Using the new Flow fin 90 fins (for the Eclipse) on a TI

I saw the new fins on the Eclipse at the dealer and decided I gotta have them. They had some in stock so I bought a pair to try out (they cost the same as Turbo fins ($39.95 ea).
For those that haven't seen them yet this is what they look like.


I was out today anyway testing out my motor mounts which I raised an inch, and tilted the motors slightly, I wanted to see if the motors now sucked air (cavitate) while sailing on a reach, thankfully raising the motors worked fine.
I didn't get the motor mounts done until late in the day and didn't get out on the water till after 4:30, so I only had time for a short jaunt. Unfortunately the winds were only 3-5 mph by that time of day, so I didn't get much help from natural wind.

In the video you can see me peddling with the new fins, when your going 8-9 mph they still have some propulsion left in them, where the regular turbo fins top out, and begin to flutter at high speed. These fins didn't flutter at all today. I opened up my throttles a little while peddling just to see if the new fins flutter at high speed, and they didn't flutter at 12-13 mph at all, and I could still feel the resistance ( I didn't get that part on video). I'll have to wait for better winds, but I'm thinking they will be ok up to 20 mph forward speed.

Here is the video, about halfway thru I was traveling around 8 mph (remember the natural wind was only 3 so I had literally nothing to work with), I was able to increase my speed up to 9 mph by peddling ( I couldn't do that with the stock turbo fins).
https://www.youtube.com/watch?v=HuGojWrGHUU


I didn't try just peddling from a dead stop or using just the flow fin 90 mirage drive with no sails (I would never do any of that crap anyway), someone else can try that and report (that's just not my thing (lol)).

If just peddling with these new fins (without all my wings and hybrid propulsion crap), you probably need to have really powerful legs, Probably won't be a popular item for most.
I'm definately keeping mine though, and I'll use the daylights out of them every weekend.
The true test will be tomorrow, I thinkin of doing a 60 miler tomorrow if the weather holds out, we will find out if my legs hold out.
FE

VERY hard to pedal from a stop and just to pedal alone. I can see where with Island sailing it could add enhanced speed, but imagine an 18 gear bike and starting in 18... that is what it's like.

Not advised and could damage the drive or well from the excessive force required.

_________________
Matt Miller
Former - Director of Parts and Accessory Sales
Warranty and Technical Support
Hobie Cat USA
(Retired 11/7/2022)

I agree with your assessment Matt, but what a wild ride on a tri-bred TI setup, just wish more people were into this tri-bred propulsion stuff on peddle boats. It appears I'm pretty much out there on my own, must be just too radical.
FE

FE, what happens at a speed of say, 5 mph, a typical speed for most? Is peddling still difficult at such a speed? Do you gain more than 1mph when when peddling at midrange speeds?

I typically don't peddle while sailing but recently got the mirage dive upgrade kit. Now I find myself peddling while sailing and not even thinking about it. It does seem to be adding a significant boost. I guess what I'm asking is if you were sailing in the 4-6 mph speed range, is there merit in using the eclipse fins? It's a given that I risk damaging the drive or well and accept that.

_________________
Greg

2016 AI - Spinn & Jib

“Out of sight of land the sailor feels safe. It is the beach that worries him.”
– Charles G. Davis

I can't really answer that yet. One problem I have with my motors is once the motors warm up, the idle on them goes up and the props turn very slowly, at lowest idle on flat water no wind, with hot motors, no sails the boat goes along at 5-6 mph, which gives me like 3.5 to 4 hrs of run time per tank of fuel (each tank holds 1 quart of fuel). I usually kill one motor when I come into shore because I come in too hot (I have dead man switches in the cockpit for the motors). I typically start the motors when I launch and idle out of the harbor, 5-6mph is basically my minimum speed. If I pedal with the turbo fins, that increases to 7mph, probably 8mph with the flow fins (just guessing, I need more time with them).
Once I clear harbor I open the sails and try to generate apparent wind, in really low winds 3-5 mph if I can catch it right (typically upwind or downwind) the boat speeds up to around 8 mph, with just turbo fins I think I'm pretty close to max speed with the turbo fins peddling lightly, of course I can pedal really hard, but I run out of energy in a mile or so. My opinion is if I can pedal steady at around 40-50 cpm (basically walking pace) I can maintain that pace up to ten hrs.
My leg power is providing about 25% of my propulsion needs. Without the motors and no wind, just peddling at that pace equates to 2-3mph. Every time I go out I try to pedal 10-15 miles minimum, on no wind days that makes for a very long day in the hot Florida sun.
If I want to go a little faster I bump up the throttles a little (typically 1/4 throttle max), I'm then generating tons of apparent wind and the sails are working very hard. The more natural wind I have to work with the better the boat performs.
I'm going to keep and use the flex fins moving forward, but keep in mind I've been peddling my hobies every weekend for the last ten years, I often do 50-60 miler day trips. I'll have the regular turbo pedals in the back seat, I can always jump back there if my sails and motors ever quit.
Actually my ultimate goal is to develop my wing wind amplifier tech to the point where two just regular people peddling at a moderate pace can propel the boat 8-10 mph and maintain that pace for several hours. I'm pretty certain with the new mirage fins and my 3rd generation wing design I'll be able to do that now. I can do it with my second generation wing and two strong peddlers but we are exhausted after a mile or so, these new fins should fix that problem.
FE