In HG Wells ‘War of the Worlds’ the HMS Thunderchild is only human creation to defeat a trio of Martian Tripods. The ship, described as an ‘iron clad torpedo ram’, charges three Tripods attacking a of fleet London evacuees at the mouth of the River Blackwater. Thunderchild rams one Tripod, destroys another with her guns, and consumes the third when her boilers explode.
The story of the Thunderchild is romantically British. A brave Royal Navy ship sacrificing itself for King and Country. What makes the story even more intreseting is that the ship is a Torpedo Ram, which is something of a historical fluke.
Torpedo Rams where an extremely short lived class of small warship in the 1880’s. They were small heavily armoured ships intended to attack enemy battleships at high speed with torpedoes and, if that failed, ramming. Like most novel weapons, they were great at capturing the public's attention and not much else. Only one was ever build, the HMS Polyphemus, and War of the Worlds is the only depictions of a torpedo ram in action.
For my version of Thunderchild I drew inspiration from the SMS Beowulf, a German ship and really life contemporary of Thunderchild. Launched in 1890, she would have been in the prime of her career during the 1899 War of the Worlds. The ship had a sloped hull and a bow with a reversed rake, broadly matching a torpedo ram’s shape. Beowulf’s artillery was mounted in twin side by side turrets, an anachronistic features that places the design firmly in another time.
Modeling the Thunderchild
Most of the ship is simple polygonal shapes, easy to model in Sketchup, but the hull presented a some special challenges.
The center section is a simple extrusion. I used Fredo 6’s ‘Round Corners’ plug-in to start the curvature of the bow and stern, then stretched the resulting geometry into shape with Fredo 6’s ‘Scale Tools’.
To create the reverse rake of the bow, I drew the basic curve and used Eneroth’s ‘Upright Extrude’ plugin to extrude it along a path while keeping the direction of the curvature constant. I intersected the resulting shape with the hull, and cut away the excess.
The ships stern proved to be more challenging. I made a section of the hull into a separate group and squashed it with Sketchup’s scale tool to create the bottom of the aft deck. (blue in the illustration) The transition between the hull and propeller is an extrusion of the hull profile along a path using ‘Upright Extrude’. (Teal) The final part is the proper shaft tunnel, which brings the two sides of the hull together and hides some of the less optimal parts of other shapes. (Magenta) Once I had all the geometry, I intersected the shapes and cut away the excess.
The rest of the modeling was straightforward. I used the basic sketchup tools to create the upper decks, superstructure, armaments, and lifeboats. The only exceptions are the three large turrets. They started as cylinders that I used Fredo 6’s ‘Round Corners’ and ‘Scale Tools’ to bend into shape. Everything was build as components, then exploded and attached together to make a single unified mesh.
Printing the Thunderchild
For this project I used a Formlabs Form 1+ desktop SLA 3D Printer. Desktop SLA printing is great for small highly detailed models, but is limited to smaller build sizes. The Thunderchild model is 200mm long, which puts it at the upper limit of what is possible with a Form 1+. I had to position it runing corner to corner at about 45 degrees to fit it into the build volume.
I used Meshmixer to hollow out the interior of the ship add drain holes in the stern. Hollowing the ship makes it more efficient to print on the Form 1+, and the drain holes let excess air and resin escape. The support structure was created by Formlabs Preform software. Print time at 100 microns is about 6 hours.
Removing the support structure was tricky, some of the supports where larger than the parts of the model they were supporting.
I gave the ship a quick coat of gray primer to even out the color and bring out the details. What amazes me about SLA printing is the level of detail you can get. The small cannon barrels are less than 1 mm in diameter. The little detail like stair treads, ventilators, and lifeboat dericks really bring the ship to life. Its not hard to picture a tiny crew running to get the Thunderchild ready of battle.
Download the Thunderchild from Thingiverse and print your own!
Thingiverse Link: www.thingiverse.com/thing:775961