If you prefer to go to the Anambas Archipelago by ferry from the Indonesian island of Batam, then you'll find all relevant details for your journey below.
First of all, obviously, you'll need to get to Batam, which from Singapore is easy, because there are quite a few ferry crossings between Singapore and batam. If your journey starts off in Jakarta, Indonesia, then you should be able to take a plane to Batam quite affordably.
Fast-ferry to Anambas
Now, once you've arrived in Batam, make your way to the ferry terminal and show your ferry ticket booking print-out at the Anambas ferry ticket counter. After you've received your ferry tickets from the counter staff, head towards the sea port tax desk, which is just across from the ferry ticket counter. The amount payable is 10,000 Rupiah.
Next, head for the ferry by following the signs. When you board the ferry, just show your ticket to the cabin crew. They'll assist you in finding your seat. You can store your luggage at the back of the ferry cabin.
The cost of a one-way ferry ticket to Tarempa varies from US$ 50 to US$ 75 per person per one-way ticket, subject to which class you prefer: Economy, Business or VIP. Batam - Letung is US$ 40 - US$65, depending on class. By the way, the Letung to Tarempa (and vice versa) hop is US$ 15 - US$ 25.
Note that weather, tide, currents and sea state can all influence the ferry journey duration. When it's windy, which is usually the case during the December to February monsoon season, the wind-swept swell may result in a slower boat speed and, hence, a longer journey.
Occassionally, the weather is too rough during the monsoon, resulting in the ferry being cancelled. The rest of the year, crossings should be uneventful.
Click here if you prefer taking the ferry to Anambas from Bintan.
Incidentally, if you haven't got that much time and just want to get to Anambas as soon as you can, then take the plane.