I am considering getting a 25cm Select X1 to replace the 23cm OES wave fin I currently use... I am looking for an earlier planning onshore fin.
The main reason I am looking for an alternative is when I am on a wave and turn downwind to ride the wave, i instantly drop off the plane the the board starts tracking sideways; even when I have the rail engaged and loads of front foot preasure... it is like the fin isn't generating enough lift. The board slides sideways down the face of the wave.
The board I use is an OES X-Wave 90Litre - I am approx 84kg. sails 4.7 - 5.8.
Just want to get an idea of suggestions for an alternative fin and comments on the X1.
Cheers
23cm is not a small fin. It should be fine for your <5.8m sails. Do you have the option of getting another sailor to try your setup to see if they have the same difficulty?
It could be fin size but it could be technique.
I tend to agree with Leech is sound like a technique issue rather than a fin issue. What you describe is a more common scenario when you are 'over boarded' for the wind conditions. The bottom turn is more about rail engagement/drive than fin lift
Which way is it spinning out? It find it hard to believe it's spinning out to leeward because that would indicate you are driving the fin hard with a lot of rear foot pressure, indicating a fair bit of wind = hard to imagine dropping off the plane
If it's spinning out to windward, sounds like a technique issue as a 23cm fin should be fine. Try loosing your straps so you can get your rear foot more towards the leeward rail and your front foot more towards the centre of the board, this will enable you to get more rail engagement. The dropping off the plane thing does confuse me somewhat as once you're on a wave it's not that easy to drop off the plane, even spun out.
Maybe i'm way off?
i think it might be your technique .. im only just learning to ride waves at the bech now and i find that as i bottom turn and start to come back up the wave u often slow right down and stop planeing ... i think its because i use 2 much back foot in my bottom turn causeing the board to stall .. is is in smaller waves thou ..waist high and smaller .. is this what u mean? and i use a 21cm fin
nicko, the certainty here is i am not a wavesailor. but i have had a similar problem in the past and it has stemmed from doing too tight a bottom turn.
draw your bottom turn out more and you will keep more speed.
Hey Bucket,
This was happening to me too.
I cured it by oversheeting the sail more (sort of like the start of a duck gybe). What's happening is that you sheet out, start to turn downwind and the sail wants to turn you back upwind, which makes you spinout. You need to really oversheet, which makes the sail go clew first, which pulls you into the turn instead of pushing you out of it.
Laying the sail down helps as well.
That said, most good wavesailors use much smaller fins than I do, I use 27 for 6.0, 25 for 5.0, 23 for 4.5.
may not be the fin size but the quality of the foil on the fin, i would give the select fin a go, as you improve then reduce the fin size.
Thanks for all the suggestions guys! 
I am not entirely sure which way the board spins out... but what Nebbian has described sounds very much like what is happening...I seem to struggle with the sail wanting to point me more upwind... I think I am needing to un-learn a lot of flatwater sailing technique.
I'll take all the technique suggestions on board. Thanks! 
also maybe the side onshore wind with mushy waves of PErth, try it in some side off with a decent wave?
Bucket I use a 26.5 X1 select in my 105 wave board and I am 105kgs. I also have an 95 litre OES twinny with 16.5 cm fins. Sounds a bit odd that you are loosing speed when turning downwind on a wave. You should be getting more powered
At your weight, board setup and sail size your fin should be fine. My biggest sail is a 5.8 and I go out in 15/16 knots no probs and wave sail (just).
Think Leech has the right idea. Let someone have a go on your kit and see what they reckon.
Me thinks it might be a technique thing that can be sorted by more practise. Get ya mates or partner to film ya as well and see what you are doing. It helps heaps.
Also crap onshore waves are challenging at the best of times
i put a the biggest select X1 wave fin i could find on my rrd fsw 110...... from memory i think it was 26.5.....it was replacing the stock standard MFC freeride fin.
used it up at gloo with a 5.7....... the difference it made to the board was amazing, loosened her up heaps with no loss of speed.
select x1=very good fins.... but they whistle
