RL question... speeding up and slowing down

[Looney11]

A 4600ton frigate (M-class or Karel Doorman, RNLN) will go to top-speed (roughly 29 knots) in under 2 minutes and will stop itself in 1 boat length by going full reverse on the pitch of the proppellors. Been there, done that.

This should give you a nice view of the manouvrebility (dreadful word btw) of todays frigates.

[LoBlo]

Originally Posted by Looney11

A 4600ton frigate (M-class or Karel Doorman, RNLN) will go to top-speed (roughly 29 knots) in under 2 minutes and will stop itself in 1 boat length by going full reverse on the pitch of the proppellors. Been there, done that.

This should give you a nice view of the manouvrebility (dreadful word btw) of todays frigates.

Wow, full stop in one boat length... I can imagine all the split coffee. That's pretty impressive. What about without going to full reverse?

[Dr.Sid]

I guess strong boats can achieve nice accelerations .. but getting to full speed in something as dense as watter can take some time .. so I guess top speed will always be in minutes, but 0-10 kts can be achieved in seconds.

But I'm just guessing .. my biggest (and almost only) boat trip was Belgium-Britain traject

[Bubblehead Nuke]

Originally Posted by Dr.Sid

I guess strong boats can achieve nice accelerations .. but getting to full speed in something as dense as watter can take some time .. so I guess top speed will always be in minutes, but 0-10 kts can be achieved in seconds.

But I'm just guessing .. my biggest (and almost only) boat trip was Belgium-Britain traject

Lets just say that when you stomp on the throttles there is nothing like feeling 6900 tons of sub accelerate (yes, you sometimes have to reach out and steady yourself). Even better is that the sudden increase of torque to the shaft rolls you about 10 degrees initially. It only goes away after ships speed makes the sail surface (not the sail planes but the vertical sail itself) more effective and it rightens the boat.

How fast can they accelerate? *IF* you are ordered to cavitate, Flank speed comes up REAL fast. It depends on how well the reactor operator and the throttleman cooperate.

[Looney11]

Originally Posted by LoBlo

Wow, full stop in one boat length... I can imagine all the split coffee. That's pretty impressive. What about without going to full reverse?

You'd simply coast to a halt, we didn't do this normally, But the built-up inertia @ 29 knots, I reckon it'll take a while

[Rip]

and seldom do you want to make the massive noise of going from a flank bell to back emergency with the manuevering, conn cavitate order at the same time. Only events like the sternpmanes jammed on dive would cause one to do such a thing. Well that or Sammy Rickover getting his jollies on Sea Trials. The plant itself could torque the shaft to the point of breaking it. That is why as been mentioned here, the real key is the skill level of the ship control/engineering watch on duty.

I can recall being woke up while offwatch to come sit on the sternplanes for an anticipated drill for an inspection. Nothing more flattering than such an event, worth a box full of commendations.

[LoBlo]

Originally Posted by Looney11

You'd simply coast to a halt, we didn't do this normally, But the built-up inertia @ 29 knots, I reckon it'll take a while

That's what I'm thinking that most subs would do since they wouldn't want the extra prop noise going in reverse (unless an emergency like Rip mentioned). My gut says 4-5 minutes to bleed speed from 30 knots to 3 knots on coast.... but that's just taken outta thin air.