To reply to my own post, I talked to Randy Nash about five sided ridges and he said no one knows the origin. This is an opportunity for all of you barn investigators to travel to England(?) and track down the existance of anything similar to a five sided ridge.

Since starting this thread I have seen another ridge beam in an 1810 cape. it is in a rafter/purlin roof and the braces are long enough they interupt the purlin: the purlins are nailed to the braces. There is an endless number of variations of traditional timber framing!

Take care;
Jim