My Tabou 3S uses Power Box fins, with their single screw. Recently, I've noticed I can wiggle my fin a few millimetres, fore and aft. The fin is solid, side to side.
My question: Does this fore/aft movement affect the board's performance? And, if so, can anyone suggest the best way to lock in the fin so that it doesn't budge when loaded up when sailing?
The joys of PB
have a look on your fin base to see if there is a scuff mark which could indicate a high point.
but it's realistically the joys of the single bolt, really noticeable with weed fins
It could be the fin screw is bottoming out, add a washer. Make a shim for the front and back tapers out of plastic or beer can.
The danger I see 9is the constant flexing of the bolt could fatigue it and lead to a broken bolt and disappearing fin.
As said, if the head is fitting tight fore and aft, it shouldn't move.
Im voting for bolt too long and its bottoming out before pulling fin into box properly
I use long powerbox fins and if I whack the tip they do move a little. It's a powerbox thing. But there are things to check to make it better. As above , check bolt length and do it up a bit tighter. When Ive tightened the screw I whack the fin forwards and backwards , it sits the fin better and lets me tighten a bit more. Also check if the fin head is flush with the board. If it's under more than a mm or so there is some fin box or fin head missing which can give some movement. P B is good for sideways wedging in , but there's not much meat on the ends of the head for front to back location. Fin boxes and fin heads tend to wear at board level. That's where a PB needs to be tight. It's easy to build up the ends of fin heads with a painted on layer of resin. That's usually all it takes.
What was not yet mentioned is the possibility of cracks inside the box along the fore and aft tapers. Inspect closely for that.
Ya gotta love Seabreeze Forums.Elmo, Mark_australia and Hydrosurf... you were bang on: the fin bolt was bottoming out... as mentioned, it's prevalent with the use of weed fins, which I use here in Warnboro Sound. Two extra washers did the trick. BTW this time, no shims required.
Decrepit... I replaced the old bolt with a new one on your advice... just in case.
Imax1... I found your protocol for inserting fins priceless (I do tap my fin, fore and aft with a small rubber mallet when starting to screw the fin in, to lock in the screw).
So thanks everyone, my fin is "one with the board". I appreciate all the input.
The fore/aft wiggle might mess a bit with your performance, especially if you're into some serious sailing. I fixed mine by adding a small rubber washer near the screw - kinda acted like a shim and kept things snug.
All my life I've had tuttle box weed fins. I never had a problem catching weeds because I could really tighten down the front (leading edge) screw. I just bought a brand new Fanatic Eagle 135 (power box) and needed a weed fin for my bigger sails. I bought a brand new MFC WB_40/50 degree which cost over $200. Yesterday, after weeks of not sailing. I finally went to a local lake which has tons of weeds. I came in three times to tighten the fin but still had to put the sail down and manually pull off the weeds five different times. I never did get planing and it became very frustrating. I'll try the extra washers as suggested in the previous posts, but I sure miss my old Exocet 100% carbon RS 6 Slalom board that had a tuttle fin box. I've planed at that same lake with the slightest of wind but the board only worked with an 8.5 - (yes I live in central PA.) This Fanatic Eagle is heavy and doesn't seem to plane early but it does allow a wide variety of sail sizes.
If the extra washers don't work, I'll have to buy some waterproof tape for the leading edge of the board. However, each time I came in to tighten my screw, that fin was solidly in the box. I couldn't move it.
Frustrated,
Clyde
^^^^ your Tuttle fin head is tight as it's just too big so using more tension on the front screw is a no no
make the fin fit right by sanding
as to power box that can also occur
the extra washers were only because he had a screw that was too long in power box ... so yes try it but measure it first. If screw is not bottomed out you will need to sand the fin head
Btw don't tape it. the tape will lift - waterproof or not - and be worse than the weed
do it right, it's an interference fit that needs work sometimes
