Ecuador, just south of Columbia is on heavy fire from the cocaine drug Kartells and the government declared a curfew to keep civilians of the streets in that very street war.
Fighting Kartells in the Americas south of the U.S. boarder is a form of gang war, but using openly military urban warfare intelligence based strategies and tactics that need support of the locals either by fear and bribing or trust and love.
For years most Cocaine is produced no more in Columbia, but in the deep jungle of Peru and since rural areas operating FARC was taken off the U.S. controlled international terror groups list they might have had so much success protecting and defending the Columbian farmers forced by fear into the Cocaine business, along with the Bogota run government forces taking out major parts of the Mexican origin Kartell operating and controlling the coast line with it's hundreds to thousands of underground cocaine trafficking harbours and submerge smuggle boat ship yards, that the Kartells moved operations further south to Ecuador.
Brazils Favelas, that had been home to Kartell stash houses to split loads for further transport towards Europe directly, Africa's hubs for Europe and Asia, but possibly also to enter North America, have been taking over by Militias that like ancient Knight or Lord Clans take tax in return for protection which is a way better deal than unpredictable junky gangs as neighbours. They tend to do what they say over constantly changing opinion based on the daemons they snore and inject.
All third world nations have the same problem financing that defence war. Against the support of he civilians trying to live in peace, they face Kartell forces equipped with high-end military equipment and, if junky gangs can't cut it, these organisations are well able to pay even high-end assassins from any secret service gone rogue or most likely from a mercenaries background. They are rare, but exist.
Also, they are often used as a dumping place for outdated western military equipment of high standard, but designed for a world war and no urban gang war, beside expensive in maintenance and often difficult to use requiring dedicated special training.
Ecuador is important to the Kartells to get the load out onto the sea. The U.S. coast guard uses high end equipment pretty much straight outa Boston Dynamics next gen think tanks like Satellite and high-end radar surveillance on expensive navy forces speed boats including intel from Air Carrier based F-15 and later surveillance jets on either routine or training missions to identify strange fishing boats or narco submerge speed boats. The 80ies style offshore race boats are already out of use since about the 90ies being intercepted in the Caribbean after those waters were turned into NATO Navy training grounds. It's the Pacific coast line now that takes the smuggling routes.
In the same way that a WW2 war bird replica, but equipped with state of the art electronics would be way cheaper to maintain and easier to operate than a cold war designed jet in a field of operation in which super sonic speed is not needed, but the running and acquisition cost is of major importance, U-Boat designs from about the same time are in no use, but would do the job.
Today, Submarines are huge rocket launch pads supposed to carry out nuclear or major rocket strikes being able to shorten the distance between launch and target or come as submarine hunters, but all modern submarines are way off the U-Boats from second world war that had been pretty much speed boats able to dive.
Despite most Hollywood movies the actual tactic of U-Boat attacks was Wolf like pack sneak on, hit hard attacks covered by darkness and out running the enemy to get away as soon spotted by frigates or destroyers. Last time I checked Wiki listed the top speed of a German U-Boat under water faster than above, which only applies for stormy weather. Actually, the strategy of narco submerge boats to dive only a few centimetres below water is adopted from U-Boat tactics running away after firing their torpedoes or hiding from air planes during daylight. They were pretty fast as a boat and not that fast diving below the flat sea, while difficult to hit moving away fast from any boats cannons.
The physics did not change, but today with modern secure digital communication between turbo-prop reconnaissance war bird replicas, and U-Boat replicas hiding from narco spotters on fisher boats, but easily outrunning narco subs also third world nations could outgun narco forces even in the naval warfare part of the war without facing bankruptcy.