Out Board Motor - Page 2 - Mountain Buzz

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Old 10-07-2016   #11
Salt Lake City, Utah
Paddling Since: 1969
Join Date: Apr 2009
Posts: 220
CO Dave has it exactly right, shorthand is "hull speed" and the equations are right on.
Based on thousands of miles of motoring experience, under perfectly calm conditions (no or downstream wind) and depending on speed of current, the very best you can expect pushing a flotilla (3-8 boats) on Green or Colorado is around 6-7 MPH. And you can do that with everything from a 4 HP Merc up to 8 HP Yamaha (both sweet motors). Yes, for short stretches your GPS may indicate 10 even 12 MPH + but that's running solo.
What motor do you want? Depends on lots of factors, especially if you have a cat or snout or larger. With the right transom, you can get a cat up on plane and haul ass - but that's running solo. A 4 stroke 10 HP is about as big a motor (approx. 85 pounds and up) as most folks want to move around, let alone hang on the back of your boat. The 2.5 HP Honda mentioned above is a sweet little unit for pushing out the bottom of WW or even on Deso, but it's noisier than my 5 HP and I like water-cooled, watching that little green light that tells me all is well...
A jackass helps a lot for finding the right height when you're pushing different rigs but truth is you can usually get enough vertical adjustment just by moving the unit up and down on a 2X10 or 2X12 transom.
Most manufacturers market short (15") and long (20") shafts, some make extra long shafts (25"). Today's WW rafts generally have enough kick that a long shaft is best, if you have an older or fishing raft with "flatter" profile you may be happy with a SS. If the frame on your cat has the transom across the flat part of your tubes you may also prefer a SS, depending on tube diameter and how much you draft. Really large tubes (say 24" and up) and no jackass, you may have to go to Xtra LS.
Rock guards are nice but they don't fit many motors (my Honda, for ex.) Fortunately there are few gravel bars on both the Green and Colorado - at least the parts I run (Mineral down, Deso and below WW, other sections accasionally) and sand bars usually won't ding your prop the way rocks do. I carry a spare but haven't had to put it on yet, usually a few swipes with a file at camp will restore your prop to new condition if you've gone to sleep in the sand/mud. Another reason a jackass is useful: easy up when you start making "soup" with your prop motoring over sandbars. Or just throw it in neutral and "pole" with oars or paddles.
This year I've been running a 5 HP Lehr and it sure is nice not to have to mess with gasoline. But they are not as stout as Honda/Yamaha/Merc, and lack the bottom end (torque). If you're running against the bank and need to goose it to avoid a branch or rock, the Honda will respond instantly, the Lehr takes awhile. Props are same diameter and similar pitch so has to be the motor. But at cruising speed (4 MPH and up) the Lehr does just fine and is quieter. The Lehr is 12 pounds lighter (53 vs. 65 pounds for the Honda) and yes, I can feel the difference when putting it on and taking off. There's no comparison about fuel: already carrying propane to cook with, I just disconnect at camp and hook back up in the morning, takes like 30 seconds. You can also run the Lehr on 1# cylinders, I carry a couple for backup. Pushing 3 or 4 boats the Lehr consumes about a pound of propane every 75 to 90 minutes in light or moderate winds (that usually means I get 6-8 miles down).
You are not allowed to even carry a motor through Dinosaur or from Lee's to Diamond (still fuming about that last one, may challenge it this winter) but on any other stretch I want the "black oar" along. I don't need any more character building or practice rowing into 20+ mph winds and both Spring and Fall (my favorite times to go) they are not uncommon. Takes maybe 10 minutes to put on or take off a little kicker, and well worth it!

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Old 10-07-2016   #12
breckenridge, colo.
Paddling Since: 79
Join Date: Oct 2009
Posts: 51
Good point Dave! My 6 hp 25 inch xlong shaft 4stroke tohotsu pushes my 22ft snout faster then my 16 ft cat, wetted area vs, hull length,,a mono can't go faster then a cat in most case's, my prop is a 4 blade 9 and 1/4 its a pusher prop,my Suzuki had a 3 blade 8 and 1/2 blade,great motor,20 inch long shaft, but a prefer the control I have with the 4 blade .
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Old 10-07-2016   #13
Denver, Colorado
Paddling Since: 1988
Join Date: Jul 2014
Posts: 35
On my little boats <22', I run a Tohatsu 5 hp 2 stroke short shaft with a jackass. A long shaft would be nice but I make do with a telescopic tiller extension.
I can push 8 boats in flotilla around 6-7 mph and everyone can feed me and give me drinks. I feel special.
When I get into the rapids on cat, I remove the motor and stow it on my stern deck. Light and small. The 2 stroke is nice because I don't have to worry about head orientation when I stow/transport it.
My fuel economy sucks compared to 4 strokes of equal hp. On my last cat, I pushed 3 boats into spanish bottom and out to Northwash and used 5 gallons of fuel. My buddy's 4 stroke used 2.
I like Tohatsu because they're the OEM builder for small Mercury and Nissan so parts availability is awesome with equivalent part numbers. I run bigger Tohatsus and Hondas on my Snout and sport boat.
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Old 10-08-2016   #14
Apache Junction, Arizona
Paddling Since: 2008
Join Date: Dec 2015
Posts: 119
Anyone ever tried a electric motor. I was thinking about trying to use one coming out of Westwater. It's got 40lbs of thrust and a marine deep cell battery do you think this would do the trick?
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Old 10-08-2016   #15
Apache Junction, Arizona
Paddling Since: 2008
Join Date: Dec 2015
Posts: 119
Pulling 13' and 10' raft
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Old 10-08-2016   #16
Electric-Mayhem's Avatar
Lakewood, Colorado
Paddling Since: 1993
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Posts: 623
I have not...but my gut feeling is that you would have to carry a pretty large capacity battery for that to last the trip. Rafts aren't particularly effecient hulls and it would probably have to be full throttle to make a difference.

Also, a quick look around the internet (so it may or may not be correct) puts 1hp =25-50 pounds of thrust depending on who is talking. I suspect that the electric trolling motor might not push the raft very fast, or at least not fast enough to make it worth it. Even with the boats they are designed for they are more for slow maneuvering, so who knows.

Not sure though...worth a try at least. I will say that the quiet nature of the electric motor would sure be nice. My 4 stroke isn't too bad, but its still noisier then I like.
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Old 10-08-2016   #17
Apache Junction, Arizona
Paddling Since: 2008
Join Date: Dec 2015
Posts: 119
How heavy is your 4 stroke motor and what do you carry it in? Any problems with the water exposure or in event of a flip?
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Old 10-08-2016   #18
Grand Junction, Colorado
Paddling Since: 2012
Join Date: Jan 2015
Posts: 115
Anything in the 4 HP to 9.8 HP range is going to be reasonably light and work for pushing into and out of Cat.

I personally wouldn't want less than 4, but obviously it is working for some folks out there.

As for the electric don't even bother bringing a 40 lb thrust trolling motor. It will be more trouble than it is worth.
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Old 10-08-2016   #19
Electric-Mayhem's Avatar
Lakewood, Colorado
Paddling Since: 1993
Join Date: Jan 2004
Posts: 623
Originally Posted by Jdsampsonite View Post
How heavy is your 4 stroke motor and what do you carry it in? Any problems with the water exposure or in event of a flip?
My Honda 4stroke 5hp is 60 pounds. Sounds like a lot, but its not bad at all. I can easily lift it.

I've thought about making/buying a storage box for it, but so far I've just strapped it on top of my frame. Might still do it, but honestly, the last trip I just left it hanging on the back of the raft for most of the trip. A couple of cam straps hold it nicely to the frame though, and its a 3 minute job to take it on or off. I've never flipped a raft at all (even without a motor...guess I haven't tried hard enough lines yet) but if you do a proper job securing it I wouldn't see a problem. You'll have to pull the spark plug and make sure all the water is out of the motor afterward, but they are honestly designed to take that kind of thing and still be allright. It just takes a bit of work afterwords. Oh...and you'll need a decent tool kit to work on it too.
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Old 10-08-2016   #20
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Fraser, Colorado
Paddling Since: 2000
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Posts: 1,386
Originally Posted by Jdsampsonite View Post
Pulling 13' and 10' raft
I'm thinking you'd be happier putting the other boats in front of you and pushing, never really have seen people towing with a raft, guessing pushing gives better control, but definitely not the expert on this.

I'll second the pusher prop as opposed to one built for speed, definitely preferable.

I have pushed two other boats beside myself, don't think I would want more then that. My 14'+ 16'+16' = over 40' of boat, felt like quite the rig to drive
especially with a cross wind!
" Hoping that everyone crazier then me, gets the mental help they need!"
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