I really like the idea of shroud extenders to help right the Hobie. I hadn't seen or heard of this before.
Is anyone doing this? Does it work as advertised?
There have been discussions regarding shroud extenders on these forums before, you might want to do a quick search for some detailed discussions.
There are some "issues" with shroud extenders.
First off, the shroud extender really won't do anything to prevent you from going turtle, and it definitely won't help you to right from the turtled position. Nor is it a substitute for a properly sealed mast.
Shroud extenders REQUIRE that your mast base be mechanically linked to the mast step. In the case of boats with capive ball mast steps (Hobie 17, 20, tiger) this means sailing with the mast step pin in. For boats without captive mast steps (Hobie 14, 16, 18) this means you need a system to hold the mast base to the mast step. This consists of a piece of wire that is shackled to the mast base and wraps around the dolphin striker. If you don't link the mast base to the mast step, it is highly likely that your mast base will pop off the mast step when you pull the shroud and you'll dismast.
The other issue is that if you use the shroud extender while sailing single handed, after you right the boat, you somehow have to manage to re-insert the pin back into the shroud on the leeward side of the boat without flipping over again. This would not be easy to do in strong winds.
Does the system work as advertised? Yes. But it's got some things about it that probably make some of the other righting assist systems a little better.