Mike Laidlaw wrote...
You know what doesn't float? Steel. And Kirkwall's a harbor city...just saying...
Steel doesn't float? I bet a couple of battleships would take exception to this claim.

Beach-assaulting Marines wear plenty of gear that doesn't float so well, also. I'm curious to see what kind of tactics the Qunari will adopt (assuming we even get a chance to see them) in their invasion. I assume they don't just want to reduce the city to rubble, as they probably will need to make use of the fortifications in order to hold territory. (Otherwise, they could just sit back and bombard the place with their guns for a few days.) If they conduct a traditional siege/blockade, there's a good chance that some other curious folks will show up and mount a counter-attack before they're ready.
If I were conducting this, I'd land a small unit of inconspicuous troops (read, HUMANS) with a few kegs of gunpowder further up the coast, give them a day or two to sneak in and get set up, then sail up and open negotiations, using this as an opportunity to offload as many of my troops as possible. Then I'd have my sappers blow out a chunk of the wall, rush my heavily armed and armored troops through the gap, take as many hostages as possible, and make it a rush priority to rebuild the dismantled section of wall. Then I'd start pacifying the rest of the city one chunk at a time, all the while bringing more troops in on ships.