I wonder if the hull could have been strengthened by using a bit of that spray foam inside the hull before adding the outside plating. I have seen quite a few hulls built that way and it seems to provide support for the entire plating, which would be a good thing to avoid warping of the outside plating form the water pressure, etc. Perhaps put in boxes where the electronics will go so as to create openings for their later installation as the foam spreads when it expands and sets, so the boxes would save the spaces you need for the internal gear. It seems without this internal support the plating has a tendancy to warp and buckle a bit. The only problem with this is that where I've seen foam used in that way the deck is already installed, but you need access to the internal workings, so it will take a bit of figuring out how to add the foam support yet leave spaces for the electronics and a way to access them when the model is finished...but I imagine you could figure that out with little problem, Yuki. ;-)
BTW, when using the foam spray I notice it really spreads a lot, and oozes out between the framing, but once set it looks as if it is easily shaved back to the framing, it only looks scary as it sets and before it is trimmed back. :smile:
I am assuming you used a similar lacquer coating to the outside of the hull as you have shown in previous R/C conversions, is that right Yuki?
Regardless of what kit is being used, this is an interesting project that shows to me, at least, how one can take a paper model and make it functional. Of course, the major concern is how water affects paper, especially when immersed for a long time. I imagine one has to be very careful to ensure the entire hull is well coated by a protective layer of some sort to keep the water from affecting the paper, and that goes for not just the exterior sections but the interior as water always seems to find a way into a hull despite your best efforts. Looking at the end on view it seems the hull has been affected to some extent by the water so perhaps an additional coating might be suggested before the next sea trial, and hopefully that will maintain the integrity of the paper hull. Once he hull is completely dry maybe you want to spray the red underwater portion with another coat or two of red paint/enamel to strengthen it a bit more and provide further water proofing as it seems in the last photo there might be some seams between the bottom hull plates that could invite water seepage.
I am looking forward to you next update to see how this turns out.
Cheers!
Jim