Sub speed underwater?

[Brock]

Does a subs speed depend on depth?  Is higher pressure a factor?

[Tucker McNeely]

The deeper the sub is the less chance for cavitation at the screw a higher propeller speeds. So not really a speed factor but less chance for cavitation and the faster the sub can go underwater while making less noise.

[Calamity Kris]

I'm sorry to derail things but I had to share this.

 

I've been working 12+ hour days for the last couple of weeks.  Needless to say, I'm kinda punchy and REALLY tired.

 

I swear the title to the thread was "Sub Speed UNDERWEAR" 

 

I'm going to bed now.  Good night.....

[Cowtown Scout, SASS #53540 L]

15 minutes ago, Calamity Kris said:

I'm sorry to derail things but I had to share this.

 

I've been working 12+ hour days for the last couple of weeks.  Needless to say, I'm kinda punchy and REALLY tired.

 

I swear the title to the thread was "Sub Speed UNDERWEAR" 

 

I'm going to bed now.  Good night.....

OK how long before you can retire from that job?

[WOLFY]

in the days of electric diesel subs they made way better time on the surface

[Sgt. C.J. Sabre, SASS #46770]

12 minutes ago, WOLFY said:

in the days of electric diesel subs they made way better time on the surface

Diesel subs were more of a ship that could submerge. They looked and sailed like surface ships. Modern nuclear subs are designed to sail submerged. They only surface when needed. 

This will give you at least a visual idea:

[Trailrider #896]

Prior to the creation of the Skipjack-class "boats" with the hydrodynamically-shaped hulls, submarines were really only submersibles. That is, they were faster surfaced than submerged. The first nuclear-powered subs still had hulls that were not ideally suited to submerged speed.  Of course, the nuclear power meant they didn't have to surface to recharge their batteries. I'm not sure if recent diesel-electric subs are shaped like the nukes. They tend to be quieter submerged, so they are harder to detect, 

Some of you modern submariner types can comment better than I can,

[Calamity Kris]

9 hours ago, Cowtown Scout, SASS #53540 L said:

OK how long before you can retire from that job?

 

I'm slated for the end of October, unless the stress puts me in the hospital again.........

[Michigan Slim]

I asked a friend who served many years in the silent service how fast his boats were. He was on a boomer mostly. He told me it was classified. Would not say.

[Brock]

my question is, does the speed change with greater depth? probly also classiied, eh?

 

[Colorado Coffinmaker]

 

I don't know the Depth/Speed differential.  I do know the widely published "speed" potentials are nowhere near accurate.

 

Butt and However, the first True operational submarine was the German type XXI.  That boat was designed and intended to be faster when submerged than when on the surface and it was.  The Type XXI could outrun Destroyer Escorts when submerged and running on it's electric motors.

 

As a further aside, the Type XXI also had huge influence on the design of our Nautilus which sorta copied the hull form of the Type XXI.

[Big Sage, SASS #49891 Life]

6 hours ago, Michigan Slim said:

I asked a friend who served many years in the silent service how fast his boats were. He was on a boomer mostly. He told me it was classified. Would not say.

I worked in  classified programs for the last 20 years of my work. When I retired I was debriefed and told unless otherwise notified everything that was classified was still classified and I couldn't talk about it. I still have a clearance 20 years later. 

[Tucker McNeely]

On 6/10/2026 at 10:00 AM, Brock said:

my question is, does the speed change with greater depth? probly also classiied, eh?

 

I was qualified as a throttle man onboard two nuclear subs. Not classified , it’s physics. Short answer, no.

[Brock]

33 minutes ago, Tucker McNeely said:

I was qualified as a throttle man onboard two nuclear subs. Not classified , it’s physics. Short answer, no.

thank you

 

[watab kid]

my FIL is no longer with us so i couldn't ask - first crew nautilus and career navy , he was a cold war submariner