The IPC stands for the International Proficiency Certificate. It is NOT the ICC.
The ICC is the International Certificate of Competency created by the United Nations. The ICC is an official international Sailing license.
The IPC was created by the US Sailing organization and subsequently then copied by ASA. It is meant to be a substitute for an official international license. Yet the IPC holds not official government status and therefore can be risky.
If you hold an IPC you may possibly get by with it in the Mediterranean BUT make sure that your resume is very strong and ask the yacht charter company to run the IPC by the port authorities. Some port authorities are strict to the rules that the license must be issued by an official government entity and some are more relaxed. Sometimes something official looking can get by.
Yacht charter companies also know that the IPC can be issued with as little as a few days of sailing training and no real experience. The yacht charter company will turn you down if you do not have a worthy resume despite holding the IPC. Think about it from an insurance company point of view if a boat is crashed the insurance company first looks at the claim and who was the skipper that the charter company gave the boat to. If the resume is too light the insurance company will not pay out on the claim. Thus charter companies check resumes as well as the sailing license.
Because NauticEd is an officially recognized sailing education body in the United States by the Untied States Coast Guard and NASBLA who is the official body overseeing boating Licenses, the NauticEd SLC is an officially recognized sailing license. In Croatia for example, the license must be on the official ministry list. The NauticEd SLC is on the Croatian official ministry list.
Ultimately, at NauticEd, we are biased toward the SLC that we administer because of the standards we adhere to. The SLC is only awarded to those who have sufficient experience to automatically qualify to charter. When the NauticEd student's resume is charter worthy and the student meets the proper legal conditions only then does our software issue the SLC license. Thus SLC holders are guaranteed to be accepted for charter - no surprises (like "oh you need to hire a captain for a week") on the dock in Croatia.
When you book a yacht charter with NauticEd Sailing Vacations, we run a check on your resume and license and we preclear you with the yacht charter company.
See www.nauticed.org/SLC for the details on the SLC. It shows the official recognition.
See http://www.nauticed.org/sailing-blog/how-to-gain-your-slc-mediterranean-sailing-license/ on how to get the SLC
If you are a competent sailor but undocumented, you will have no trouble gaining the SLC. Basically you do online lessons and a one day assessment of your skills and knowledge on the water. You will not be subjected to a multi-day training that is required for the IPC. When you sign in to your student account on NauticEd, click on the curriculum button. There you will be able to see the requirements for the on the water assessment.