[Jeff Donovan]

I found this link earlier which indicates a simple design to changing a tube fly without the need of untying and retying the hook...........
http://globalflyfisher.com/fishbetter/fly-on/

Simples! 

[Marc Fauvet]

great find, thanks !

[Rob Brownfield]

Not sure I like the idea of the leader running down the outside of the tube. Risk of a kelt biting through and leaving a hook in the fish and the risk of the leader being damaged on rocks and the bottom during the course of a days fishing.

I am sure re-tying a hook, when you can also check for bluntness, is a far more sensible option.

[Hamish Young]

An interesting share, but I'm firmly with Rob on this one 

I can see the merits of that system, but it's not for me.

H

[Jeff Donovan]

The leader running outside the tube isn't a new idea.....John Gray's Needle Fly for example, that's been around a number of years. 

[Rob Brownfield]

The whole concept is used in carp fishing to "dump an inline weight" when a fish is hooked. Nothing is new in fishing