I’m not going to lie, I had a blast writing this today and wanted to sing it from the rooftops. The tune is the well-known South Australia sea shanty, with new lyrics.
It’s about the raid on Dubhtraig last downtime, and if you want to sing it in character do go ahead.
One note: British sea shanties are not on brief for the Brass Coast. If anything it’s a Marcher tune, and a Highborn wrote the lyrics. Just because it’s an easy mistake to make. 
Bound Across the Bay (link to recording)
Bound Across the Bay (filked from “South Australia” South Australia - YouTube)
From Highborn docks I hear the sound:
[Heave away, haul away]
It’s off to Dubhtraig I am bound
[We’re bound across the Bay, oh]
[Heave away, the bells do ring
Heave away, haul away
Heave away, you’ll hear me sing
We’re bound across the Bay, oh]
Ten nations stand together
Prepared for any weather
There’s facets in the moonlight
Their spears and armour shining bright
The Night brings forth the Shadows
The Hollow Men from forests old
Each prow does call a beast its own
Bears and bulls of firey stone
The message sweeps the coastline
The beacons lit, their orders shine
We find a Grendel schooner
We board and set fire to- 'er
A trading dhow comes into sight
They take one look and take their flight
The fleet has got to Tathar
And all their weirwood we do char
We burn the forts and free the slaves
And send the Grendel to their graves
To Dubhtraig now we’re marching
To fight them on the quayside
The city is a-brawling
We send the Grendel sprawling
The Highborn summon fire
Three bulls, two rams, a savage bear
They break the Salt Lord’s towers
Lady Suriad’s gatehouse falls
The shipyard is a-burning
And mines we’re overturning
Our job is done; we set to sea
We tell our tales with joyous glee
Trad ‘South Australia’ / Rebekkah of the Shattered Tower