Re: Is external rudder a good idea?
There is absolutely nothing wrong with having a transom-mounted rudder for racing or cruising, coastal or ocean voyages - and whoever said there was knows nothing of what they speak..
There are major advantages - like less holes in the boat and the ability to repair or jury-rig something without having to haul the boat out to do so - and perhaps some minor disadvantages if you're hanging an outboard on the back also, but from a performance point of view it makes absolutely no difference at all... it simply comes down to personal preference and the abilities of the yacht's designer.
"Honestly, I don't know why seamen persist in getting wrecked in some of the outlandish places they do, when they can do it in a nice place like Fiji." -- John Caldwell, "Desperate Voyage"