I asked Jimmy. Unfortunately he did not have a solution.
Maybe I will try to retrofit it myself. Does anyone have the dimensions of the end of the OO/Axis mast (length, width, depth) and the placement of the bolt holes?
I just added a few more skinny masts to the article:
www.wouzel.com/post/10-000-miles-of-notes-on-mast-selection-searching-for-perfection
Specifically, I added in the F4 masts and a comment or two about rumored Code, KT, and F-One masts. K-Parts is also releasing multiple skinny UHM adaptable masts which look sick with their thickness at 13mm and chord at 105mm.
kparts-watersports.com/categorie-produit/foils/mats-fuselages-adaptateurs-wingfoil/
I don't want to have names or brand to trash brand. But my understanding UHM is not a ISO or a method that guarantied a superior stiffness or construction. Is there any UHM in the 12-13mm noodle that was tested? So from the lecture, all what you tested in the 12-13...you are referring seemed to be stiffer while using UHM vs for example 14 HM.Is it what is your observation?
That's a great qualifying question.
I have NOT ridden every mast on that list. I compiled it so people could see what's out there for options and keep adding to it as I hear about more masts in that realm.
You are correct that simply putting UHM in the mast doesn't guarantee superior stiffness or construction. That's why I mentioned the craftsmanship element in the article. The companies building these masts need to be masters of their craft in order to give us the results we need in the water. What UHM does allow the accomplished manufacturer to do is make the masts thinner and shorter chorded while still having a high level of stiffness.
Long story short stiffness is not the only metric that matters. The mast needs to be well rounded. Stiff, thin, and many will embrace in the years to come, short chorded.
My favorite mast, the 75cm skinny UHM, is NOT the stiffest mast I could choose to ride. I'm willing to sacrifice some stiffness because of the HUGE benefits granted by having the mast 12.8mm thick with a 100mm chord. You can dive deeper into my look on that mast here: www.wouzel.com/post/2000-miles-of-notes-on-the-afs-75cm-skinny-uhm-mast
Conversely, I'm not willing to ride a thicker mast to gain more stiffness. The tradeoff isn't worth it to me.
Why not the One Ocean SSS UHM mast ? 12mm and very stiff but only lift/code and Axis compatible.
Super nice mast!
Tried to get my dealer friend to nab the North 73UHM from AWSI but No-Can-Do.
Wow I didn't realize North had all those skinny masts. Eye opening for me. I'll add them to the list!
Hi everyone ,
North UHM masts goes down up to a 12.5 mm thickness (105cm long, racing focus) at the expense of stiffness:
Could someone with real expertise explain the last three parameters (bending cantilever & eccentric, torsion) in North table ?
How do they affect the feel while wing-sailing ?
Thanks in advance!
Thanks for sharing the table! Very interesting and kudos to North for publishing this.
As far as the three load cases go, your bolding of someone with real expertise is pretty exclusive. The Cedrus guy is the only person I can think of that meets your criteria and is active on forums. While you are waiting possibly in vain for that someone to show up, I can suggest you google cantilever and torsion, those are very classic beam load cases. Eccentric is a bit more of an esoteric load case, but it is the most representative of how a mast is loaded in bending during use, so here is a link to help you along:
foilcedrus.com/blogs/news/mast-flex-setting-the-record-straight
The link does cover torsion and also includes some discussion on current trends in torsion and bending stiffness with respect to feel. The X-foils podcast with F4 also touches on the subject briefly, if I recall correctly.
Why not the One Ocean SSS UHM mast ? 12mm and very stiff but only lift/code and Axis compatible.
Super nice mast!
Tried to get my dealer friend to nab the North 73UHM from AWSI but No-Can-Do.
Wow I didn't realize North had all those skinny masts. Eye opening for me. I'll add them to the list!
I've been using the North 80UHM for awhile now and you def can feel a difference. It feels like so much drag goes away when you pump high. I'm frothing for the release of the 73UHM. I like the more direct feel of a shorter mast and we have some shallow sandbars. ;)
I'm frothing for the release of the 73UHM. I like the more direct feel of a shorter mast and we have some shallow sandbars. ;)
I expect you'll love that mast and cant wait to hear a report on it. Those dims remind me of my 75cm AFS skinny UHM.
Thanks for sharing the table! Very interesting and kudos to North for publishing this.
Very cool for North to share that table. We don't get anything like that from other brands so we can't cross compare but it's at least nice to see the difference between North masts and especially cool that they compared their skinny UHM masts vs their standard masts.
As far as the three load cases go, your bolding of someone with real expertise is pretty exclusive.
Agree. Let's keep this a fun and inclusive rider to rider conversation.
I asked North directly since they should be the experts to rely on for their own table. They got back to me and have a nice graphic already made as well as the simple description for their UHM masts that I included below.

So, everything stiffer = everything is more direct and responsive. Then you chase thinner and shorter chords for efficiency. In chatting with the folks from North they've also confirmed pump is one of the very specific things that gets better with increased stiffness.
As far as speaking on how stiffness impacts the ride I'd venture to guess that the only high level rider/engineer on forums that could knowledgeably speak to that in engineering terms translated to riders is Kane de Wilde. He's the only person out there who has ridden tons of gear, still rides full time, and is designing cutting edge stuff that he tests, races, wins on, and inevitably it trickles down to the rest of us. People can try to message him on instagram or other forums but I don't think he's on seabreeze.
For me, I break down what happens when masts aren't stiff enough in the article:
www.wouzel.com/post/10-000-miles-of-notes-on-mast-selection-searching-for-perfection
There's a section under mast stiffness where I talk about what happens when a mast isn't stiff enough.
I can't give specific measured thresholds for when issues do and don't arise because I don't have the test equipment and there's too many variables to consider for each rider, their style, board selection, and foil selection. All I can say is that the stiffest mast I've ridden significant mileage on is the 80cm UHM from AFS and it exhibits no problems in any riding scenario I've thrown at it.