band energy involved works differently. The same with bands ... while small ID bands around 14 to 14.5mm might be best for classic guns ... I feel thicker bands are better for Invert Rollers.

No such thing as terminal velocity, but there is an acceleration limit on shafts that are being tail driven unless the shaft is bound on all sides by being surrounded by a barrel tube. The shaft still tries to bend, but the barrel acts as a splint. Once the spear emerges the push from the impelling unit has gone, so now the shaft cruises while hydrodynamic drag and cavitation behind the shaft slows it down. As an applied physicist that is what is going on.

If the shaft in an open track gun bends momentarily enough to hit something on the way out of the gun it can then deviate from the intended course. The hit can be on the track or it can clip part of the muzzle. Some tube guns tried to eliminate this problem by a big space between the spear and the barrel tube with zero track, but that required the spear shaft to rattle its way through the muzzle opening. Because band rubber was not much to write home about early guns lacked the grunt to get into any trouble.

An examination of tube guns in the sixties showed the hits on the barrel tube about a foot out from the sear box mouth, or closer, where the spear left a scuff mark. On tube guns with tape wrapped barrels the tape bore the same marks. These guns were three banders with closed or open muzzles, the latter using tabbed line slides that sit in a muzzle slot. Tape wrapped barrels were used to suppress the clonk of the shaft on the gun barrel during the shot.

[armandozx]

Originally Posted by spearq8

A 140 @ 8mm is tricky for a classic gun as it is a short shaft and thus not enough band stretch to get close to max performance of that weight of shaft. Of course I have used a 140 @ 8mm with excellent results, but it is just that you can get better performance with a 7mm or 7.5mm shaft. With an invert roller, it makes a lot of sense to use an 8mm or even 8.5mm shaft @140 as the band energy involved works differently. The same with bands ... while small ID bands around 14 to 14.5mm might be best for classic guns ... I feel thicker bands are better for Invert Rollers.

If you want to go all out on max power without massive recoil, then inverters can handle it better than traditional. Inverters basically give you added room to hopefully get that shaft to max desired speed. I can see why the heavier wood/carbon inverters stack up on bands with a 8mm shaft. To some extent, it's personal and hopefully regional. The 7.5mm with the 3 band stacks work very well for me with less than 7in of overhang.