Here is my take away for knowing what your most efficient and fastest stroke is. Even if you generally aren't in a hurry, there are times when you need to move as fast as possible. Maybe it's just a few powerful strokes to miss an obstacle, like a rock on a river. Or you could be off shore when a storm is approaching and need to make a sprint to shore. Maybe you're out fishing and it starts to rain and you remember that your camp isn't properly prepared for rain.
Even if none of those scenarios never happens to you, possibly the greatest benefit is that your fastest stroke is also your most efficient one. So even if you aren't in a hurry, knowing and using the most efficient stroke will save you energy allowing you to either make more distance or arrive at your destination less fatigued. I don't use it all the time but when I have a long way to go I try to remind myself to keep using it.
After experimenting on what my fastest stroke is over that last several years I came up with something very similar to what Marc Ornstein is describing. There are a couple differences. Where he says to plant the blade vertically by pulling down and then pulling back, I just pull down (trying to use both hands equally) and don't pull back at all. I can feel the acceleration and that I'm getting more weight on the blade than I do using any other stroke. It's a very short stroke, or I should say that the power phase is very short. You can keep your paddle in the water as long as you like to do a correction. With this stroke I know immediately when the power phase is complete (my hands bottom out) and I relax my muscles for the correction. This eliminates wasted energy.
This stroke probably wouldn't work for Marc. Most likely he will be healed over to the side and closer to the water, so his hand would get wet before his stroke bottomed out. That's why he, and most others, pull back. It only works for me because I sit on a high enough seat and I choke up with my lower hand. (there is only about 18" of shaft showing between my lower hand and grip hand)
Another difference between our strokes is that I don't rotate my upper body. It does rock back and forth, so I'm using my torso in that way.
I had been using this stroke for a number of years but I wasn't using it for speed or power. I mentioned it here in a post as the most energy efficient way to move my boat when I don't want to expend any energy. I used it when out for a quiet evening paddle and just allowed the weight of my arms and paddle falling down from gravity to move the boat. I joked that if I want to go faster I would just get a heavier paddle. Little did I know that a few years later this same stroke would become the power stroke that I had been seeking.
I took a little bit of info from a few different sources to come up with this stroke. Some of it was common knowledge, like keeping your blade as vertical as possible and perpendicular to the keel line. I got the initial catch from a John Puakea video, he also said to eliminated torso rotation. The final piece came from my wife. After years of me telling her how I wanted her to do a stroke I noticed that there had been a change in her stroke that didn't come from me. I could feel the power in it, I could also feel that it was smooth and consistent throughout the stroke. It felt so effective I had to ask her what she was doing. She told me she only pulls down and not back at all. I was like "wow, how'd you come up with that." When she told me she learned it from Chris, I knew I was on to something. You see, Chris is our friend in Hawaii that takes us out surfing waves in outrigger canoes. He's in his seventies and has been a professional waterman his whole life, so I have a lot of respect for his knowledge. I wondered why I didn't pick that up from Chris. Maybe I wasn't listening or I thought I knew it all. Or maybe he was giving Gail instruction while we were on the water where I, being in the bow couldn't hear him.
Chris was the guy that got me searching for the ultimate power stroke for the last 8 or 10 years. After being a paddler for so many years I thought I had a good stroke. I was surprised when he said I needed more power. I remember he gave me instruction, but I guess I didn't get it. I haven't been back out with Chris since "getting it" to confirm, but I think it's it. Chris was also the guy who told me to choke up with my lower hand, that at least I did understand.