Hi,
I'm currently running an IQ foil on a Starboard Foil 147 and this set-up feels very balanced. However, I'd like the option of using a fin occasionally. Would a freerace/slalom board be too narrow for the IQ foil?

Depends what width board you decide to get.

The problem with slalom boards is not the width of the board but the tail width.

Why do you need the tail width for race foils? Is it to get righting moment upwind?

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dohertpk said..
Why do you need the tail width for race foils? Is it to get righting moment upwind?

Leverage over the foil and ability to sheet the sail to the centerline of the board.

Notice how close the sail is pulled to the foil screws. Could get more upright and sheet in more here.

I put a foil on my foil ready slalom board and I came to the conclusion that if I really wanted to get into that freerace thing I would need a wide tail foil board. Apparently, the people were using formula boards when foil slalom started, not their slalom boards

I have a foil with higher aspect wings on a Goya Bolt 135 freerace board 80 cm wide, I recently started resting the arch of my rear foot on the rail when gusts hit me, and that worked good and felt comfortable though a little odd with my heel over the water, and gave me the leverage I need for the sail. But I had to do that because of the relatively narrow tail. The advantage is it is easy to get the board moving subfoiling to get enough forward speed in really light winds 8-10 knot, versus a wider board.

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aeroegnr said..

dohertpk said..
Why do you need the tail width for race foils? Is it to get righting moment upwind?

Leverage over the foil and ability to sheet the sail to the centerline of the board.

Notice how close the sail is pulled to the foil screws. Could get more upright and sheet in more here.

This - the ability to sheet in. Even when using smaller sails and narrower boards, you can really sheet in to the very forward apparent wind that is more difficult and awkward with a narrow tail. That's why, consistently, foil boards tend to have a OFO measurement of 10cm or less than the width of the board.

You can ride a foil on a foil-ready slalom board but over time, you'll find yourself wanting to put the back foot further out. I rode one for a couple of years as my higher wind board but since I've got a similar width foil board, the slalom board has been sitting in the garage. If you pick one up cheap, go for it but I wouldn't buy one new thinking I was getting the best of both worlds. Mine foiled a lot better without back straps, btw.

I run a race foil (slalom configuration i.e. 100cm fuselage) in a foil board that's relatively narrow, 70cm. I think the issues you may encounter are:
- due to board being narrower, race foils from my observations may be a designed to be a bit less stable in roll, as typically ridden with wider boards which seem to make it easier to control in roll.
- if you want to carry larger sails you definitely want the tail width. Echoing what others have already said, I'd say anything over 6m, and on my board it just felt like you always wanted a bit more board.

So don't think it'd work well if you want to run the 9m iqfoil rig as well, but if you just want to rip around with a 5-6m sail in say 12kts+ then it could work. If you are planning on sailing more on a reach or downwind then the width maybe is less of an issue. But sounds like your question is can I have a 1 board solution where I sail use an 8m sail with foil up to 15kts, then plug a fin in it? I think that would be a fairly compromised setup.

I'm not a slalom guy, but interested to know from those who are and also foil, does the same sail i.e. 8m in 15kts on the fin, vs 8m in 10kts on the foil, sail better on the foil with more tail width then you need with a fin?

8 meter on a HA 1800 foil would be scary in 15 knot breeze.
8 meters on a 375 front wing should be slightly underpowered in 15 knot breeze.

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LeeD said..
8 meter on a HA 1800 foil would be scary in 15 knot breeze.
8 meters on a 375 front wing should be slightly underpowered in 15 knot breeze.

The iQFoil is 900 square cm so 8 m sail in 15 knot winds is not bad. I have used the 1000 s.cm wing, 115 plus fuselage and 8.5 3 cam Flyer in that wind. regarding the board width, I use a Roberts Flight GT (freerace foilboard) and it's 76 cm wide and around 70 cm OFO. The board is plenty wide for that size of sail and foil. Of course, a fin slalom board is much narrower than 70 OFO. As a big compromise it might work but do not expect much upwind capability.



Bruce Peterson (sailworks) uses a 76 cm wide foilboard with the Moses 900 wing all the time.

Board width isn't so much related to the foil as to sail size. For me a 75cm wide board can just barely manage a 7.5m sail, perhaps 90cm can't just barely manage a 9.0m?

I can relate to the comment about tail width and the ability to sheet in the sail. On my EvoFF132 with i76, if I run my back foot in the middle between the mounted footstraps, I can comfortably foil on a beam reach and downwind. If I place my back foot into the back footstrap (4 inches further outboard), then whole dynamic changes, and I can crank upwind with the sail sheeted in over the centerline of the board.

Just back in from a session on my IQ foil and Starboard Foil 147. Yep - I see what you mean. My back foot was hanging over the rail.