Why does ship cruise at Cavitation speed?

[Wiz33]

Why did the game set cruise speed to 20knots? It seem that cruise speed should be the max speed without cavitation.

[jomni]

Cruise is usually the speed with the most efficient fuel consumption.

Actually I'm not too familiar with all this ssensor stuff. I blast away at full speed with all sensors blaring. When should I become sneaky and does tthe benefits outweigh the cost?

[Dimitris]

For many ships, depending on their mission, cavitation is not a big concern.

[frpandore@free.fr]

Important if you expect ASW threat and think you have not yet been detected.
Once detected, no matter cavitation.

[Primarchx]

Lots of ships cavitate at cruise speed. Not every ship has specially-lathed props and Prairie Masker.

[jtoatoktoe]

Pretty much depends on the Submarine threat. Generally most modern Submarines should have no problem picking up surface ships regardless of cavitation. But it could help them be picked up farther out of course by making more noise.

[ExMachina]

Cavitation happens a lot for surface vessels (b/c minimum cavitation speed is proportional to water pressure/depth-->less depth=lower cav speed)

[tocaff]

This is why submariners say that there are subs and there are targets.

[Wiz33]

I'm sure it makes a difference when there is a hostile sub out there. Since it's just a 1-2 knots difference. Why can't it be set to 18-19. It's just that CAV symbol freaks me out sometimes until I realize it was a ship ;-P

[jdkbph]

It's not a matter of 1 or 2 knots. Whether or not a screw causes cavitation is a function of rotation speed and water pressure. Pressure is a function of depth. Anywhere near the surface, there's just not enough pressure to prevent cavitation at any but the slowest rotation speeds. So surface ships will cavitate at any reasonable tactical or transit speed. Nothing much you can do about that but, as an upstream poster mentioned, try to mask it. Without examining the dynamics and doing all sorts of wild calculations I can't say for sure what the cavitation threshold speed might be for any given surface ship, but I would guess - even for pointy, high performance hulls - it would typically be in the 10 knot range.

JD