Comment by mrandish

Transiting by themselves is a lot different than escorting merchant vessels. By themselves warships are free to maneuver at any time and do so at military speeds. Convoy duty with merchant vessels requires repeatedly moving slowly along a predictable route for sustained periods. Mobility and speed are two of a warship's main strengths.

The extreme narrowness of the strait right next to so much enemy-controlled shoreline is a unique problem. All of the destroyers and frigates from all the world's navies combined couldn't sustain protecting the massive number of merchant vessels wishing to transit the Strait of Hormuz on a daily basis.