First Parts: Stern Planes

To create masters, the process we've settled on is to draw up a part then send the drawing to the team member who wants to tackle it. Matt is doing the drawing in AutoCad then importing the geometry we want to model in 3D into Rhino. All of the correct cross-sections are then extracted out of Rhino and sent back to AutoCad for final documentation. We've begun to realize we are going to have a tremendous amount of data on our hands, not only of Wahoo but fleet boats in general, once the project is completed.

The first part selected were the stern planes. As I planned to take on the creation of the master I started to search for photos and plans. Matt and I agreed that the Floating Drydock drawings looked a little suspect.

What is interesting is you think you have an understanding of something then when it comes down to wanting to know definitively what it looks like you didn't really know as much as you thought you did. My experience with fleet boat stern planes is they have a certain shape and are flat in profile with tapered edges, like bow planes. This was reinforced by the planes in the Revell Lionfish kit and the Scale Shipyard Gato parts.

Since most all existing museum boats are either in the water or ground we couldn't just jack one up and take a look. We combed through the image galleries and got some good shots from Wayne Frey who spent some time last summer photographing USS Drum in Mobile. She is jacked up -- permanently resting on concrete blocks. Below is a shot of the starboard stern plane of USS Bonefish taken prior to her launch.

We discovered the stern plane geometry was much more complicated than we originally thought. The stern planes had a definite airfoil shape, tapered to a knife edge on the trailing end and slightly rounded on the leading edge. The outboard sides were flat but significantly thinner than the root. The pronounced taper from root to outer edge along with the fore and aft foil shape makes for a complicated piece. As a result the drawing will be sent to Tom Anderson in California and he will CNC the port and starboard masters for us. This will ensure all the curves are true and both port and starboard planes will match perfectly. Matt did an excellent job drawing the part. Here is a perspective from his work.

For those familiar with the stern planes of the Revell Gato in 1/72, you will notice that it does have a foil shape to it. However, the part is a constant thickness across the span giving it a chunky outboard edge.

Once the masters are CNC'd then we will detail them with the appropriate weld lines.

PHC