R/C Naval Combat

That is the three brass tube bushing idea. Also mount your tubes so that where your motors are going, they clear your gun stuff. Motors have a nasty habit of ending up right under the interupters. I agree with the others that powering all four looses turning ability. i would power the center two.

It also complicates things no matter what ruleset you are battling. Try to keep it simple. It is a big boat and you will have many issues to cure. Things will go a lot smoother if there is less "strange" systems to maintain.

IMHO,

The hobbiest that recommended that 2/4 prop setup is most likely a scale builder and not a combater. The 2/4 setup is common on larger scale ships.

Well there is a little glitch in the MWC rules about this, and with the new high capacity batteries, it can be made to work pretty easily. Since my Duke was set up to accept 4 motors, after Nats I plan on trying it out.

In the MWC, you can power all 4 motors, which is legal. The last rule change, which I think was talking about twin screw ships, but this is where I think they messed up, does not say that.  Rick and I did quite a bit of testing on his Scheer last year, to come up with the right props, prop spin direction, pinions, and drag disks. Well in the process of making the many changes I noticed different things happening.
What you do is power all 4 shafts, you must use the same props, RPM, and gears, to make it legal. Now on the outer shafts, place your drag disks directly in front of the props, with no spacing between them. These props do nothing for the propulsion since the drag disks cover the props, but the drag disks slow you down.  They actually will not draw much power since they are not moving much water.

Now since all the props are powered, place 2 more drag disks in front of the stuffing tube supports on the center shafts, fixed in place. The ships motors will have to turn faster just to get to speed since you have 4 drag disks on the boat, and with the increased prop wash from the center motors, the ship will stop, and turn faster. The extra drag disks are allowed in the MWC, since all props are powered.

As you can see below, the above drive system does not violate any of the current rules.

MWC Rule on drag disks and props.

4) The ship shall be equipped with a scale number of shafts. Each ship must have a scale number of props. Non-powered props must be the same size or smaller than the powered props.
a) In addition to non-powered props, one speed trim disk may be used on each non-powered shaft.
b) If a ship does not have any unpowered shafts, one speed trim disk may be used on each powered shaft.
c) Speed trim disks must be circular, flat, may not exceed the diameter of the drive props, and must be center mounted. Speed trim disks may not be any type of device that is designed to create variations in drag force from one direction to another.
i) Some examples of prohibited devices are: cups, domes, hinged disks, hinged flaps, etc.
d) Props on all powered shafts must be the same diameter and pitch and have the same number of blades.
i) Props used only to reverse the ship may be smaller, have fewer blades, and less pitch than the props used for forward
propulsion.

MWC turning motor rules

Turning motors can be defined as any of the following:Turning off/on motors only when the ship is turning.
Turing motors at different RPMs only when the ship is turning.

Running any drive motor(s) in reverse when the other drive motor(s) are running forward.

Running any drive motor(s) with significant RPM differences between them.

Side of ship thrusters are turning systems.
Using a pump stream to turn the ship is a turning system

Hey, well heres an update. We finished cutting the tubes down, sanding the ends, insdes, and outsides to prepare for soldering them into making bushings. Here is a picture of all the pieces ready for the big show.

We have not done the internal layout yet, so the stuffing tubes are not cut to length (thats why they don't look all same sizes). We plan on doing the layout, estimate as best where the motors are, and measure the stuffing tubes accordingly. Once that is complete, we will solder in the concentric tubes and cut the ends off to the correct length.

We managed to try it out on on one of the stuffing tube ends, and the picture below is the end result. I put another stuffing tube next to it to put in into perspective.

An issue that I can't seem to fix is cutting the ends at a straight angle. I have tried using a dremel with a reinforced cutting wheel and sanding it, as well as a clamp/jig and a hacksaw, nothing seems to create a perfectly straight edge. Any suggestions?