Tuning Hobie Turbo Fins

[dsafety]

Santa brought me a set of Turbo Fins for my Revo. Now maybe I will be able to keep up with the rest of the fleet.

These fins have an adjustment that controls the stiffness of the blades. According to the instructions, stiffer blades go faster but take more energy. More flexible blades are easier to peddle but do not provide as much thrust.

I am curious as to how other users tune their fins. Is there a noticeable difference between one end of the adjustment spectrum and the other? Is it important that both blades have the same tension? If so, how do you measure the tension to make each each blade has similar stiffness?

Bob

[dorado50]

Keep 'em tight Bob. If you don't want to expend energy an electric motor would come in handy. Its pretty cool watching those with motors zip around. On the other hand, fishing from a paddle or peddle yak provides one with a great workout. If it were'nt for the workout and the challenge of boating a big fish from the yak I'd fish from a boat all the time...

[WahooUSMA]

I have those babies tightened all the up.

[mtnbykr2]

run em tight "D" you won't believe the difference I have had them for a couple years now they make a huge difference

[steveooo]

Originally Posted by dsafety

Is there a noticeable difference between one end of the adjustment spectrum and the other? Is it important that both blades have the same tension?

Bob

I'm sure this will vary with user, but I can't really tell a difference between the two settings. I do want the most out of them (even if is only in my mind), so I tightened them up from the get-go. However, I do notice that over time, they will loosen themselves. I used to check them every trip, but not I've gotten so lazy that I've let them slip, and I couldn't tell you what setting it is on now...

[lterrero]

I keep my fins tight, too loose it feel like I'll drop theme Any time

[Billy V]

Tight is good.

Also- check to see your fins are even when the pedals are held together. This adjustment is done by turning the nuts on the end of the steel cables. Its a balancing act.

[Hypoxic1]

If ya wanna go fast just get an evolve!!

[lterrero]

Originally Posted by Hypoxic1

If ya wanna go fast just get an evolve!!

What's the hurry???

[-scallywag-]

There is a pretty good post/test on the hobie forum....I think it was done by a local member "roadrunner". Also lots of good info on lubing/adjusting your drives too.

It seems like the conclusion was that although running the fins "tight" makes the fins harder to push, it did not increase the top speed.

After messing around with the settings alot, I decided I like to run mine pretty loose.....alot less peddle pressure with no loss in speed.

[dsafety]

Originally Posted by -scallywag-

There is a pretty good post/test on the hobie forum....I think it was done by a local member "roadrunner". Also lots of good info on lubing/adjusting your drives too.

It seems like the conclusion was that although running the fins "tight" makes the fins harder to push, it did not increase the top speed.

After messing around with the settings alot, I decided I like to run mine pretty loose.....alot less peddle pressure with no loss in speed.

Thanks Scally,

I found the post on the Hobie site. If Roadrunner is right, and it appears that he knows what he is talking about, most of the posts prior to yours have been passing on bad advice. I have asked Roadrunner to join this discussion when he has a chance.

As for me, I think I will start out with the fins set loose. Thanks for the heads up.

Bob

[Iceman]

I decided I like to run mine pretty loose.....alot less peddle pressure with no loss in speed

This makes sense in the way the fins propel you. The stiff fin would create more resistance, but not more forward momentum. The slight cupping and bend seems like it would give you more forward momentum without working as hard. The forward part of the fin is always equal due to the stainless mast.

[Nic D]

I have mine set in the middle some where... and I like them that way

[dorado50]

I prefer them tight. The harder the workout the better I feel.. Bad advise? I'd say more like personal preference Bob.

[Nic D]

Originally Posted by dorado50

I prefer them tight. The harder the workout the better I feel.. Bad advise? I'd say more like personal preference Bob.

I don't think its bad advise...

I haven't read the thread spoken about above, but wouldn't make sense that you either are pushing more water or less water?

The way I think physics work is if you peddled two different sets of fins, (one tight and one loose ) at the same pace the tighter fins would move more water than the loose fins.

Now in my albeit small brain, its logical that that tighter fins would require you to spend more energy. The loose fins would require you to peddle more times to move the same amount of water as the tighter fins. So it turns out to be less reps but harder or more reps but easier. Your pick!

I'll stay with the middle of the road in this case.

[dsafety]

As a person who has spent a lot of time on sailboats I will add own my small brain opinion. The Hobie fins are really foils just like sails or airplane wings. You get lift or in the case of the fins, forward thrust.

On a sailboat, when the wind is light, you want a lot of curve in the sail. When the wind is strong, you flatten the sail and get more speed. I cannot explain the physics but it just works.

One of the things mentioned in the post on the Hobie site was that kayaks never reach a speed where the "flatter is faster" rule works. I have no idea if that is a true statement but if it is, it makes sense that having a fin with more curve will provide more thrust.

I should not have labeled other's opinions as "bad advice" so if anyone was offended, please accept my apology. What I should have said is that we now have a different theory to consider.

When everything settles out, the difference between one setting and another is probably in the noise and will not have much of an effect on the average guy's day on the water. On the other hand, if you take into consideration that some guys, Skallywag comes to mind, put thousands of miles on their yaks every year, having your gear set up so it provides the most most efficient propulsion could save a lot of wear and tear on the body.

Bob

[dorado50]

I kinda figured you were a sailboat guy.

[FischerFritz]

Just received a new revolution ultimate fishing package from OEX ocean side. Those guys are great. Wondering the same thing. I set my previous outback at the stiffest setting and it worked well.

[lterrero]

Bob, is a moving foil and I think is more like a prop, high & low RPM, high pitch low RPM ?

[roadrunner]

It's perfectly understandable that many here believe the fins are faster when adjusted to the tight position. After all, that's what the Hobie instructions say. Moreover, Hobie initially set up the Turbos this way for the first Pro Angler boats.

The concept was based on some of the faster fish, so if you're pedaling along at about 20 MPH or so, it would probably work fine. Unfortunately it just doesn't happen that way in the kayak speed realm that we operate in.

Now in their 3d generation, the current Turbos are more forgiving of an overtightened leach than the original version, but the difference is still very noticeable, especially over time and distance.

As Iterrero indicates, the fins rotate much like a prop blades, needing more twist as the cross section gets further away from the hub (sprocket shaft). When set too tight, the fins are over-pitched and feel like you're batting boards back and forth -- indeed, a large part of your thrust is going straight out the side and providing lots of extra exercise for the pedaler.

IMO, the ideal fin setting should be as loose as possible, with the clew anchored in the outhaul pocket by about 1/8 inch. This maximizes the twist and allows the fin to wind up the mast about 1/4 inch (assumes your mast is not bent).

This setting gives you greater speed/range over time with much less fatigue while maximizing your acceleration as well. It will also give the fastest sprint speeds. Running at a medium to fast cruise for 1/2 hour or more the difference is like night and day.

I used to think the rear fin should be set slightly tighter than the front fin. Technically this is true since the rear fin plays off the front fin. But in reality, it's insignificant and less important than maximizing balance betwen the fins (overtightening one fin tends to wiggle the boat slightly).

There was a fad in Austrailia where it was thought running an ST in the front and a Turbo in the back was the most efficient. While easier to push, it's not as fast as two matched Turbos.

Finally, the loose clew concept is valid for ST fins as well, and even more important for optimal performance.

Personally, I like to go fast. During races, I modify the Drive to open up the pitch even more. But that's another matter.