The same held true for convoys heading westward across the Pacific, dodging Japanese submarines and planes.
The convoys often lost one or two merchantmen, but most made it to their destinations. The nazis and Japanese paid a price in lost U-boats and their crews.
NOW PIRATES ARE THE SCOURGE of the seas off Africa, despite promises by many nations to patrol the waters and sink the pirates.
Having a warship trolling for pirates is similar to the local police patrolling a neighborhood with flashing lights and noisy siren; a four-letter word comes to mind: "DUMB" Also useless.
The remedy to the pirate problem has been recommended here before, but like some other suggestions (often about airplane security), the recommendations were ignored by people who failed to study history.
Not one cent for tribute
What was suggested here in the past was to have merchantmen rendezvous at a safe site prior to transiting pirate infested waters.
When several ships have been assembled, they would be escorted by participating nations' warships. The participating countries only have to agree on who will captain the convoy; alternatively, one country (e.g., China) can provide several ships to escort the merchantmen while another country (e.g., U.S.) can protect the next group of merchantmen.
All participating navies must have the same rules of engagement, otherwise the pirates will wait for warships that only fire over the bow of the pirates' vessels but don't do any damage to the attackers. If, say, Chinese ships sink pirate ships and U.S. ships only fire warning shots, the pirates will let Chinese convoys pass unmolested and wait for easy picking under U.S. escort. (The days of Theo. Roosevelt's Great White Fleet and Speak softly and carry a big stick ended for the U.S. a few years ago. America is, as China once pointed out, a paper tiger.)
Currently, the pirates seem to be attacking from Nigeria. That country's navy cannot seem to keep the pirates on shore, but then its army can seem to control Muslim extremists (e.g., Boko Haram) either.
Somalia is another African nation that seems to offer safe haven for pirates.
From the shores of Tripoli
As with Nigeria, merchant ships should be convoyed around pirate-infested waters.
Having worked for an international shipping company, I know scheduling can accommodate BRIEF delays to assemble several merchant ships into a convoy
If a merchantman insisted on traversing dangerous waters sans escort, any losses would be the merchant ship's owners problem. Since most merchant ships are devoid of weapons, save for perhaps handguns that offer no protection from pirates armed with RPGs and similar weaponry, "going it alone" seems foolish.
Several nations loudly signed up to clear the waters of pirates, but, based on continuing reports of pirate attacks, nothing of consequence has occurred. It won't until merchant ships are escorted past pirate hideouts. Sailing up and down Nigeria's or Somalia's coast shouting "Come out, come out, wherever you are" is an exercise in futility.
Since - apparently - no nation is willing to take the battle to the pirates, the least navies can do is provide convoy protection until piracy on the high seas no longer is economical.
The problem with that is that the pirates simply will relocate and eventually ships sailing near Africa will need escorts from the Suez, around the horn, to the Nile.
Meanwhile, pirates also plague shipping off Asia.
The bottom line for companies carrying freight is higher insurance costs. The bottom line for companies shipping freight is higher costs, costs eventually passed on to the consumer.
Of course if the world's navies would aggressively take the battle to the pirates, the need for convoys might become a history lesson, as did the need for convoys across the oceans during WW II.