I don’t know much about stepup boards other than what I’ve read, which is to just increase the size of your normal board a bit, harden up the rails a bit and some people suggest to add a bit of wieght for chop.
I have a mini simmons which for the most part I’m very happy with in the smallest all the way to head high or more. It’s 5’6"x22x~3" (~37L)
^ I’d like to get some aspects of these 2 boards (i.e. rounded pin, full nose) into something longer and maybe a bit heavier to handle chop. The peanut I have got rid of now because it had lost some volume and wasn’t working for me anymore, forcing me with deep take offs (lasted a month in PU…). I like to get up and early to my feet. Conversely the Krypto I think could have been too big for me - I found it corky - especially in chop where it would zip over the surface buffeting around. But I think if it was smaller I wouldn’t enjoy it as much - I like small wave boards and the voume (37L was really nice) - it just didn’t feel particularly smaller wave so I prefer my simmons.
I want a board to be better in bigger stuff but at the same time give me a plan-B for medium or even medium-small waves.
Where do I go from here?
I’m really really into the mini simmons but if it means going to 3 board quiver I would swap it to a round nose fish to prevent going 3 boards.
Are you in an area with a lot of surfers? If so, Craigslist is your friend. Buy em and try em, then sell em and buy another.
Have you looked at the Stretch 2x4?
I’d like to attempt some other more specific suggestions, but there’s just too much I don’t know about your circumstances, and it’s all subjective anyway.
All I’m able gather from those links is standard “length/width/thickness/volume” stuff. You probably owe it to yourself to learn a bit more about the boards you now have. Additional investigation may reveal what it is about the boards that you like/dislike.
For starters, nose and tail widths, wide point position relative to center, as well as thickness proportioning are worth checking. Rocker can hold a few clues and you shouldn’t ignore bottom contours.
A ‘step-up’ board for you is going to be relative to what you’re riding now. I’d say you have the general idea down OK.
The ‘corkiness’ you describe could well be due more to rocker and bottom contours, particularly concaves, than length. In an effort to enhance paddling in a shorter board, the designer might have beefed up the rails to the point they are difficult to engage at speed. You don’t mention your size and weight but a heavier rider can go with fuller rails… rails that indeed might feel corky to a lighter rider.
So go ahead and go longer. Smooth out the rocker, lose the concave and pinch the rails a bit. Maybe throw a bit of forward belly to smooth things out(?) A board for bigger choppier conditions might benefit from 1/4" - 3/8" of belly in the forward 2/3 of the board.
Since you claim that the one board “lost volume” making late take-offs necessary, don’t pull the tail width too much. In my opinion, that’s a common mistake that can lead to the exact condition you describe.
Stick with your current fin layout but increase the spread a bit… I.E. move the side fins forward 1/2" -1" but don’t make any drastic changes from what you have. A short F/U center box and a couple sizes of center fins will increase the board’s range.