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PostPosted: Thu Jun 21, 2012 11:02 am 
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"You won't get 5MPH out of any of the electric motors out there - power is not the issue. Prop pitch is. The trolling motor prop to get you 5 MPH doesn't exist commercially."


Sorry Tom ......... but I got 5.3 on my PA with the mirage drive in when testing the my new PA configuration using the Torqeedo Ultra light ........... posted it on the MKF board 2 weeks ago ............


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PostPosted: Thu Jun 21, 2012 12:07 pm 
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That's good the the Torqeedo Ultra light can go over 5mph, but $1,800 is too expensive for me.


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PostPosted: Fri Jun 22, 2012 2:16 am 
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"One thing though - a more powerful motor won't necessarily make you go any faster. None of these motors is the least bit taxed pushing something as light as our kayaks - they were designed with very shallow pitch props for pushing boats that weigh many hundreds, even thousands, of pounds. So, a bigger motor turning the prop at the same speed as the smaller motor gains you nothing. You just burn up your battery more quickly."

Tom...I wish I'd known that before I bought my Motorguide Varimax T55. Oh well...After reading this thread, I called my trolling motor guru to find out if he knew of any props built for speed. He said there were a couple companies out there that made performance props, but only 1-2 mph over 5 mph. BTW...Torquedo was one of the 2 companies, and a couple days ago I saw a clip of a guy testing his Torquedo using his GPS for reference and his GPS calculated his speed at 6.3 mph...Anyway, after talking to my guru, he gave me a number to an engineer that designs props for commercial vessels. The engineer told me that the issue with designing a prop with more pitch for speed for a small vessel would be the additional battery power needed, which would take up more space and also weigh much more. A 12 volt battery would not be enough to last very long. You'd need 24 or 36 volts minimum.

Sooo...What do you do. The hull speed for the PA is only about 7mph anyway, right? So it wouldn't do any good to try to get something that would get you over 7 MPH, which only leaves 2 mph max above the 5 MPH prop you'd want to get. So...If you want to go over 5 mph you either find a high performance prop and spend alot of money, and extra on batteries and live with the additional weight, OR...You just buy a small outboard gas motor.

I've got to admit that I'm a little disapointed because the reason for me going through the trouble of building a transom and getting a larger trolling motor was to be able to fight strong 4-6mph currents around the Chesapeake Bay Bridge Tunnel in Virginia where I live. All it took was one time being sucked under a bridge and out toward the ocean miles from shore, not being able to peddle fast enough to fight the current, for me to make the decision to get a motor. Unfortunately for me, now I believe I should have invested in a gas powered motor rather than electric.

Anyone have any suggestions? My current battery and T55 motor weigh 85 pounds. The battery alone weighs 65 pounds. I really don't want to add another 130 pounds for 2 more batteries, even if I could find a high performance prop...Or maybe I just live with what I have now with 5 mph ;)


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PostPosted: Fri Jun 22, 2012 9:33 am 
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YAKFISh sorry started typing this up last night and finished it today and was openes on my browser...

as for a better prop try this prop, I know the pitch is higher.

http://www.kipawapropellers.com/

based upon all my research in the past 6 months , this is the only commerical avail prop that would help somewhat. this prop did imrove the preformance on my prevous boats from a custom built 16 footer with 2 55lb MK all the way to my prevoius 2 Ranger 621's: one with an MK EM motor and the other with a MK terrova.

*unless one were be able to customize a kayak prop with the correct pitch and diameter to accomidate a 1200-1400 rpm motor on a rig thats weighs 5-500-600 lbs for any kaysak with a 30 to 55 lbs thrust brushed motor

thrust is not the issue, its all about the pitch to combine power, speed and effiency.

Frank


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PostPosted: Fri Jun 22, 2012 10:45 am 
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Yakfish,

I would love to mount an outboard on my kayak. I posted a thread asking how to mount one on and no one replied. There are a couple of YouTube videos showing pa with outboards. I need help on how to mount it, how to start it from the seat, and how lift it up from the seat.


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PostPosted: Fri Jun 22, 2012 11:24 am 
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Location: High Point, NC
The Torqueedo uses a completely different prop than the Minn-Kota, Motor Guide, etc.

Again, it's the prop, not the power. Any of these motors are more than powerful enough to push the PA 7 or 8 MPH, with prop with more pitch.


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PostPosted: Fri Jun 22, 2012 11:26 am 
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The PA can be pushed faster than 7MPH. As long as the boat can be steered in a straight line, you can go faster. It won't come off course at just 7MPH. I've done 12 on mine with an outboard.


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PostPosted: Fri Jun 22, 2012 11:38 am 
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Tom, how did u mount the outboard?


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PostPosted: Fri Jun 22, 2012 12:09 pm 
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Remove the rear handle. Bolt on an L-channel aluminum strut, or a hardwood 1x4 and hang the motor on it. Not at all hard to do.

I only did it to see what might perhaps be the speed limit on this boat, but I still don't know. This was a small outboard. A larger one would push it faster, but at some point the motor is more substantial than the rest of the boat and becomes completely impractical.


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PostPosted: Fri Jun 22, 2012 12:41 pm 
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Drybones:
I use a 35Ah 12volt battery AGM.
The battery fits in through the cutting board hole, lays on it's side, and slides in under the seat.
I got my PWM off e-bay. The guy keeps a running listing. Here it is;
http://www.ebay.com/itm/12V-30A-DC-Moto ... 3375e89b83

It's less than $27 shipped. It hooks up the battery and motor just like the label says. Turn the pot and the motor is variable speed. Current draw changes with speed and torque put on the trolling motor blade.

My battery, charged, will troll me at 1.3mph for 10 hours at least. At full throttle, I've gone over 10 miles and my top speed never changed. Top speed is 4.2mph if there's no wind

I got busy last night so I hope to link up photos tonight. Tomorrow I leave for 2 weeks of camping and won't be able to access on-line so I hope to get this done.


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PostPosted: Fri Jun 22, 2012 2:19 pm 
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Thanks Tom.

I was more concerned with how do I start the outboard and turn it off with it back there. And how do i put it in gear or lift it in shallow water?


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PostPosted: Fri Jun 22, 2012 4:13 pm 
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I understand. The thing is, I never intended to run an outboard on a regular basis so I never tackled those issues. What I did was just to see at what point the PA could no longer be steered in a straight line.

You'll really have to put your thinking cap on. It should be a straightforward matter to extend the tiller control (I assume yours contains a twist grip throttle and perhaps the control for forward and reverse?). If so, you only need to work on the starting aspect. If yours is an electric start, that's not hard either. If a hand pull, it's going to be tougher but not impossible.

You might consider not using the motor for steering control, but instead locking it dead ahead and simply using the Hobie rudder for steering. Not sure how much control you have a the higher speeds, however, so you'd just have to try it. But this would certainly simplify things greatly.


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PostPosted: Fri Jun 22, 2012 5:53 pm 
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Thanks guys for all the feedback. I called Kipawa from the number listed on their website and the tech guy told me that their props were designed for much larger thrust motors than my T55...And as far as going to a gas powered engine, I'll hold off on that for sometime until I get my money's worth from the electric ;) I'm not ready now to pay $2-3000.00 for a new 4 stroke, 4-6hp engine that will also have it's own challenges to connect it to the PA, such as tilting it up or down for launching, starting it and controlling it, all from the seat...

For now I'll just have to try to be happy with my electric T55...I haven't had my PA out yet for sea trials since the trolling motor installation, so who knows...I might just be satisfied with keeping what I've already spent blood, sweat, money & tears on ;)


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PostPosted: Fri Jun 22, 2012 6:00 pm 
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Tom Kirkman wrote:
The PA can be pushed faster than 7MPH. As long as the boat can be steered in a straight line, you can go faster. It won't come off course at just 7MPH. I've done 12 on mine with an outboard.


Thanks Tom for the feedback on exceeding the 7mph. In the future if I decide to go to an outboard I'll keep in mind what you said about the steering and the 12mph.


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PostPosted: Fri Jun 22, 2012 9:29 pm 
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SkiPro3 wrote:
Drybones:
I use a 35Ah 12volt battery AGM.
The battery fits in through the cutting board hole, lays on it's side, and slides in under the seat.
I got my PWM off e-bay. The guy keeps a running listing. Here it is;
http://www.ebay.com/itm/12V-30A-DC-Moto ... 3375e89b83

It's less than $27 shipped. It hooks up the battery and motor just like the label says. Turn the pot and the motor is variable speed. Current draw changes with speed and torque put on the trolling motor blade.

My battery, charged, will troll me at 1.3mph for 10 hours at least. At full throttle, I've gone over 10 miles and my top speed never changed. Top speed is 4.2mph if there's no wind

I got busy last night so I hope to link up photos tonight. Tomorrow I leave for 2 weeks of camping and won't be able to access on-line so I hope to get this done.


Thanks for the info. I also have my battery under the cutting board. I use a 45 lb. thrust motor with the stock prop. I'm not sure what my top speed is but I'll guess its between 4 and 5 mph. I haven't used it in a while because trout has slowed down and the Saltwater season is now open. I go old school with the Mirage Drive for Saltwater.


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