REFURBISHING THE NAUTILUS MINISUB

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“Two steps forward, one step back.” The plans we made our replacement raker arch from weren’t accurate. The underside of this arch curves too far down before meeting the wheelhouse, and the arch itself is too wide in that area. The movie NAUTILUS isn’t like that.

This is an excerpt from the plans we made our replacement raker arch from, reversed for comparison to these photos. We took these to the local blueprint shop, had them enlarged and printed, and used that for the template from which the actual part was made in steel.

Here’s a look at the Disney SFX NAUTILUS model from approximately the same angle. Even taking into consideration the visual difference between plans and photographs of a three dimensional object, it’s plain to see the curvature of the 11-footer arch is different from the plans we used, or the replacement raker arch we produced. So, it had to go.

Here’s a view of the exposed wheelhouse pressure hull after the inaccurate replacement raker arch was torched off and scrapped. Fortunately, now we have better graphic references, so the next arch will be right. This might seem trivial to some, but a proper raker arch is critical to how authentic the sub looks when surfaced.

We also scrapped our wheelhouse pressure hull cover. I made this sheetmetal cover several years ago, without good plans to work from, before the shape of the light housings became an issue, and without an accurate raker arch to compare it to. So, there were some inaccuracies here, too.

But we really decided to scrap this piece after determining that, at the high speeds we’ll be traveling with the new propulsion system, this thin metal shroud would be torn apart by the hydrodynamic flow.

“High speeds?” Have I let the cat out of the bag? Watch and see, Leagues fans! J

Here’s a rather poor quality candid shot that was taken in the shop. The yellow object in the foreground is my Corvette. Beyond that is my Harley. And the camouflaged item behind the motorcycle is a Kawasaki Jet Ski that was used in the filming of Kevin Costner’s WATERWORLD here on the Big Island a few years ago. Hmmmm….three interesting sources of propulsion. Might any of them end up in the submarine? Only time will tell. J

Besides any plans for exotic propulsion we might have for the NAUTILUS MINISUB, we definitely wanted an improved electric motor system; so we bought the biggest one Minn Kota makes. This is a picture of the motor mount for the electric drive motor. I “relieved” the metal considerably, to reduce weight and minimize the ferrous mass around the motor’s magnetic field. I’m still thinking about it, though. Might just torch this assembly off and replace it with one made from aluminum.

Here’s something I always wanted: an externally-accessible air inlet valve concealed under the aft deck structure. There’s just a whole lot of reasons why we want one of these, but most of them have to do with safety and survivability in emergency situations, keeping the NAUTILUS from sinking while being towed, raising the sub if it ever sinks, and little things like that. Real handy little item here.

And while we’re talking about improvements to the sub’s valve system: this is one of two remotely-located emergency valves for the aft ballast tanks. When we first tested the submarine, I would have had to crawl back into the tailcone to actuate the emergency blow valves. That could be tricky if the sub was at an unusual attitude. So, I had thought to make this an electrically operated solenoid valve; but when it comes to emergency equipment, I want it as simple and reliable as possible. So this valve is fitted with a bell crank that will encorporate a linkage rod assembly, so I can operate it manually from the pilot’s station.

Other improvements to the submarine deal with life support and cabin ventillation. Here’s a look at the components for a blower assembly: basically, the 12-volt heater fan motor from a Chevy truck, and a homemade steel housing. Sort of like a great big hair dryer.

Here, the blower assembly is together and running off a battery. The blue tape around the exhaust has several threads attached to indicate the air flow. Trust me: these babies BLOW, and will aggressively ventillate the passenger compartment. There are three of these altogether. When surfaced, one will intake from the cabin and exhaust outside the sub; another will draw fresh air from outside into the cabin; and a third will provide maximum CO2 scrubbing capabilities (when submerged) in an emergency.

This is the emergency CO2 scrubber. That black cylindrical object at the intake of the blower is a filter cannister filled with SODASORB carbon dioxide absorbant. Under normal operating conditions, we use something much more passive than this: a small, very quiet, low volume fan which operates occasionally to pass the cabin atmosphere through a scrubber filter of its own. One of those is all we need; but there will be two on board. The high-velocity brute shown above is actually overdoing it, but if the need ever arrises to rapidly circulate and cleanse the atmosphere of excess CO2, we have that capability. This falls under the heading of “Better to have and not need, than to need and not have.”

This is a separate battery box for the emergency blower system. (The grid is just the table I do my torch-cutting on.) Nothing fancy here: just a box welded together from pieces of steel.

While we’re talking about electrical components, this is a very simple wiring harness through-hull: it will be packed with watertight material, and accommodate a wire running from the pilot’s control panel, out through the pressure hull, to the external lights of the salon window fairing.

Here’s another wiring harness through-hull. This one’s mounted on top of the “wheelhouse” portion of the pressure hull, and will accommodate the wiring for the “aligator eye” headlamps.

And, being the great fan of Jimi Hendrix that I am, here’s a picture I call PURPLE HAZE. It’s just an interesting visual effect that occurred spontaneously when I was shooting some video while welding a fitting for the pilot’s “last ditch emergency breathing tube” assembly into the pressure hull. I thought it looked kinda cool, so what the heck…here it is.

Working with large, heavy objects like submarines is sometimes dangerous. Accidents do happen. One night, while rotating the sub on its roller cradle, the cable and pulley system supporting the tail section failed and she fell, bending the port side prop guard.

In this scene, the damaged prop guard half has been removed and is staged for the camera prior to repair.

I try to use the handiest expedient means available when I work. To reshape the damaged prop ring half, I applied “gentle persuasion” with a rubber mallet (to avoid metal hammer marks) while positioning the piece in the control cutout of a horizontal fin. By adjusting the curvature one way or the other, the original arc is recreated. (Yeah, I know…the sub got rusty. No problem. It’s thick steel, and the oxidation will come off with a wire wheel before we repaint. And anyway, what’s a NAUTILUS without some rust? J )

Once the cold forming is complete, the prop guard half is clamped to the undamaged ring, to hold it in place while being stress-relieved with an oxy-acetylene torch.

“Stress-relieving” is the process of applying heat to rearrange the molecular structure of the metal. This “undoes” damage imparted during all that banging and bending, so we don’t end up with stress cracks later on after the part is in use and subject to vibration. The idea is to return the metal to a semi-plastic state. When cooled, it will have no “memory” of the damage incurred in the accident, or the stress imparted during repair.

Here’s the repaired and relieved part: it’s been wire-brushed to remove the “scale” of heating, and tack-welded into place. A little more welding and finish grinding, and she’ll be as good as ever.

I hear this a lot: “Why doesn’t it have any rivets?” It made sense to get the NAUTILUS operational before we got deep into the scale exterior detailing. But actually, there were some simulated rivets on the sub right from the start. The above-waterline plating has faux rivets at the panel lines, like those shown above. These were simulated with small tack welds.

PROPULSION SYSTEM IMPROVEMENTS

The NAUTILUS MINISUB is becoming a dual-drive submarine: the electric motor has been upgraded to 36-volts and 101-pounds of thrust; and an Engine-Driven Jet-Pump drivetrain is also being installed. The new E-motor will provide greater speeds under silent running while on the surface or submerged. The Hydrojet will enable longer range and greater maneuverability during high speed surface operations; and also short term / high speed runs underwater.

This is a Kawasaki jetski that was ridden by one of the “smokers” in Kevin Costner’s WATERWORLD, filmed at Kawaihae here on the Big Island back in 1994. I bought it several years ago, and it’s been sitting for quite a while.

The ski actually ran when I first got it, but it smoked a lot and there was some gray oily crud coming out of the exhaust. (Maybe something they added to make it smoke more for the movie?) Here’s a look at the engine, with the carburetor flame arrestor, waterbox, and fuel tank removed. Looking pretty tired!

With the ski rolled to starboard and both the intake grate and cover plate removed, we get a look at the jet pump. It’s seen better days, too. (NOTE: Usually, you should roll a jet ski to the port side to avoid the chance that water in the exhaust might drain into the engine. This ski has been sitting for so many years it’s bone dry. And, the engine’s getting rebuilt anyway. So rolling it to starboard for this photo posed no problems, and was convenient in these surroundings. Don’t do this with your ski, though.) I could probably pull this stuff out of the ski, install it in the NAUTILUS MINISUB, and make it work as-is. But for something this important, that would be foolish.

The heart of the propulsion system is, of course, the engine. Here’s our long block, completely rebuilt and ready to go.

Our newly rebuilt jetpump, driveshaft, and bearing box. Compare this to the image, two pictures above.

The stainless steel driveshaft spins at up to 6,000 RPM. A rebuilt bearing box is an absolute necessity, and now this one turns nice and smooth, just like new. The bearing box is also the watertight through-hull for the driveshaft: another reason to make sure everything is in good working order.

The intake of our newly-rebuilt jetpump with a high performance SKAT TRAK impeller installed. Notice the machining inside the housing, and the close fit of the impeller vanes. Necessary for peak performance. The entire pump, steering nozzle and all, only weighs 10.8 pounds.

They say “Chrome don’t get ya home”, but this carburetor flame arrestor is polished aluminum, and we figured the rebuilt engine deserved a little bling. I’m thinking of grinding the name KAWASAKI off, polishing that panel, and engraving a NAUTILUS image and /or the words NAUTILUS MINISUB into it. We’ll see.

Here’s the flame arrestor sitting atop a rebuilt 40mm MIKUNI BN-44 Jetski carburetor we bought for about the price of a rebuild kit alone. Low hours, and came off a running ’89 JS-550 like ours.

THAT’S ALL FOR NOW. MORE REBUILD PICS TO FOLLOW.

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