Vesuvius Hull – part 1

Using the plans for the ship’s lines, which I had long ago photo-reduced to 1/8″ scale from the original plan, I first enlarged them to 3/16″ scale.

Here is the portion of the plan with ship lines showing the profile of the hull at the marked stations

The plans had about 27 stations and I simply used them as templates to cut bulkheads/ribs for the model.  Through the wonders of a copier with zoom and image reversal, I could make up full size paper patterns for the hull at the stations.

Here is the combined plan for hull sections in the forward part of the hull

 

 

 

Here is the combined plan for hull sections in the after part of the hull.

 

 

I extended the ribs and keel as described below to extend them and allow them to be glued to the building board, then glued the patterns onto 1/8″ birch plywood from a hobby shop and cut them on a scroll saw.  I did the keel similarly.  I glue the paper onto the plywood with school glue, so the paper can be removed easily after cutting.

I use the “Hahn Method” to build the hull.  The hull is framed upside down by gluing to a building board, and is planked while still on the board.  Then the hull is cut free from the board and further finished off.

To use this method, it is necessary to extend the ribs and keel as above to a line corresponding to the building board. The Vesuvius has a hull with a long run of a straight horizontal keel, so it is particularly easy to use this technique.  First I drew a line on the plans about an inch above the top of the sides and a similar line on the side view, above the keel, making certain the location of the lines corresponded.  Then I extended the patterns for ribs and keel up to that line and cut the ribs out with a scroll saw.  I cut away the center on most of the ribs, leaving about a quarter inch thick rib along the side, and half an inch at the bottom, and notched the ribs to fit on the keel.

A 7″ x 48″ piece of half inch plywood from another project made a fine building board. I drew a line for the center of the hull/keel, then marked off the locations of the stations using the plan.  Then lines for the stations/rib positions were drawn perpendicular to the center line, and longitudinal lines at half and one inch intervals parallel to the center line.  These lines make and easy guide to positioning the ribs and greatly speed up the process.

In this photo, I am starting to set up the frames on the keel.  The small squares used to true the frames are above, and the remaining frames are lined up ready to glue in position.  The center frame in this photo is not glued yet, but is just holding the keel upright as the frames are glued into place starting at the bow.

Once the keel was spliced and set up on the board, the ribs were added working from front to back and using a small square to make certain they are perpendicular to the board.  The ribs and keel ends are glued securely to the building board.

The ribs are in place and ready for the planking.   At the stern, there are additional plywood pieces glued to the keel to accommodate the rudder shaft to be installed later.  The stern is so sharp, the rudder installation needed to be modified a bit, as will be discussed later.  At the bow, the keel is stepped up at the location of the most forward frames until it is at the height of the deck beam.

After the glue has dried, the hull is planked with 1/16″ thick pine planks, 1/4″ wide.  I cut the planks from 4 foot pieces of quarter inch think pine, available at the local lumber/hardware store.  Using 4 foot lengths of planking allowed me to run the planks the length of the boat and eliminated the need for butt joints in the planking, except as noted below..

Since the original vessel was made of steel plated riveted to steel frames, the wooden planks running longitudinally are hardly authentic, but it was an easy way to get the job done.  I ran several planks along the keel, using a slightly wider (1/2″) plank for the first plank, tapered fore and aft to fit snugly against the keel.  A garboard plank, if you will, as shown in the photo above..  These were only 24 inches long, as that is what I had on hand.  I followed with the first of the 48″ long 1/4″ planks.  Then I ran several planks along the top of the sides, and began to work down from that point, beginning to taper planks as needed to accommodate the shape of the hull.  Again, not the way I would normally plank a wooden hull, but quite satisfactory for this model.

Once planked, the hull was sanded, given two thin coats of epoxy, and then given several coats of polyurethane varnish.  Once the hull is varnished, it is cut free from the building board.  With the hull off the board, I made up a couple cradles for the hull and glued them to the board to hold the hull for the next steps.

 The hull cut free of the board.  The next steps include some additional planking along the top of the sides, trimming off the extraneous rib and keel material above the side, and epoxy coating the interior of the hull.