Just had a look through the article on line. Some back ground into knots, basically the weakest point on a rope / cord is the knot. eg: a bowline reduces the effective breaking strain of a cord to 40%. ie: @ 180kg it will be reduced to 70 - 80kg. The strongest knots are NOT knots. for eg; a Knouds knot (not for spearing, fishing only), check it on youtube, give 100%. so the line breaks before the knot.
The knot shown on the article is basically a rapala knot. That initial over hand knot has a massive effect on reducing the effective breaking strain. BUT in that using Dyneema would a diver actually be able to apply a down rated 100kg of pressure on a rig? probly not.

My personal opinion is a good crimp would also do.

Could i take this a step further and ask the advantages of dyneema for spear line over mono. Can you crimp dyneema?

Hi Don

Hope all is well in Indo and that you are not working too hard..

It would be nice to know the advantages and disadvantages of dyneema, mono etc?
What is the best for what setup etc?(normal, reel gun, breakaway.)
What knots are the best?
Why dont you use a muzzel bungee on a reel gun?

That is all things I wonder about..
I just rig my things as they were bought as I think R.A. and Freedivers probably sell with the right/strongest/best setup..?

So I would now like to hear from you and all other guys on the forum

I bet Mr. Coates will also shed some light on the subject.

Regards
Johann

Sweating like hell out here, water is crystal, but i cant touch it.
Anyway, my opinion of Dyneema as a spear line; I had this set up for nearly 15 yrs and cant say i had any problems. I then had the fortunate oppertunity of spending 8 months working with Ryan Burms and he insisted that the mono is better for muzzle wraps etc. I take that advise and run with it. Again spend quite a bit of time with Alan Fraser, same thing mono only. SO i dont quetsion it, I just use it. from my side i cant say, but i take the proffesional advise. Bungy on a reel gun, for me it is just another consumable that i want to do with out. Im not sure.
Crimping Dyneema, interresting, as it is a very solid cord. I would maybe consider using the next size down on the crimping tool, not the 2.0mm. whats it 1.8mm?? I know the Marlin guys use crimps extensively, im sure dyneema may have been crimped some where along the line. If i need to make an eye with Dyneema, 2 options, double bowline (80%) or a BOUY knot ie: figure of 8 fed back on its self.

Good discussion!

On the knots side the best way is to sew & glue the dynema, it is a real mission and be prepared to have loads of pin pricks in your fingers. This is pretty much the only way to get the full strength of the dynema in a small enough knot. There are other knots but even the one on this site is bulky, and the better ones are even more bulky.

The point made earlier that a spearo wont break 100kg is true and the main reason for using dynema is not necessarily its breaking strain its the abrasion resistance. Think of plain polyester line with 80kg breaking strain .. its more than enough come to think of it its probably impossible to pull more than 40kg in the water ..even with a sudden jerk and definitely not downward.

I am not too sure about crimping dynema, but do remeber some one saying that the crimps damage the dynema .... not sure about that one.

On using dynema as shooting line, I use it on my small guns when shooting reef fish. The new muzzles that let your rubbers open out have decreased muzzle wraps a hundred times over ... well at least for me. (and touch wood have not had a muzzle wrap in the past 2 years with dynema ... even when it is slack)

The reason I use dynema is that it does not ware as quick as mono. Often you shoot right through a fish which then spirals twisting your line, mono has a memory and this wrecks the line. Also when fish run into the reef it scuffs the line, with dynema it doesn't. This means that when I throw away a spear because its bent etc the dynema line is still good and usable, so the line out last the spear. Mono I found I was changing fairly often.

I still use mono on all my other guns because there I usually double wrap and dynema is expensive. Its also easier to put on.

That's my take