Hatching an Alligator

The pictures below are of David Merriman's model; Tim Smalley's efforts on a model of de Villeroi's pre-Alligator salvage submarine are catalogued on his website, "Modeling de Villeroi's 'Alligator junior'."

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Explanations for each
picture are below.




Click on any picture to
link to a larger image.

1. The diver's hatch is shaped from a block of RenShape material.
2. The hull curve is lofted from the area of the diver's hatch using five layers of 7oz fiberglass cloth, the RenShape block carved to fit, and a master "puck" made from which to vacuum form the actual hatch.
3. The drop-pen compass is used again to mark the circumference of the main hatch on layers of fiberglass clothe which will serve as the flange around the conning tower.
4. Note the conning tower in foreground. This was created from RenShape on a lathe and hollowed out to the final diameter.
5. Details of drop-pen compass and main hatch flange after removal from hull.
6. Tools used to trim and shape the fiberglass flange.
7. Fitting the conning tower combing to the hull . . .
8. . . . and the dome.
9. Port hole flanges for the conning tower were turned on a lathe and, with the brass piece still in the chuck, holes drilled to later accept rivets.
10. Returned to the lathe, the porthole flanges are parted into individual pieces.
11. Parts of the diver's and main hatch and conning tower before assembly.
12. Main hatch.
13. Preparing the propeller shaft for the process of creating the shaft and blades and mounting on the hull. This shaft is one of the conjectural elements on the Alligator model. The 1861 version, of course, had no propeller since it used oars for propulsion. During the 1862/63 refit, the propeller was added--but were the rudders moved to accommodate it or was the shaft extended beyond the rudder? Adding a propeller extension seems the simplest solution . . .
14. After alignment, the prop shaft is pressed against the stern with carbon paper sandwiched in between to show any points that do not align.
15. Diagram of the propeller shaft and rough pieces of the propeller blades.
16. Final prop blade is mounted vertically and the mold container set over it (clear cylinder to right) and sealed with clay. Silicon rubber is poured in and allowed to solidify.
17. After removing master blade by slicing the mold along its vertical sides, the mold is resealed with rubber bands, and Alumilite resin is poured into the cavity through the prop shaft that had been allowed to protrude through one end of the mold. Also shown are a number of the poured blades.
18. Prop blades are mounted onto the hub at identical angles by affixing each one to the shaft while it lies atop a bed of clay.
19 & 20. Views of the final propeller and shaft.
21. Mounting the final propeller and shaft onto the hull.
22. Figures, hatches, portholes, propeller, and rudders.
23. Plans and parts for the diver's helmet.
24. Diver and helmet parts.
25. Final helmet. This is the Miller-Dunn style helmet, which is not evidenced officially until after the Civil War. The standard deep sea diver Siebe helmet would have been too large and cumbersome for the diver to have used in moving through the hatch. Another alternative is a leather helmet first created in Paris for firemen to use in smoky buildings; de Villeroi may have been aware of it. The US Navy also experimented with a leather diving helmet, but, officially, not until 1863.
26-30. Views of the diver as he nears completion. Married to the air hose is the lifeline that anchors the diver to the submarine.
31 & 32. Marking out the buoyancy tanks with the drop-pen compass.

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