Fill the Diving Attachment with any type of Oil. After you put the fuel in, click the "equip diving suit" button. You'll burn through 1 oil per minute. The deeper you dive, the greater the consume factor.
Keep in mind that as you are attached to a hose, you can only travel so far from the Diving Attachment before you will rubber band back. I believe the radius is something like 20 meters (It isn't far).
While wearing the Diving Suit you have a few key advantages:
- As long as the Diving Attachment is powered with some type of Oil, you will be able to breathe freely.
- The suit provides significant hypothermal protection.
- Wild underwater creatures will ignore you unless you attack them.
The Diving Suit also has a few drawbacks:
- The suit unquips all your armor slots and provides no armor protection.
- It significantly reduces swim speed when at the water's surface.
- The suit's hose keeps you from swimming too far away from the platform from side-to-side, although it won't restrict how far down you dive.
- The suit will automatically unequip if the ship still moves.