So, I keep thinking to myself how it’d be nice if I can get my hands on the heirloom rings from the naval missions in the garrison, but no matter what they just don’t spawn for me.
I’m sure there’s plenty of other people who have been waiting for those naval missions to spawn with no luck. Is it possible that we’ll just see these added to the heirloom vendors to make them easier for people to get?
Just maintain a few alts with rank 3 Shipyard is the best advice, and max out your ships/upgrades/etc so you are prepared when it does eventually pop
Took me all the way until ~mid Legion when the mission randomly popped up one day and I was ready, put together a good comp and got the ring - I was elated to say the least (in a “phew! it’s finally over” kind of way) 
I think it took me almost a year before I saw them.
Yeah there really is no “secret” to it, it’s a simple waiting game. Just gotta check the mission table consistently to see if the mission is up - the OP needs to check mission table every single day
I think mine originally popped in 2017 on an alt I didn’t play much (cringe RNG 
) - but my fleet/ships on that toon were poopy-tier/weak at the time so I failed the mission 
Then one winter morning in ~early 2018 the mission appeared again, and luckily this time my ships were properly upgraded/maxed out and I beat it
The heirloom still has not showed for me yet and finally the bmah showed for me about 2 months ago but the mission failed 