On regular patrol, it is unlikely to run the boats at high speed though. Ambush means attacking in a surprisingly fashion. According to the descriptions of the incidents leading to this patrol mission, the other side just run out and shoot. If it adds a few inches of steel side protection (even 1/8 thick) and the windshields use bullet proof glasses, it will not increase the weight much but will be much better than what it looks now since the other side is mostly like to have light weapons.
Just remember the Iraqi war, US army used Hummers without side protection at beginning but scrambed for any metal to add on the Hummers.