Have one
I have a rigid boom vang, am sorry to say I don't remember the brand. I want to say NavTech - will look next time on board. It was on the boat when I bought it last spring. The boat is a H34. I know the previous owner just had the cylinder rebuilt, I guess it was leaking fluid. A rigger at Fawcetts in Annapolis made some negetive comments about it in reference to leaking while on board for a non related problem. I have really liked it and it has functioned flawlessly so far. It is hydraulic and operates with a lever from the cockpit, adjusting either the vang or the back stay. It is nice to see the sail flatten or the forstay tighten with a few cranks. If it fails, however, I am not sure I would replace it given that my main interest is cruising, not racing. Hope that helps. Eric