Friends...when a high speed craft is operated in water, taking turns is not a heavy problem, as such crafts are normaly operated at high speeds.we know,the pressure on a control surface increases when the speed increases.so, with a high pressure at control surfaces we need only a small area to control the craft.and the response also will be higher.but when we consider a semi, or fully displacement craft, its a different story.all such crafts are operated at low speeds, but high torque,the direction control properties will be far lesser.means , with a conventional rudder,such crafts responds a less.so, when we try to turn such crafts from a stand still, its almost impossible to alter the dirction from its neutral position.so we invented the ever classic device...the THRUST PUMPS..and more advanced THRUST VECTORING MECHANISMS.all these mechanisms are complicated, especially the second one.one of the main head ache is while fixing a normal thrust pump to our hull, is the specific space of the hull.it must be predesigned.as i inspired by my friends in MBMH,i started playing with my crafts seriously.soon i came up with two problems.first one was the leaves and debries...i overcame this by purchasing a plot for myself, as part of our prawn farm.after cleaning it, its OK..