Although located on a high hill and far from any significant body of water, King Solomon endeavoured to establish a royal navy for Jerusalem

He wanted his own fleet of trading ships to bring in silks, spices and oddities from all around the world

These merchant vessels brought such things as gold, silver, ivory, apes and monkeys (1 Ki.10:22; 2 Chr.9:21)

Since Jerusalem was not a port city, and not many of the Jewish people had knowledge of sailing, Solomon appealed to the King of Phoenicia for help. King Hiram helped by loaning out his own sailors to man the fleet and using them to train the new recruits (1 Ki.9:26-27)

The SDA Bible Commentary had this to say about Solomon's navy:

"This “navy of Tharshish,” operating with the aid of Hiram of Tyre, seems to have been based at Eziongeber (ch. 9:26); it could have sailed from there to distant ports in Africa, India, possibly even in China. Thus a voyage of three years, with frequent stops at ports of call, would be reasonable. It is expressly stated, however, that Solomon’s ships went to Tarshish (2 Chron. 9:21); Jehoshaphat and Ahaziah made ships at “Ezion-gaber” “to go to Tarshish” (2 Chron. 20:36).

"Since a fleet sailing from Ezion-geber, on the Gulf of Aqabah, could hardly have gone to Spain, and since the cargoes included “apes and peacocks”, some have held that this was a Tarshish in Africa, probably in Ophir, or Punt, in Somaliland."

The port that is mentioned in this quote is on an arm of the Red Sea. My understanding is that the territory between the port and Jerusalem was part of Solomon's empire; hence it would be natural to have a navy.

Thanks for the info, James! Interesting!