US military uses airpower to destroy ISIS's fleet of evacuation boats in Mosul.

One of the five bridges over the Tigris river destroyed in previous airstrikes. AFP/USA Today.

US airstrikes have destroyed a fleet of ISIS evacuation boats being used in the battle of Mosul. USA Today. 90 boats were destroyed, along with three barges, in the airstrikes. ISIS was using the boats to evacuate the eastern part of the city. The boats were the only escape route for the ISIS fighters, short of swimming, All the bridges over the Tigris in the city have been destroyed and are now in control of Iraqi forces on the eastern side. With the fleet of boats destroyed the Iraqi forces in the area will now concentrate on liberating the western half of Mosul, which ISIS still controls. 

My Comment:
This is probably a critical move in the battle of Mosul. Whatever ISIS troops are still left in the eastern half of the city are stuck there now with no way out short of swimming. And I don't even know how possible that is. It would depend on the depth, current and width of the river and how good the ISIS fighter was at swimming. And that assumes that they don't get picked off by Iraqi troops near the river itself. My guess is that most of the ISIS fighters wouldn't even try it.

It's mostly academic though. Almost all of the eastern half of Mosul is under Iraqi control now. From the maps I have seen it looks like ISIS only controls a sliver in the north of the city while the rest is under Iraqi control. There are certainly stragglers and sappers left behind to cause as much chaos behind enemy lines as possible but these will be few and far between. The eastern part of the city itself has been largely liberated.

I have to admit, the bombing of the bridges by US forces really did help speed up the battle. I was skeptical at first, because of the obvious humanitarian damage it would cause, but it created a logistical nightmare for ISIS. With the bridges destroyed ISIS could no longer move troops and equipment across the river, except by boat, and now that option is gone as well. Most importantly they could not transport their most effective weapons, car and truck bombs, over the rive. With that weapon gone they ended up losing the battle for the east of the city.

With the eastern part of Mosul mostly retaken, the battle is going better than I expected. I hadn't expected the battle to be half over at this point and my earlier prediction that Mosul would not be liberated until Fall at the earliest seems like it might have been premature. Of course if Mosul is liberated sooner that would be great but I probably should have realized that bombing the bridges would have this effect on the battle.

But what happens now on the eastern side? From what I have seen there is quite a bit of crap in the way of the Iraqi forces before they can really hit Mosul itself. To the south there are several villages that need to be retaken, along with the Mosul airport and the north and west still belong to ISIS and will take some time to liberate. I am guessing that after the cleanup operation on the east side of the river is over, it will take some time to move forces around to attack from the other directions

I don't think simply crossing the river is an option. I am betting if they have some kind of riverine force it could be deployed but there isn't a reliable way to get the vehicles the Iraqi Army needs to operate with across the river. The Iraqi's probably don't have the capability to repair the bridges fast enough and the US government just blew up all the available boats in the area. I am guessing that other then a few light forces, they will just have to attack from a different area for the time being.

I do think that the battle for Mosul will continue to be tough. It won't be as simple to destroy the supply lines for ISIS this time around, which means they will be able to use car bombs effectively. Those car bombs are a force multiplier and also act to harm the morale of Iraqi forces fighting against them. My guess is that the battle will probably go more slowly then the eastern side went. Will the city be liberated before next Fall? Maybe. It really depends on the next couple of months because I am guessing that the war will slow down in the sweltering summer months.

Finally, I wonder if the Iraqi's aren't squandering an opportunity west of the city. The ISIS stronghold of  Tal Afar lies to the west of the city and is currently being threatened by ISIS forces. Though Tal Afar is a tough nut to crack and is rumored to be home of some of ISIS's most brutal fighters, taking the city would largely cut off the city of Mosul from ISIS strongholds in Syria. I think if they shifted their forces around to hit that city first they might lose some time but make the battle of Mosul go much quicker. And if they do take the city they will trap the forces in Mosul which would help to ensure that none of the fighters and leaders there make it back to Syria...