Re: Bow Thruster
This step is a little vague: "Both full-sized holes for the tunnel can now be scribed onto the hull. These holes should be 1/8" larger than the O.D. of the tube to allow for epoxy adhesive."
A little technique is involved in scribing these holes unless your hull has the form of a box. If you bend a deep "U" into one end of that long 1/4" rod such that a Sharpie taped to the outside leg of the "U" defines the radius of your tunnel (+1/8") you can easily mark the outline of your hole by rotating the 1/4" rod while moving it in/out of your center holes as required to keep the Sharpie in contact with the hull.
