Slip tip not penetrating completely, or in weird angle

[John Marr]

Hello,
i recently lost some heavily thrashing bigger fish on a regular spear with flopper, so I decided to try a slip tip.
Where I am, I only have limited choice and no proper tools to build my own so I went with a Beuchat version.

I tried it today with my 85cm shaft and a double rubber configuration.
After shooting a smaller ( 80 cm ) Barracuda I thought all was well, but the spear and tip came out of the fish when it swam away.
Since I unfortunately could not shoot it again I did not see what excatly happened.
Later I came across a 2kg Pompano jack which i tried to shoot and alas the same thing happened.
This time however I was able to quickly follow it with my polespear and was able to get a hold of it.
I could see that the slip-tip had entered the body nicely in the height of the spine but then somehow came out of the body on the top same side, so it seems the tip went in a weird direction.
With a normal tip the same configuration was used to penetrate even a big 6kg Kingfish so I am quite sure that power is not the issue.
I used a 1.2 Dyneema line instead of the steel cable. Length being around 30cm.
Does anyone know what might be the problem ?

Thanks!

 

[Mr. X]

The 85cm spear length sounds short for the sort of fish you are spearing. Are you rig diving? What type of speargun ate you using (e.g. barrel length, number and type of rubbers, spear diameter)?

 

[Mr. X]

Also, what type of spear was your original flopper spear? In my experience, the heavy downward facing Rob Allen floppers open and stay open reliably but my light, low profile, upward facing Omer floppers sometimes do not open and sometimes open then close - it is vital to keep some tension on the spearline once the fish is speared.

FYI I am wondering if you speargun is under powered, inappropriately powered and/or too small for the job.

If you are using a band gun(?), an 85cm spear suggests a barrel tube length of only 44cm-55cm, which is very small.

 

[John Marr]

Hello,
well the gun is made from Rob Allen parts. Spear is 6.5mm threaded with a 9cm tip and 5cm floppers
You can see it in my DIY thread (https://forums.deeperblue.com/threads/need-help-on-which-rubbers-to-get-for-half-diy-speargun.113524)
However I started to use the double bands also on the shorter version of the gun to get a bit more power. Works fine without wobble.
Diving is done from shore or in open water reefs in between 0 and 30m, no rigs.

 

[Bill McIntyre]

Its hard to say what the problem is but that is a very primitive slip tip design, something like I used in the 1970s. That cable sticking out of both sides would certainly retard penetration, particularly through gill cover or bone. You say you replaced the cable with Dyneema. Is there a crimp or knot on the Dyneema that might hang up?

Then there is that long straight adapter that the tip rests on. That would have to come a long way out of the tip before it could start to turn and toggle in the fish.

That slide ring is big and bulky and would resist penetration if the shaft went through far enough to fully extend the cable. If possible, I'd recommend getting a more modern design like the ones made by Masihiro Mori in Los Angeles. That spectra offers almost no resistance to the shot or to penetration, and the tapered adapter lets the tip start to turn almost immediately. The pass-through slide ring is sleeker too.

Mori Sliptip

The Mori Slip Tip is one of the best tips currently available! Mori Cable & Spectra Slip Tips available along with replacements, check them out!

neptonics.com

Mori pretty much pioneered this design, but there are many good copies now including the tips from Daryl Wong.

 

[Mr. X]

Hello,
well the gun is made from Rob Allen parts. Spear is 6.5mm threaded with a 9cm tip and 5cm floppers
You can see it in my DIY thread (https://forums.deeperblue.com/threads/need-help-on-which-rubbers-to-get-for-half-diy-speargun.113524)
However I started to use the double bands also on the shorter version of the gun to get a bit more power. Works fine without wobble.
Diving is done from shore or in open water reefs in between 0 and 30m, no rigs.

Cool travel speargun I want one

I almost wrote that it would likely be too small and under powered unless it is something like a custom length Rob Allen railgun with multiple bands - which it kind of is!

How long is the barrel when using the 85cm spear, about 75cm or less?

Bill knows a lot more about slip tips than I ever will, so I expect he is right. I think of slip tips being used mainly with big Woodies with multiple bands (2 or often more). But there are some excellent videos of a young Japanese spearo using a long, Japanese carbon pole spear with a slip tip (no doubt well engineered), so perhaps high speed/power is not essential? Perhaps higher momentum (mass x velocity) is? Your spear is relatively short and thin (relatively low mass) and the barrel length relatively short. 2x14mm we usually estimate as being similar power to 1x19 or 20mm band - more than powerful enough for most regular spearing , assuming they are appropriately sized for the barrel .

I notice you use a reel, is it possible the fish were out- of-range? Yes you hit and penetrated the fish but was there sufficient power/ momentum left in it? Esp. bearing in mind Bill's observation about the slip tip design.

 

[John Marr]

Is there a crimp or knot on the Dyneema that might hang up?

A knot is what I used. But it is quite small and I do not thing that judging by the forces we are dealing with here that this is too big of an issue.
Especially considering that with the thin dyneema it is smaller then the original design with the steel cable.

That slide ring is big and bulky and would resist penetration if the shaft went through far enough to fully extend the cable.

That is a very good point. If it does not penetrate it would even add tension to the dyneema thus keeping the tip firmly in place.

I'd recommend getting a more modern design like the ones made by Masihiro Mori in Los Angeles. That spectra offers almost no resistance to the shot or to penetration, and the tapered adapter lets the tip start to turn almost immediately. The pass-through slide ring is sleeker too.

I unfortnately have limited access to other equipment, but maybe I can re-shape / re-work the current one.
For now, maybe making the connecting line longer might help.

Cool travel speargun I want one

Its easy to make

How long is the barrel when using the 85cm spear, about 75cm or less?

Around 70 / 75 cm.

I notice you use a reel, is it possible the fish were out- of-range? Yes you hit and penetrated the fish but was there sufficient power/ momentum left in it? Esp. bearing in mind Bill's observation about the slip tip design.

Also a very valid point.
However the shooting line with the small setup is 5 times the length of the barrel before it is attached to the shock absorber / reel.
Especially with the barracuda distance was maybe a mere 1m.
With the longer spear I usually only use 3 times the barrel length for shooting line. But I do think that this should be more then enough?

Thanks all!

 

[Bill McIntyre]

That is a very good point. If it does not penetrate it would even add tension to the dyneema thus keeping the tip firmly in place.

Here's a way to address that. First switch to a pass through slide ring. They're cheap and surely one could be mailed to you. But then with a pass through ring there is another possible problem. If your shot passes through the fish and fully extends the spectra cable, a scale or meat can jam between the slide ring and shaft so that the tip is unable to deploy. I've had it happen. The solution is to wrap some plastic tape around the shaft right in front of the muzzle. The slide ring will stop when it hits the tape. Even if it jams there its no problem because it doesn't hold the spectra extended. The tip can deploy and all that spectra behind the slide ring is free to slide forward. I've had them jam in front of the tape so hard that I had to use pliers to free it up. In this photo, the shaft on the right has black tape that's hard to see, but the one on the left has blue tape that easy to see.

 

[John Marr]

hmm, interesting.