Final answer:
There is no standardized signal blasts for 'ATTENTION TO PORT' during rendering honors between ships, as this phrase is commonly associated with navigational situations. Honors are traditionally conveyed through visual signals and sounds like a boatswain's pipe.
Step-by-step explanation:
When a ship is passing another ship and rendering honors, the specific number of signal blasts to call ATTENTION TO PORT is not standardized in the context of maritime honor salutes; such signals are more commonly associated with maneuvering or navigational situations.
In ceremonial honors, flag hoists or other visual signals along with the sound of a boatswain's pipe are more traditionally used for rendering honors. However, if this is in reference to maritime navigational rules, one blast of a ship's horn typically signifies the intention to pass on the port side in a meeting or overtaking scenario, but this is not specifically an honor salute.