View Full Version : 46cm fin in isonic 101 2010

22nd February 2012, 01:48 AM
I'm experimenting with an old fin's interantional slalom fin in 46cm in my isonic 101 for extremely low winds and 8.5 sails. At the very low end, the fin planes like crazy and goes upwind easily. However, I hit a wall very fast when the wind picks up even a little.
The fin is a very stiff carbon fin that dates back to the mid 90s. When I bought it at the time, it was supposed to be top of the line and quite expensive.
Is the fin a mismatch for the isonic or is it just junk period? I'm considering trying a smaller 44 cm fin for ultra light wind planing with the isonic Isonic recommends 42 as the biggest fin.

22nd February 2012, 05:36 PM
Hi troll,

A 46 fin on the IS101 - my favourite and most used board all times - seems a bit too large, even with a 8.5 sail.
The largest sail that I use on my IS101 is a 7.8 with a 39 fin. If you really want to use an 8.5 on that board, I would go for the 42 fin.
What's your weight ?

mark h
22nd February 2012, 07:30 PM
I agree with Bel, 39-41cm should be the max size you need on an iS101. Your 46cm is wider than the OFO on the iS101, so it will not work correctly and will be very slow.

For comparison, I use a 41cm and the bigger iS107/9m and 8m in light/med winds and I change down to a 39cm when I start to get well to over powered.

Im guessing that Bel is on Select fins (like me).

Also fin size is not always the best way to choose fins as they all vary in feel. For example, a C3 venom 40cm has much less power than a C3 Sting 40cm. Same goes for Select S10 Vs S11.

Just my 2 cents worth:)

23rd February 2012, 06:35 PM
Hi Mark,

Good guess, my 39 fin is an older Select SL7 fin.
Nothing special, but a decent fin.

All the best !

23rd February 2012, 08:51 PM
I'm 86 kilos. I've used an 8.5 on the isonic, but indeed it felt like the biggest reasonable sail. I was using a 40cm goldwing and it was ok. Was looking for 44-42cm to get extra power. Can't afford a bigger isonic right now, so am looking for cheap tweaks to extend range.
I have old 90cm formula board as my next size up.

mark h
23rd February 2012, 09:54 PM
Just thought, but maybe cut your old 46cm down to a 42/43. Not ideal, but could work for the odd super light wind days

26th February 2012, 01:16 PM
I did use once a 101 with a RS Slalom 8.4 and meanline 42, it worked quite well with a constant breeze.