I suspect the issue with SUPs, especially in small waves, is mass.
Paipos have a flat bottom, very little rocker if any at all, and they are very thin. They were the modern version of the Alaia boards.
Put a flat bottom, almost no rocker and very thin rails with a hard edge on a surfboard, and you’ll see what fast is.
I went through a period of heavy experimentation with rockers, bottoms, rails, etc. I wanted to learn how it all affects the board first hand. I did a series of 8’ eggs with different rockers and thicknesses and the low rocker boards were great in small surf, but more rocker was better in overhead surf. As the board gets longer, you need to add rocker to be able to fit into the wave face, and to be able to turn easily. How you do that is the key, and I’m still learning.
I have a shot of the eggs I did back around 2005 - 2006. Number one was designed for small days and good paddling, and it does the job really well. Very slight concave up front, to flat then double concave out the back, maybe 3" of nose rocker. Number 2 was an experiment my brother and I did using Home Depot EPS. This was the first board we tried pressing a rocker into the board while vacuum bagging wood. The board is stringerless and the skins wrapped around the rails. Even with lots of weight used during the vacuum process, it flattened out. I think it has less than an inch of tail rocker and less than 1.5" nose rocker. I included a video of the first day riding it and you can see that it will glide through flat sections. No rocker tends to make it harder to ride. By number 3 and 4, I got the rocker that fit the waves I normally ride well (shoulder to overhead and offshore). It is a constant curve, like a arc sliced from a big circle. Number 3 was very thin and I needed to work hard to paddle with any crowds, so I gave it away to a friends daughter. It had nice tucked under rails and worked really well. On number 4, I got the tickness I needed for good paddling, and it was my go to for average days. Of all the boards I had then, my daughter liked that one the most.
I included a photo of a 7-6 x 21" x 3" board with just over 2" of nose rocker and just over 1" in the tail, it’s a great small wave board. I rode it in overhead surf a few times, but I had much better boards for good days. I went though a period of extremely low rockers, then went in the opposite direction till I realized where I had too much rocker for good planing. Rocker is great for steeper powerful waves.
I also did bottoms. I did multi-plane bottoms, rolled bottoms, etc. I ended with slightly concave up front then flat, and maybe vee or spiral vee out the tail. I think the flatter bottom seems faster. My opinion… I don’t think width has as much affect on speed compared to the bottom and rails.
You need to think of width in terms of aspect ratio. This will define curves which will be the main factor for speed along with rocker.
If you do an archives search, or just general internet search, of the term “trunk board” you should find some interesting shapes along these lines, the general idea being a board that would fit in the trunk of a car so you’d always have a board handy if you unexpectedly found yourself at the beach with good waves.
There have also been other boards designed along similar lines over the years, short, wide, thick, for a variety of different reasons. It would be worthwhile to study what’s been done in this vein if the subject is of interest to you. Pictured is the Bing Speed Square,
<iframe width=“560” height=“315” src=“YouTube” frameborder=“0” allow=“autoplay; encrypted-media” allowfullscreen></iframe>
Here is a photo of one that is 6’3" X 29". The O.P. didn’t really mention anything about ‘high performance’ surfing, whatever that is, just speed. This board goes pretty damn fast (and catches waves very easily.) Sometimes bellyboards or paipos or whatever you call them can outrun a surfboard… especially when riding on the back of a boat with a couple 60 HP outboards!
The Bing Speed Square looks very much like the the Morey Boogie (Vega) I bought my daughter 11 years ago – but with keel fins.
John, that board looks like the short SUP foils, except thinner.
Yeah the video I linked to explains the design genesis from the morey boogie