Interesting propeller shape. Any idea?

[Bubblehead Nuke]

Originally Posted by Dr.Sid

My few cents .. X planes vs. cross

pros:
- backup functionality - one pair can counter jam of the other pair (in pitch control, that's what matters)
- lower draft and side extension with same effective surface area

cons:
- more complicated mechanism
- not direct translation from controls to planes

I guess the shallow water subs use X especially because lower draft. As for controls, they are computerized anyway (so one man can control it, as small sub cannot afford two man to do that). Complexity is not problem as you are always close to home.

For attack subs, draft is usually not the main design element. The simplicity is useful especially if you want to fix it when far from home. Also bigger ship means bigger forces .. so some solutions which can be used on small sub (like having half-axis instead of full axis) might not work.
The backup functionality can be done in different ways, like split control planes with backup HP system (though I'm not sure what system is used on let's say Virginia).

You pretty much hit on the head in my opinion. We liked the ability to go ALL manual if we had to. The X-Plane configuration would have really complicated it. Sure, you can make a combination control horn (think V-Tail RC airplanes and such), but that would be a complicated arrangement that is BEGGING to get jammed. Thus in a jam dive situation, you would have to control TWO different control surfaces in a combination to effectively control ships depth and heading. It is all about SIMPLICITY. In a causuality, I cared about the STERN planes, OR, the rudder, not both.