Hmmmmmmm....
* Eth takes it War hasn't look at the fixed ship yet *
I'll give you a holler tonight War.
Ok, long story which applies ONLY to multi-part turrets (ones having a base _and_ arms as _seperate_ subobjects)...
When War sent me the Xanthus for turret fiddling, it did indeed have "true" side turrets on the model. In my usual way I was bound and determined to figure out a "magic path" to making them work and give him the first cap with working side multi-part turrets. After many hours of banging my head on the keyboard, looking at
ships with a hex editor, trying various manipulations of subobject meshes and axises, and various combinations of rotational settings in the POF file until I looked like this
I found out several interesting things about multi-part turrets.
If you check closely all the cap ships that Volition made, you will find a veritable hodge-podge of rotation bit settings. I found turret bases that had the rotation set in the x-axis, ones set in the y-axis, and ones set in the z-axis.
Yet they all rotated the exact same way 
I even found out that if it is a
multi-part turret, having a base and an arm(s), that it will rotate
even if you specify NO ROTATION!!
It appears that for some reason what
ended up doing is
hard coding the rotational properties for multi-part turrets. The result is that any
multi-part turret will
always operate the same way (if you don't confuse the FS2 engine...I found you can prevent rotation by mis-setting certain rotational bits).
This means that for multi-part turrets, the base rotates around the Y-axis and the arms rotate around the X-axis (FS2 Y and X axises) Also, this rotation is based on
the default position of the 
(in other words, its orientation in the original model). For this reason, the following rules apply to get multi-part turrets to operate correctly:
1) The base must be parallel to the X-axis such that it's center of rotation is a line through the base oriented in the Y-axis.
2) The arms must be oriented such that they are parallel to the Y-axis initially (pointing straight up or down) _and_ such that if they were rotated to either of their "downward" positions they would be pointing towards the front or back of the ship.
The result is that to be able to have
multi-part turrets that work properly on the sides of a ship, you have 3 options (at least until I figure out the "magic path")...
You can place turrets on the sides by mounting them on a horizontal surface so that they are oriented as if they were on the top or bottom of the ship. This is what I ended up doing with the Xanthus.
or
You can have a turret made with a _single_ subobject with barrels that point out the side and whose "base" is oriented horizontally (which is what Venom is talking about I think)
or
well... the 3rd way I've come up with you'll have to wait for
Important note too: MV32 shows how multi-part turrets would rotate _IF_ Volition had implemented the feature fully, _NOT_ how they actually will rotate in game.
