EVery time I gybed today and put my back foot down near the tail I heard what sounded like a creaking/cracking noise. It seemed to coming from the tail just around where the back footstrap is. The strange thing is the noise would only occur when I powered up the sail and put foot down on the tail. But if I then sheeted out, went off the plane and tried to replicate the noise I couldn't. So I'd plane away, gybe and same thing. Checked for cracks, couldnt see a thing, fin was A OK. I can't imagine the board cracking near the tail from something like a flat landing. Maybe it was coming from the mast, but it defo sounded that it was coming from the board. Any ideas?? Its an 08 Evo 80l.

Look behind you before you gybe, you could be running over a kiter[}:)]

555 said...

Zed said...

EVery time I gybed today and put my back foot down near the tail I heard what sounded like a creaking/cracking noise. It seemed to coming from the tail just around where the back footstrap is. The strange thing is the noise would only occur when I powered up the sail and put foot down on the tail. But if I then sheeted out, went off the plane and tried to replicate the noise I couldn't. So I'd plane away, gybe and same thing. Checked for cracks, couldnt see a thing, fin was A OK. I can't imagine the board cracking near the tail from something like a flat landing. Maybe it was coming from the mast, but it defo sounded that it was coming from the board. Any ideas?? Its an 08 Evo 80l.

Could be your back foot..

Perhaps it's a timber deck, and there's a join in the timber just there that's moving under load?

Sounds odd though. Usually it's the area under the front foot that cops a hiding.

Maybe try standing on it on dry land and bouncing up and down a bit?

Yeah it's a timber deck. It was almost as though something moved into place, because once it creaked you couldn't then replicate ther noise. I'd try slowing down, putting down my foot hard on the deck etc As long as there's nothing structurally wrong with it, its cool, I just don't want my board to snap 2kms out at sea.

With your fin in the box grab it and flex it sideways, sounds like that tiny bit of movement you get when the fin moves against the box. Symptoms seem right too- only does it when loading fin sideways through gybe or powering up sail. One of the waveboards I had made that noise sometimes, can't remember which brand it was.

I agree with mkseven, every time you gybe the fin is loading is changed to the opposite side.
It's not power on power off that makes the crack, it's the fin moving sideways in the box.
Shouldn't be a problem, as long as it's not flexing and fatiguing the bolts, they could eventually snap.

Mark _australia said...

Sounds like the board is stuffed, unserviceable, kangaroo edward, bvggered.
Mas as well give it away Zed. Where do I pick it up from?

damn it. I loved that board.

16 dubious way, mandurah

decrepit said...

So Zed, did you find the fin loose in the box like we predicted?????

Cause I had another nasty thought, what if the box is loose in the board????

Could also make a similar noise, but would need an immediate repair, apart from letting in water, it could drop out of the board the next gybe you go into.

Yeah mate, pushing the fun sideways quite hard caused the cracking noise. So well diagnosed guys. So is it the fin making the noise or the actual fin box?

Change the fin and find out

if it was the actual box moving wouldn't you see cracks or bubbles in the paint on the board?

Zed said...

decrepit said...

So Zed, did you find the fin loose in the box like we predicted?????

Cause I had another nasty thought, what if the box is loose in the board????

Could also make a similar noise, but would need an immediate repair, apart from letting in water, it could drop out of the board the next gybe you go into.

Yeah mate, pushing the fun sideways quite hard caused the cracking noise. So well diagnosed guys. So is it the fin making the noise or the actual fin box?

Zed,

I've noticed a similar noise when using some of my fins that were a little loose in the fin box. I think that most of the noise came from the securing screw because of the sideways pressure being exerted onto the screw. I made all of the fins a tight fit in the box by coating the inside of the finbox with a mould release agent, then rough sanding the sides of the fin base and coated both sides with a mixture of epoxy resin and filler (I used graphite powder as a filler). I then pressed the fin into the box and secured it with the screws, with the excess epoxy mix squeezing out the sides which I then scraped off level with the bottom. Getting the fin out after the epoxy has set can be a little tricky, better to remove it before the epoxy sets too hard (hint: try to use only a small amount of epoxy, just enough to stabilise the fin in the box). No more strange noises after doing this!

Also suggest you check for any hairline cracks at the base of the fin (level with the bottom of the board) when you push the fin sideways in both directions. Also, when you do this, does a gap appear between the sides of the fin and the moulded base?

GazMan said...

Zed said...

decrepit said...

So Zed, did you find the fin loose in the box like we predicted?????

Cause I had another nasty thought, what if the box is loose in the board????

Could also make a similar noise, but would need an immediate repair, apart from letting in water, it could drop out of the board the next gybe you go into.

Yeah mate, pushing the fun sideways quite hard caused the cracking noise. So well diagnosed guys. So is it the fin making the noise or the actual fin box?

Zed,

I've noticed a similar noise when using some of my fins that were a little loose in the fin box. I think that most of the noise came from the securing screw because of the sideways pressure being exerted onto the screw. I made all of the fins a tight fit in the box by coating the inside of the finbox with a mould release agent, then rough sanding the sides of the fin base and coated both sides with a mixture of epoxy resin and filler (I used graphite powder as a filler). I then pressed the fin into the box and secured it with the screws, with the excess epoxy mix squeezing out the sides which I then scraped off level with the bottom. Getting the fin out after the epoxy has set can be a little tricky, better to remove it before the epoxy sets too hard (hint: try to use only a small amount of epoxy, just enough to stabilise the fin in the box). No more strange noises after doing this!

Also suggest you check for any hairline cracks at the base of the fin (level with the bottom of the board) when you push the fin sideways in both directions. Also, when you do this, does a gap appear between the sides of the fin and the moulded base?

I'll pull it out at the weekend and have a butchers. Just glad it doesnt appear to be the board.

Keef,

Correct me if I'm wrong, I was sure that an 08 Evo 80l would have a tuttle box and not a US box?

Mostly done the job on powerbox fins but have also had to do the same with a number of std tuttle box fins as well. Little bit harder to do with tuttle base as the sides of the fin base don't have as much angle as a powerbox base which makes getting the fin out afterwards a bit trickier!

sorry gazman i havent seen the evo's, but if your looking for a good cheep mould release, try plastilease clear from fgi and give it two coats that should give you the same thickness as glad wrap, it's about $10 for 500g, 1/3 the price of other brands. and if your going to use a fin base as a mould dont have it so the fin comes in contact with any area where its bolted to the board, the idea of the fin is too wedge the fin in the box thats why the fin is tapered

I believe the wave & freestyle boards are all US box and yes the remainder of the range are tuttle/deep tuttle.

jp747 said...
i have always wondered why american box when it's the flimsiest why not just make all boxes tuttleregardless of kind of board!

Maybe because you can't tune the fin position in the box if it's Tuttle. Trimbox was an attempt at making a 'stronger' tunable fin, but it never really caught on. It was bigger, heavier and more expensive to produce.

Moving the fin forward or back by 10mm significantly changes the feel/handling of both my wave boards.

Besides, the US box isn't really a problem - you don't hear of many being torn out of boards, and they get some pretty severe treatment in the waves.

Pull the fin out get a torch look inside the box for cracks, get a thick screw driver put it in box and put pressure on like a fin would do and look for cracks opening or movement of the box using the torch.