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  #1966  
Old 08-30-2014, 12:50 PM
jehardiman jehardiman is offline
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Quote:
Originally Posted by Yobarnacle View Post
Here is a youtube of interest and the quote is the blurb beneath the video.
https://www.youtube.com/watch?v=8I-H47uuQF0

"Uploaded on Oct 14, 2010
Testing a 40lb trolling motor on a Cobra Fish N Dive kayak. The first bit of footage shows use with the standard propeller and the second bit (final 25%) shows use with an 10 x 4 model aircraft propeller. We tested the standard prop as well as 3 other props of varying pitches. The standard prop gave a top speed of around 8km/h and drew 33 amps whilst the aircraft prop that came out in front gave a top speed of around 10km/h and drew 29 amps. The other pitches (10x6 and 10x8) gave slightly better speed but used too much power.
That is exactly as expected given the displacement/ length of the hull and design rational of a trolling motor. I also bet the 10x4 took longer to accelerate the boat...which is the exact opposite of the design goal of a trolling motor. There are so many nuisances to propeller design, especially when working on HPV which are such a small scale where you are not running up against practical limits (such as root bending and submergence drafts). Going to an 11x3 would most likely lower the amps even further for that speed.
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  #1967  
Old 08-30-2014, 01:23 PM
portacruise portacruise is offline
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TC:

The MK speed control claim to go 5X longer needs to be qualified for a particular low speed. The mechanical switch system of cheaper motors is slightly more efficient at FULL speed, where most troll motors are used for the greatest time...

There is also somewhat of a myth about motor cooling with a submerged troll motor head which only cools the field magnets directly. This is because of the insulating air gap between the centrally located hot armature and brushes doesn't allow for efficient cooling. Better to go with an electronically commutated outrunner motor for efficiency and cooling....

We may be getting off topic here, so perhaps should move to the electric boat thread?

PC

Quote:
Originally Posted by TomCat58 View Post
portacruise: Thank you

Yes any drag effects the performance so I design the pontoons to barely touch the water on just the rear sections while cruising. As the need increases the pontoons use more of there surface to stabilize.

The trolling motor is very affordable and yes not so efficient but with a limited budget its working ok. I did however buy one of the newer Minn Kota's that claim to go 5x longer then some of their other cheaper models. It has a computer control board using a pulse system. The other factor is the trolling motor is almost water proof. Everything on this canoe has or will get wet sooner or later. The trolling motor has come off once while the boat was tied up on a sandy shore. I got it out of the 2 feet of water and dried it the best I could and it works just like new :-)

Thank you for your comments I am on a constant learning curve to improve my canoe. The next improvement I think I will make is to replace the two 29 series deep cycle batteries with Lithium Lifepo4 electric car type batteries.

That improvement from my research promises to greatly improve speed and extend how long the batteries last.

TomCat
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  #1968  
Old 08-31-2014, 09:02 PM
TomCat58 TomCat58 is offline
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Electric boat thread ?

PC,
Yes your correct this has gotten off topic here. Where should I post at to keep it going?

I am trying to move this thread to the electric boat thread but am not having any luck finding it. I see gas powered, diesel powered but no solar or electrical powered ?

Thanks
TomCat
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  #1969  
Old 08-31-2014, 10:08 PM
TomCat58 TomCat58 is offline
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OK this thread has been moved to:


http://www.boatdesign.net/forums/boa...gns-19444.html

Small boats and Solar Power
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  #1970  
Old 09-01-2014, 09:05 PM
P Flados P Flados is offline
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The link above should have been Small boats and Solar Power
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  #1971  
Old 09-01-2014, 10:55 PM
TomCat58 TomCat58 is offline
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Thank you Flados..... I am still trying to figure out this forum and how it functions..
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  #1972  
Old 09-01-2014, 10:59 PM
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Yobarnacle Yobarnacle is offline
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Originally Posted by TomCat58 View Post
Thank you Flados..... I am still trying to figure out this forum and how it functions..
Me too!
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  #1973  
Old 09-02-2014, 01:27 AM
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Leo Lazauskas Leo Lazauskas is online now
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Quote:
Originally Posted by jehardiman View Post
And that is for dead flat calm, so add 20-30% seaway margin for real conditions. 74-79 watts is ~ 1/10 Hp sustained, which is approaching serious amateur cyclist ability.
I'd also add a bit more if the hull isn't going to be kept very clean.
And more for any appendages, especially if they aren't filleted well.
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  #1974  
Old 09-07-2014, 01:00 AM
Rocky Mtn Russ Rocky Mtn Russ is offline
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Thanks guys for all of your comments and advice. Not sure why I stopped getting notice that posts were happening. I've been struggling to learn Free!ship, and emailing with Rick W. about some of his designs. He's been very helpful too.

The numbers Dave generated actually sound pretty good to me.

On our latest 10 day kayak trip, my tandem island Hobie with twin mirage drives was loaded heavier than usual. Speed fell off considerably as a result. That boat is 18.5 feet, with a 30" beam, and would have tipped the scales around 840 lbs. The boat is 190 lbs empty. There were 2 of us onboard, and a bunch of gear in the hull and lashed to the tramps. It was a challenge to sustain 3.2 mph on our 10-12 mile ride out to our camp into about a 15 mph headwind. Typically, that boat with 2 guys peddling will do 4.0 mph continuous, and 3.7 if I'm by myself without the sail and outriggers. One of the guys was in a 13.5 foot, 28 inch beam Hobie, with camping gear, and he sustained 4.2 mph on the ride back, in fairly flat water. That was fast for that short boat.

I also have a wooden sea kayak, that I'm fairly experienced in. I've done up to 5 days camping in that boat, but the volume is pretty low, and I don't like strapping stuff to the decks. It's a speedy boat at 17.5 feet and 22.5 inch beam, and only 40 lbs empty. But not big enough for me to carry enough camping gear, and not stable enough to fish... which would be awkward while holding a paddle.

I'm in agreement with the comments about 10 inches of freeboard, and windage. But to add a peddle drive, at least some of the deck must be open. And to carry more gear, I need either width, height, or more length. At least height is above the waterline and helps towards the drier ride my wife is looking for. I'll see what I can do to deal with these conflicting goals. My design already includes both stern and bow rudders (the bow rudder is 3 feet back from the bow).

Currently, the outriggers are 5.4 inches wide at their widest, and 5 feet long. I don't have any numbers on them yet, but they look pretty sleek in freeship so I didn't think they'd be too draggy.

I've also been looking at a flexible shaft combined with a drive leg. Does anyone know about flexible shafts? The specs on them sound great, and there's a company in Canada using them as after-market drives for canoes and kayaks. I may still use the 5/16 steel shaft with Rick's prop, but if I can keep from having 8 feet of steel in the water, I'd prefer to... I'm sure I'll be snagging my fishing line if I'm landing a big one on that side of the boat.

Thanks for all the great help!

Russ
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  #1975  
Old 09-07-2014, 11:09 AM
portacruise portacruise is offline
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Quote:
Originally Posted by Rocky Mtn Russ View Post
Thanks guys for all of your comments and advice. Not sure why I stopped getting notice that posts were happening. I've been struggling to learn Free!ship, and emailing with Rick W. about some of his designs. He's been very helpful too.

The numbers Dave generated actually sound pretty good to me.

On our latest 10 day kayak trip, my tandem island Hobie with twin mirage drives was loaded heavier than usual. Speed fell off considerably as a result. That boat is 18.5 feet, with a 30" beam, and would have tipped the scales around 840 lbs. The boat is 190 lbs empty. There were 2 of us onboard, and a bunch of gear in the hull and lashed to the tramps. It was a challenge to sustain 3.2 mph on our 10-12 mile ride out to our camp into about a 15 mph headwind. Typically, that boat with 2 guys peddling will do 4.0 mph continuous, and 3.7 if I'm by myself without the sail and outriggers. One of the guys was in a 13.5 foot, 28 inch beam Hobie, with camping gear, and he sustained 4.2 mph on the ride back, in fairly flat water. That was fast for that short boat.

I also have a wooden sea kayak, that I'm fairly experienced in. I've done up to 5 days camping in that boat, but the volume is pretty low, and I don't like strapping stuff to the decks. It's a speedy boat at 17.5 feet and 22.5 inch beam, and only 40 lbs empty. But not big enough for me to carry enough camping gear, and not stable enough to fish... which would be awkward while holding a paddle.

I'm in agreement with the comments about 10 inches of freeboard, and windage. But to add a peddle drive, at least some of the deck must be open. And to carry more gear, I need either width, height, or more length. At least height is above the waterline and helps towards the drier ride my wife is looking for. I'll see what I can do to deal with these conflicting goals. My design already includes both stern and bow rudders (the bow rudder is 3 feet back from the bow).

Currently, the outriggers are 5.4 inches wide at their widest, and 5 feet long. I don't have any numbers on them yet, but they look pretty sleek in freeship so I didn't think they'd be too draggy.

I've also been looking at a flexible shaft combined with a drive leg. Does anyone know about flexible shafts? The specs on them sound great, and there's a company in Canada using them as after-market drives for canoes and kayaks. I may still use the 5/16 steel shaft with Rick's prop, but if I can keep from having 8 feet of steel in the water, I'd prefer to... I'm sure I'll be snagging my fishing line if I'm landing a big one on that side of the boat.

Thanks for all the great help!

Russ
Russ:

Do you have a link on the company in Canada, that you write about? Curious as to how they have set it up.
Rick has tried different materials for flex shafts including CF, SS and spring steel. SS spring has been hard to find in the US in the past, and the CF (much larger diameter compared to others) was custom made for him. You can experiment with long electrician drill bits and sewer rod to get an idea for your project. You can avoid some fishing tangles by using a pontoon design and mounting the shaft drive between, but it will be a slower boat. It might serve you just as well to use a thinner, stronger, rust proof steel straight shaft which is less costly and easy to source. Your bends can be done with compact universal joints similar to those found on ratchet tools sets, if you will be mounting a skeg type bearing. Flex shafts are at their best when they can run directly and untethered without bearings because this allows them to conform to obstructions, be easily pulled up for beaching and even for steering instead of a rudder: Prop Shaft Systems. post #53, 54

The HP speed you desire may be not be sustainable in wind and waves as the outriggers will hang up/cause control issues and be an additional drag. Maybe a small, lightweight backup motor would be the way to go: http://www.electricpaddle.com/products.html

Hope this helps.

PC
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  #1976  
Old 09-07-2014, 11:44 AM
Rocky Mtn Russ Rocky Mtn Russ is offline
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PC: that link is http://h2proped.com/index.htm You'll see his flexshaft is encased. Those are the ones I've been studying. They're no good under water though, hence the drive leg. I've actually designed a drive leg that uses a twisted timing belt on small pulleys driven directly by the pedal crank shaft. The drive can kick up if it strikes something. I'd have to test the drive leg to check the durability of running the belt with a twist. Rick had sent me a link to an outfit that is doing something very similar except theirs has 4 turns of 90 degrees.

In any case, my 2.5 hp 4 stroke Suzuki (30 lbs) will be mounted onboard as a backup or for those really long excursion days.

The real issue with getting a dryer ride is to raise the seat or the freeboard. I'm taking a hard look at using the low, self bailing deck that Rick has popularized, and just raising the deck under the seat area and maybe a second small bump in the back if more storage is needed. I'm also going to study adjustable width stabilizers to see what that looks like. Thanks again.

Russ
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