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Mordem Molac

Thread Status: Hello , There was no answer in this thread for more than 60 days.
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Gizzo

Member
Oct 8, 2010
45
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MORabito DEMetrio was an inventor of spearguns in Milano, and in 1963 he put on the market this unique speargun MOLAC (MOLla =spring, ACqua=water) working with hydro spring principle. Two parallel barrels with the arrow in the upper and the spring in the lower. The barrels are connected in the back. The arrow have four ORs and compress water, the water pulls a piston in the lower barrel that compress the spring.
It is a very rare rescue, but I do not have the arrow and I cannot reproduce because I do not have a picture of the shape (if anybody have one I will be grate for the details of the arrow). You see the first advertising when it was presented in January 1963 and was not very expensive for his time and very simple in the working principle. Was a competitive speargun? I cannot say, in the same age there were many good spearguns on the market like Mares Jet, Nemrod Corbeta, and of course Hydra that was more expensive
Intero.jpg
Calcio.jpg
Coda.jpg
Pubblicità1.jpg
Pubblicità2.jpg
etc..
 
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Spring guns are inefficient as the metal spring coils drag on the inner wall of the barrel because a compressed spring buckles along its length in a series of small side to side curves or bends. This adds to friction both during loading and the shot, even in water filled barrels, which is why spring guns had greased springs as well as to stop them rusting. A water column transmission adds to inefficiency if the spring drives the water column which in turn drives the spear as the water column uses seals that run on the lower reservoir tube and they also involve friction as do the seals on the tail end of the spear which run in the upper barrel tube. This gun is in a sense a spring powered analogue of a hydropneumatic speargun, but the latter has a powerful air spring to make it work effectively, rather than efficiently. A metal coil spring has more energy losses, so unlike the hydropneumatic gun it has less energy to throw away and still have enough left for good spear propulsion.

Diagram shows how I believe the gun works. The advantage is a full length spear, usually compression spring guns only have a spear that is half the length of the gun.

Never seen this gun before, so thanks for showing it to us.
Mordem Inner works.jpg
 
Thank you Pete...ipedia. I was sure you will add your comment to this post. I agree with your comment and I like your schematic that is right. I think this speargun is quite rare because not so many people have bought it. Anyway when you read recommendations of the producer it says to put grease in both barrels, that are chrome plated brass. Furthermore it says that is particularly useful for fishing deep because do not lose power with depth and in 1963 most of the divers go hunting with air, so I think that it was designed for that particular scope. I would like to find a picture/description of the spear.
 
I think that the "Molac" spear will have a tail end similar to the one used on the "Strale" hydropneumatic speargun also made by Mordem. However the extreme end with the mushroom head will be omitted as the friction of the tail "O" rings will retain the spear in the barrel. Also for the spear to fall out of the gun it would need a vacuum to form behind it, or the "O" rings to leak water, but you said that there were four of them. On the "Strale" the spear tail carried three "O" rings, but if the sealing is good you really only need one "O" ring. Does the spring containing section flood? I assume that it does as the sear catch or tooth must penetrate the tubing as shown on the diagram. If you dismantle the handle we will be able to see the actual trigger mechanism which works in the opposite direction as the piston pushed by the spring expanding moves rearwards, not forwards.
 
Dear Pete I will open the gun when I come back from my holidays in Greece, I am just leaving now. I have also three Strale so I know what you say. Anyway I was wrong also this spear have three OR, not 4, like Strale it is written in the text of advertising.
 
You could try the "Strale" spear if it is the same barrel ID on both guns, the "mushroom head" on the tail will just not allow the spear to be inserted as far into the gun (only a few centimetres, if that).
 
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