Just,
Sailing a submarine out there quietly under water is one thing; sailing the fleet from harbour is quite another. Political choice and the ability to deny, delay or de-escalate is key. Even if the Ark had been here it would not have been ready or able. Ocean only managed because it was on a pre-planned exercise - lucky guess?
Lj101 - 4 hours from the PM deciding to act, not the passing of the UN resolution.