Rational Report

Rationale Report for ROV Alternate Solutions

            During my research that I conducted on my portion of the ROV design and building process, I came up with several alternate solutions. These alternate solutions are the ideas and designs that I am choosing from to design my ROV after. They are a triangular prism shape, a cylindrical shape, a cube shape, and a rectangular prism shape. These solutions are the result of lots of research and contact with my mentors. The next step is to choose the best solution to move forward with and why.

           The first solution is the triangular prism shape. ROVs come in all shapes and sizes and triangular is no exception. The triangular shape has some advantages. It could possibly aid in the water physics behind propulsion because the point on the triangle could aid in being hydrodynamic. This allows for easier movement in the water. This design also has some cons to it. Because of the unusual degree measures of the angles for the triangle, it would be hard to find pieces already made. This would mean that they would have to be specially ordered or made with a 3D printer or other means of creating or molding plastics. This solution while very hydrodynamic would be costly and hard to manufacture and build if done incorrectly. Some of these problems are fixed with the next alternate solution.

            The next alternate solution is the shape of a cylinder. Cylindrical shaped ROVs have been used several times before, even by the US Navy to aid in the destruction and combat of mines. This shape has the unique property of providing the least drag out of all of the solutions. The rounded sides allow the vehicle to move through the water with the least resistance. This allows it to move easily in the water using the motors to propel it. It also has parts that are easily obtainable which cuts down on cost. This shape comes with its own set of disadvantages as well. The cylindrical shape poses the problem of finding a place to attach the instruments and motors onto. But if done correctly, this is a minimal problem. The real problem is that of buoyancy. The round shape makes it hard to get the ROV to sit correctly in the water. The next ROV does not have this problem with buoyancy or of motor attachment.

               The next ROV that I designed was the cube shaped design. The cube is a 1’x1’x1’ design and is made out of PVC piping. This design is a very simplistic one but is easy to make and produce. The parts are easy to find and buy and are not that expensive. This cuts down on the cost and the struggle of trying to find parts. It also has plenty of space to attach motors and the claw appendage. However, even with all of these advantages, it does have some bad qualities. First of all, it is not as hydrodynamic as the other two solutions before this. A square is obviously not as dynamic as a cylinder or a triangle because it just has the same six faces on all sides and not curves or pointed edges. It is also a smaller design than the others. The cylinder is a little elongated and the triangle is as well. This could be a hindrance or an advantage depending on how you look at it. I believe that the next solution offers the best of all of the solutions in one package.

           The next solution is similar to the last one in that it keeps the basic cube shape; it is just elongated by a half foot. I would call it a rectangular prism shape. The design is a 1-foot tall, 1-foot wide, and 1.5 feet long. This provides the shape needed to attach the motors and the elongation needed to stabilize the structure. This shape also does not have most of the disadvantages that the others do such as the rolling problem with the cylinder or the part problem of the triangular. This cuts down on cost and adds to this solutions viability. This shape design, while it provides many advantages over the others, it isn’t without its fair share of flaws. It is still not as hydrodynamic as the cylinder or the triangular shaped design. This could cause me to have to use better motors to propel it through the water.

            Out of the four shapes discussed in this document, there is one I am moving forward with. This design is that of the rectangular prism. This design allows for motors, propellers, the mechanical claw, and anything else like the electronics to be attached easily and with plenty of room so nothing is tight together. The design does not cost as much as some of the others would. The parts are also pretty easy to find and put together. Not many adjustments would be needed to fit them together and putting holes in the PVC to attach parts would also be very easy. My mentor was the one who recommended this shape to me because he built an ROV in this shape and he told me it worked very well for him. That is why I am moving forward with this design and am now going to do research on building this part and the parts I need such as PVC piping.