Newbie with questions regarding rafting under power (outboard) - Mountain Buzz

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Old 11-30-2018   #1
Join Date: Nov 2018
Posts: 2
Newbie with questions regarding rafting under power (outboard)

I'm buying a raft style drift boat for fly fishing Northern California waters. Specifically, I'm looking at a StealthCraft Hooligan:

It's a framed boat that will take an outboard motor up to 9.9hp. However, due to cavitation issues, they say don't bother putting more than a 6hp on it, as a 6 appears to achieve the same top speed as a 9 due to the design of the boat.

They are telling me it'll hit about 6 MPH on a still water lake, but I need to know if it'll be capable of actually motoring UP RIVER in relatively slow meandering rivers like the Feather River and Lower American River in the Sacramento area. There are no actual "rapids" in those stretches.

Below is a link to a video of the boat rigged with a 6hp on a lake. Seeing it move, I can't imaging not being able to get upriver in a flat water stretch, but Ii hate forking over the money without some kind of feedback by people who've actually done it.

I've seen several references by members on this board saying they tow multiple rafts under power, but it's always down river to get through frogwater... no references to going against the current. If anyone has any experience going UP RIVER in those stretches or similar rivers, their feedback would be GREATLY appreciated. THANKS!!

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Old 12-01-2018   #2
caverdan's Avatar
C. Springs, Colorado
Join Date: Aug 2004
Posts: 1,927
I'll bite. In order to motor up river, you need enough horse power to overcome the current. A 9.9hp will get you there a lot sooner than a 6 hp when trying to overcome such 3.9hp quicker. In the fall, when the river is running slow, it shouldn't be much of a problem to overcome two or three mph current. High water is a different ball game. Rapids or not, if the current is fast, you won't be able to overcome it's speed with a small motor.

You need to think about the weight of the motor hanging off the back. A 6hp four stroke weighs around 55lbs. A new 9.9 four stroke weighs around 100lbs. My 8 hp two stroke Johnson weighs 58lbs. You get too much weight hanging off the back and your going to have a scary ride into the current unless you weigh the raft down some. Some engine manufacturers change the carburetor to get the different hp ratings out of the motor, which is why you see 4 and 6 hp motors weighing the same. Something to think about. 2 hp makes a big difference in thrust.

I think your optimum motor for that boat would be a 90's 8hp Johnson or Evenrude 2 stroke, long shaft. That's just me and others will differ from my opinion. I'm not a big fan of the four strokes when it comes to storing and transporting them off the boat. If you don't set them down right while transporting them, they leak oil. If you submerge them, you have to do a lot more to them, to get them to restart. Both make noise when running and I don't find the four strokes to be much quieter, if any, when running full throttle like you do when trying to go against the current.

A guess my point is that the more HP the better going into the current. The hull speed is what it is, but if the current speed is say 4 mph, you'll need the extra hp to get to that 6 mph hull speed. Weight and balance of the raft are all factors in making headway with your boat. Too much nose weight and you'll be digging in when the current surges, filling your boat with water. Are you getting the optional self bailing floor in it? If you get the solid non bailing floor, this could be a real problem. The guy in the video is running an empty boat. Put a cooler full of beer and a guy fishing and you've added 2 to 3 hundred pounds to push up river. Make it a 14' Avon full of gear and you will be wanting the biggest motor you can fit on the back with or without current.

When you put a motor on a raft, you need to register it with the state as a motor boat. You'll need to follow your state boating rules and carry things like a fire extinguisher and add registration tags and numbers to your boat. Your now in a different category of boating. You need to make sure that the rivers you are wanting to boat on allow upstream travel. Just a few more things to think about when adding a motor.
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Old 12-02-2018   #3
Join Date: Jun 2018
Posts: 19
a raft moving upstream....

I don’t know what your expectations are exactly, but I think you need to lower them. J/k. But I think you’re right to be a little nervous about how well this might work.

I haven’t been on the rivers you referenced. I have spent a lot of time fishing on slower sections of the upper Snake River in Idaho. From a row boat. Eventually a drift boat. Most recently a John boat. I also row a raft, but learned the raft after years of the other boats. (You might be able to identify me and my buddies move up into higher wages by that list of boats &#x1f609.

I can only share my perception and experience. Hope you find it helpful.

A two stroke 6 hp (I think) evinrude (yeah from back in the day-we were both young and broke and this was mid 1990s) would barely move us up stream in the row boat. I don’t know current speed (and that river is constantly speeding up and slowing down anyway as it goes deep/shallow/wide/braided channel etc) but, I can offer this (probably useless) comparison. We could never really row upstream because the current was too strong. We could hold position rowing, but not really gain. And totally spent physically after less than a minute trying. The drift boat made holding position in strategic locations much more possible.
....pause for effect.....
This what I mean when I say it would barely move us: It did move us upstream in the row boat. And we noticed that weight distribution was way more important than actual weight. We would go up stream, at full throttle, for what felt like a full minute or so to retrieve an expensive lure or a favorite fly that snagged up. A full minute-ish to go only as far as the amount of line on our reel...or less.
A row boat. A 6ish hp motor. Row boats are pretty efficient on the water. Rafts are horribly inefficient on the water by comparison. When I learned to row a raft I was shocked at how much effort was needed to move an empty rig. And moving it fast has never happened in my perspective. Additionally, and this is important, a row boat is very ridged and has a keel, so it responds to current and motor and weight distribution- all of which add up to an ability to steer when going up stream. My fear (although I don’t know) is that the current will simply push the nose of the raft a little left or right and you won’t be able to get it straightened out before the current finishes pushing the nose around so you’re pointed down stream again.

Just my opinion, but you better test drive this rig before committing the high $$. My guess is that you might hold your position in the current and possibly, just maybe, go upstream at the same speed you could have walked upstream after you rowed to the bank. Even if the bank is a tangle of brush and branches. Walking might be more enjoyable too; stretch your legs and not listen to an engine scream for several minutes.
A fair number of guys do fish out of a raft on the river, I’ve just never seen any of them so much as attempt upstream travel.
Of course current speed and current uniformity (ie eddys or confused water verses water flowing in a uniform fashion) will make a huge difference. You know your river; my experience might not be similar to yours.

Good luck on the decision! And post results. I’m curious now.
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Old 12-03-2018   #4
Join Date: Nov 2018
Posts: 2
CAVERDAN: Thanks for the reply and the insight. Just a quick note on the 4 vs. the 2 stroke. Totally agree on weight. Unfortunately, one use for this thing is going to be stillwater alpine lakes, and most all of the ones that are big enough to require a motor also require a 4S in this state. On smaller waters, I'll just be drifting / paddling anyway, or have the option of an electric. I've had my eye on several that I currently kayak fish. Normally if I want a casting deck or want to be able to take several family members out, I take my Ranger. But the Ranger has a 2 stroke and is banned on these lakes.

Both you and Amoon (thanks to you too for the great feedback) have pretty much nailed the issue. The dynamics of a raft do NOT lend themselves to speed under power... and more power doesn't equate to more speed because of cavitation and those dynamics... so just bumping the power from a 6 to a 9.9 doesn't actually give me 3.9 additional "usable" horsepower... just digs me in further due to engine weight and cavitation.

Fortunately, I don't need much (roughly 2.5 MPH on a slow river, or as Amoon puts it - comparable to walking the bank speed . Just enough to get a striper lure to move up stream to seek out schools. I have no delusions about actually "motoring upriver" with enough efficiency to actually take out where I put in (although damn that would be nice). It's really about just that one scenario... trolling for striper in the feather more than anything. For all else, I can drift, put in, take out down stream and be good to go.

Fortunately, I think this rig gives me enough of what I want to make it worthwhile with or without a motor, so I'm going to pull the trigger on it. But I'm not going to power it right away. We'll see how she paddles, then I'll put it under electric. Have some contacts with small o/b options too, so I'll give that a shot before putting the money into a gas engine.

I'll let you know how it goes, as clearly, it seems to be a mystery that hasn't been solved by a lot of folks

Thanks again to both of you for the feedback.
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Old 12-03-2018   #5
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C. Springs, Colorado
Join Date: Aug 2004
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Ya yes.....two strokes are slowly going by the way side. Sounds like you will do fine with a 6 hp. When going against the current, cavitation won't be reached until you overcome the current speed plus the hull speed, so more hp does help in this case. I'm a little surprised that they are saying the hull speed is only 6 mph. I would have guessed it to be more like 9 or 10 with enough hp. The power boats I've owned and driven come up on plane around 18-20. If you end up getting the rig, I'd be interested in what kind of speed you really get out of it. Good luck and may the fish be with you.
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