View Full Version : Fin bolts/screws for 2012 iSonic 137

25th January 2013, 07:45 AM
I' ve just got a 2012 iSonic 137 and I'am a bit confused about what size of fin bolts I will need.
Anybody owning the 2012 iSonic 137 has figured it out?
Thanks a lot in advance!

25th January 2013, 08:45 AM
Hi Unregistered

This the screw that is deliver with the board :

iSonic 137 M6 x 45 = 2 + M6 x 60 = 2

The smaller one for a fin who have deep Tuttle base and longer one with simple Tuttle base.

All the best

31st January 2013, 08:19 AM
Hi Remi
Thanks a lot for replying

I had already seen your quotation (M6 x 45 = 2 + M6 x 60 = 2) on the fin-bolt-chart. This quotation refers to 2013, while for 2012 there is no quotation for iSonics (and for 2011 there is no quotation for the 137L iSonic) so I supposed that the 2013 quotation should apply for my board too.

The reason Iím a bit confused is that I was given M6 x 100 to use for a simple (short) tuttle fin.
Actually after your reply I borrowed a simple tuttle fin from a friend and indeed the M6 x 100 screws fit fine on my board. But why do I need longer screws?

2nd February 2013, 05:39 PM
You need longer srews because on the tuttlefin the base is a bitt less long then the Deeptuttle base.

So the mounting points for a tuttlefin in Deeptuttle is lower then for the deeptutttle fin in deeptuttle.

2nd February 2013, 08:40 PM
Remi did not say longer screws.
The fin bolt chart lists M6x 45mm and M6x60mm screws for the normal Deep Tuttle Fin root.
The M6x 100mm screws would seem to be far too long because the Deep Tuttle fin only extends
into the fin box approx. 18mm more deeply than the std, Tuttle fin root..
If the std. screws (for a Deep Tuttle fin) are M6 x 45mm and M6 x 60 it would seem that you would
need M6 x 60-65 mm and M6 x 75-80mm to fit a std.Tuttle fin root.

4th February 2013, 06:58 AM
Hi everybody (Iím the initiator of the thread)

Two M6 x 100 screws are definitely the wright ones for my board, as I already tried them on (for simple tuttle fins). Maybe M6 x 95 could also work, but not shorter.

Now Iím thinking that maybe the quotation on the fin-bolt-chart (two M6 x 60 for simple-short tuttle fins) is for boards that have those walnut size (oval) holes on the back of the deck (above the finbox) and the screw holes are lower compared to the deckís surface. So the screws go lower than the deck.

My board doesnít have those and instead it has the screw holes right on the deckís surface. On each hole it also has a white rubber washer (glued on the deck) and for each screw head I also got a white rubber protector (plus the metal washers). Obviously this setup needs longer screws than the other above (with the walnut size holes).

To REMI and ROGER: Is this the explanation of the difference? And why are some boards made with different kind of fin box (like mine)?

Thanks again everybody

4th February 2013, 12:49 PM
Since you do not have the large oval cavities for the fin screws, then yes, my guess would be that somehow your
board didn't get those when it was manufactured, and that would account for the difference in fin screw length.