Vesuvius Hull – Part 2

Once the hull was off the building board and well coated with epoxy on the inside and polyurethane varnish on the outside, I did some buoyancy testing to get a sense of how stable this rather extreme hull would be.  As expected, without any ballast, it floated high and turned turtle quickly.  I added ballast to the bottom of the hull to increase stability and to also get a measure of how much weight it would take for the hull to float at about the proper waterline.  I determined that 4 to 5 pounds would be the approximate capacity of the hull.  Later, I re-tested the hull floatation with the motor, drive gears, ESC, and battery in place and used paper-wrapped rolls of 25 copper pennies as additional ballast.  These rolls fit snugly between the frames and against the keel.  Eight such rolls seemed about right, but I will re-adjust later in the process as needed.

The next steps included installation of propeller shafts and the drive system.  Because of the weight limitations and the need to keep ballast low, I decided to power the model with a single 550 brushed motor linked through gears with about a 2:1 reduction in speed to the two propellers.  Power will be from a 7.4 volt  LiPo battery, again a weight saving feature.

This view shows the drive in place.  The gears used at standard Dumas gears fitted into a piece of aluminum L-channel.  The motor mount is made similarly.  The ESC is in place, and you can see some of the paper-wrapped penny rolls used for additional ballast in place.

The prop shafts were set as low in the hull as I could manage and still clear the gears.  They emerge from the hull through a long stuffing box and then pass through struts at the very back of the hull, just before the rudder.  The result is a sort of Jules Verne looking rig, which seems right for the era of the vessel and is pretty consistent with the original plan.  The propeller shafts are made up from 3/16 ” brass rod, and the stuffing boxes are 7/32 ” brass tubing.  The boxes are also built up with telescoping 1/4″ and 9/32″ tubing where they emerge from the hull to better duplicate the original.  The stuffing boxes were then epoxied to the hull with marine epoxy inside and out.

Prop shafts, struts, and stuffing boxes in place and epoxied


For props, I used plastic props of 2 inch diameter.  I cut them down to 1.5 inches and also sanded the blade edges to make them less modern in appearance and more consistent with what I thought the original vessel’s propellers may have looked like.  The propellers are notched and fit against pins soldered into holes in the shafts.  They are then held in place with 3/16″ collars anchored with set screws.

At this point, I also installed the rudder stuffing box.  I drilled through the center plywood of the keel between the additional material on each side of it and epoxied the stuffing box in place.  The rudder post will be 1/8″ brass rod, so the stuffing box was made from 5/32″ tubing.  The sides of the stern at this point were also built up with additional wood, wood filler, and epoxy on the sides.

After the preliminary assembly, above, I decided to further modify the propellers to more resemble what I thought the props on the original vessel might have looked like.  With the heavy stuffing boxes and the large diameter prop shafts, and the struts holding the props away from the hull, the ship was taking on a Jules Verne look, so I modified the props to fit with that.

This snap shows the props modified for the Vesuvius.  The original is on the left, painted bronze, and the modified props to the right.  They will be also painted bronze prior to final installation.


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.

Vesuvius – The Model

I became interested in this vessel in the late 1960’s while a member of the Philadelphia Ship Model Society.  The group toured the NY Yacht Club and visited a small store, which sold ship plans of interest to us.  There I found a plan of the Vesuvius as built and as converted to torpedo testing boat.  I was fascinated with the extreme shape of the hull and the yacht-like overall appearance, not to mention the rather unusual armament.  One of the members of the Society in prior years had served on the ship and later shared a scrapbook of newspaper clippings and other memorabilia with me.

At first, I planned a model in 1/8″ scale which would have been a convenient size for shelf top display.  I actually started work on the model in that scale as a solid hull model in the 1980s, but it ended up stowed away, largely because I did not like working in that scale.  And in the meantime, the house filled up with large models of sailing ships in 3/16″ (1:64) scale, so the size of a larger model was no longer a problem.  I am married to a tolerant woman.

After building several RC PT boats, as described elsewhere in these pages, I decided to return to the Vesuvius project and dug out the plans I had on hand for the last 30+ years.  The plans had been obtained from the National Archives, and photos from the Naval Historical Center.  I planned a model in 1:64 scale, which would be RC with electric power.  This would result in a model with a length of about 48 inches and breadth of about 5.5 inches.  A very sharp bow and stern with a round bottom results in a canoe-like shape.  No wonder she exceeded the contract requirement for 20 knot speed!

Here are the lines and some drawings of the ship I used to  layout the hull and get started.

USS Vesuvius – The Dynamite Cruiser of 1888

Vesuvius (1888)

Displacement 930 tons;

Length Overall: 252’4”; Breadth: 26’6″; Draft: 9′

The USS Vesuvius was a one-of-a-kind experimental vessel launched in 1888.  She was built by William Cramps and Sons in Philadelphia, PA and powered by two triple expansion steam engines, each driving one propeller.  The contract called for a top speed of 20 knots, and the Vesuvius made 21 knots at her sea trials for acceptance.

The main battery consisted of three pneumatic cannon, which were mounted in fixed position taking up most of the forward part of the hull.  The three guns can  be seen protruding from the deck in the photo above.  The photo below shows the guns looking forward.

The guns fired projectiles of nitrocellulose and nitroglycerine, explosives that were more stable than dynamite, but still sensitive enough to require the pneumatic cannon for firing.  The guns were fired by compressed air, and the hull also had space for large compressed air tanks, compressors, and storage for multiple projectiles.

One purpose of the design was to permit “silent bombardment” of civilian targets, rather than ship to ship gun battles.  Popular press at the time of her launch referred to the Vesuvius as the “Dynamite Cruiser” and “The Terror Ship” because the cannon were silent when fired and a target could be bombarded without warning.  The first indication of attack would be the explosion of the projectiles.

The Vesuvius participated in 8 shore bombardments of Santiago, Cuba, during the Spanish-American war.  Although some reports of the results were positive, particularly the fear induced in the civilian population, the ship was largely unsuccessful.  Aiming the cannon required orientation of the ship, as in the older former mortar-equipped bomb vessels, and the Vesuvius was also poorly armed to counter an attack from even small vessels coming out from the shore.  Vesuvius mounted only three 3-pounder guns in addition to the pneumatic cannon.

The Vesuvius had an extremely sharp hull, with an overall length of 252 feet, breadth of 26.5 feet, and draft of 9 feet.  Her lines at given below in a plan obtained from the National Archives.  The original plan is dated 1887.

Below is another contemporary plan including an outboard profile drawing of the ship, also from the National Archives.

One consequence of the rather extreme hull design and the powerful engines became evident when she was came under attack from shore based craft during one bombardment of Santiago.  Lacking adequate defensive weaponry, the ship needed to reverse quickly to escape the attackers and nearly put her stern under water due to the power of the propellers and the low freeboard astern.

As a result of the experience with the Vesuvius, there were no more pneumatic cannon equipped ships built, and in 1904-5 Vesuvius was refitted as a torpedo-testing vessel, equipped with three 18 inch torpedo tubes and one 21 inch tube.  At least one of these tubes was mounted in the hull, athwartships.  She conducted torpedo experiments for a couple of years before ending up at Newport as a station ship until sold and scrapped in 1921.