So when surfing the web looking for outrigger plans, I came across this boat--the Cobra. Link is
http://www.john-tom.com/RCPowerBoats/RCPowerBoat.html (scroll down to see it).
Given my model airplane background, I couldn't resist, so away I went. I must say boats do seem to build faster than aircraft.
Anyway, it was designed as a catamaran but without a step in the hulls. Overall size is 35" long plus a couple of inches for the rudder and 15" wide at the widest point. It was designed for engines, so rpms would be limited to the 10-12K range, depending on the engine. Seemed like a good candidate for an electric to me, as I can use a high Kv outrunner on 5 or 6S with a small diameter high pitch prop--which should really make it move.
Given the beam, I felt it looked more like a hydro than a cat, so proceeded to make it more like one. I added a step, 1.5 inches in front of the CG, and also put a mini-sponson in the back, a la a rigger. I felt this should make the boat get up and go (pun intended). Given I am adding in what I expect will be more power via an outrunner, I decided to rename it to "Super Cobra" Besides, if it doesn't run well, I can always convert the hull back to the original no-step cat design--but I don't think I will have to.
However, as I am not really a boat guy, I do have a couple of questions for input.
As shown in the picture, the boat has an air rudder that extends into the water. Should I maintain this, or maybe just go with a water rudder only (King of Shaves style rudder, maybe? or something else?) I think I at least want to keep the original if only for the looks, but if there is info that says otherwise, I do want to hear it.
The other picture shows a center mounted turn fin. Again, should I keep this? And since I expect performance to be jazzed up a bit over the original, should it be deeper? Plans show a fin that extends 1 3/8" below the hull. Again, my lack of FE experience shows, as I don't have a clue about turn fin size and depth.
Appreciate any input and opinions--and when I get it on the water, will be sure to mount a GPS and get a speed. Thanks…Pete M
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