Sounds contradictory does it not? How can one be in torment, and not suffer? But we have just such a case in Matthew 14:24. And the boat was already a considerable distance from land, buffeted by the waves because the wind was against it.
The word translated "tormented" has a number of meanings, one of which is to be in constant, violent motion. In this scene, where Jesus walks upon the water, just such motion is in view. Sounds like a "reach" on my part, perhaps?
In looking at the scene in Revelation 14:10, one of the great "proof texts" used to illustrate eternal suffering, I was struck by its similarity to the passage in Isaiah 66:24, where unquenchable fire is used to describe the fate of transgressors. But in Isaiah these are corpses. This is an earthly scene, with "all flesh" as spectators.
When "brimstone" is mentioned, you may expect an earthly scene. The interior of the earth does not need sulfur to make it hot. Both boats and corpses are described as being tormented in the Bible, but neither of them suffer.