Get this!

Can't find the right forum, then post your general surf-related remarks here!

Moderators: jimmy, collnarra, PeepeelaPew, Butts, beach_defender, Shari, Forum Moderators

User avatar
MrMik
regular
Posts: 356
Joined: Wed Jul 18, 2012 7:24 pm

Re: Get this!

Post by MrMik » Wed Jan 14, 2015 2:04 pm

The only fin hum I've ever experienced was on a 9' Nigel Beckham twin fin mal. The fins were glassed on and not wobbly. I kind of liked the hum, it was like the board was cheering me on when I was starting to go fast.

I thought hum has something to do with the trailing edge being too blunt, or rough, but I really don't know.

Roy_Stewart
barnacle
Posts: 1540
Joined: Sun Mar 14, 2010 4:39 pm

Re: Get this!

Post by Roy_Stewart » Thu Jan 15, 2015 6:28 am

MrMik wrote:
Roy_Stewart wrote: ...
...
The real issue here though is that the shaper has taken what looks like about 5mm off the top of the box at the rear and 2.5mm off the front. It would have been better if he'd removed the material from the bottom of the box prior to installation. It's a hassle as the box is designed to be a certain height.
...
...
I don't understand how this could possibly help. Removing material from the bottom (closed) side of the fin box could help if the tail thickness is thinner than the thickness of the box. But the box would then still not match the tail rocker and at least 2.5mm would need to be removed at the top rear.
In short, one could only remove that portion from the top of the box that would otherwise be removed from the bottom in the middle, but not all of what gets removed from either end.
That's nonsense, it's nothing to do with tail rocker and everything to do with the board being thinner than the box.

I can show you via a drawing if you don't get it.

Grinding large amounts off the top of boxes is a shoddy practice.

Roy_Stewart
barnacle
Posts: 1540
Joined: Sun Mar 14, 2010 4:39 pm

Re: Get this!

Post by Roy_Stewart » Thu Jan 15, 2015 6:42 am

el rancho wrote:measure the depth of the fin box and then the depth of Roy's fin before you do anything
Best not to do anything to the existing fin, as it can't be fixed unless the pin is moved up. Moving the pin on the existing fin isn't a good idea, best to print another fin.

If I'm going to make custom adjustments to the fin tab with a higher pin position for this particular board then I'll be needing the original fin back intact.

User avatar
huie
Local
Posts: 607
Joined: Thu Sep 18, 2008 7:28 pm

Re: Get this!

Post by huie » Thu Jan 15, 2015 7:42 am

roy
i dont want to rock the boat

but the pin in the plastic fin is to high compare it to the t/a y ou can see that

the yank box total depth 1'' ausie 1'' i custom fit single fins to boxes for the yanks on a daily basis''
believe me when you do this you can only fit to a clean installed box
you CAN NOT ADJUST TO STUPIDITY

the pin is to high

Roy_Stewart
barnacle
Posts: 1540
Joined: Sun Mar 14, 2010 4:39 pm

Re: Get this!

Post by Roy_Stewart » Thu Jan 15, 2015 9:52 am

huie wrote:roy
i dont want to rock the boat

but the pin in the plastic fin is to high compare it to the t/a y ou can see that

Nah the pin is in the correct place for a properly installed box, the pin is shallower on the TA fin because to allow for people grinding the top of the box they make the foiled part of the fin enter the box i.e. below the top of the box there's some fin before reaching down to the top of the tab. That's not what the box designer intended, it's a workaround by fin makers to make up for box installers who screw up.

The catch with that workaround is that it means that fins are limited in thickness to the width of the box slot i.e. about 9mm. All our singles are thicker than that at the base so the fin can't be made to enter the box. Therefore if significant amounts have been removed from the top of the box we have to do a custom pin position for that box.

the yank box total depth 1'' ausie 1'' i custom fit single fins to boxes for the yanks on a daily basis''
believe me when you do this you can only fit to a clean installed box
you CAN NOT ADJUST TO STUPIDITY
Actually the yank boxes are shallower by 2.5mm.

I've done a sh(tload of research on this and had the word from Jim Phillips regarding how Bill Bahne designed the box to work. Most fin makers don't even get how it is suppposed to be and the box installers don't either.

There's a reason why the USA boxes have tabs to position the box ( height wise) in the board.. it's so that the boxes are not set too high and then ground off.

User avatar
huie
Local
Posts: 607
Joined: Thu Sep 18, 2008 7:28 pm

Re: Get this!

Post by huie » Thu Jan 15, 2015 11:10 am

more to say latter busy


cheers huie

User avatar
tootr
Duke Status
Posts: 14544
Joined: Tue Jun 21, 2005 9:50 am
Location: orstrayleeyah

Re: Get this!

Post by tootr » Thu Jan 15, 2015 7:55 pm

What's the consensus for size/ type of BLEFs to try in a bonzer?

6.5"??

Roy_Stewart
barnacle
Posts: 1540
Joined: Sun Mar 14, 2010 4:39 pm

Re: Get this!

Post by Roy_Stewart » Thu Jan 15, 2015 8:24 pm

To the best of my knowledge 6.5" Spitfire blef is the only size which has been used in bonzers so far (by two riders, with good results).

User avatar
kayu
Local
Posts: 612
Joined: Mon Dec 27, 2010 1:24 pm

Re: Get this!

Post by kayu » Thu Jan 15, 2015 10:17 pm

Roy_Stewart wrote:

That's nonsense, it's nothing to do with tail rocker and everything to do with the board being thinner than the box.
Fin boxes are manufactured straight........and bottom curves are curved 99.99% on the time...its impossible to install a slide box correctly , without grinding it to suit the tail rocker.

User avatar
huie
Local
Posts: 607
Joined: Thu Sep 18, 2008 7:28 pm

Re: Get this!

Post by huie » Thu Jan 15, 2015 10:33 pm

Roy_Stewart wrote:
huie wrote:roy
i dont want to rock the boat

but the pin in the plastic fin is to high compare it to the t/a y ou can see that

Nah the pin is in the correct place for a properly installed box, the pin is shallower on the TA fin because to allow for people grinding the top of the box they make the foiled part of the fin enter the box i.e. below the top of the box there's some fin before reaching down to the top of the tab. That's not what the box designer intended, it's a workaround by fin makers to make up for box installers who screw up.

The catch with that workaround is that it means that fins are limited in thickness to the width of the box slot i.e. about 9mm. All our singles are thicker than that at the base so the fin can't be made to enter the box. Therefore if significant amounts have been removed from the top of the box we have to do a custom pin position for that box.


Actually the yank boxes are shallower by 2.5mm.

I've done a sh(tload of research on this and had the word from Jim Phillips regarding how Bill Bahne designed the box to work. Most fin makers don't even get how it is suppposed to be and the box installers don't either.

There's a reason why the USA boxes have tabs to position the box ( height wise) in the board.. it's so that the boxes are not set too high and then ground off.[/quote]



yes all my single fins are 11- 12 ml but roy i learn t that if i machined the base to a good fit before i foiled
pin center hole7 ml i don't get problems i am guessing the center on your pin hole to be 8 ml
for these ausie boxes its to high
i send the same fin to yanks with no complaints if there's problems i am not hearing it?
i have never used a bahne box but my reliable source gives me a depth of 1' from top of box to inside bottom which matches my instal pattern but you do have me thinking so i will get a couple out dissect one and instal the other as my yank version something you may need to look at
i do not see how making fins to satisfy bad instals is a good way to go but i stand by its the pin and the pin channels that is the most important you can see this in the link http://1.bp.blogspot.com/-3w4d5ZiGUH8/V ... C02692.JPG
http://1.bp.blogspot.com/-FaEsB7VLmv4/V ... C02595.JPG

User avatar
huie
Local
Posts: 607
Joined: Thu Sep 18, 2008 7:28 pm

Re: Get this!

Post by huie » Thu Jan 15, 2015 10:45 pm


Roy_Stewart
barnacle
Posts: 1540
Joined: Sun Mar 14, 2010 4:39 pm

Re: Get this!

Post by Roy_Stewart » Fri Jan 16, 2015 4:29 am

Hi Huie,

All our fins are fitted to a box perfectly before they are sent, there's no issue with the pin position for any box which hasn't been munted by the box installer.

If your fins have a position of 7mm then they'll have exactly the same problem if 5mm is ground off the box, maybe you've just been lucky ...so far we've only come across two boards which have had bad box installations.

Anyway we can do custom pin positions if required.

What most fin makers don't realise is that the boxes were not designed to have the bottom of the fin base contacting the bottom of the box. It's supposed to be an interference fit with the tab being thicker at the tab/fin junction. If the fin is thicker than the tab then the fin provides the interference fit. Most fin makers used the contact between the tab and the base or floor of the box to locate the fin but that's an ad hoc solution.

Many fin tabs are made narrower than the box, which is why there are shim kits sold to fix it. Our fins are exactly correct in tab width.

User avatar
huie
Local
Posts: 607
Joined: Thu Sep 18, 2008 7:28 pm

Re: Get this!

Post by huie » Fri Jan 16, 2015 11:17 am

Roy_Stewart wrote:Hi Huie,

All our fins are fitted to a box perfectly before they are sent, there's no issue with the pin position for any box which hasn't been munted by the box installer.

If your fins have a position of 7mm then they'll have exactly the same problem if 5mm is ground off the box, maybe you've just been lucky ...so far we've only come across two boards which have had bad box installations.
[b]no the true position in the box i posted is 7 mil any higher and the pin will ride on the top of the channel hence making the front sit proud
Anyway we can do custom pin positions if required.

What most fin makers don't realise is that the boxes were not designed to have the bottom of the fin base contacting the bottom of the box. It's supposed to be an interference fit with the tab being thicker at the tab/fin junction. If the fin is thicker than the tab then the fin provides the interference fit. Most fin makers used the contact between the tab and the base or floor of the box to locate the fin but that's an ad hoc solution.

Many fin tabs are made narrower than the box, which is why there are shim kits sold to fix it. Our fins are exactly correct in tab width.
well they should not make fins
anyway Roy it is good to dissect these matters
i am of to order some bahne boxes

cheers huie

User avatar
huie
Local
Posts: 607
Joined: Thu Sep 18, 2008 7:28 pm

Re: Get this!

Post by huie » Sat Jan 17, 2015 7:31 am

saltman you have missed my point to roy'' it is the center of the pin hole'' there is less than 1 ml between good and bad in the box i posted
your pics are to small to argue the point on-- but with all i can see there is no way they are in the same alignment as i do not buy t/a fins or any others i can not say
weather the pin size for t/a is different
roys pin by looks is the same as the one i posted. which is 4ml counting for the very small residual fillet from the molding the difference is 2 ml for up and down movement so its a fine line that the setting of the pin becomes
this is not to cause angst but to enlighten :-D-: bigger pics may prove your point ? as of now i remain convinced i am right the pin is to high
http://1.bp.blogspot.com/-3w4d5ZiGUH8/V ... C02692.JPG

cheers huie

Roy_Stewart
barnacle
Posts: 1540
Joined: Sun Mar 14, 2010 4:39 pm

Re: Get this!

Post by Roy_Stewart » Sat Jan 17, 2015 9:15 am

Sorry Huie but the pin position is fine for properly installed boxes, the point is that no pin position can be correct for boxes which are ground down by 5mm AND boxes which have not been ground down significantly, on fins which are thicker than the box slot... it's elementary old sport.

User avatar
huie
Local
Posts: 607
Joined: Thu Sep 18, 2008 7:28 pm

Re: Get this!

Post by huie » Sat Jan 17, 2015 9:46 am

ok Roy i understand you defending your position''

but i do not understand why? you want to turn good logical information into an i know best.

if i look at the poor quality pic i see your front tab siting high yet in the yank made fin it sits flush
the thickness of the fin has no bearing on it as most box fins are machined to fit regardless of foil thickness
and if you are suggesting that a sander has sanded the box down 5 mll or more then why would we be even bothered about such stupidity.
no matter how we do something someone will all-ways be complaing
Roy you will learn you will never ever be able to accommodate the clowns that buy boards and can not even tighten some screws on a fin -- they will lose them and all ways blame you.
(not aimed at saltman)
pin center line 7ML
have a nice day old sport :-D-:
cheers huie

Roy_Stewart
barnacle
Posts: 1540
Joined: Sun Mar 14, 2010 4:39 pm

Re: Get this!

Post by Roy_Stewart » Sat Jan 17, 2015 4:12 pm

huie wrote:[


and if you are suggesting that a sander has sanded the box down 5 mll or more then why would we be even bothered about such stupidity.
That's exactly what's happened, and I'm bothered about it because Saltman needs a fin to fit the box.

I made several points about fins fitting Bahne boxes, you've mixed them up a bit in your reply so I'm not surprised that it doesn't make sense. Your reply wasn't quite logical.

I've covered the relevant info above so don't want to repeat it.

All the best and thanks for weighing in.

User avatar
huie
Local
Posts: 607
Joined: Thu Sep 18, 2008 7:28 pm

Re: Get this!

Post by huie » Sat Jan 17, 2015 8:07 pm

Roy_Stewart wrote:
huie wrote:[


and if you are suggesting that a sander has sanded the box down 5 mll or more then why would we be even bothered about such stupidity.
That's exactly what's happened, and I'm bothered about it because Saltman needs a fin to fit the box.
off course and thats good'' but why did you not ask saltman to measure the depth and then the debate would have changed slightly
I made several points about fins fitting Bahne boxes, you've mixed them up a bit in your reply so I'm not surprised that it doesn't make sense. Your reply wasn't quite logical.
so now your saying he has a bahne box installed and they have sanded 5 mil of it
i find that hard to believe
if you are confused with my detailed info then you are in denial


I've covered the relevant info above so don't want to repeat it.

All the best and thanks for weighing in.

Post Reply

Who is online

Users browsing this forum: No registered users and 52 guests