Ohio Class, Ballistic Missile Nuclear Powered Submarine, USS Kentucky SSBN737

Mounting / connecting the control surfaces:

All of the control surfaces needs to be connected to servos inside the hull. The two dive planes on the sail can be directly mechanically linked to the aft dive planes, or given their own servo with a pitch controller. This would allow them to follow the aft dive planes when you give the orders, but, when left alone, the pitch controller would adjust the submarines pitch using these dive planes alone. In the initial stage, I choose to connect the sail dive planes directly to the aft planes, and only later retrofit a pitch controller if needed. Some subs tend to "dolphin swim" (jumpy style) without a pitch controller, but not all. I'll wait and see what mine does before adding the pitch controller.

Here's a perfect view from the pre-fitting face of the aft dive planes, showing that the fixed part of the dive plane are secured with a bolt. The bolt ensures that the control surface can not brake loose and fall completely of the sub in the event of a collision.
The widest point of the entire sub are the aft dive planes, and they are pretty exposed by the location as well, so thinking that they won't ever take a hit, would be wrong.

This shows the stand including guide lines drawn on it. The stand was used to ensure a proper location of the dive planes, and gave a rather good fix too! The masking tape prevents resin from spilling on the actual hull when gluing later on. Note that the hull surface has been filed rough, where the glue needs to go.

Before gluing: Drill the holes for the bearings for the moving parts. There will be no space for this later...

Now the fixed part has been glued and bolted on. Using a cotton pick, I removed the surplus resin around the structure, leaving an almost complete finish right of. Now the masking tape can come of again.

A nice front view of the now glued and bolted control surfaces.
The "middle" of the hull was found by placing a drawing tool in the exact half height of the entire main hull ( 80 mm ), and then drawing a line where the center of the dive planes should go on the aft ends sides. This process involved placing the hull exactly leveled, so the rudders would be fitted evenly with the zero-balanced hull. (Roll = 0 degrees) 

Now it needs to be left alone for 16 hours, allowing the resin to completely cure. The masking tape on the stand ensures that nothing slowly slides any where. This is one of the most visible areas on the sub, and any error would be nothing smaller than a disaster.

Ensuring that the fix is symmetrical is important, which this confirms. The small gap between the stand and the dive plane on the starboard side, is caused by a small deviation in the stand construction, not the rudder location.

This is the port side nylon bearing for the moving part of the dive planes. The actual shaft is used to hold it in place until the resin is fully cured. The initial fix of the bearings was done using superglue, followed by a complete fix in resin. Drilling this hole for the bearing was done prior to fitting the dive plane, and only slightly adjusted afterwards with a thin file, before fitting the bearing.

The finished port side result! The starboard is symmetrical alike, and the process result was a perfect hit.
When the shafts have been connected internally, and the moving parts of the dive planes has been fitted, then the vertical stabilizing fin will go on to the end of the fixed half. The stabilizing fin will "close" the hole made for the shaft, ensuring that it can not ever fall out.

When it comes to the mechanical link of the aft control planes, there are one major problem: We have three axis crossing each other in one point. First, the rudders and dive planes need to operate without being in each others way at all times, and the propeller shaft needs to go right through the center line of the sub too. How do we do that? Well, take a look at this image, which is from another sub builder on the internet.


By looking at this blue print, and the four small step-by-step linkage horns, you can get a picture of how the three shafts that are crossing each other in one point. (And yes, the drawing is for free...)

The 1st servo
horn is the raw one.
The 2nd servo
horn has had it's center hole filled with resin. (hole too big otherwise)
The 3rd servo
horn has been cut and shaped.
The 4th servo
horn has been shortened even more, as it's the one on the far side. (see images below)

Here the linkage has been fitted, and gives a rather good idea of how the control surface controls are linked. Notice the masking tape on the right servo horn. It's there only to protect the hole needed for the remaining linkage, and will be removed once the resin has cured.

An out side view of the now linked dive planes. They ride so easy in their nylon bearings, that the weight alone pull them down when not supported. This is important to save servo power consumption, thus battery life.

Here the vertical stabilizers has been fitted. The small nail was filed down, after it had secured the component during curing. Special care was taken to ensure that the two vertical stabilizers was completely parallel, and that NO resin had got into the dive plane shaft bearing at the outer ends... pretty important..


This is the basic rudder components.

Seen from left to right:
The rudder with the brass shaft mounted, then the small Teflon bearing, then the black (stationary) bearing that goes in
to the hull, then the brass lock, and finally the servo horn. (Last two components not finished.)


The rudders are pretty much alike, except for the light in the top one. This image shows the top one, exposing the channels for the wires, and the hole in the rudder shaft, where these wires will later run from the top light, into the hollow shaft, and down inside the hull.
Notice that the hole is right below the Teflon bearing, which is now secured within the rudder.

The lower rudder is as mentioned before alike, except for this wire channel, and that the shaft on the lower rudder has been filled with resin, giving strength.

The two black, fixed bearings was fitted on the hull, and one long shaft held them aligned while curing.

The shaft diameter is 6mm (app. 1/4").


The next day, the shaft was removed, and any excess resin was removed. Now it was time to test-fit the rudders, that had also cured over night.


The clearance between the dive plane shafts, and the rudder shafts, are just as it should be. The propeller shaft will run right through the middle, thus leaving only very little room for mechanical travel.

However, the maximum rudder movement are set by that fact that the rudders and the dive planes can get into outside contact, if the angles on either exceeds app. 40 degrees. This will be programmed into the remote later on.


This is the finished result.

The dive planes are angled down due to their own weight, as none of the control surfaces has been linked yet. The rudders move just as easy, and the overall impression is satisfying.


Well... I HAD to see what it looked like, with the propeller fitted as well.

It's pretty amazing that all three axis of the sub is controlled from this relative little area on the sub, and it's going to be interesting to see it work in it's real environment some day..


This image from very late in the building shows the fitted rods for the control surfaces, and the wires for the aft upper rudder navigational light.

This image from very late in the building shows the now complete linkage to the rudders. Space is left in the very middle for the prop shaft, one of the next things that goes in.

This shows the completed ridder shaft arrangement. The push rods go through holes in the bridge that also supports the oil-bearing for the prop shaft. This should give the push rods extra stability.

Close-up of the support bridge for prop shaft and rudder rods.

This is the overall lingage from WTC1 and to the props and rudders.

The small light brown block with three holes in it towards the very aft has since this been removed.

The metal thing towards the hull edge is the zink plate, preventing corrosion.

The dive planes on the sail are fitted on one long shaft, extending all the way through the sail. Within the sail, and on the shaft, a similar servo horn is fitted. As this horn is supposed to point straight forward in order to make room for the periscopes, the dive planes are angled so that the horn points straight down while curing. This ensures that it will not slide around, and get out of alignment.

The sail- and aft dive planes can be linked to the same servo, or one of the pairs can be linked to their own individual servo, through an automatic leveler control.

I choose to link it to the aft linkage by mechanical means. (Circled in red in picture)
This images shows the magnet fitted to the pushrod from the dive plane servo.
The magnet was glued to an ordinary 3-way rod connector similar to other rod connector in the picture.

The magnet sticks above the center of the hull, so the magnet in the upper part will not extend under the lower edge, as that might damage it, when the top is put down normally. (E.g.. not up side down.)

This shows the inverted missile deck with the counterpart. The blue tubing holds a long rather flexible plastic rod.
The blue tube and the rod is called "Golden rod" and is normally used to transfer mechanical force in planes, as not-straight path are often needed.
Again, a magnet was glued to a 3-way rod connector.

This is the mechanism that goes under the sail, transferring the mechanical movement to the sail planes, inverted to the aft dive planes.
The arm on the far side will later serve as a fixing point for the wires going to the light in the sail.

Here it's fitted, and the Golden Rod is connected.
If looking into the sail (top half inverted in picture), you can see how the longer of the two arms is attached to the servo horn on the dive plane shaft.


This shows an overall view of the Golden Rod, and the entire mechanism.

The mechanism will not interfere with the scopes. (Not in picture.)

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