fin placement twin with trailer???

chippy61 · February 25, 2012, 5:16am

HI Mitch !

maybe if you are going to cut off the fins and NOT put in plugs or boxes [??!!] , you could shorten the sideys 1/2" as plugging would have done , and have a larger [than , say , 'GS' sized] back fin , if it is a 'THRUSTER 'feeling you are after ?

" How about you (sorry to hijack this thread!)? How do you find the Walden?"

as I posted on the 'chip's pic[k]s ' thread , 'I am still LOVING this setup !!' the most of all I have tried .

So far , what I have been feeling with this setup , versus 'traditional' fins , is the ability to turn a bit more 'top to bottom' ... and hold . Where previously , with four smaller 'traditional' fins , with the board's thickness , and width , and flatness , and wide , thick , flattish tail ....[combine this with only 63kgs rider weight ] ... there was some slip and skip during turns [and I'm not really a big fan of that !]

cheers !

ben

pico · February 25, 2012, 5:41am

"I was thinking of foiling up some more, less keel like fins. That way I could move the fin base back without the fins hanging out past the rail. "

try out my suggestion. with the 1/8" toe and much less cant your rail line wont be compromised. my keels have a short base and extended rake just like yours. I got my placement measurement by marking the back of the fins for a 6" keel base, even though the ones i used have like a 3.75" base. I just marked the rear dot then measured 6" up with a 1/8 toe and marked the front. I used the front as the placement marker and drew a thin line to attach the fin to. works very well with out tracking due to the minimal base.

mitcho · February 25, 2012, 7:53am

Right, I’m working on 6 Narions Rugby today, my birthday tomorrow, so Monday I’m onto it. Hopefully I’ll get it finished before Friday as I plan a little day trip down the coast (4 hours away!)

Your fins look amazing. They must give some serious hold! Did you make them?

Thanks for your input.

Mitch

chippy61 · February 25, 2012, 11:02am

hi mitch !

good stuff ,

I look forward to seeing your modified board !

the fins you see are four of the fcs webber crv's [commercial ones]

...happy birthday for tomorrow , mate ...have a GREAT one !

cheers !

ben

yes..they hold in well !

chippy61 · February 26, 2012, 2:07am

"I was thinking of foiling up some more, less keel like fins. That way I could move the fin base back without the fins hanging out past the rail. "

hi Mitch !

Well, I played around with your template [traced from my computer's screen ] , so...here are a few smaller , more upright trailing edge variations that I came up with , for a more 'thruster'-like feeling [... if that is still what you are after [ ?yes?] , rather than a 'stabilised' twin keel feeling ??]

I 'may' go with 'template 2' , myself , in my Walden ...I'd be thinking a yellow-fluoro-tinted fibreglass , 'corematted' , and thin-foiled version , to hopefully get a bit of flex / 'twang' out of them ?

Then I guess , when you have a larger back fin in your modified fin setup, we can compare notes on how yours rides , and mine ...

oh , and ...

"HAPPY BIRTHDAY TO YOU " ....enjoy !

cheers mate !

ben

[close to ? ] your original template ...

the one I 'may' do for the Walden .

Also, by dropping a [slightly curved-back ] line between the '2' and '3' [inch] measurements on this grid , and rounding the tip of the fin , I 'could' make a [small cutaway, and about 4 1/2" deep] thruster fin , if I was after a 'truer thruster' setup template ...just thinking aloud / allowed !]

"that's not a cutaway ...THIS is a 'CUT-AWAY' !" [ Paul Hogan , eat ya heart out !] ...ha !

[in fact , this may be closer to a 'hockey stick'-type fin template [?or a hatchet? from Futures ?]

chippy61 · February 26, 2012, 3:49am

hi again , Mitch !

here again is 'template 2'. This time , it's been further modified , as I mentioned , so you could get a 'thruster' side fin template [or 3] out of it , if you wanted ?

mitcho · February 26, 2012, 7:22am

Wow, you’ve been busy Ben! My only point of reference is the Hydrodynamica Simster set up (and what I’ve seen on here), and keels seem to be what works on these little boards. Maybe a pure thruster fin setup would be too loose and squirrelly? Decisions!

chippy61 · February 26, 2012, 9:57am

big back fin ?

chippy61 · February 26, 2012, 9:32am

plan b's : -

big QUAD fin setup ???

5 fins ?

6 fins , all the same size ?

mitcho · February 26, 2012, 9:14pm

I’m going to go the chop in the morning and sand the crap off. I’ll make a few pencil marks and see how I feel. My gut says to keep the trailer small but move it forward and then see how your suggested side fin positions look on the board. That should allow me to decide what mods to make to the keels/rail. I like the look of your version 1 template and that would probably be my first port of call. I’ll let you know in about 15 hours!

Cheers!

Mitch (another year the wiser.)

mitcho · February 26, 2012, 9:27pm

Plan b! This is plan b! You’re talking c, d and e!!! Question: for the increasingly cut down templates, would you alter the position, toe cant etc? If not I could mod them in situ. It would be a bit of a headache to put in fin plugs at this point I don’t want to mess about with the structural integrity of the hollow wooden construction. I’m happy enough to cut off find and start again. Plus I believe fin tabs are tricky with wooden fins. Grub screws can pierce the tabs and water ingress can ruin the fins. I want a surf on Friday too so glass ons will be quicker! Next HWS I build will have them because I will have had this discussion already!

6 fins, are you serious!

I must admit, I do like the look of Slaters 4+1 setup but then again I’m not riding a sub 6 foot board at pipe! it’s a bit like my keels and stabaliser any way!

Cheers,

Mitch

chippy61 · February 26, 2012, 11:00pm

"6 fins, are you serious! "

....sure , Bert Burger [from the 'old days' here] , had seven on a few of his ?'barracuda'? boards

"Question: for the increasingly cut down templates, would you alter the position, toe cant etc? If not I could mod them in situ."

the QUICKEST and easiest solution would be to re-template them with the no.1 template , where they are now. That way , you only have the back fin to move forward , so you can work out the difference THAT one movement is making , firstly.

If you still don't like it , then , well, I guess you can move the sideys back.

but I would reshape those sideys first , and go with a bigger back fin [not as big as the sideys but something , say , 4 x 4" , with an inch or two worth of rake ]

anyway , that's just me ![I would have made a narrower board all around , too , but then it wouldn't be the simster type thing or whatever it's called , that you have there

So, can you please keep us posted on your progress , and ...your first surf on the modified version , eh , Mitch ?

cheers mate !

ben , fintinkerer , west oz

mitcho · February 27, 2012, 9:02pm

OK Ben, having taken all the advice have told me into consideration, I’ve now cut all 3 fins off and marked up your original recomendation.

Rear fin (same size), (it’s a scaled down John-John Florence thruster template if you are interested!) is 3 1/2" from tail and the as yet unmodified keels are 10 1/2" You can see I would have to extend the wings about an inch in this instance. (The little black mark next to rear base of keel is where the wing would need to extend to.) The fins are just sticky taped to the board at this point! The rear does look small but I’m going to try it like that. Once I reshape and foil the keels down to your 1st suggested template it all might look a bit more balanced. My thinking here goes back to your question twin + trailer v thruster setup. I guess stricly speaking its a twin with stabaliser but somewhere towards a thruster! This board isnt designed for a thruster config (planing hull) so I suppose I’m heading down the right path. The keels offer a level of stability due to thier size so I’m happy to keep the trailer small as it is. I wanted the trailer for when the surf is a little bigger. I thought it may give me a bit more versatility with the board. Also, it’s a nod to the thruster design! (Am I confusing you/myself!!?) If it doesnt work, I’ll beef up the rear fin at a later date.

Then I got thinking. (Always a worry!) So I moved the keels back up an inch to match with the existing wing and remarked them from there:

As you can see it kind of lines up ok and looks “right”? I think once I have reduced the rake on the trailing edge the whole thing will start to look better. Reducing that toe in has helped a heap with the fin overhanging the rail. It’s not exactly as you suggested so what do you think?

I’ll try and get those fins sorted tomorrow and post some more photos.

Cheers,

Mitch

mitcho · February 27, 2012, 9:11pm

I just re-read your comment:

“try out my suggestion. with the 1/8” toe and much less cant your rail
line wont be compromised. my keels have a short base and extended rake
just like yours. I got my placement measurement by marking the back of
the fins for a 6" keel base, even though the ones i used have like a
3.75" base. I just marked the rear dot then measured 6" up with a 1/8
toe and marked the front. I used the front as the placement marker and
drew a thin line to attach the fin to. works very well with out tracking
due to the minimal base."

Hmm, I’ll think about that once I’ve reshaped the keels. That would have them heading north again and I quite like the position I came up with. One more question, I’m tempted to pull the keels out 1/8" towards the rail so they match the hip a little better. Do you think it’s worth it?

Just to qualify EVERTHING I’ve posted about fins, I actually know very little. I’m going on gut instinct here!

Cheers,

Mitch

chippy61 · February 27, 2012, 9:34pm

hi mitch !

I like the second photo , but would even move the fins closer to the rail , and slightly forward of where they are in that photo [but that's just if it was me ?!]

where are the fins pointing ? at the nose ? , or ....outside of it ?

I would also put in three back fin plugs , [or , preferably ...a small [?6"? ] fin box , or probox , even?] , and make a gs or bigger sized back fin.

this , of course , is making it more like a 'thruster' , instead of the 'twin with trailer' [your original setup idea]

[bear in mind ... because of the wide thick flat outline , it will still not surf 100 % like a shortboard 'normal' thruster , as long as youre okay with that ??!!]

so ....it will depend which YOU want to do , eh ?

cheers !

ben

mitcho · February 27, 2012, 9:52pm

Yes Ben, I think I will move the keels out that little bit so the hit the wing just sweet. That will have them 1 inch from rail. I’ll keep that 1/8 toe in. Like I say, it looks right! They are pointing well outside the nose but like I said, the nose is so foreshortened that they are bound to. I’ll move them that little bit forward too. I take it there’s no magic numbers here, just trial and error and feedback! Most appreciated too.

Mitch

chippy61 · February 27, 2012, 11:35pm

" I take it there's no magic numbers here, just trial and error and feedback! "

Yes , I think so !

....'purists' , pseudo-scientists, and the theorists may disagree , however .

I'm fine with that , to each their own , eh ?!

To me , personally , there is just NO substitute for time spent in the water . Riding lots of different boards , trying fins , and different things , and FEELING out a board , and what works for you , with your style , your waves ...

cheers !

ben

mitcho · February 28, 2012, 9:27am

Good morning/evening!

Well my latest slight complication is that our fin outlines are different.I’ve lined up the rear cut away section on template and fin to show you:

However, I’ve had another look at your suggestions, had a little play, and come up with this:

That’s reduced the area by quite a bit but still maintaining it’s keel-ish properties. Any touughts? If I don’t hear back I’ll just get on with it! I have 3 days to get these babys foiled, glassed, attached and sanded! That sounds like a long time but not for a back yard hack like me!

Mitch

chippy61 · February 28, 2012, 10:12am

go for it mitch !

cheers

ben

mitcho · February 28, 2012, 2:56pm

OK,

I’m covered in sanding dust and resin but making progress (if anyone is interested!) This is where the keels ended up once cut down:

I think this will be a good position for them. Only an inch off the rail (I hope they will be ok out there!) but lined up with wing/hip on flat side of base and trailing edge of keel:

Top View (no cant as yet, stuck on with sticky tape!):

The new (modified) fins look right on the board so now I’m glassing them up for strength and hopefully I’ll get them tacked on tonight. I’ve tacked the rear on already and I have to say it’s looking rather small! I’ll give the board a test drive on Friday and see if that needs beefing up (as Ben suggested). I cant wait!

The Keel bases are 5 inches long before the cut away section. I’m wondering if 1/8 inch toe in is enough? I don’t have a clue but everything is looking very parallel. I’m sure it will be fine but I thought it worth mentioning.

Any feedback?

Side view: