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Thread: Motor for Cat

  1. #1
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    Question Motor for Cat

    I have a AIRE LEOPARD cataraft and I'm going to get a motor for it but was wondering what sizes people are running on their cats. I have a 7 1/2 Merc that I have used in lakes for fishing and messing around but I want something bigger. I want to be able to run upstream with out a issue. I was thinking something along a 15-20hp but just wondering what other people were using. Also I know about the splash you get when running a motor plus I have the splash shield that Alaska Raft and Kayak sold. Thanks in advance for any info.

  2. #2

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    I have done plenty of experimenting with motor setups on cats and my friends have as well. Honestly, without some serious, costly and weight adding modifications the spray generated from higher horsepower units is a serious factor to contend with. Another design issue that seems to get overlooked is that a river cat has too much rocker on the rear of the tube to effectively get on step, especially on a boat like the Leopard. Think about it, motorized inflatables are virtually flat at the rear of the boat for a reason, to keep the rear of the boat from sinking during the initial start while trying to get on step. What I'm slowly but surely getting at is I personally feel that putting 15, 20 or more hp outboards on catarafts is a battle with the law of diminishing returns. What you gain in the end ain't worth it. The sweetest running setup I have ever witnessed with a Leopard was an 8 hp two stroke on the lower Kenai (not legal now). The boat ran "flat" and used the advantage of the low and long profile of the tubes, two canoes basically. It never got on step, but it made really good time and it had three people aboard with two dipnetting. My buddy has a 25 hp setup on the same boat and it will get going ok but it is touchy regarding weight and balance the speed difference and fuel consumption don't add up to me. The motor is a whole lot heavier as well. If you want to go fast with an inflatable get a boat built for it. Maybe someday soon someone will build a truly versatile boat for this but until then I feel it just isn't worth it in the end. I say save your money and go small, I wish I had.

  3. #3

    Default Power

    Quote Originally Posted by 450HUNTER View Post
    I have a AIRE LEOPARD cataraft and I'm going to get a motor for it but was wondering what sizes people are running on their cats. I have a 7 1/2 Merc that I have used in lakes for fishing and messing around but I want something bigger. I want to be able to run upstream with out a issue. I was thinking something along a 15-20hp but just wondering what other people were using. Also I know about the splash you get when running a motor plus I have the splash shield that Alaska Raft and Kayak sold. Thanks in advance for any info.
    I have a 2 hp honda four stroke that is light, runs forever on a tank or gas (part of the motor) and does fine with a Skookem pontoon boat, myself, dog and gear. I live on the Snake in Idaho and it works great. However I have not tried to go up stream on a really fast river.

    Spank

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    Member AlaskaTrueAdventure's Avatar
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    Default Get a better raincoat,,,

    Brackman 47 is 100% correct.

    I really dislike saying "look at the archives", but this topic has been covered many times in rather exhaustive detail. Mike S and Track H. have played with this concept as well as myself. In a nutshell, what Brackman47 describes is exactly, I think, what we have previously written about in the last 2 or 3 years.

    You will need more than a splash shield. Any tiny gap between the tubes and your floor, or any holes in the floor, will create a water geyser many feet high. 10 gaps will become 10 geysers.

    But if you do decide to test a larger motor out then get better raingear, or a drysuit. The wake-water becomes impresssive while you speed will not increase above 11 or 12 miles per hour on smooth, flat lake.

    But if it works for you do please post your success. I'm all for training and learning new tricks.

    Dennis
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    Member 6XLeech's Avatar
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    Default 8's and 20's

    Just working through the best outboard for cat question myself.
    Most advice seemed to me to puddle around the 8hp and 20hp outboards.

    I also ran into someone who suggested "PVC diamond plate" for flooring/wet shield on cats, to reduce the planing/splash probs. No, not the foam-core type, that I had in mind. Still researching this stuff myself.

    Two other threads with related discussions. The second one has an interesting comment about using mud motor on a raft:
    http://forums.outdoorsdirectory.com/...d.php?p=418523
    http://forums.outdoorsdirectory.com/...ead.php?t=4415

    Good luck.

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    Default

    I used a 30hp Suzuki for a while. It would make that cat scoot. But I couldn't get the power wipers to work on my goggles, so I had to give it up.

    I use a 2.5hp now, and it works great.

  7. #7
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    Lightbulb Leopards w/ outboards...

    Also agree w/ 'brackman47'

    1.) The continuous curve "rocker" (even more pronounced on new model Leopard cats) does not have the ideal geometry or the proper dynamic for good ocean, lake, or up-river power boat performance. The LEO is a pure whitewater boat... one of the best available for rowing Alaska's rivers and creeks.

    2.) Intersecting wakes tunnel and converge steeply just in front of or right at the engine shafts line of attack. This causes extreme turbulence and bubbles resulting in blade cavitation with overall poor, generally unpredictable performance.

    3.) Wet, exposed ride!!! Water-shielding and all... prepare for a soaking in your face kinda trip. A dry suit is the best idea for certain!!! As one added on here - some shields are more involved than others (darn near turning two hotdog tubes into RHIBCAT) but the weight & expenditure on personal experimentation borders on less than hoped for expectations that are not worth the effort.

    4.) Lots of water shields can be quite dangerous in larger wind driven waves (6-10'), strong rip current, and surf conditions... just know this... be smart and be conservative.

    5.) I find 15hp 4-strokes by several makes and models will push a Leopard 11 knots with a mesh floor 'or' v-tail spray shield with two-three people, 20 some gallons of gas, and going light on camping/fishing/hunting gear. I get this consistently! For a small boat/skiff over long distances this is too slow unless you have experience and know exactly where you are on the high seas if the weather conditions go bad en-route between major crossings. On a 60 mile round trip I burn an average 6 gallons. I keep the LEO as stripped lightweight and simple as possible. Everything gets strapped in hard with redundancy strapping!!! I always wear a drysuit!!!

    Cats are great if needing to land on a surf beach - because they will not swamp. You still must be vigilant of the fact that they (read as: a lot of boat weight & water force here) will try to pin you on a beachhead sideways immediately upon landing or trying to launch an escape through the surf.

    I've gone smaller & gone out with 35 super long shafts. Less than a 8 or 9.9 is not worth it in many cases. Greater than 25 is typically a waste of potential HP & additional fuel... you just do not get the returns.

    Most any longer shaft smaller outboard will work OK for messing around or the needing little kicker push --- just not as primary engine for serious power boating.

    Food for thought... this next summer, I will use a large dagger board, rudder, and traction kite with mesh floor. I think cat sailing will be a possibility even on the 18' LEO. It must have the dagger and rudder so it won't be as apt to instantly skid out across the water sideways.

    I wish I had a few recent pics to show you... but the last three times out in PWS had 6'-8' and 6'-11' seas. Saw very few bigger commercial or personal ocean worthy boats out there those days. Any boat out was seeing the spray of waves midst threadin' needles and haystacks.

  8. #8
    Member 6XLeech's Avatar
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    Default Short shaft outboards with motor lift...

    Wow, a cataraft in 6 (&more) foot seas. That's quite an image. Amazing craft aren't they?

    Another interesting power option that I guess Mike Strahan has used on his cat is a motor lift with a short-shaft outboard. I haven't checked to confirm the details with him yet, but thought it seemed a cool way to get your outboard way out of the way when not needed - further away from rocks, possible damage. Maybe Mike will comment on that.

    Alaska Raft & Kayak today confirmed it's the Garelik Adjustable Motor Lift that Mike uses. This lift has a 30 hp/135 lbs max - if you went with that option.

  9. #9
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    Default 6 Footers

    Six+ foot haystacks on Lionshead. OK.
    Six+ foot seas on PWS....I'm on the sat phone calling out an SOS-May Day.
    Different strokes...
    Brian, Your Explore Where Few Have Been Before easily thrumps my idea of True Adventure...

    Dennis
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  10. #10
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    Default

    Quote Originally Posted by 6XLeech View Post
    Wow, a cataraft in 6 (&more) foot seas. That's quite an image. Amazing craft aren't they?

    Another interesting power option that I guess Mike Strahan has used on his cat is a motor lift with a short-shaft outboard. I haven't checked to confirm the details with him yet, but thought it seemed a cool way to get your outboard way out of the way when not needed - further away from rocks, possible damage. Maybe Mike will comment on that.

    Alaska Raft & Kayak today confirmed it's the Garelik Adjustable Motor Lift that Mike uses. This lift has a 30 hp/135 lbs max - if you went with that option.
    Hi Leech,

    Yeah, I've been watching this thread to see if I needed to chime in. It would be worth a trip through the forum archives on this; a lot has been written on it already.

    The adjustable lift mount is what I use on my cats. They come in two sizes (the motor mounts). One has two lift brackets and the smaller one has one. I use the smaller one and it would be acceptable for outboards up to about 10-horse. I would go with the larger bracket for 12 horses on up.

    As others said, you have to start with what you want to do with the boat. In my case all I want is to push the boat a little faster than the current while I'm floating downstream on float hunts. With my setup I have been able to effectively hunt 180 miles of river in 14 days, with plenty of hunting time at the hotspots, by using an eight-horse to motor downstream. It really makes a difference. But if you want to go upstream, or get on step, you need not only a larger outboard, but the spray shield too. Lots of folks have played around with this concept, including the now-defunct "Wild Alaska Rivers Company", and Alaska Raft and Kayak, but in my opinion we are still a long ways from an elegant, production-type solution. We are still in R&D mode, in my opinion. But some of the systems work better than others. Currently the best thing going is the setup offered by Alaska Raft and Kayak.

    I don't think the original poster is going to be able to consistently push his Leopard upstream with a 20-horse. A lot depends on the river and how much load he is pushing. I would be more comfortable with a 25 or even a 35, but if you go that large you're better off if you can make a 2-stroke work for you. The 4-strokes are way too heavy in my opinion. With that setup, you need the spray shield for sure.

    Another issue that doesn't get talked about much is the danger of flipping under power. This is a problem with all cataraft-type boats, but is especially problematic with light boats like the inflatable cats. Simply put, the spray shield / decking between the tubes catches the air and pulls the bow up and over. It gets worse of course in rough water and headwinds, where the bow is moving up and down a lot. In those conditions, you have to throttle back a bit (okay, maybe a lot) to keep the boat on the water.

    Hope it helps!

    -Mike
    LOST CREEK COMPANY: Specializing in Alaska hunt consultation and planning for do-it-yourself hunts, fully outfitted hunts, and guided hunts.
    CLICK HERE to send me a private message.
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  11. #11
    Member 6XLeech's Avatar
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    Default Adjustable motor lift reasons?

    First, 450Hunter - I sure hope you're still finding all this helpful RE your original post.

    "The adjustable lift mount is what I use on my cats."
    Mike - is it correct that these lifts are used with short shaft outboards?
    If so, are the advantages then the weight savings (vs long shaft outboard)?
    Or keeping the outboard away from rocks/damage when not in use?
    Or maybe both?

    Thank you all for another informative thread.

  12. #12
    webmaster Michael Strahan's Avatar
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    Default

    Quote Originally Posted by 6XLeech View Post
    First, 450Hunter - I sure hope you're still finding all this helpful RE your original post.

    "The adjustable lift mount is what I use on my cats."
    Mike - is it correct that these lifts are used with short shaft outboards?
    If so, are the advantages then the weight savings (vs long shaft outboard)?
    Or keeping the outboard away from rocks/damage when not in use?
    Or maybe both?

    Thank you all for another informative thread.
    Great questions!

    The adjustable life will work with short or long shafts, and I believe it will also work with a jet.

    I frequently adjust mine when the boat gets heavier, and I have even adjusted it while we were running. When you first get going, the lower unit has to be a little deeper in the water to avoid cavitation. But once you get some forward movement, you start generating a wake and the water near the stern area gets "deeper" because of the upwelling of the wake. So once you have that going for you it is possible to move the lift up a notch, which allows you to run shallower. Naturally I would only do this with great caution, and never with a larger motor, because you are moving forward under power at that point (I'm not even gonna show you where I'm sitting when I'm doing this- or what I'm wearing...)

    Anyway I also raise the motor to the highest notch when I'm not using it. This allows me the choice of either tilting the motor or leaving it straight up and down, which makes it nice if we're shallow and I have to get out and push (the lower unit isn't sticking in my face).

    Hope it helps!

    -Mike
    LOST CREEK COMPANY: Specializing in Alaska hunt consultation and planning for do-it-yourself hunts, fully outfitted hunts, and guided hunts.
    CLICK HERE to send me a private message.
    Web Address: http://alaskaoutdoorssupersite.com/hunt-planner/
    Mob: 1 (907) 229-4501
    "Dream big, and dare to fail." -Norman Vaughan
    "I have climbed my mountain, but I must still live my life." - Tenzig Norgay

  13. #13

    Default cats and motors

    With a 16 Aire Jag, 7.5 hp long shaft with motor mount lift works fine downstream, even barging a round boat in front nestled between the tubes I can do 5-7 mph and its easy on the gas.

    Upstream in 5 mph current with gear and two aboard doesn't work, not enough horses.

    In general floors for cats used with motors are dissappointing. Like everyone says, its a wet, cold ride.

    Agree with Mike; smaller motors, w/ a lift type motor mount, and maybe add an extension handle for the throttle, so you can put your weight forward is a good compromise.

  14. #14

    Default 14' Catw/ 5hp

    I borrowed a 5hp 2 stroke (45#) to run Skilac from Kenai River. The 2 stroke was light weight moved me at 6mph.
    I also have a 8hp Honda LS (80#), but it seems heavy. I might have to try the 8hp out on a lake but I'm looking to buy something and don't plan on going much lower that 5hp.

    It's still a question in my mind, hate to buy and go darn it not enough or oh darn to much.
    Catch 22???

  15. #15
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    Default

    I have a adjustable lift on my cat when I use a motor. I have tried playing around with a jet unit but never had real good luck.

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