Speed and quiet - 1/3 vs 2/3 vs full stop

[The Bandit]

Originally Posted by schurem

Aren't Narwhal and the 688's the only boats that have natural convection reactors that don't need to actively pump their coolant when running slowly? Is it modelled that they make a big step in quieting when going 1/3rd?

Also Rickover was a dick lol.

The 688s use an S6G reactor which isn't natural convection, you're probably thinking of the Ohio's S8G.

[Kazuaki Shimazaki II]

Originally Posted by The Bandit

The 688s use an S6G reactor which isn't natural convection, you're probably thinking of the Ohio's S8G.

I've been told the S6G can also nat-circ, but you have to be STOPPED (hotel load only).

[The Bandit]

Originally Posted by Kazuaki Shimazaki II

I've been told the S6G can also nat-circ, but you have to be STOPPED (hotel load only).

Well in theory if sound is that important just about any boat could be SCRAM'd and run off the battery for some time, as long as enough power is reserved to do a reactor start up again. Screw that up and you're back in the 1950s and its time to raise the snorkel.

Would also be pretty cool if you could put the boat into turbo-electric mode or use the EPM. My understanding is that the EPM is pretty loud though.

[Shadriss]

Originally Posted by The Bandit

My understanding is that the EPM is pretty loud though.

EPM and SPM both. Does the term, "Screaming Banshee" mean anything to you?

[Bubblehead Nuke]

Originally Posted by The Bandit

Well in theory if sound is that important just about any boat could be SCRAM'd and run off the battery for some time, as long as enough power is reserved to do a reactor start up again. Screw that up and you're back in the 1950s and its time to raise the snorkel.

Would also be pretty cool if you could put the boat into turbo-electric mode or use the EPM. My understanding is that the EPM is pretty loud though.

We actually did this once down in AUTEC. We entered the range and scrammed the plant out. We turned almost everything in the boat off, including the fans.

With the EPM you are not going to be winning any speed races and you are VERY range limited but you will be a hole in the water. They tracked us by the LACK of noise in the water. We ran the range and then had to recover the plant and bring the boat back on-line quickly. It was quite the experience.

It was QUIET in the engine room. Scary quiet.

The outboard?? That would be for maneuvering in port. In theory you COULD use it to go somewhere if you have a propulsion train casualty, but that would be a LONG, LOUD, and SLOW. That was a screaming banshee as someone said earlier.

[Bubblehead Nuke]

Originally Posted by Kazuaki Shimazaki II

I've been told the S6G can also nat-circ, but you have to be STOPPED (hotel load only).

Nope.. Pumps have to be on all the time while critical.

There is enough thermal head to provide emergency cooling after a scram if the pumps have to be turned off.

[jmr]

I always enjoy reading first hand accounts of technical minutia from ex-submariners on this board. There used to be a blog called The Stupid Shall Be Punished that was operated by an ex submariner but he stopped updating it some time ago. The best part was reading the comments from former and active submariners.