Some Ballard locks questions:
1. You are required to have two 50-ft lines with an eye of at least 12 inches diameter at one end. Must the eye be spliced or can you use a big bowline?
A bowline is fine. Don't spend a lot of money on these for your boat. The very long lines are only used if you are on the outside wall on the large lock. They load the largest boats first, so your 24' sailboat is very unlikely to ever end up in that position.
I use fairly cheap nylon 3 strand and they do double duty as my dinghy tow line.
2. Do they ever run the large and small locks simultaneously? In opposite or same directions?
Yes, both are often in use in the summer. The large locks take much longer to load and unload than the small locks, so the small locks will often carry traffic in both directions before the large locks even finish going in one direction.
3. If so, when approaching how do you know whether you are to use the small or large lock if you have a small vessel? I know there are red and green lights for each. Do you ever encounter two green lights and have to choose large vs. small?
It happens, but not too often. If you have a choice choose the small locks, they are a lot faster. Typically if both are in use there will have been a queue to get through the small locks and then the large locks will open up and handle the entire queue.
* Have at least 6 fenders, and mount them at rail height (not down low at dock height). If you have big and small fenders put the biggest ones at the beamiest part of the boat.
* Have 4 normal length (~20') dock lines cleated and ready to use, one in each corner of the boat. Have the 2 long lines handy to use on the north side, but the chances of you using them are very remote.
* I would suggest having at least two crew plus yourself the first time you go through. You can do it solo with practice, but I wouldn't recommend doing that the first time.
* If you do go solo coil the docking lines and run them under then hanging on your dock lines. This will allow someone to pick them up with a boat hook.
* When you are rafting up you will pass your line to the boat next to you, they will loop it under a cleat and pass it back to you. You cleat it off. This way you control when you leave the neighboring boat.
* NEVER leave until you've been directed to do so. I've watched some spectacular messes when boats randomly decided to just go on their own.
* If you are going into the large locks it is biggest boats first, small boats at the very end. Rushing in early doesn't help, it just sets it up so that a much larger boat may need to raft up to the outside of you, an unsafe setup. In the small locks get filled in queue order, so remember which boats were there when you arrived and who arrived after you.
* Commercial traffic has priority. When the Argosy ship shows up it will take the entire small lock.
* The locks require good slow speed boat handling with the motor going, both for maneuvering in the locks and sometimes for waiting in the queue if the wall is full. It's good to practice being able to stay roughly in place while in standing water.
* Finally, your KR24 should fit under all of the bridges except for Fremont.
I think the locks are pretty fun. My wife hated going through them (mostly due to the random queue times) and is happy that we keep our boat on the sound now. We probably went through the locks about 10-15 times last summer and have had everything from no queues to long ones.
If you want to avoid the long queues on a busy summer weekend you can use the guest moorage at Shilshole. Start your weekend trip with low stress by going through on Friday night and docking at Shilshole (guest moorage will run about $30). Launch from Shilshole on Saturday morning and get a full day on the sound. I would also go through the locks solo or by myself and pick up crew at Shilshole X dock.