http://www.africanarcher.com/survivor/art_pipegun.htm  ???

that reminds me of this arrow slingshot that is on the bottom of the picture, except that there is a trigger on that one you are showing, and this one is just controlled by your grip

Yeah, it sort of reminds me of the Hawaiian speargun that I saw a post of some time ago. Not a bad weapon, though.

yeah me too here's a good example

http://rocknfish.com/HingeGun.html

That's nice! :D

I saw another site with more details on how to construct them. ::) I just wonder what is the effect of using these on land. ::) ???

check this thread

http://www.slinging.org/forum2/yabb/YaBB.cgi?board=other;action=display;num=1149392511;start=30#30

stenny was trying to make a real speargun ..wonder how that turned out

a thought just came to my head about why the spear gun can shoot farther under water than it can on land:
under water, the effects of gravity are dramatically reduced, and that is why it is able to travel so far under water and not out of water.  also, the reason that underwater darts don't need fletching to keep them going straight is because of the dramatically increased drag that water has on things, which forces the dart to go point first, or sink immeiatly.

hmm i don't know siguy i read on a forum for spearfishers that the maximum range for a speargun is about 3 t 4 times the length of the barrel so i would say thats Not very far is it  :-/

course thats underwater  ;D

Siguy and Taiki,

wrote on Aug 18^th, 2006 at 2:33pm:

a thought just came to my head about why the spear gun can shoot farther under water than it can on land: under water, the effects of gravity are dramatically reduced, and that is why it is able to travel so far under water and not out of water.  also, the reason that underwater darts don't need fletching to keep them going straight is because of the dramatically increased drag that water has on things, which forces the dart to go point first, or sink immeiatly.

I can promise that all of gravity is still there. A spear will most definitely fly further if shot from land. Fletching isn't needed mostly because of the drag imparted by water, but also by the short ranges being used. I may make one of these at some point.
A spear with a head that detaches and runs on a spool of line makes the most sense to me, but I suppose it depends on what/where your spearing.

http://rocknfish.com/Jack%27s_Tuna_Gun.html

All that I can say is: Don't get caught in that line when the Tuna takes off!

Here:

http://www.geocities.com/freedivespearo/aboutslings.html