The first potential obstacle is a railroad draw bridge, but in my memory it is normally open, but closes when trains are coming. Next up is the Ballard locks. They are pretty easy to go through. After the locks you are in fresh water. The next obstacle is the Ballard bridge which is a draw bridge that opens after you sound your horn. After you go through the Ballard Bridge you enter a fairly narrow channel. It isn't as bad as it looks on the charts. Then you come to the Fremont drawbridge which will open when you sound your horn. After the fremont bridge you do under the Aurora bridge which is a fixed span with about a 160' clearance. One you go under the Aurora bridge the waterway widens out and you are in Lake Union. Except for the extreme SW corner there are no hazards in Lake Union. When you exit Lake Union on the NE side, you go under the I-5 bridge (it is so high you may not even notice it) then immediately come to the University drawbridge (sound your horn again). Once you pass the University Bridge you are in Portage Bay. There is ample water in the Bay. The final bridge before Lake Washington is the Montlake drawbridge (horn). After you pass the Montlake bridge you are in a narrow channel for about a mile across Union Bay before you get into the deeper waters of Lake Washington. When you enter Lake Washington the Evergreen Point floating bridge (highway 520) will be on your right. Charlie gave the details about openings for that bridge. The northern part of Lake Washington is wide open with no hazards except right along the shore. It is quite pleasant sailing.

As far as the drawbridges go, after you sound your horn be prepared for a 3-5 minute wait before the bridges open. They have quite a lot of traffic and have to lower barriers and wait until the bridge is clear to open. Once they start opening they go up pretty fast. They don't like to leave the bridges open for long, so get through as quickly as you can.

I have sailed Lake Union and Lake Washington many times. There is a lot to see along the shores, particularly of Lake Union. There is often a LOT of boat traffic in Lake Union and it can get choppy from all the wakes. Despite the hills around the lake there is good wind. When I lived in Seattle there were several restaurants with docks where you could tie up while eating.

The passage is easy. I have done it at various times during the day and at night without any problems