Railgun slip tips

[RabiDeath]

I was wondering if anyone had any experience with using slip tips on their railguns. I am experimenting with one now to cut down on bent spears. Probably will only be good on the reef, but hopefully somone will have some thoughts. Here is the concept from Polarsub:

 

[fuzz]

This concept is so simple, yet amazingly effective. I've only had the opportunity to try out one, but it seated well & slipped off my shaft easily. They can be bought along with Rob Allen Railguns & other gear online at http://www.norcalfreedive.com

The only thing that's necessary is to round out the tri-tip of RA shafts to a conical shape for even fitting, remove the barb, & fit the anchor line through the now vacant barb-hole.

Very innovative & a smooth design. :hmm

The slim design & solid seating address a majority of the concerns below:

Quoted from http://www.roballen.co.za/
Why are single fixed barbs most common on railguns?

We have found that the vast majority of spearfishermen have at one time or another used or tried a drop head (slip tip). They virtually all change back to a single barb for a variety of reasons, the main reason being accuracy. Here we have found that it is very difficult to get the drop head to sit on the tip of the spear without any play (basically sideways movement). If you can get it to fit without play, then invariably it is too tight to come off resulting in the head pulling back through the fish and the fish being lost. The very tip has to be perfectly stable and central to maintain the straight flight of the spear. Even a very small amount of play will cause the spear to be inaccurate. This is because the extreme tip is what keeps the spear travelling true. A slight movement to one side or the other will cause a varying degree of inaccuracy depending on the amount of play. To show this you just need to sharpen a spear, which has a fixed barb, slightly off center, and you will see how much the accuracy is affected. Another problem with a drop head is the hassle. Slightly too loose and it falls off when you dive down, to tight and it stays on and pulls back out of the fish. This can be most frustrating. In terms of drag the drop head is bad, since the diameter is greater than the spear. Another disadvantage is costs; a fixed barb spear is much less a spear with a drop head.

 

[Rolando]

Blake,

I believe the threaded Euro Riffe Shafts fit the SA railguns. You can always install a slip tip to them...

R

 

[fuzz]

Rolando,

The 2 main problems I have with the threaded slip-tips are:

The size(even of the slim ones) really detracts from the primary advantage of a railgun. - it's speed. The Riffe 6.75mm euro-shaft is a great shaft(albeit double the cost of a RA shaft), but typical slip-tips are not made for 17/64 diameter shafts & that extra size does detract from accuracy.

The cost. Combine a Riffe shaft(~ double RA shaft cost) with a conventional slip-tip (~80-120 for better ones)...

For a Riffe or Wong, I'd go with a threaded shaft & wong slip-tip. For a euro gun, I think using one of your existing shafts & one of these slip-tips is a good way to go. Cost-wise, I think it's worth a try

 

[RabiDeath]

Rolando,
Riffe shafts do not bend back. I have been disappointed with them all around. The Rob Allen spears can be bent back if it isn't too bad. Ditto what Fuzz said about the slip tips. The Polarsub concept will save your spears on those big groupers!

 

[shaneshac]

How thick are Euro Riffe Shafts? In mm please I'm european

Would they fit other eurogun mechs?

THanks
Shane

 

[shaneshac]

Duh!!!! The thickness is quoted above sorry. 6.75mm

 

[RabiDeath]

Fuzz,
Does the line it comes with fray easily? I am still skeptical about using it in bluewater. Something about those knots... Anyway, I am looking forward to trying it on reef fish to save my spears.

 

[shaneshac]

The italians do it again.

Check this out http://www.devotosub.com/2003/pag_6.htm

I love the italians

 

[Murat]

That slip tip looks GREAT ! ! !.

Now you are saying that you just remove floper and tie the knot there then slip tip is ready to use. And it does not effect accuracy but deploy easily. In which spears does it fit? 6.5mm-7mm?

 

[fuzz]

Rabideath,
I messaged the owner of the site & asked him to comment - perhaps he can better assess the full capabilities of his equipment. I agree that it'd be a lot better to test out on reef fish first. I look forward to going back to Hawaii in next couple weeks to try it out in a little clearer waters

Shane,
That tip looks awesome! I find the recessed double flopper quite impressive - it looks nice & streamlined. The release function is similar to This JBL Model The main problem with the JBL has over this Italian model is it's bulkiness.

Murat,
The tip is for 7mm shafts. Direct Link here Accuracy is always affected by any protrusion(even a stock barb); however, I feel this is a great concept & a new way to look at the mousetrap.

 

[shaneshac]

Fuzz, the totem guns all use Devoto shafts. They are made with 230kg Stainless. Hard as nails.

The slip tips come in 2 thicknesses. 6.5mm designes for Dentex and 7mm for AJ

Picasso also make a slip tip like that.

 

[roballenusa]

The Polarsub Euro slip tip is designed for RA 7mm shafts, but will also fit others of that diameter. It will be loose on a 6.5mm and this could effect long-range accuracy.

The tip is installed on a RA shaft by simply removing the barb and rounding the tri-cut head. You can also countersink the barb hole on both sides to reduce drag on the knot and fraying of the dyneema line.

I belive the dyneema is 400 or 500#. If necessary, replacement is cheap and easy. (less that .50/ft)

The tip is held secure by a small rubber tensioner which hugs the line to the shaft. Placement of the tensioner should be at the very end of the line, as to not prevent the tip from detatching.

The design of the tip results in excellent accuracy and holding power.

Aaron Lauer

 

[shaneshac]

Nice to have you one the forum. Hello from Gibraltar and thanx for the info.

 

[roballenusa]

Thanks! No problem...anytime.

Aaron

 

[Murat]

Now i noticed that these knots may cause the shaft to shoot bit right. They seems bit bulky for front of the tip. I think that you can modify it someway. If you attach slim metal disc to ends of the dynema you can get rid of that knots.

 

[Iyadiver]

My experience with slip tip ( only Riffe Ice Pick so far ) is that if you hit a big fish capable of fast burst speed, the shaft or the adaptor will still have a chance at bending. This is especially true if you hit that fish from sideway or 90 degrees to the direction of the fleeing fish. Pure water force.

If you hit a fish like grouper ( very big ones ) with a thick skull and the skull is where you hit, the shaft still can get bent even though grouper is a slower fish.

Slip tip only works well when the slip tip has fallen off its adaptor but if you hit something very hard on the fish ( skull & gill plates ), the shaft also get embedded as such for a while it does not detach the slip tip yet.......that's when it will get bend.

Those shafts & adaptors I bent are for 3/8" (9.5mm) shaft, not the thinner 5/16" (8mm) or 9/32" (7mm).

Slip tip can break too but in my cases, it is only the skirt, not mid body......not yet.

That Slip Tip over the Euro shaft is sweet and simple looking.....very nice.

 

[Spearooo]

slip tip

Check these out, My buddies uncle makes the they are also pretty sick. I havent had the priviladge of diving in a place were I would need one yet but I have one stashed away for that trip to big fishvile.
http://groups.msn.com/FREEDIVINGSPEARFISHING/spearpoles.msnw?Page=1