Looks like 4-6 months. Don't forget a reasonable amount of agitation every now and then along with considerable temperature changes.
QUESTION: Before steamships, how long did the sea route around the Cape take from Calcutta to London?
By commercial carriers, do you mean passenger lines and not trading vessels?
(It's amazing to think that year round passenger service existed in the early 1800s)
Do you know the names of any of the commercial lines, and the types of ships they sailed?
Was it dangerous, sailing around the Cape? Sounds like a rough ride.
The voyage would have taken about four to six months[/B][/COLOR] depending on the weather and the speed of the ship.
There were no such things as dedicated passenger ships in the first half of the 19th century. Passengers travelled in merchant ships, which is why passenger numbers were quite small per ship, most of the spce was taken up with cargo.
By far the most dominant company sailing to/from India was the East India Company. Although it lost its monopoly of trade with India in 1813 it remained the dominant player in the trade until the 1850s.
The voyage could be dangerous, a number of ships were lost on the long voyage to/from India.
In 2005 there was a TV drama titled "To the Ends of the Earth" based on the William Golding trilogy of the same name about a voyage to Australia in 1813 on board a Navy warship. If you can get it on DVD or read the novel it gives a good idea of what a long sea voyage was like at that time.