We had a nice stay on Goncalo's boat. The place is very small, but ok for two people with little luggage. A couple of things to be aware of:
1. To get to Porto, you have to drive for 10-15 minutes.
2. The restroom on the boat is ok for some purposes but not for others. :) We ended up going to the marina complex quite often.
3. The showers are also in the marina building.