KJGCT1

I have a plan for an outrigger boat I have been thinking of building. It is big, 36" long, and of I would be building it for fun. My question is can I build the boat to turn well in both directions? If the boat has no turn fins will it turn? I read that a turn fin on each sponson will not work. Has anyone seen one built that turned equally well in each direction? When I was 12 I sent away for a boat plan for a real boat. It was basically the same as a RC Outrigger. It had "chines" on the outriggers, they were pieces of 1/4" aluminum that ran the length of the sponson and extended 6" below the sponson. The boat handled awesome, my dad said it turned so fast it was a pain in the neck! When I was sanding the boat the old man across the street asked what motor was I going to use. I did not have one. He went home and came back with a 15 hp Mercury. So I sprayed the boat bright red and when we put it in the water my dad and my brothers. They got in my dads ski boat and when I took off I left them in the dust....spray! I slowed down and they caught up and my dad said that boat must do 70 MPH! Dad put a governor on it, but I was the only 12 year old on the lake with a boat that did 50!
Any ideas would be appreciated!

Hydro Junkie

In a word, NO to all of the above. Riggers only turn to the right while at speed. That is due to the fact that the prop is only half in the water so it will act like a paddle wheel, pushing the back of the boat to the left and forcing the boat to turn right. As far as being able to turn without a turn fin, the boat would only slide sideways across the water. The fin is a anchor that holds the front of the boat from sliding, not to mention that it acts as a pivot point that the boat turns around. When it comes to dual fins, that's asking to flip the boat. The fin on the right side acts like a string on an airplane, all the weight is outboard of the attachment point. If you try to turn against the fin, the boat will literally trip itself on the outside fin, ending up either upside down or cartwheeling across the water.

I'm glad your experience with the boat was positive. We have a program at the Hydroplane & Raceboat Museum, in Kent Washington, that is similar to your building the boat. You can read about it here:
https://thunderboats.ning.com/page/j-hydro