Author Topic: Advice needed on quad fin setup for a 2018 Blackfish  (Read 1169 times)

Luc Benac

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Re: Advice needed on quad fin setup for a 2018 Blackfish
« Reply #15 on: July 11, 2018, 07:16:12 AM »
You need some information of what you need and regretfully it looks like Infinity did not provide that to you.
The inserts for the ProBox comes in four different colors/type that reflect the angle compare to vertical the fin would be subject to.
The purpose is to ensure that regardless of the bottom of the board, the fin once secured are vertical.
I have seen several time boards shipped without inserts, with wrong inserts and you then need to try which insert is the one that work for the board.
this also assume that the fin came with no cant or again this will need to be ascertained manually.

There are a few companies that stock the inserts and you will need do do a search for them as I have npot kept teh names and link. You can also contact Larry directly but be aware that turn-around can be uncertain at best.
Some shop sell a package but not sure if all four types come with it:
https://www.paddleboardspecialists.com/Pro-Box-Fin-Set/productinfo/LAPROBXFIN/
« Last Edit: July 11, 2018, 07:24:18 AM by Luc Benac »
Bark Vapor 14' x 26" 271L
* Black Project Hydro 77
* Kenalu Mana 82

Ace-GT 17'4" x 27" 313L
* Black Project Hydro 85
* Kenalu Mana 90

Infinity Whiplash 14" x 25" 262L

Bean

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Re: Advice needed on quad fin setup for a 2018 Blackfish
« Reply #16 on: July 11, 2018, 07:40:03 AM »
Thanks Bean for the advice, testing all the possible combinations is the plan as soon as I manage to get hold of probox inserts. Do you have by any chance the dimensions (lenght & depth) of the twins, centre and ventral fins you were using, to check if my impressions that the Stavron fins are too big is just that, an impression?

Also, I remember reading a while ago in a thread which I cannot manage to find that there are two fin box standards (US and cannot remember the other) that are very similar but differ by a small amount in width, does anybody have the width of the two box types?

Ripple, the board I was using was a 14' Fanatic Fly Race, so the tail alone will be different enough to render any comparison worthless for your more modern Infinity.  Also I was using the keel or elliptical style fins only.  As you probably already know, your fin size will be dictated by ability, conditions, your physical size and the board size and shape.

Yes, there are at least two different center boxes out there, primarily US Box and SURF Box.  The fins that have a hump on the bottom fo the tab are US Box.  For some reference, take a look at the black project web site.

http://www.blackprojectfins.com/which-base-do-i-need/

« Last Edit: July 11, 2018, 07:42:00 AM by Bean »

Ripple

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Re: Advice needed on quad fin setup for a 2018 Blackfish
« Reply #17 on: July 11, 2018, 07:42:31 PM »
Cheers, this is all very informative and i can see the light at the end of the tunnel. :-)

Bean, I would still be interested in knowing the dimensions of the fins you were using, not so much for knowing whatís the best setup for  my board, but just to understand if the central fin the board came with is supposed to be used in conjunction with the side fins or only as a single. Iíve seen some photos online of the blackfish being ridden with that same fin as a single (which I also do with no particular problem) so i am dubious that it would also work on a multi fin setup as it would probably be too big; as far as I understand the principle of the multi fin setup is to have an equivalent or similar area of a larger single not to increase drag. I am only after ballpark figures for the dimensions of the fins for a multi fin setup just to understand if the ones i have are way too big or not.

Also, does anyone know which angle correspond to the different inserts colours?

Ripple

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Re: Advice needed on quad fin setup for a 2018 Blackfish
« Reply #18 on: July 11, 2018, 07:46:40 PM »
Ps my side fins seem to have 0 cant, I have not yet checked if the boxes have any.

Luc,
Do you mind measuring your fins as well?

Luc Benac

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Re: Advice needed on quad fin setup for a 2018 Blackfish
« Reply #19 on: July 11, 2018, 08:01:48 PM »
If you are talking about a center fin, Larry has been promoting a 6" Stinger with a 7" base and 32 sqi surface. It has always been too big of a central fin for me when used with side fins.
When I still had a Blackfish, my favourite side fins where the 9" elliptical, the other again where too big for my use (I am only 6' and 170 pounds).
I am not running a multi-fin setup anymore anyway except sometime a ventral on my Whiplash. I had been trying to get the original center fin for it, a small triangular fin like the side  but could never get Larry to send me one so I decided to just give up on the whole thing and keep it simple after-all. I just use a board that is wide enough and stable enough for me in the first place without further ado. I keep it very simple and I stop trying to run a board too narrow for me and gaining some stability with the multi-fin.

Bark Vapor 14' x 26" 271L
* Black Project Hydro 77
* Kenalu Mana 82

Ace-GT 17'4" x 27" 313L
* Black Project Hydro 85
* Kenalu Mana 90

Infinity Whiplash 14" x 25" 262L

BrentP

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Re: Advice needed on quad fin setup for a 2018 Blackfish
« Reply #20 on: July 12, 2018, 12:22:55 PM »
Yes sorry I meant probox. It was past bedtime when i posted. :-)

I did start sanding down the ventral base but then I thought that not knowing if the fin is too wide or the box too narrow, it would be better to wait for the Larry Allison fins to arrive to make sure I sand the right part......

What bothers me the most is that Iíve made very clear to the dealer that I was buying that board from him specifically because it had the 4 fin boxes and because he included the fins in the price. I would have probably bought a different board otherwise, or a 2017 blackfish from a different shop for 33% less than what i paid for his, but he promised that he could get me a set of LA fins within few days so took the plunge on that.

I appreciate that maybe I will never get to the point of noticing any appreciable difference in performance between single and quad fin setup, but Moreton Bay is strongly tidal, and sometime two inches difference in fin depth can make the difference between having to carry the board from/to the shore for 100 metres or not, hence my intention to try the 4 smaller fins setup.

Also, the Stavron centre fin seems to be almost a full size fin, so adding the side fins, which seem also big compared to the LA, would probably slow down the board considerably.

By the way, is the flat side of the side fins supposed to face inboard or outboard on a race sup?


Hi Ripple i worked at Infinity for a few years and am familiar with the set up. FCS works in the boxes just fine but yes you need the cant inserts to use even the ProBox fins in the boxes. Larry can sell them to you or email direct Dave they can get you dialed i am sure. That's the whole point to the system. The Blackfish usually fits 6 degree or 8 degree depending on which year you have. I am not sure which degree it would be for 2018 sorry. The Stavron set is a good starter kit. The center fin is not too big or full sized at all it's a "kick" fin. If anything it may be too small. They made this set to have access to the system quicker since Larry's stuff is in high demand and usually a little tricky to find them available. I would check with him directly. It looks like you have fins sounds like you are over thinking it already (which is easy to do!) don't worry so much about it just put them in and paddle then adjust from there!

BrentP

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Re: Advice needed on quad fin setup for a 2018 Blackfish
« Reply #21 on: July 12, 2018, 12:27:45 PM »
I'm not questioning the quality of the Stavron fins, it's just that the side fins don't fit without inserts, and the 3 rear fins to me seem too big to be used all three together, as the central on its own is almost a full size single.

Also, before sanding the fin, I want to make sure that is the fin base which needs sanding, not the box.

You will need inserts whether they are FCS tab or ProBox that's how the system works. All you do is take 200 and sand both sides of the base from just infront of the pin to the front screw hole. The 3 rear fins are not too big if anything they might be too small depending on what you want to do.

Ripple

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Re: Advice needed on quad fin setup for a 2018 Blackfish
« Reply #22 on: July 12, 2018, 08:36:24 PM »
From what I have read in the many posts on this forum from Larry himself, the concept is to have three fins at the back that have a similar ďside liftĒ of a standard size single fin, so not to increase drag. Considering that the centre I have is pretty similar in size to the oem centre fins on my other sups, and that everyone seems to use the same fin as a single on the blackfish, adding side fins to it would be contradicting the principle above and make the board overfinned - more drag. At least this is according to my logic, but Iím happy to listen to different opinions. Maybe I should ask to the man himself. Is there a way of tagging forum members?

Larry Allison

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Re: Advice needed on quad fin setup for a 2018 Blackfish
« Reply #23 on: July 14, 2018, 10:39:57 AM »
From what I have read in the many posts on this forum from Larry himself, the concept is to have three fins at the back that have a similar ďside liftĒ of a standard size single fin, so not to increase drag. Considering that the centre I have is pretty similar in size to the oem centre fins on my other sups, and that everyone seems to use the same fin as a single on the blackfish, adding side fins to it would be contradicting the principle above and make the board overfinned - more drag. At least this is according to my logic, but Iím happy to listen to different opinions. Maybe I should ask to the man himself. Is there a way of tagging forum members?
Sorry for problems my friend. I cant control what board companies do but I can help you. PM me here and I will Square you up with the right set up. Mahalo,,Larry

Larry Allison

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Re: Advice needed on quad fin setup for a 2018 Blackfish
« Reply #24 on: July 14, 2018, 10:51:26 AM »
 Considering that the centre I have is pretty similar in size to the oem centre fins on my other sups, and that everyone seems to use the same fin as a single on the blackfish, adding side fins to it would be contradicting the principle above and make the board overfinned - more drag. At least this is according to my logic, but Iím happy to listen to different opinions. Maybe I should ask to the man himself. Is there a way of tagging forum members?

This is because something is better then nothing which drives me crazy by these companies to sell Stuff. You are right DRAGGGGGGGGGG. Dave at Infinity is my buddy and sometimes when trying to make stuff like fins isn't the easiest. But that is why I am here to help you and Dave get it right for your liking my friend.

Ripple

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Re: Advice needed on quad fin setup for a 2018 Blackfish
« Reply #25 on: July 14, 2018, 05:17:50 PM »
Thanks Larry, PM sent.

Just to clarify the situation and to avoid spreading unnecessary bad feedback on companies/people not directly involved, my dealings were with an Australian retailer, not directly with Infinity or Dave himself.