USS IOWA arrives at Port Canaveral

[Das Boot]

Pretty cool watching the rudder move at 6:24. Lots of security. Looks like there’s even an armed crew member on the deck behind the sail.

https://youtu.be/ypoKXkwco2c?si=TCVdsjv4SSVCYXf0

[Albacore 569]

Pretty cool watching the rudder move at 6:24. Lots of security. Looks like there’s even an armed crew member on the deck behind the sail.
https://youtu.be/ypoKXkwco2c?si=TCVdsjv4SSVCYXf0

Thank you for posting here 'Das'.

It is Interesting to watch USS Iowa's turning ability performance with that pump jet shroud somewhere underwater back aft. In the videos initial appearance, watch her turn and the position of the rudder. Interesting. It's as if the pump jet shroud has negligible effect. Also, the tugs are not assisting in the turn, just close alongside moving with her. Iowa makes a 90-degree sharp turn to port.

I discovered Suffern has covered bow thrusters, they are doors and are smooth, in the lower part of her bow that open for precise positioning when using divers and DDS. I wonder do the Virginias have same?

[Das Boot]

Thank you for posting here 'Das'.

It is Interesting to watch USS Iowa's turning ability performance with that pump jet shroud somewhere underwater back aft. In the videos initial appearance, watch her turn and the position of the rudder. Interesting. It's as if the pump jet shroud has negligible effect. Also, the tugs are not assisting in the turn, just close alongside moving with her. Iowa makes a 90-degree sharp turn to port.

I discovered Suffern has covered bow thrusters, they are doors and are smooth, in the lower part of her bow that open for precise positioning when using divers and DDS. I wonder do the Virginias have same?

Yes, the turning ability of that submarine is amazing, especially at that slow of a speed. It sure takes a long time for a submarine to see the water. She was ordered in 2014, her keel was laid in 2019, christened in 2023, and finally delivered in 2024. I wonder when she’ll finally go on patrol?

[Fishb0y]

U.S. nuclear submarines are built with extensive layers of redundancy—most systems have backups, and many of those backups have backups of their own. As a result, the propulsion plant is exceptionally reliable.

However, if the main shaft becomes unusable for any reason—such as a loss of shaft lube oil, a cracked shaft, or damage to the propeller—a retractable outboard motor can be deployed. This auxiliary motor provides enough thrust to move the submarine at low speed on the surface when the primary shaft cannot turn, and it can also be used to enhance maneuverability when returning to port.

[Albacore 569]

U.S. nuclear submarines are built with extensive layers of redundancy—most systems have backups, and many of those backups have backups of their own. As a result, the propulsion plant is exceptionally reliable.

However, if the main shaft becomes unusable for any reason—such as a loss of shaft lube oil, a cracked shaft, or damage to the propeller—a retractable outboard motor can be deployed. This auxiliary motor provides enough thrust to move the submarine at low speed on the surface when the primary shaft cannot turn, and it can also be used to enhance maneuverability when returning to port.

Yup the Secondary Propulsion Motor. About the size of a Volkswagen Beetle. On the Virginias SPM is located aft in the Virginia ballast tanks. On my 1/96 Permit USS Permit SSN-594 static model in the Vallejo museum, (this is a basswood static model, made before all the later rc model hulls ever existed) the SPM I modeled extended is in the midship ballast waist tanks. Here is a photo closeup of the SPM on my 1/96 model. The other is a illustration of the Virginia class SPM location (Highlighted in red).

[Das Boot]

Is that motor enough to drive the sub to the surface, if it has an emergency, where blowing of the tanks aren’t quite enough? It brings me back to thinking of the Thresher. If there had been enough propulsion, they probably could’ve made it. I read that there was possibly enough steam left in the system to drive the propulsion, but it was possibly overlooked when the reactor scrammed, and all hell was breaking loose.

[Albacore 569]

Is that motor enough to drive the sub to the surface, if it has an emergency, where blowing of the tanks aren’t quite enough? It brings me back to thinking of the Thresher. If there had been enough propulsion, they probably could’ve made it. I read that there was possibly enough steam left in the system to drive the propulsion, but it was possibly overlooked when the reactor scrammed, and all hell was breaking loose.

I am not an authority, but the SPM I was told was (or is) a retractable motor that uses electrical power from the Aux diesel to get you home (if slowly) if needed in an emergency. Like the earlier above post wrote, redundancy's designed in. They are also used in assisting docking (since it is a single screw vessel) when perhaps tugs were not available. It is rotatable 360 degrees.

[He Who Shall Not Be Named]

I am not an authority, but the SPM I was told was (or is) a retractable motor that uses electrical power from the Aux diesel to get you home (if slowly) if needed in an emergency. Like the earlier above post wrote, redundancy's designed in. They are also used in assisting docking (since it is a single screw vessel) when perhaps tugs were not available. It is rotatable 360 degrees.

The retractable Secondary Propulsion Motor (SPM) was used for maneuvering within the breakwater, not tooling around the ocean. The Emergency Propulsion Motor (EPM) was in line from the main turbines and would spin the shaft as long as there was enough battery to run that thing. If the diesel could keep up with the EPM's load and still float the battery you were good, but if the diesel was OOC or you could not get the snorkel up, you were ****ed, as the ships battery was needed if you were ever going to get the reactor cooking again. Juice the Pressurizer or run the EPM. A Hobson's choice in some scenarios.

[Fishb0y]

Is that motor enough to drive the sub to the surface, if it has an emergency, where blowing of the tanks aren’t quite enough? It brings me back to thinking of the Thresher. If there had been enough propulsion, they probably could’ve made it. I read that there was possibly enough steam left in the system to drive the propulsion, but it was possibly overlooked when the reactor scrammed, and all hell was breaking loose.

I’m not sure how much I can say, but the immediate actions for a reactor SCRAM have changed since the Thresher disaster. In a flooding scenario like Thresher faced, it’s now easier to use reserve steam to power the main engines and drive the ship to the surface. The SPM is primarily used when returning to port or when there’s damage to the shaft or screw. Still, I’d hate to ride that surface transient all the way back to port.

Both USS Tullibee and USS Nathanael Greene suffered sudden and severe propulsion-shaft casualties. Tullibee was submerged when she lost hers and was barely saved by inflating her emergency shaft seals.