Looks great, but you need a bigger (bathtub) porcelain test tank.

Those windows are tough especially in balsa wood, it always tears and shreds. I recall the Lumba Lumba has a fairly thick hull which makes the windows look funny anyhow. I would give serious consideration to just painting them on.

Another possibility is to make a separate strip with the windows neatly cut into it and then cut out a hull section and install the strip windows and all. You can make duplicates for both sides by using double face tape to secure two pieces of wood together. Then you can use thin plywood which would give better looking windows.

Hi everyone, I hope you all have a great holiday season!👍
I have done some detail work on the Lumba, still have a few things to polish and add, still haven't figured out what to do to put in the windows properly on the sides. I need a 3D printed bezel to make the line perfect...I want this as perfect as I can make it. If anyone knows someone who could print them for me, I would appreciate any ideas you folks might have.
I removed the lead-acid 12 volt battery and am using two 7.4 volt NiMH now, it is so amazing. The boat is balanced now and I can move it pick it up without throwing out my back again. This boat is going to fly, I will be very careful with it, as it is overpowered. You can tell she is much happier boat now, not ponderous and plowing like she did with the lead acid.
I will be posting images of her on the pond as soon as possible, side windows or not. I guess a router might do it for me on the windows, hmmmm...but I am looking for perfect edges. It is very important🤓😎🙄🙄
Peace everyone, thanks for your time!