One can locate Dreadnought, HMS Looe, HMS Orange and HMS Unity/Unite in Wikipedia. From the dates given in Wiki, the Dreadnought is out of the picture. However, the same name was applied to the next ship when one was destroyed, sunk or de-commissioned. Start and end dates for the ships: Dreadnought, 1573 to 1648. HMS Looe, 1696 to 1759. HMS Orange, 1665-1673. HMS Unity/Unite, 1665 to 1673. (Some of the names appear again in WW I and I think WW II, but they are automatically out of the equation. In short, regarding the following stanza, I doubt the historical accuracy of it.

"If I must name these three ships to you, (those ships)
First was the Orange, the next the Looe, (Loo)
the third it was the Dreadnought gay, (The next it was the Unity)
That ended all the bloody fray. (Who made the Frenchmen quickly fly)"