Tying to lock wall is actually fairly easy with the Ranger 25. With the exception of the lock wall in Ballard, Washington that separates Puget Sound from Lake Union, the lock walls on the Mississippi, Tennessee River and the Tenn-Tom Waterway are all the same, the bollards (large diameter yet short steel poles) float on a notch inside the lock wall. As the water rises or falls, the bollard stays alongside the boat.
The Ballard Lock in Seattle is so busy that no radio traffic is necessary with the lockmaster and it has a floating tie-up wall that is heavily staffed with Corps of Engineers employees. You tie up the stern first to a cleat, then tie up the bow to the nearest cleat. Stern first because this stops the boat from forward progress.
Anyway, for all the other locks call the lock master on the VHF radio with the name of their lock and dam and your boat's name when you can see the dam and the lock doors. Each lock and dam has a pre-determined radio frequency which is listed in the guidebooks and most charts. When they answer your call, you tell the lockmaster that you are a 25 foot recreational vessel asking to "lock up (go upstream)" or "lock down (go downstream)." They will tell you how long the wait will be. Recreational vessels are the third priority, government and commercial vessels are one and two, fisherman are fourth. Be prepared to wait. For very long waits, we waited 4 hours once, ask if you can tie to the lock wall outside the gates, otherwise just idling around is fine.
Be prepared before entering the lock with: A 50 foot, 1/2" line of twisted nylon-this is your line to tie to the bollard, have a loop in one end that is put around the cleat under the cabin window; have mega-fenders deployed on both sides and bow and stern, those cone types will not cut it because they are too narrow, we use the ball type fenders because they keep the boat the farthest away from the slimy and rough lock wall and the amount of surface area that is actually in contact with the boat's gel coat is minimal; and everyone, especially anyone in the cockpit must be wearing a personal floatation device, the lockmaster will often use the PA to call your attention to this necessity.
Enter the lock only when the green light (like a traffic light) is shown. Sometimes they tell you where and which side to tie to and sometimes it is completely up to you. If you are "locking up" the lock chamber will flood with water and raise the boat and the bollard up. In this event, choose one of the four corners of the lock because often the water floods the chamber through pipes in the middle. The turbulence caused by this flooding can be incredible. We learned the hard way to not tie up in the middle when locking up.
Locking down is a breeze, the water level slowly descends and is quite peaceful. You can tie up anywhere on the lock wall and have a nice trip.
For the Ranger, tying up to the starboard side of the boat is best because the pilot has the best view of the total operation. For all of our 33 locks, we did the starboard side of the boat. The 1/2" lock line was pre-set on the forward cleat and was pulled back and tied to the railing in the cockpit. Two ball fenders are down, bow and stern, idle up to the bollard and stop the boat putting the bollard at the cockpit and use the thrusters to keep it there. This keeps the crew member off of the narrow toe rail where bad things can happen while wrestling with a bollard. Also, keep the engine idling the whole time.
The cockpit crew member puts THREE wraps around the bollard in a COUNTER CLOCKWISE rotation. Three wraps keeps the line from slipping on the bollard and a counterclockwise rotation keeps the line away from the edge of the lock wall where it will rub, chafe and eventually break from the friction against the rough wall. (Now, if the Ranger is docked on the port side of the boat, the line will need to be wrap clockwise around the bollard to get the same protection.) Don't sweat this: dock on the starboard side, three counterclockwise wraps is the mantra.
Now the pilot has another job: reach through the window, grab the lock line that is still looped around the cleat and pull it, moving the bollard to the mid-point on the boat which is about where the galley window is. Then, everyone secures their line around their cleats, keeping the line tight so the boat does not more forward or back on the bollard.
DO NOT cleat and walk away from the line because, though it has never happened to us, these very old locks and bollards have been known to stick and jam as they are floating up or down. Boats have been pulled down underwater or hung in the air until a cleat was pulled out. In other words, always monitor the situation and be ready to quickly take the line off the cleat.
Have a nice trip in the lock, watch the line and the boat's placement against the lock wall. We use the thrusters as necessary for major adjustments. After the lock doors are open, wait for the sound and sign to leave. Release the lines, thruster away from the wall, leave the lock at idle speed and say Thank You to the lock master when you are clear.
Be prepared with the right equipment, talk through the event with everyone before doing it, no yelling, no jumping and then there are no problems.