TO BE ABLE TO READ THE DIAGRAM, CLICK HERE:http://static2.instructables.com/ID/F7S/YPXY/Q6SEP27UXHB/4AA2923407121029853F001143E7E506.gif
the rest of the pictures show the construction of the sub. It was made out of two C channels connected by an aluminum sheet. A skid was added to the bottom to allow the sub to skate over the bottom to gather quantitative video samples of the ecology. The skid and two C channels (necessary to hold the large # of sensors desired) was a little heavy so the sub had trouble moving up and down using it's one vertical motor (although there is a fourth small motor in the diagram, we never added that). You should definately be able to make the body a lot lighter so that a single vertical trolling motor will be fine.