CG Model of the Sturgeon-Class Short-Hull Submarine

[CDR_Ret]

Rather than continuing to clog up a thread on the features and foils of the DELFTship modeling software with my personal project, I decided to move the relevant posts regarding the project to a separate thread.

 

If Admins can move the original posts and responses to this thread, that would be appreciated. Otherwise, not a biggie.

 

The original posts can be found at the following links:

 

Hull against background plans.

 

Seven-bladed screw.

 

Stern Planes and Control Surfaces.

 

Follow-on progress will appear here.

 

Does this qualify for a "build log?" 🤔

 

Terry

[CDR_Ret]

Took a few hours this weekend to build the submarine rudders and the stern light.

 

 

The Sturgeon balanced rudders acted together on a single shaft. The lower rudder worked as a standard rudder when the ship was surfaced. Submerged, the upper rudder added twice the turning leverage. Let's just say that these SSNs were pretty nimble when submerged. At a flank bell, you had to hang on during the turn!

 

Sturgeons had a single, combination stern light housing. The lower enclosure provided the screening needed for the 135-degree stern light used underway. The upper lamp was the 360-degree aft anchor light. Both lamps were in pressure-proof globes rated to the ship's maximum operating depth. The light to be illuminated was selectable from inside the ship.

 

 

Terry

 

 

[ccoyle]

One of my dad's former students was stationed aboard USS Aspro (SSN-648), a Sturgeon-class boat.

[CDR_Ret]

Continuing to work from aft to forward, today is the towed sonar array tube and faring.

 

The Sturgeons were already being constructed when the US submarine force received their towed arrays. These sonars were towed a long distance behind the ships to remove the receivers from the vicinity of the largest sound source in the area—the towing submarine itself. So the early towed array systems were add-ons for the Permit-, Sturgeon-, and the Los Angeles-classes. (The towed array systems for the Sea Wolfs and Virginias are totally internal.)

 

The handling gear for the array cable was installed in a forward ballast tank and the sonar array itself was stowed in a long tube that led to the stern planes. The "flushing tube" laid against the hull and was covered by a low fairing topside. The aft end of the tube had to extend far enough aft so that when the ship executed a sharp turn, the array wouldn't be cut off by the prop. (The Soviets solved this problem by putting their array and handling gear in a pod on top of the vertical stabilizer of the rudder.)

 

The sonar tube was called the "flushing tube" because the array was deployed and retracted by pumping water through it to "flush" the array out and lubricate its retraction.

 

The most difficult part of modeling this component was the topside flushing tube fairing, which twists in three dimensions as it lies along the hull.

 

Sturgeon Class Towed Array Flushing Tube and Support

 

 

Aft view of the Towed Array Flushing Tube

 

Towed Array Fairing

 

Modeled in DELFTship

 

Terry

[CDR_Ret]

Working on the escape trunks, now that the grandfather journals have been delivered to all the cousins and siblings...

 

The Sturgeons had two escape trunks. These acted like airlocks in spacecraft to allow emergency egress in case the boat was bottomed for some reason. The only difference is that there is high-pressure sea water outside instead of a vacuum.

 

Basically all US submarines following WW II had the capability to mate with the McCann rescue chamber. This required a flat surface surrounding the upper escape hatch fairing, which was equipped with a haul-down bale, external hatch operating gear, and, later, anchor points for the Deep Submergence Rescue Vehicle (DSRV) snubbers. The flat landing surface on the albacore/cylindrical hulls had to be faired into the hull shape.

 

So, I tried to illustrate all of these features in this model. The haul-down bale was actually attached to the emergency buoy cable, which was manually released from inside the ship. The buoy carried a cable to the surface of the ocean, to which the rescue device was attached by divers. The DSRVs used the cable to visually guide the vehicle to the stricken sub. The DSRV would mate to the hull above the hatch, then attach snubbers to the four rings to steady the vessel before blowing the skirt dry and entering the sub. In truth, this is a lot of surmising, since none of my boats ever went through a DSRV drill or deployment exercise.

 

Location of the fore and aft escape trunks. The forward trunk was in the bow compartment and the aft trunk was in the engineroom.

 

This is the forward escape trunk landing area. I had difficulty modeling these because I don't recall them being so prominent. But there were other things surrounding them like safety tracks, so perhaps they were.

 

The aft escape trunk.

 

Since the upper parts of the escape trunks and hatches were located within free-flooding areas and/or ballast tanks, there were a lot of other pieces of gear associated with them that couldn't be installed in way of the pressure hull. These included line lockers, the emergency buoy, retractable cleats, towing fairleads, hydraulic capstans, and so on. Given time, I may actually get to those.

 

Terry

Edited April 8, 2021 by CDR_Ret