How to sneak into a port

[Deathblow]

Okiedokie,

so we see this mission type over and over and over again from mission designers and I've yet to find a reasonable approach at solving it: Sneak your sub into a heavily defended port for some reconnaisance.... Only one problem though, there is always 2-3 frigates with active sonars blaring right at the entrance of the port... so how do we get passed them?

All of the obvious tatics usually don't apply. The water is always too shallow to "go under the layer" so that options out. Also, there's usually a time restraint... "Get into and out of the port by X hours"... so taking the long way around and skirting the coast usually is out too....

...Also most of the boats that are blaring their sonar are "pacing" back and forth across the port entrance turning with enough frequency to forbid a "quick sprint" when their backs are turned...

so the only tatics thats left is... hmm... ... there are no tatics left

Any ideas? Active sonars stink