Out of curiosity, what is so intimidating about Hell Gate? I have looked at the current tables and videos. Videos seldom show the true picture.
Out west I will go though a pass at 3 knots or less, although slack is prefered. Our worst is probably Skookumchuk Rapids at 16.5 knots; I have not been through there. Our busiest is Dodd Narrows which runs 8.5 knots; that I do at or near slack. It is about 75 meters wide.
I think a big part is the name. There can often be some very large traffic and once we took it the same time as a tug pushing a double barge.
The combination of narrow, curving big traffic and just enough current so if you catch it wrong and have a small boat you can get stuck and not make it.
Another possibility is that the ebb current flow one way in the sound and the other way in NY I suspect that some very crazy water can happen under certain conditions. But I have not experience anything other than traffic and the current. In Plum Gut I have heard of certain storms creating a wall of water that just sweeps over whatever is in it's path like a monster wave.
Also in the Sound we are used to 2 knots or less. So The Race, Plum Gut, and Hell Gate are all issues for us especially if you only have 10 horse.
So obviously you guys are used to much more action. Proving my point that experience one place may not prepare one for someplace else.
So I have a question for you. At 8 to 16 knots if the tide is going your way and you have a boat that can motor at 4 knots can you control the boat or do you have to wait for slack?