Tri/Quad conversion of my old Goya, let the fun begin!

[manuel]

After trying a few boards with different fin setups and going back to my old trusty 2006 Goya Freewave 2006 in 77L, I was thinking that it'd be a great candidate for a quad/tri conversion...

Strong points:
- Instant planing
- Speed
- High wind control
- Chop control
- Volume under feet, ease of balance
- Light
- Jumps
- Easy to sail

Points to improve
- Can be a bit bouncy when the mast foot is backwards over chop at the jibe for example
- Feels a little stiff, doesn't turn fast enough
- A little too directional, can slide from under my feet
- Too crazyish
- Not easy to set the rail in the water
- Power box rear fin too far back
- Rear footstrap could be rather back (wide and long tail)

Tri Option:
First, I thought I'd look at what manufacturers do and I saw rapidly that they have a little of everything out there. The Tri setup seems relatively straight forward although the difference between the Pocket and the Pyramid is quite unbelievable when we look at the position and spread of the fins but it seems somewhat logical overall.

Quad Option:
However for the Quads, it's a little but of a mess, we have many differences in fins spread and position. Apparently, the most common thing is to line up the fins with the rear footstraps.

Rear strap + wide tail:
My goal is to make sharp turns easier despite its wide and voluminous rear end. Just like a Single, I was thinking about bringing the fins forward to loosen the board.

Fin type and size:
I was leaning towards a 2 x 10/11 and 1 x 16/17 in Tri. With assyms + toe (2 deg) + twist or a slight toe in with the symmetricals.
As for the Quad, 2 x 10/11 + 2 x 14/15. I'd like to try with big fins up front, it might make sharp turns easier?

Then, since the ProBox boxes are easy to install and to order, since they can be reinforced digging around some channels in the foam for the resin to bite, I could use them for all of my boxes.
http://www.proboxfinsystems.com/pages/install_movie.html
http://www.proboxfinsystems.com/pages/tips_movie.html

Do surf fins work well as side fins for a windsurfing application and as back twin fins?

Here are some config samples.
Remember that my Power Box fin cannot move and is slightly back

Quad




Tri


Quad + Tri

[MalibuGuru]

I own all 3 fin styles in various boards. One thing I can tell you is the board will perform differently. As a matter of fact, it might ruin the dynamics . I suggest that you only go with the thrusters . This would allow you to easily change it back .

PS, check out Chinook sailing. They have a bunch of Fins and repair products and might offer you some good advice.

[motogon]

Yes. It's not simply number of fins, it's different shape of bottom, width of tail,...

[U2U2U2]

Tri Option:
First, I thought I'd look at what manufacturers do and I saw rapidly that they have a little of everything out there. The Tri setup seems relatively straight forward although the difference between the Pocket and the Pyramid is quite unbelievable when we look at the position and spread of the fins but it seems somewhat logical overall.

Quad Option:
However for the Quads, it's a little but of a mess, we have many differences in fins spread and position. Apparently, the most common thing is to line up the fins with the rear footstraps.

Rear strap + wide tail:
My goal is to make sharp turns easier despite its wide and voluminous rear end. Just like a Single, I was thinking about bringing the fins forward to loosen the board.

Fin type and size:
I was leaning towards a 2 x 10/11 and 1 x 16/17 in Tri. With assyms + toe (2 deg) + twist or a slight toe in with the symmetricals.
As for the Quad, 2 x 10/11 + 2 x 14/15. I'd like to try with big fins up front, it might make sharp turns easier?

Then, since the ProBox boxes are easy to install and to order, since they can be reinforced digging around some channels in the foam for the resin to bite, I could use them for all of my boxes.
http://www.proboxfinsystems.com/pages/install_movie.html
http://www.proboxfinsystems.com/pages/tips_movie.html

Do surf fins work well as side fins for a windsurfing application and as back twin fins?

Here are some config samples.
Remember that my Power Box fin cannot move and is slightly back .%%%%%%

again IMO dont do the quad. Tri, TOE IN2 degree asymmetrical is great. 0--1.5 TOEIN symmetrical ok. ProBox for me limited to 15cm in length
Symmetrical surf fins ? is too general, yes they work as twins or sides if the proper shape and size. ProBox offer cant inserts, if inclined you can experiment with various angles just by changing the insert.

Some of the ProBox strength examples were prompted ny my suggestions.

On installation: I router out the hole to the underside of the board, slightly larger/wider than needed. I thne use pour foam 8lb to fill the entire cavity, re router the hole the the correct dimensions, inlay carbon and sglass as support for the box. Overlay the new box with the board bottom surface with sglass. All these can be obtained from Fiberglass Supply.

Its important to reflect the placement of the center fin on the boards in your example, how far from the tail. The tail width also affects placement
the 30cm point is the normal measure of tail width.

[westender]

After reading your list of Strong Points, I admire your ambition.

[U2U2U2]

[jingebritsen]

added weight vs any benefit may make this a futile exercise.

experiment with different fins, as is, may be far more fruitful. maybe change to an A box would be the extent of any major surgery.

again, technique may overcome any of the shortfalls you may perceive in this board. sail more lit up with a smaller fin. boom lower, harness lines longer comes to mind. friend of mine chronically rigs small sails, has his boom really high to help get planing earlier. he claims he can't get the rail to bite. i watch him, and keep saying the same stuff. lower boom, larger sail. he can't crouch low enough to leverage the rail down deep.

[U2U2U2]

yes indeed weight will effect things .

the box weight is 49 grams with screws

the installation materials 70 grams/ epoxy carbon, pour foam and s-glass

the small fins in the board photo weigh 44grams each, these are really light even for small fins, but are very hi tech with fin profile and material.

total for the addition 207grams OR 7.3 oz.

Never weighted the materials removed from the board to install, consider them insignificant.

Uou would take away the weight difference between the longer fin used as a single and the smaller thruster center fin, and subtract, from above.

In some of my conversions I have weighted things and keep notes, the typical gain has been 1/2 a pound , 8oz. When you add paint you will increase, depending of course how much you paint.

just as a weight example a foot strap, some DaKine unit when dry was 170grams, same when soaked 232grams = 62grams, or 2.5oz thats for 1
times 3 = 7.5oz, ever notice the difference ? Me neither

The very slight weight gain is offset to the extreme by the additional strong points.
Oh $ and ¢ spent, going to vary , depends on how much can be done by the builder, epoxy and carbon , sand paper ETC will all add up. Worth it, for me the first ride ends the speculation.

[cgoudie1]

I have ridden a Starboard Quad in every configuration I can think of.
My favorite was as a trifin (12 cm symmetrical side bites with a 20cm rear fin). More of a thruster configuration than trifin really. In this config,
it was turny and straight line solid in gnarly chop and big swell, but a
little bouncy.

As a Quad with 16cm fins forward and 12cm surf fins back, my best
description would be mushy under power, and sticky at the end of a
jibe. It would track ok , but rear foot input, just mushed the tail out to leeward. turny on a swell, but the feel was so imprecise, that I had
trouble figuring out exactly what the board was going to do next. This
really worked poorly in disorganized chop.

As a Quad with 12s forward, and 16s back it was better. Still a little
mushy, but in big swell the thing would turn with precision, and was very
playful. I had a lot of fun with the Quad this way, but only in big
smooth swell.

I never used the board in real waves, so I can't comment on that, but
if you don't sail with more bias toward your front foot, a quad setup may
not be for you, and the less front foot oriented you are, the less you
may like bigger front fins.

I sold the Quad after a season and it was gone in a week,
so obviously, there's a good market for them, just not the board for me,
and where I sail.

I'm riding an 2015 Open Ocean 79ltr tri fin now (again really a thruster
single combination with canted asym side fins). All the good aspects
of the Starboard in trifin mode, but a little surfier, and not as bouncy.
For me and my conditions, It's a keeper!


-Craig

[manuel]