It would seem funny that I would add the stern tubes as a detail item.  Well, believe it or not, it is.  The stern tubes (stuffing boxes) I got in the running hardware kit were designed to use a 3/16" drive shaft.  When I wanted to change the propellers, I found that the 3/16" shafts were far too big for the propeller diameter I wanted to use.  All of the propellers I found used a 1/8" shaft in the diameter I wanted, smaller than the shaft I had already installed.  I could have "fudged" something together, but it would not have looked right.

Although I had already installed the stern tubes and had the boat working, I decided to remove them!  With my motor tool, I cut through the hull and removed the tubes and cleaned the old epoxy from inside the hull.   I then set out to tackle a few problems I had with the Dumas struts.

The Dumas hardware configuration has the propeller "thrusting" against the strut.  The stress caused "Spider" cracks around the hull where the struts were mounted.  This caused no leaks, just looked ugly.  I wanted to have the thrust of the propeller to be supported by the stern tube and the hull.  This configuration would be much stronger.   A simple way to do this would be to add a wheel collar to the drive shaft.   This collar would be placed so it would ride up against the outside of the stern tube.

As you can see from the picture above, this arrangement works.  But the wheel collar is ugly and takes away from the appearance of the ship.  Here is the solution to my problem:

   
(    Click on image to enlarge)

So now I had a plan to tackle my problem, now I sat out to build my new tubes.  I made them from brass tubing and brass stock.   After they were soldered together, I cleaned them and rubbed them with sandpaper to rough them up.  This helps the epoxy adhere to them better.

      
       (Click on image to enlarge)

I made a jig out of plywood to support the shafts at the right height.  The hull was marked where the ends of the shafts rested.   I enlarged the holes to accept the stern tubes. 

Now slide the shafts into the stern tubes and support the end of the shafts at the transom with the jig.  Leave the shafts and jig in place.  I used tape to secure the shafts in alignment. Now add epoxy around the stuffing boxes.  I used 30 min. for this step.  Then, I mixed some more 5 min. epoxy and micro balloons to use as filler.  Add this around the outside of the hull where the stuffing boxes exit.  Trim, and sand to contour when dry.

After the epoxy has dried on the outside, add epoxy around the stern tubes on the inside of the hull.  Don't skimp on the epoxy in this step.  You want to make sure there are no holes and the joint is water tight.   I tend to add a pool of epoxy in my boats to add support to the stern tubes and the surrounding balsa (hull).

    
     (Click on image to enlarge)

Here is a picture one of my installed stern tubes.  Notice the two 1/8" wheel collars and Teflon washers.  Also note that I added a rubber grommet under the tube.  This works great when running at the higher speeds when I changed to 540 type motors.