system
Given the following post, respond as if you're commenting on Reddit:
human
[40k] Which space marine legion had the best navy?

The Sons of Horus have the Vengeful Spirit, the Imperial Fists have the Phalanx, the White Scars have modified all their ships to be abnormally fast. Which space marine legion's navy was the best of them all?
It is perhaps worth counting legion tactics too, as boarders from a faction used to working in tight corridors like the Salamanders would probably preform better than ones that usually operates via stealth like the Raven guard (it's hard to sneak around a ship when you're 8 feet tall and every step goes "CLANK!").*
gpt
It was stated in horus heresy book three that the Imperial fists maintained a fleet of 1,500 warships, a force quantitatively and qualitatively superior to any other legion. And they also have the phalanx which is a big asset by itself.