It hasn't hit the streets yet, but I was able to test the newest rudder specifically designed for shallow water operation. Obviously related to Hobie's large rudder, it is one third shorter yet still retains 4/5 the surface area of its larger cousin. In the test model I made some depth marks to see what the actual draft is with the Revo 11:
The first test was to note the actual draw on this rudder. It varies slightly by boat and application but in this case, it is about 8.5" standing and 9.5" at about 3 MPH (probably the fastest you would want to travel in shallow waters).
This shows the bottom silt sticking to the paddle at about 8" depth and Drive installed but pinned up. If it gets any shallower, you can get out and walk!
Next, I took the little Revo to the busy San Diego Harbor to see how the rudder responded in tide, wind and confused seas. I apparently must have been transported into a major navel gun battle where the rudder got put to the test of avoiding getting blown out of the water amid this obvious predicament! In exiting, you can also see here there was plenty of choppy water. Maneuverability was excellent and there was no lack of "bite" at any time.
Back at the local lake, I checked out low speed operation. Like the full size rudder, this has "0/0" capability -- I can execute a 360 degree turn at a dead stop, no wind, calm water (hint look up "sculling" or Yuloh" for an explanation). Likewise, this rudder can back down in wind while retaining directional control then execute a 180 degree turn (with practice). Excellent job.
Finally, using the rudder as a skeg, the Revo 11 was paddled around the lake without any tracking issues. As some of you know, the Revo 11 is probaably the least directionally stable of all without effective rudder control. This is a rudder that if adjusted properly (no slack in directional control) it holds the boat in position with little or no corrections.
In my experience with various rudder mods, the Hobie large rudder can lose up to 35% of its area and still perform all of its functions without degradation. Talk about being over sized. This allows various custom applications of the rudder without losing any noticeable authority.
In summary, the "Phat Albert" is an excellent shallow operation rudder without sacrificing any other functions. I would recommend it for anyone who wants a rudder that doesn't need to kick up in shallow water. Unfortunately Hobie is out of stock on these rudders until further notice, but you can make your own version by ordering a large rudder and loping 4.25" off the bottom. I think the price is about $34 plus tax these days. FYI, this rudder is actually one inch shorter than Hobie's small rudder while providing vastly superior performance.
Edit: To be perfectly clear, this is not a Hobie factory option, but a DIY project. Here are a couple of pics showing how it is easily made:
Works great in all respects except in reverse the max safe speed limit is about 2.5 MPH
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