We have experience of Ribing in South of Spain. The boat is based there in paid for storage and we are fortunate to have a well connected local to help us with geting the use of temporary berthing. We are not allowed to use any of the fishing harbours.
From our experience you need:
Copy of registration of boat
Copy of insurance.
Prearranged launch faclities
We are aware of situation where someone was using a locally owned rib, stopped by authorities and boat impounded, Because of lack of storage facilities the boat was auctioned off at a pierside auction that evening. Aparently it did not fetch a big price. When the owner arrived next morning they were given the price of the boat ,less the amount of the fines having been deducted.
The spanish do not like RIBS. Given their smuggling problems and attached violence I can understand. Some harbours have an outright ban. I am told Gibraltar has also have banned Ribs.
Marina berths are very hard to find. Especially in the more popular south of spain, Look at how hard it is to get a berth in south of England and you have some idea. Multiply the attraction of Spanish berth spaces by a factor of ten and you have some idea. A lot of marina seek a high level of public liability.
A lot of the harbours are completely booked out and acess is only for berth holders.
Launching can be very difficult also. Most of the slips are closed in south of spain and your only alternative is crane. Again some local yards won't crane RIBS.
Parking can also be a problem,
There are, I am told some issues with towing in Spain. We are aware of a dutch couple who purchased a Rib in Germany, towed it to South of Spain and were then told that the German trailer did not qualify for use on spainish roads. Trailer looked alright to me.
Maybe the best thing for this year is to get an ICC, go down without your rib, hire some boats locally and check out the scene for next year. There is a lot to be said for being able to enjoy the coastline.
best of luck
Take it easy ....but, take it all the way.