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PostPosted: Sat Aug 16, 2008 1:42 pm 
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Location: Prescott, AZ
Roadrunner wrote:
The bottom line is, loose clews give virtually the same performance for significantly less effort at cruise speeds. Less effort translates to less fatigue over longer distances.

What about sprint speeds? Sorry to say, I actually went faster with relaxed clews (loose fins) than tight fins. Like a propeller blade, the fins need to be able to develop a pitch (i.e. flex) to generate forward thrust. Very tight clews restrict pitch and end up wasting energy by batting water back and forth.

What is the optimal setting? I like to set the back edge of the fin about 1/8 inch in the outhaul slot, just enough so it doesn't pop out when flexed. See picture above.



Naturally, when I got my Turbo Fins I went to the "full tight" setting and just assumed that I was getting the best speed and accepting the fatigue. After loosening as per your post, my Turbos seem almost as easy as the standard fins that came with my Adventure. I have not noticed any loss in speed, it would not surprise me if the boat is marginally faster now.


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PostPosted: Wed Dec 09, 2009 10:30 am 
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Location: Belgium (Flanders)
We are complete newbies :( , but next week we will order an Oasis :D .
After reading as much as we could understand on this forum, we opted for the Oasis, a sail rudder and turbo-fins.
There are many posts about the turbo-fins :)
For newbies a bit to many :lol:
These fins should give us a good cruising speed on a lower "rpm"
Is it still correct, with the newest turbo-fins, to give the front fin a loose clew setting and he back fin a medium clew setting?
And would it be a good idea to lubricate the mast with a light silicon grease before putting the fin on?


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PostPosted: Wed Dec 09, 2009 1:24 pm 
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I can't answer about the silicone. I've not done it. Don't try to overpower the turbo fins and they should last you a good long time. As stated, and I agree, if you want to give the system a work out, just slam em around with the turbo fins and eventually something's going to give. But if you move yourself about respecting the fact that you've got an awful lot of leverage at the top of those pedal cranks, and you've got a strong muscle group working those same pedal cranks, ...... you should be fine. Also, agree that you only have to loan your boat out a couple times and you'll be making repairs. Maybe only once. It happened to me. On the high speed, loose clew stuff.... I remember reading early on that Matt made the statement that for top speed you want a tight clew.... for quicker acceleration and moderate cruising speed, loose is the key. It makes sense to me. I've always kept mine somewhat loose and I'll experiment with the rear being a tad tighter. I also noticed some batting water around at cruise speeds and slower take off when the clew was tight.... that's how it came to me. Tight as hell. The 'tucking' up inside just far enough to not pop is where I've kept it and it seems to be the best all around setting.

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PostPosted: Wed Dec 09, 2009 11:06 pm 
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Thierry, welcome to the forum and congratulations on your future Oasis.

Thierry wrote:
Is it still correct, with the newest turbo-fins, to give the front fin a loose clew setting and he back fin a medium clew setting?
IMO, the best starting position for both fins is as shown below. The fin's clew (#1) is inside the outhaul gap about 1/8" (3-4 mm). Notice this provides a sufficient space (#2) for the fin to twist up the mast without restriction.
Image
You can always experiment from there to see if you can improve the setting.

Quote:
And would it be a good idea to lubricate the mast with a light silicon grease before putting the fin on?
Silicone grease seems to attract sand and grit, which would be abrasive and hard to clean out. A better choice might be silicone spray. The carrier evaporates, leaving only the silicone. This also makes ideal lubricant for your "Twist N Stow" rudder and rudder lines if necessary. Hobie does use a silicone grease on the hatch seals however. 8)


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PostPosted: Thu Dec 10, 2009 10:20 am 
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I have been going bad and forth on whether to upgrade my ST fins to turbo fins. I had a 2006 Outback with turbo fins. I ended up getting a crack in mirage drive area. I upgraded to a 2008 Revo (ST fins and big rudder). It has the twist cam knob for holding down the drive not the new clip system. I still use my old drive from 2006 outback. I did upgrade last year to the screw in masts. It's easier to fix and the mast doesn't come out if you hit a rock. In rx7vt's postp, he mentioned about strong legs. I have strong legs. I like to go fast and race boats as i make my way out to my fishing spots. Even though my 2008 revo has more plastic in the drive area, I am still alittle concerned about getting another crack.

I fish in the LI sound (ocean). It can get very cloppy/windy and dangerous quick. Last year, I was in heavy clop and wind as I was making my way back. I was wondering if the turbo fins would have helped. Will the uprades to the hull (drive area) for 2008 revo handle my strong legs? I am on the fence about going from ST to turbos...

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PostPosted: Fri Dec 11, 2009 12:03 am 
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Popeye, that's a very good question. IMO, if you have very strong legs, you're better off staying with the ST fins for your '08 Revo. A strong pedaler may eventually crack a cam column with Turbofins. Perhaps a good strategy would be to sell your '08 Revo next spring and get a '09 or newer model with the Click N Go system. Additionally, the '09 (and newer) Drives have both the stronger drums and threaded masts. I think this system was built for the Turbofin application.

An alternative is to reinforce your cam columns as insurance with one of the specialized epoxies formulated for polyethylene and upgrade the drums and chain/cables on your '06 Drive (you've already switched to the new sprockets and masts) in conjunction with a Turbofin upgrade. Most users have no problems, but then again, most users would not consider themselves strong pedalers.

All parts wear out in time so it's good to frequently inspect your gear including drivewells, cam columns and Drive components. If a part fails, it will give notice in most cases -- the trick is to spot it before it happens and prevent it.

Yakking, I use Turbos with a current generation Drive (upgraded to '09 specs) and run it without reservation in sprints, boat wakes and races. It has logged over 500 miles this year at speeds in excess of 5 MPH (Adventure) and over 100 miles at average speeds in excess of 5.5 MPH. That's a lot of wear and tear. I've replaced a few parts that were getting a little worn at about the 800 mile point. Of the few parts I've managed to break, most are my own doing (custom modified parts or previously damaged). The Drive gets inspected and lubed frequently. I have no concerns whatsoever about its dependability with any activity that it happens to get 8)


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PostPosted: Fri Dec 11, 2009 2:55 am 
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Location: Belgium (Flanders)
It's reassuring that the drives and drivewells are reinforced for people with very strong legs. :)
It's a good thing you sporty guys and girls will be able to use your kayaks without damage to the mechanical side.
For us, not so sporty users :? , it is a benefit to the longevity of the kayak.
Our style is more like cruising in nature, like in this video we found on a French site http://vimeo.com/7348186

Roadrunner, thanks for the tip on the clewsetting :)
The reason I mentioned the silicone treatment is I presume that silicone wil make it much easier for the fin rubber to twist and glide on the metal mast.
And perhaps it could enhance the output of the fin by a small amount.
Also thanks for the tip on not using the grease but the spray :wink:
I use the silicongrease on gaskets and the doorrubbers of my car, it is an excellent protection and it keeps the rubber flexible.


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PostPosted: Fri Dec 11, 2009 11:26 am 
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Newbies! Newbies! :roll: :roll:
I did mention it.... to much information for us :lol:

I just found Roadrunners post on lubrication: viewtopic.php?f=11&t=6320&start=0&hilit=performance+fins
There he mentions using silicon spray on the mast and mixing graphite in the grease for the drumshaft.
My questions completely melted away :-)
Don't shoot on the newbies, we just try to keep afloat :D that's why we bought a Hobie :wink:

Thanks, thanks for al your reactions !!


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PostPosted: Fri Dec 11, 2009 1:23 pm 
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Roadrunner,

You bring up some good points.

My best ugrade last year was the sprocket and screw-in mast for my 2006 drive. It was well worth it. I seem to hit rocks when not racing boats. You mentioned about the upgrade to the drums and chain/cables. Is this a good one to do? I bring my yak and drive every year to my Hobie dealer for a tune-up and upgrades. The kit that came for 2006 outback that reinforces the column. Should I use it on my 2008 revo? I think it would be harder to see cracks. What do you mean by specialized epoxies formulated for polyethylene for reinforcing the cam columns?

Have you actually measured the plastic in the column/mirage drive area? I wonder if my 2008 revo has the same amount of plastic as the newer models. This area seems to have the potential as a weak spot on the yak. I wonder if the newer models can handle a strong pedalers using turbo fins. Ths area should be beefy. My firiend has a 2009 revo. The clips seem to hold the drive tighter than my column knobs.

Sorry for all the questions...

John

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PostPosted: Fri Dec 11, 2009 9:31 pm 
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popeye wrote:
You mentioned about the upgrade to the drums and chain/cables. Is this a good one to do?
As long as your current drums are working well, there is no reason to make the upgrade. It's expensive and would be best considered in conjunction with a needed replacement for a current drum or cable.

Quote:
The kit that came for 2006 outback that reinforces the column. Should I use it on my 2008 revo? I think it would be harder to see cracks.
No. The factory incorporated all the "kit" changes already in your boat.

Quote:
What do you mean by specialized epoxies formulated for polyethylene for reinforcing the cam columns?
There are two excellent epoxies for PE: One is 3M scotchweld DP 8010 and the other is Locktite3030. They are both industrial epoxies and may be found at an industrial supplier. You can check with the manufacturers for a nearby location. This is a "reinforced" cam column using DP 8010:
Image
Not pretty, but it increases the strength substantially.
Note, there is another epoxy by West Systems called G-flex that is sometimes promoted for PE. It does not have the bonding strength for a job like this and should be avoided for any high strength PE work.

Quote:
Have you actually measured the plastic in the column/mirage drive area?
I made a cut-away of my old Adventure drivewell area -- there is plenty of plastic. The nose of the drivewell area takes a tremendous repeated stress over time -- 7200 pulses per hour at a typical 60 cycles (120 strokes) per minute. All Hobie Mirage Drives incorporate a brass block embedded in a solid plastic base under the nose of the drivewell since '07 (in some cases earlier). This was done to better accommodate the Turbofins. There can be other reasons for cracks though due to abnormal manufacturing conditions relating to cooking time and temperature of the plastic. It is pretty rare, but possible. IMO, the best thing to do is use your boat the way you want to and if there is any abnormal defect it should show up well within the warranty period.

Quote:
I wonder if my 2008 revo has the same amount of plastic as the newer models.
Yes, but it is rearranged a little bit. Gone are the plastic cam columns, screws and cams. These have been replaced with the Click N Go system, which I believe is stronger.

Quote:
The clips seem to hold the drive tighter than my column knobs.
When you insert your Drive, you should tighten your cams good and (finger) tight so they lock up solidly. The Drive should rock a little fore and aft but be very solid side-to-side. 8)


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PostPosted: Sat Dec 12, 2009 7:41 am 
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Roadrunner,

You are right. If I had defect, it should show up well within the warranty period. So the only thing to be aware of is cracks from heavy use. I feel better there's a lot of plastic and a plate for the turbo fins. It sounds like adding some epoxy (DP 8010) around the cam column is a good thing to do to prevent cracks. I wonder if a crack did developed if you would still be able to see it around the column.

Do you think if I added the epoxy I would be able to upgrade to the turbos or just keep the STs for my strong legs?

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PostPosted: Sat Dec 12, 2009 1:25 pm 
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A cracked cam column is easy to spot. It would most likely show up in the bottom third near where the cam screw terminates (as shown here):
Image
The DP 8010 has the structural strength to stabilize this area, even if severely cracked or severed. If you examine the earlier pic you will notice the concentration of glue in this area, and extending up the column and around the base for additional load distribution.

IMO this epoxy, properly applied, easily doubles the strength of the cam columns and I would have no hesitation recommending Turbofins to anyone with the older cam columns and this reinforcement.

My own Adventure has taken a lot of punishment. Whether towing heavy loads...
Image

...sprinting...
Image

...or ripping through wind and chop...
Image

...this Turbofin powered boat has met the task time after time. There are probably not a lot of users who regularly put this level of service demand on their boat. 8)


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PostPosted: Sat Dec 12, 2009 3:16 pm 
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Roadrunner,

You know your stuff... When you put on the epoxy? Light or heavy coat. Should I put on a few coats of it? Maybe more is better. Last year, I almost used the super glue epoxy that came with the hobie cam kit for beefing up the columns. I had the same thoughts you had on it. Good thing I didn't the super glue epoxy. It sound like the DP 8010 is much better.

John

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PostPosted: Sat Dec 12, 2009 7:47 pm 
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The forum has a wealth of information that is accessible using the search feature. Here are a couple of topics that will answer most of your questions and give you a little more insight into the procedure. 8)

viewtopic.php?f=11&t=11245

viewtopic.php?f=11&t=12558


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PostPosted: Sat Dec 26, 2009 11:29 pm 
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I know this is probably a basic question but you guys definitely know what you are talking about....My parents just recently bought an Outfitter kayak and they were wondering if you can fit ST Turbo fins on it? They bought the hobie in Australia and can't seem to get much info down there about replacing the standard fins with the ST Turbo fins...can you help me out please?


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