www.autosserapia.com
Cars from 140€/week
Also have cars for (wind-) surfers incl. roofrack. Delivery at the airport.
Or just google to find the best offers. Some companies don´t rent to (wind)surfers and deny if you ask for a roofrack.
Tip: Bring your own (soft)rack, load up out of sight and, most importantly, don´t abuse your car.