Digging up an old thread here....
Some good points all around, a few that I disagree with.
OK, maybe just one.
Haven't read this entire thread, but someone on page 1 says that a spade is just as strong as skeg hung.
Not saying there is anything wrong with spades, but a full skeg, with a nice sloped lead edge is gonna take more abuse than a spade. It is nearly as bombproof as a keel hung rudder on a full keel boat, which is essentially a skeg hung rudder with a ginormous skeg.
Of course the improved performance is a worthwhile tradeoff for many which is why the great majority of boats built today are skegless.
The one other comment I would like to second is the cofferdam. Seems to me that every single
spade rudder boat out there should be built with them. It could save your boat when a whale rips the spade off and being able to remove/service the rudder without putting the boat on the hard
is a great benefit.
I am currently looking to buy something old and cheap
in the 30 ft range and there's a very good chance that it will have a spade. If it does not have a cofferdam when I get it, it will shortly.
How about the idea of a skeg that doesn't actually touch the rudder? I guess technically, it isn't a skeg. More of a fairing there to deflect anything intending to bash your rudder. It wouldn't even have to be that heavy. Design it as a sacrificial piece that would break off as it does its job to avoid or at least lessen the impact with the rudder.