I really enjoyed my stay in the Rosita! The location is nice if you want to get away from the more tourist focused areas, and is quiet but still easy to navigate to via Central Station or by biking/walking.
I was really impressed with the amenities as I wasnt sure what to expect on a boat, and the inclusion of two fans was a nice touch (it being quite warm a few of the days during midday).
The Rosita is gorgeous, I spent a good amount of time reading on and belowdecks and just enjoying the nieghborhood. I only occasionally noticed the motion of the waves - and not while I was sleeping (it didnt storm while I was there and the wind was around 9mph).
I'd readily stay again in this area, and especially with Friedrich as a host - he and the Rosita were both great!