[Boatanchors] Tribander question

[RAY FRIESS]

I have a question for the group that I need advice and thoughts on.

This is a tale of two tribanders.   One is a Hygain Explorer Tribander ... the other is a Mosley Classic 33.
I've been using the Hygain for years, but now it appears one of the traps has gone bad.
The Mosley was sitting atop a 50 foot tower until a couple months ago.   A friend of mine moved from Utah up to
the panhandle of Idaho.  He still owns the house in Utah, and among the things he left behind was the 50 foot tower
with the Mosley on top of it.  A couple months ago, in a windstorm packing winds up to 85 mph, the tower snapped at
the base and came crashing down on top of the garage.  Luckily no damage to the garage, but the tower, bent in a couple of
places when it crashed down on the peaked garage.  The Mosley, of course, took a whallop, but the driven element
remained intact.  My friend told me I could have whatever of the tower and antenna I could salvage.  (We'll save 
about 40 feet of the tower).

My question is this....  What relationship do triband parasitic elements (i.e. the reflector and director) have with
the driven element, if any.  What I am wondering is, can I take the driven element from the Mosley 3 element
tribander and just put it in place of the driven element on the Mosley, which has five elements on it.  
If  you are familiar with the Explorer, it is a three element beam with an RF coupled element a few inches in front
of the driven element and one a few inches behind it, plus the usual reflector and director at opposite ends of the boom.

Since the driven element of both beams is tuned (with traps) for 10-15-20, my thinking is that what I propose should
be okay.  But, I'm not sure if the distance of parasitic elements from the driven element has any relationship to the
type of driven element or if a beam's length is basically whatever the designers decided they wanted the boom length
to be.  Do reflectors and directors care what type of driven element they are near as long as the driven element is
resonant?  I know that there are formulas for how far apart elements are to be from each other on a boom, but
I think that's a function of boom length, rather than the type of driven element.

Ray  WA7ITZ