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MD 180 Blades/Fins, deminsions compared GTT blue fins
http://www.hobie.com/au/en/forums/viewtopic.php?f=78&t=62376		 Page 1 of 1
Author:  oldmaninthelake [ Fri Mar 23, 2018 9:44 am ]
Post subject:  MD 180 Blades/Fins, deminsions compared GTT blue fins
Just interested as I measured the MD 180 drive at its overall blade length and it was about 12” on the ST Turbo model. As for my GTT blue fins they measure about 13.75”. Is this correct? If the the efficiency is better and I have less chances of snagging something isn’t that a good thing? I just never see it mentioned anywhere. Understand it’s suppose to be 14% more area but haven’t seen the dimensions yet. Any info would be appreciated. Thanks
Author:  mmiller [ Fri Mar 23, 2018 10:28 am ]
Post subject:  Re: MD 180 Blades/Fins, deminsions compared GTT blue fins
The length are correct 11" for 180 Turbo and about 13" for the GTT

GT Turbo and 180 Turbo were designed to have as close to the same performance as possible. Seems that it's odd since the 180 fin is shorter, but they do.

There is a difference in the distance of the fin base to the sprocket shaft and the masts of the 180 are not swept aft as much. That places the fin tips closer to even.
Author:  Roadrunner [ Fri Mar 23, 2018 8:19 pm ]
Post subject:  Re: MD 180 Blades/Fins, deminsions compared GTT blue fins
oldmaninthelake wrote:
If the the efficiency is better and I have less chances of snagging something isn’t that a good thing?
Yes, but....

Depth of the Mirage Drive should be measured from the pivot point (sprocket shaft CL), not the fin in order to compare apples to apples. Note that the foot (base) of the GT fin is closer to the pivot point than the 180 fin.

Image Image
Note: the GT is not a Turbo -- couldn't find a comparable pic. Also, the scale is not the same, but this illustrates the different mounting points.

As I recall, the final depth is close to the same for both Drives. Keep in mind that more thrust is generated near the tips of the fins rather than the bases, so depth has its advantages. Use of the flutter kick allows the Turbo fins to go anywhere the smaller fins go, so any perceived disadvantage of having longer fins is only due to technique issues. 8)
Author:  oldmaninthelake [ Sat Mar 24, 2018 4:00 am ]
Post subject:  Re: MD 180 Blades/Fins, deminsions compared GTT blue fins
Thanks for the info guys. The blades look to be thoroughly engineered to displace as much water as possible for the given size. The appearance does look stealthy, as does the ARC drive. Can’t wait to get one. Again Thanks.
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