So a little googling says your boats are 23 and 21" beam. That’s good for a sea kayak but in beginner surfski territory (equivalent to a Epic V7). How skinny to go will depend on your natural (stability) ability, willingness to put in seat hours, and how soon you want to paddle in rough conditions.
I would say if you can paddle the extreme in haystacked waves you could easily move down to a 19" / 48cm ski like a Fenn XT or Vega Flex.
Once you get down to a 45cm ski you’re going to need some decent balance and an instant, intuitive stroke brace to keep upright in rough stuff.
I would highly highly recommend against an elite level boat (43cm / 17.1" or less). In very rough conditions like I show in my video, and even in somewhat less extreme conditions, a 45cm will be a better boat unless you’re truly an elite level paddler with elite balance.
The Mocke brothers are legends of South African surfski and Dawid says if you brace more than once every few minutes you should be in a wider boat. As soon as conditions get bad, very very few people can actually handle an elite boat by that standard. Also, you are likely to develop bad habits, a sloppy stroke, and you wont have much fun sitting on shore when its too big to safely handle an elite boat.
I could step down to a 43cm elite boat and have paddled them a few times in moderate waves (like 2-4 ft) and indeed they are easier to jump and link waves with, but linking waves requires every paddle stroke. as soon as you miss a couple strokes or brace hard, you’ve lost your advantage. I know for sure I would not have gone out Monday in a 43, and I live for days like that.
It sounds like you want a rough water boat, and there is not much speed difference between 48, 45, and 43cm boats the bigger the conditions get. As waves increase, more speed comes from picking a proper line, linking waves, knowing when to go and when to let off, and keeping up the tempo between sets.
Another consideration, only the new epics are worth a damn in rough water (that is the V10 gen 3 and the V12 gen 3). Older generations epics had very little rocker which means they sucked at surfing and given your goals I would not get an older epic. The Gen 3’s have a noticably more rockered hull and nose profile and surf much, much better. Also Fenn’s have been made for 10’ waves from day 1. I would highly recommend a Fenn XT-S (48cm beam) or the Swordfish S (45cm). Actually the Fenn’s are my first recommendation. Also if you have deep pockets, the Kai Bartlett designed Ozone manufactured Vega Flex (49cm?) has been said to be the best surfing surfski ever designed (but they’re $6k new as they are pre-preg monocoque 18lb feathers)
I strongly recommend against stellar boats for rough water surfing. Their designers come from a rowing or sprint kayak background and it shows in their hulls. Their G2 boats are significantly better than the G1’s (which surf like total junk), but I still would not buy a stellar if my goal was rough water paddling.
Another point - a wing paddle is basically required. Get a small one (like an Epic Small-Med wing). Big paddles and surfski dont mix unless you’re an olympian, and even then you’d likely be served better with a smaller blade over any mederate distance. Find a wing around 720cm2 area. 750cm2 max (which is an epic mid-wing). Many new wing padders buy a bigger paddle than they need. Im strong and young and never overpower my 720cm2.
You need a wing to do a proper ‘stroke brace’. That is, 90%+ of your power goes into forward propulsion, but you push, pull, or sweep a little bit to stabilize yourself. This is much different than a ‘hard brace’ or ‘slap brace’ where you slam the back of the blade in the water which provides a lot of righting force, but also nearly stops you.
Developing an instant, unconscious stroke brace is critical for successful rough water paddling. I do not believe this could be done with a euro blade because the ability to apply lateral force during the natural stroke motion comes from the airfoil shape of the wing blade. (maybe im wrong as I havent paddled euro much, but I believe it to be true). Literaly everyone on a ski uses a wing blade, and for good reason. Just make the transition. A Euro blade will handicap your progress.
Ivan Lawler and Oscar Chalupsky both have excellent technique videos on youtube to help you learn.
I see your werner is 720cm surface area which is good, but the wing is still needed. I come from a canoe racing background and a carbon canoe paddle has very good bracing capability probably similar to a Euro. A wing definitely does not have as much Slap Brace potential, but if you’re doing a slap brace frequently on a ski you should be in a wider boat. The Stroke Brace is the key skill to learn for unstable boats and rough water. In elite level boats with very little primary stability, every single stroke is also a balance correction using stroke braces.
Last thought, on even moderate days (as in <15kts wind) the Swordfish is stable enough to kick back, relax and drink a beer on. The same could not be said for 43cm elite boats. They require constant attention to balance. 45cm has enough more stability that balance can slip into the unconscious mind which I enjoy more than constantly maintain focus on a benign (but very important) aspect of the sport.
Edit - If you can, try before you buy in conditions other than flat water. An elite boat (or just generally a boat that is too skinny for your ability) may feel ok on flat water. Find some (haystacks no matter how small) and paddle through them. Find a steep boat wake and paddle at a 45* angle to it. This will tell you much more about your current ability than a flat water paddle.
Same for paddles. If you can try multiples, one will just ‘feel right’ while others dont. Its very personal so you just have to try some out.
Also check out surfski.info for dedicated surfski nuts on that forum.
