How effective would the naval forces of the Coast Guard be if pitted against other countries as a navy? Let’s assume they have to suddenly replace the US Navy. How much of a downgrade is that.
The USCG is a highly professional naval force, but they’re sadly short on guided missiles and anti-missile defenses. They wouldn’t stand a chance against Belgium.
Ironiclly, despite the opinions of some, up until 9/11 the Coast Guard saw more day to day combat that any other military branch. From the Vietnam War to 9/11, the USCG was busy interdicting drug shipments, among other things. They are often fired upon while busting drug dealers at sea.
Drug dealers rarely have guided missiles, too.
Look, you asked whether the Coast Guard could handle an opposing navy, not how good it was at its stated job - which hunting down criminals and other irregulars. Fighting actual fleets is not mainly a matter of skill, it’s a matter of hardware. Modern navies fight in three ways - by fighter jet (launched from aircraft carriers); by torpedo (launched from and against submarines) and by guided missile (launched from frigates and cruisers). The Coast Guard has none of these things. Most navies don’t have carriers, and can’t afford too many subs, so most naval warfare involves firing missiles at very long ranges. The USCG has no way to defend against these and no way to respond to them. In any fleet-on-fleet action, they’d be toast.
I imagine that the USCG could do very well against many of the small navies of the world. The Coast Guard’s fleet includes 12 High Endurance Cutters and more than 30 Medium Endurance Cutters, each of which are full seagoing ships, as well as numerous patrol craft, icebreakers, bouy tenders and other vessels. They also have a very large aviation branch.
The High Endurance Cutters armament includes: “1 76mm OTO DP, 1 20mm Phalanx CIWS, 2 25mm Bushmaster low-angle, 4 12.7mm MG” I’m not sure of the terminology, but I think that is a 3-inch deck gun, a Phalanx close in weapons system, and 25mm and 12.7mm machine guns. Armament of the Medium Endurance Cutters varies.
The Haze Grey website has fleet lists of the navies of the world. Quite a few navies have only patrol crafts/frigates that are similarly armed to the heavier USCG cutters, and many have much smaller fleets. To take one example of a maritime nation, Ireland’s Navy has only about six patrol craft comparable or weaker than the USCG high endurance cutters.
Many nations are now starting their own Coast Guards, not as just an extension of their navies, but as a separate branch.
Speaking as a Canadian, I’m afraid your Coast Guard could probably whup us. We have no aircraft carrier, and our second-hand submarines are apparently not seaworthy. We have destroyers capable of launching both missiles and torpedoes, and of course there are always the good old deck guns. But ammo costs money, and the gummint is cutting back on unnecessary frivolities like target practice.
Fortunately we are a bilingual nation, so we can always stand on the bridge and yell “We fart in your general direction” and then lob a cow at you… 
And if it dosen’t work the first time you could say "Stop, or we will taunt you some more!
Funniest thing I have seen on this board in a while. Thanks for the laugh.
It seems like I’m always out of town when these threads come up. Anyway, I think Billdo summed it up quite nicely. We could hold our own until missles and planes were involved, then we’d be on the phone with the USN. It was not long ago that our larger cutters did have torpedos and “Harpoon” missles (while ADM Yost was Commandant), but those have since gone away.
Anyway, I just wanted to clear something up:
This is not true by any stretch. Shootings, by either side, are extremely rare. Warning shots and disabling fire are more common. Especially so in the drug smuggling business. Smuggling is a game of stealth and tactic, not firepower. No smuggler in his right mind would ever try to “blast” his way through the lines - it would be suicidal. IIRC, the last Coasty to shoot (at someone, on duty) was about 15 years ago.
A quick correction - the last shooting was a few years ago, while Coasties were assisting a Sheriff’s deputy and State Policemen as they served a warrant on a guy who lived on a river bank. Before that, it was about 15 years ago.