Most anyone anchored up on the Columbia right now is fishing for Sturgeon. Make note of the areas where you see them. There are maps you can buy and there is quite a bit of info on the site to be found using the search function. Those are good methods of finding places to start. If you have a fish finder and a map, look for deep holes. This time of year a lot of anglers are focusing on water 60-80 feet deep. The slow water close to Willamette Falls and is a good place for a 16 foot boat.
Be careful out there. There is a lot of water on the Columbia where I would not feel safe in a 16 foot boat, most of it in fact. Calm days above Bonneville could be your best bet because the current is slower. Anyplace on the Columbia is going to whip up into small craft sink fest with a moderate wind.
My disclaimer here is that I have caught my share of Sturgeon, but there are anglers on the forum who are Sturgeon experts. I encourage them to correct my shortcoming on Sturgeon knowledge and help you with some of their advanced knowledge .
For bait squid, herring or shrimp all work. Take a little bit of each with you, and do not hesitate to switch things up untiil you start getting bites. If Sturgeon are there you will start getting some rod bouncing shortly after casting. If I do not have a solid take down within 30 minute I will move to a new spot.
Use heavy line and as much weight as necessary to get the bait to the bottom. 100 pound line and 4-6 ounce weight is not uncommon. i do not use Salmon or Steelhead rods for Sturgeon. You will be catching fish from 2ft-9ft long (5-300 pounds). Bigger fish will take 30-60 minutes to wear down and bring to boatside even with heavy tackle. Salmon rods and lines will take too long to wear the big ones down. The longer the fight the more physical stress to the fish. They can take many hours to recover after a long fight.
Good luck to you, and let us know how it goes.