Engel's Akula II - 1/125 scale
by Ralph Fendley (Ralph --- SSBN 598) SubRonLA
November 2017, I ordered and received this boat from Engel. It took me 21 days to assemble it ready for water trimming. I work no more than 2 hours per day on this kit. It is not a build. It is an assembly or parts pre made and almost pre fitted except some small parts.
Follow the instructions and fit all parts before committing to final assembly. There are a couple of places that making a change in the instructions helped tremendously. Wiring for an example. Instead of a black and red together, try a red a black together but of different sizes. This was a suggestion from another builder with much more experience. In fact it was this man who had already assembled 2 of these boats at the same time that got me to buy this boat. He suggested the wire method.
Back to the rudder modification.
Now for the dislikes.
I finally became so frustrated, I modified the rudder. My approach was to remove 1/4" of the rudder skag and extend the rudder forward in to the water flow in front of the rudder shaft.
This reduced the turning radius to about 24'. A little more than 10' reduction. I ran the boat about 6 months with this modification. But the turning radius is still too much.
Some where I read about river log tugs having a fishtail rudder for quick maneuvering of logs rafts. So I looked in to it farther.
Well it was simple enough. Just a couple of angle iron extensions at the very back of the rudder. Then I found an engineering chart showing numbers of straight and fishtail rudders. Comparing the two There were several variations of size for the fishtail.
Out on my work bench I measured the Akula II rudder and guess at how big to make the extension. I picked up some scrap pieces of 1/16" thick sheet plastic from the trash box. And I proceeded to make an extension with plans to make it removable.
Here is the original rudders on the Akula II.
Here is the planned modification.
I started beveling the two fishtail strips.
Once the bevel was straight and 45 degrees, the strips were cemented
to the rudder piece.
After trimming to shape, I used a very small round file to shape the
I used .028" piano wire to drill two holes in the new rudder and matching
placement in the original rudder.
Now this is where the reward comes.
First test was running on the surface. Before, to make turns the boat
had to be desks awash or the turn was wider.
Stop the boat and trim it at periscope depth. Continue the slow run. The boat turned a 6' to 7' circle. Now turn in the other direction. Same thing again.
I spent the next 2 hours making small circles in front my chair. Surfaced, submerged at various depths.
I can not believe how well the fishtail rudder extension works. Something that took me all of about 2 hour to make including glue curing time and painting repair.
My Skipjack turns a little quicker but not by much.
Now the Akula II spends more time at the lake. It is a pleasure to run. . . NOW.
This fishtail rudder extension turns a 35' radius in to a 7' radius.