I would recommend using 2.6. It is fully compatible with the official versions. I haven't see the newer Russian versions but the last ones I saw offered no new features that were useful for small boats. I still use 2.6 for some things.

As for your model, some of the vertical edges you have made creased. Probably shows up as red lines, depending on your color choices. Uncrease those and it will look like you want.