Search me, but seems from latest grapevine it's not working or recommended.
http://www.tourismhuahin.com/ferry-huahin.php
You might want to catch up with this ferry services reseller:
http://www.huahinmedia.com/huahinferry.php
As for logistics, believe they will drop you off at some main points. Example the landmark clock tower place at Petkasem road.
HHin's a small place, within easy short distance to the 2 main malls (Villa and BluePort)
Finally the details and prices for the Pattaya to Hua Hin ferry service have been announced.
The service officially launches on 12th January 2017, and will operate from the Bali Hai Pier in Pattaya to
Saphan Pla ( the main port in the centre of Hua Hin).
The Pattaya-Hua Hin ferry service is part of the Thai government's East-West Ferry Project, which aims to boost tourism between Chonburi and Prachuap Khiri Khan.
For those who've been to Hua Hin in recent times, you'll know that Saphan Pla has recently undergone renovation and is in a much better state than it was a couple of years back. Decrepit is one word I would have used.
This service is being launched following a crackdown on business owners who had set up illegally on the beach at Saphan Pla. On the other side of the water, officials in Pattaya removed speed boats that had operated in Bali Hai Pier for more than a decade.