What you describe is known as a "US box" and is only really used for wave and freestyle boards these days. If you search around a few fin websites you should be able to find something a bit more freeridey or freestyle wave but pickings will be slim compared to Power Box or Tuttle. A more upright fin may make the board feel a bit uncomfortable, like you have to push sideways on the tail to counter the extra lift. A larger wave fin would probably be a better choice, and would be much easier to find. The extra area will help.

Thanks.I called it a powerbox setup then realised I was wrong & tried tuttle..oh well at least I know what it is now.
I'll chase that up.Looks like thats the one that is in it..except a new one would be + 1cm and a better shape!

Mark _australia said...

Sue,

secondhand US box wave fins around 23-24cm grow on trees
Whatever shop is closest to you will have one
Or have a search on here, somebody had an assortment of fins not long ago for $20 - $30 each

Bear in mind it is much harder to get a waveboard upwind anyway

The recommended size is 21cm .. will i have trouble if I go to a 23cm? Also I suppose the fact that the fin is prob only 20cm & a random sanded shape would explain why the board is so prone to skating sideways/spinout with any pressure..?

Mark _australia said...

The factory supplied size on waveboards is usually on the small side so they are nice and loose (ie: the fin is pro sized not normal person sized in many cases)

I'd use 21 in that if it was nuking windy, up to 24 for lighter winds.

A 23 that has not got chunks out of it will transform it

Oh yeah and fin right back for getting upwind.

Isn't there a formula for figuring out the largest size fin a board can comfortably have..? Something to do with the width of the tail..?

Mark _australia said...


I'd use 21 in that if it was nuking windy, up to 24 for lighter winds.

A 23 that has not got chunks out of it will transform it

+1

On my 80 litre board I use a 23.5 when nuking, 25 when normal.
Never felt the need to go smaller than 23.5.

Try leaning on the windward rail a bit more.

I've got a 16cm fin in my freestyle board and you can't really use any backfoot pressure.

I lean in the rail heaps to get upwind and it works well. I can cut upwind suprisingly hard with next to no backfoot pressure.

Mark _australia said...

sboardcrazy said...

nebbian said...

Mark _australia said...


I'd use 21 in that if it was nuking windy, up to 24 for lighter winds.

A 23 that has not got chunks out of it will transform it

+1

On my 80 litre board I use a 23.5 when nuking, 25 when normal.
Never felt the need to go smaller than 23.5.

Does the weight of the rider make any difference to the fin size thats best? I'll be using it in 25kts+ - 65kgs rider..

Yes - you could be OK on a 19 - 21 at your weight (and plenty of wind) no probs .... but I am aware that you are used to a freeride board with all the backfoot pressure so thus recommended a bit larger until you get used to how to get a waveboard upwind. As wes said it is all about weight forward

Any downside to running the larger 23 cm fin with my weight?

The fin box is only 9-10mm wide? Is that normal? I had one manufacturer quoting me on fins and they were 15mm wide so they won't fit.

Mark _australia said...

Are u sure you didn't ask for Powerbox again? Powerbox is the tapered base like a Tuttle but only has one bolt thru from the deck. They are 15mm (tapering down to about 8.5)

Yours is definitely US box like 99.9% of waveboards - and that is 9mm.

Heres what was said..
fins available in US box listed below,
MFC 19.7cm 2K (box 14.5) cm
MFC 21.5cm 2K (box 14.5) cm
MFC Freewave 21cm (box 15)cm
Maybe they are talking the length of the finbox but mine is roughly 18cm..

Mark _australia said...

They are talking about box length as some boards do have shorter boxes

MFC freewave 21 would be ideal as they are a nice upright fin and go upwind like mad compared to a cross-shore wave fin

ok that makes sense.Thanks.

I have a few wave fins which are similar in length, but some them have a very deep profile near the base, so a much bigger surface area and they provide very good drive. One of them is an older MFC, which is the deep one, compared to a Select fin I have which probably has about 20% less surface area in the same size.

I would not not be in a hurry to get anything bigger than a proper 21cm wave fin for that board (which sound like you already have), that should be more than big enough. I don't own anything bigger than that for either my 100 freestyle or 76 wave board (when I use it as a single fin) and I weight 74kg at the moment. At your weight you could even go smaller when your comfortable on the one you already have!

Instead concentrate on using the forward rails more and keeping the board moving fast, and you will truck upwind. My point is that it can be done, and once you get it worked out you won't look back. If you're having trouble by all means get something longer until you feel comfortable but it can be done very easily at your weight, perhaps for the heaver guys its a different story, I would not know.

BTW I did have trouble initially getting upwind on my wave board, but once I figured it out, it is no problem, and its worth the effort to learn, rather than buy something you don't necessarily need.

racerX said...

I would not not be in a hurry to get anything bigger than a proper 21cm wave fin for that board (which sound like you already have), that should be more than big enough. I don't own anything bigger than that for either my 100 freestyle or 76 wave board (when I use it as a single fin) and I weight 74kg at the moment. At your weight you could even go smaller when your comfortable on the one you already have!

Instead concentrate on using the forward rails more and keeping the board moving fast, and you will truck upwind. My point is that it can be done, and once you get it worked out you won't look back. If you're having trouble by all means get something longer until you feel comfortable but it can be done very easily at your weight, perhaps for the heaver guys its a different story, I would not know.

BTW I did have trouble initially getting upwind on my wave board, but once I figured it out, it is no problem, and its worth the effort to learn, rather than buy something you don't necessarily need.

I was getting upwind but not as good as my freeride..maybe I won't be able to..but the fin I have is damaged & missing its true length + shape so that must affect things.

Is there something in the physics that means a kiteboard can get upwind with no fins (or just those tiny ones they have), and a windsurf needs a fin?


I remember sailing a longboard backwards standing on the nose,
can't remember if it went upwind (i think sinking the nose to get tail up and fin out of water meant no chance of sinking the windward rail)

Another plug for the MFC freewave. I have one on my RRD FSW ( powerbox though) and it cranks up wind.
I suspect it will stiffen the board up a little over a true wave fin but will give you better upwind performance.