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Thread: 13'9" Zodiac-type boat: 25hp enough power?

  1. #1
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    Default 13'9" Zodiac-type boat: 25hp enough power?

    Will a 25hp motor be enough power for a 13'9" inflatable sport boat?

    The boat is rated for 40hp, but the price difference is +$2K for a 40 vs a 25.

    I will mostly be using this setup in PWS and Resurrection Bay (weather permitting), but would also like to explore some rivers and lakes as well. 90% of the time it will be me (200#), my wife (130#), our dog (80#), and camping/fishing gear (about 100#). The boat weighs 215#. The motor I'm considering only weighs 106# (2 stroke). *It took me an hour of searching, but I found a dealer with new 25hp Yamaha 2 strokes in stock! I dont see using this boat for hunting for a few years until I get the hang of everything, so forget about needing to handle the weight of a moose...

    Would I be much better off with a 40hp 4 stroke that weighs ~220#? The extra expense will exceed my budget for 1 year. I don't want a 40hp 2 stroke because then the Kenai would be off limits...

    This will be my first motorized boat .

    Thanks in advance for the help and advise.

    Zeb

  2. #2
    Member Tight Lines's Avatar
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    Wink

    I've spent allot of time in an 11' Zodiac with a 15hp on it, hauling about 500# total and it would get along pretty good. It was rated at 20 hp.
    I have always been told that you want to be 85-90% of the rated HP and I have always been happy with that set up. So net-net; I think you should have at least a 35hp outboard or your not going to be satisfied.

    2 stroke vs. 4 stroke; 2 stroke's are lighter but burn 1.5X-2X the fuel and make a lot more noise than a 4 stroke. Typically a 4 stroke is more reliable and longer lasting. So net-net; If it were me I would go for the 40hp 4 stroke and never look back.

    Here's my 20' all aluminum sportfisher, she is rated at 150hp so I said 85% would be close to a 120hp........I've had it for 10 years and I should have gotten the 150hp.
    I'll hold on to my Bible & my Guns, you can keep the change!!!

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    Member patrickL's Avatar
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    I wouldn't necessarily say that two strokes burn more fuel. Yeah the old ones did but some of the direct injects are pretty good on gas. Take the Etec for instance. That 40hp Etec is nearly as good as our 40hp Yamaha and Honda I use for work. In fact, lightly loaded I can barely tell the difference. That being say, that 40hp Etec weighs in at 250lbs while the Honda is a touch over 200lbs and the Yamaha is just under 200.

    We use alot of smaller, 16-18ft, lunds for work out in Western AK. We don't run anything over a 40hp. Overall, the Honda is the most reliable, but is the worst on power. The Etec is a monster on power but you have to use 2-cycle oil and it weighs a ton. The Yamaha is in the middle on power, doesn't weigh much and so far has been a pretty good reliable motor.

    I would say look at what you want to use the boat for. Just running around I'd say you're fine with a smaller motor. We've run zodias with 15hp, 25hp, and 30hp. They do fine on the 15hp until you add in a couple guys, fuel for a long trip and then gear. Add in some gear for hunting and then bringing back game, you might be hauling a fair bit of weight. You might want to move up. I say look into a 40hp Yamaha 4-stroke...good on fuel, quiet, not too heavy. You'd have plenty of power to haul weight and its a good motor. Nothing worse than being in some tough water with an underpowered boat.

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    My girlfriends dad had a 40yamaha on his 14ft. It worked great. Till someone stole the motor off of it.

  5. #5
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    Default Zodiak MKII

    I've owned one that exact size for over twenty years, and I'm on my 2nd motor. A 25hp engine is plenty for that size Zodiak. My sister had the exact same boat with a 35, and it is a trade off. A 35 is quite a bit harder to take on and off by yourself. My 25 weighs about 125 pounds, so it's a one man show.

    What you need to ask yourself, is where are you going to use it. Are you going to beach launch? Only trailer launch? I no sooner bought a brand new Yamaha 25hp two stroke, and they banned them on the Kenai.

    I use my boat primarily in lower Cook Inlet off the beach, so it wasn't that big of deal. I did enjoy using the Zodiak on the Kenai in the fall when there aren't many boats on the river.

    If I had it to do over again, I'd go for 4-stroke, but no bigger than 25 or 30hp. (unless you have some pretty good help to attach the motor)
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    Default More Zodiaks

    We all had 25hp 2-strokes on our 14 foot Zodiaks. That was plenty for scooting up and down the Kenai with a haul of silvers.
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    Member kodiakrain's Avatar
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    Default I agree with 25hp

    I had a 12ft Zodiac with a 35hp Merc on there and cruised all over Kodiak and the Aleutians with it, and I must say the point made about wt of engine when beach landing or exploring lakes and rivers as you intend is a big factor.

    My 35 was fun, but not necessary, in my opinion a 25 will get an inflatable going well even in rough weather. Zodiacs are Super Safe boats by the way and don't need to be flying to navigate really nasty weather. watch overloading obviously as it seems you are aware

    When you pull up to an ocean beach the extra wt on the engine is hard on the bottom of your boat also as you drag it across the barnacles and rocks

    I'm usually a big advocate of "More power is best" but in the case of a Zodiac on the beaches I think that's money not needing to be spent and weight you won't want to be lifting or dragging around

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    Default Just found out about 2 strokes on the Kenai

    I thought anything under 35hp is ok, but I guess NO regular (non DFI) 2-stroke is ok on the Kenai in July...

    That's kind of a game changer.

    Now I'm leaning toward the Evinrude 30hp etec. Anyone familiar with these new outboards? It's only 40lbs heavier (148lbs) than the 2 stroke 25hp Yamaha I was considering.

    It's $1200 more expensive, but the extra power and lower fuel consumption should be worth it, I suppose...

    Would this be a good match for my 13'9" inflatable sport boat?

  9. #9
    Member spoiled one's Avatar
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    Don't discount the tohatsu outboards. The 30 horse 4-stroke is 158 pounds and I suspect it is a lot cheaper than the etec. I used a 9.8 tohatsu this spring and it was the quietest, smoothest running smaller outboard that I have run.
    Spending my kids' inheritance with them, one adventure at a time.

  10. #10
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    Default That would be a great motor

    Something in the 30 horse range would be great. As I pointed out earlier, the weight may be the more critical item depending how you're going to use it. If you are going to leave the motor mounted all the time and trailer launch only, weight isn't such a big deal.

    If you're going to operate off the beach, or transport the motor off the boat, you'll want light weight.

    I have a Yamaha 25hp 2-stroke. I bought it just prior to the ban. Doh!
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  11. #11

    Default Down sized from a 25HP 2 stroke to a 20hp 4 stroke

    Quote Originally Posted by zeb View Post
    Will a 25hp motor be enough power for a 13'9" inflatable sport boat?

    The boat is rated for 40hp, but the price difference is +$2K for a 40 vs a 25.

    I will mostly be using this setup in PWS and Resurrection Bay (weather permitting), but would also like to explore some rivers and lakes as well. 90% of the time it will be me (200#), my wife (130#), our dog (80#), and camping/fishing gear (about 100#). The boat weighs 215#. The motor I'm considering only weighs 106# (2 stroke). *It took me an hour of searching, but I found a dealer with new 25hp Yamaha 2 strokes in stock! I dont see using this boat for hunting for a few years until I get the hang of everything, so forget about needing to handle the weight of a moose...

    Would I be much better off with a 40hp 4 stroke that weighs ~220#? The extra expense will exceed my budget for 1 year. I don't want a 40hp 2 stroke because then the Kenai would be off limits...

    This will be my first motorized boat .

    Thanks in advance for the help and advise.

    Zeb
    I've used my Alaskan Ranger 420AR (13'9") with a Merc 25hp 2 stroke for years. Iíd used this boat throughout south central AK, on both Salt water and Rivers. I use it for halibut fishing; dip netting, huntingÖ..

    With 2 guys, camping gear and on smooth water, My GPS said 25mph.

    Dip netting on the Kenai I could get on step with 3 guys and about 50 salmon.

    The extra width of the 420AR allows me to put 2 of those 165QT Costco coolers snugly inside between the tubes. This makes for a good dip netting set up.

    With the Rule change on the Kenai, I got a 20hp Honda 4 stroke. I'm now down to 18mph and the same 3 guys and about 35 salmon on step.

    Portability is a key item for me. I can easily handle a 120 pound outboard by myself and with launch wheels 2 guys can beach launch and land this size boat with no problem.

    I can even fit everything in the back of my Volvo wagon or a Cessna 206 (2 guys, 1 cooler, boat, motor and camping gear)
    Good boating

    Jim King


    Alaska Series Inflatable Boats, The Toughest Bottoms in the Business, River Rafts, Catarafts, Inflatable Kayaks, Inflatable Canoes, Inflatable Sport Boats, Inflatable Jet Boats, Tenders and Dinghies. WWW.alaskaseries.com (907)248-2900
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    Quote Originally Posted by akmike30 View Post
    This is the one we have with 40 horse on it. Going to be putting a etec 50 on it this spring. It went great with the 40. You could go faster than you wanted too. Did great. I love these little boats. I have taken it way out of deep creek than I should.

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    Default Tohatsu

    The boat I want (AK Series 420AR) is rated for a short shaft, so I'm assuming that I don't want a long shaft?

    In the 30hp class Tohatsu only offers the 15" version with electric start and power T&T which pushes the weight and price up considerably. The 25hp Tohatsu weighs 156lbs.

    So, my two front runner engine choices are a very lightweight Yamaha 25hp stroke (106lbs) at $2600, or a more powerful but heavier (148lbs), fuel efficient and Kenai legal Evinrude Etec at ~$3800 (I haven't called for the exact price yet).

    I will be doing a lot of beach launching. I don't have a boat trailer, so I'm planning on using my 2 place 4wheeler trailer, launch wheels, and lifting the motor on and off by myself.

    Should I just skip the Kenai in July and save some back pain, or would the etec be a much better motor overall, even with the extra heft and cost?

  14. #14
    Member spoiled one's Avatar
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    Quote Originally Posted by zeb View Post
    In the 30hp class Tohatsu only offers the 15" version with electric start and power T&T which pushes the weight and price up considerably. The 25hp Tohatsu weighs 156lbs.
    It looks like they offer it in 15" and manual start from their website.

    http://www.tohatsu.com/outboards/30_4st_spec.html
    Spending my kids' inheritance with them, one adventure at a time.

  15. #15
    Member Bullelkklr's Avatar
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    Default crank vs. prop

    Remember that the old outboards measured HP at the Crank -and the new ones at the Prop.

    I have a 40hp zuki on mine - it runs about 24-26 WOT no matter how much is in it. The motor is old so I think that I only really have 27.5 horse or so.

    Does anyone know when the change occurred between crank vs. prop HP ratings?


    Mine is rated for 60 horse - - but I that would be too much - a nice new 4 stroker in a 50 would be sweet and probably extend my range by twofold. Really though - the HP is not needed.

  16. #16

    Default Stay Kenai Legal

    Quote Originally Posted by zeb View Post
    The boat I want (AK Series 420AR) is rated for a short shaft, so I'm assuming that I don't want a long shaft?

    In the 30hp class Tohatsu only offers the 15" version with electric start and power T&T which pushes the weight and price up considerably. The 25hp Tohatsu weighs 156lbs.

    So, my two front runner engine choices are a very lightweight Yamaha 25hp stroke (106lbs) at $2600, or a more powerful but heavier (148lbs), fuel efficient and Kenai legal Evinrude Etec at ~$3800 (I haven't called for the exact price yet).

    I will be doing a lot of beach launching. I don't have a boat trailer, so I'm planning on using my 2 place 4wheeler trailer, launch wheels, and lifting the motor on and off by myself.

    Should I just skip the Kenai in July and save some back pain, or would the etec be a much better motor overall, even with the extra heft and cost?

    The dip netting and fishing in general on the Kenai River in July are way too good of a resource to discount out of your fishing options. Drifting the upper Kenai using the HD oar locks and river rafting oars is another good way to make full use of the Alaska Series 420AR. This opens up the entire river between Jimís landing and the lake. July is prime time for this trip too.
    When you can fill the freezer with 40 to 50 salmon in a couple good tides of dip netting it takes the entire freezer filling pressure of the rest of the rest of the season.

    The only time I feel under powered with my 20hp Honda 4 stroke is that last trip up the river with 3 guys and 35-40 salmon on board. That's pushing close to 1000 pounds plus the boat and motor.

    Weight and Portability sounds like they are key issues for the set up you're trying to put together. Iím not a real big guy but wrestling with a 160 pound outboard sounds like a two man job to me. Maybe thatís because 160 pounds seems to weigh more than it did 20 years ago.

    If you plan to trailer your boat and push bigger loads up river then the additional weight of the larger outboard would be a good choice.
    Just a note on the electric start and power tilt, they both add weight to the outboard but are nice features to have if the boat is used off a trailer and weight is not an issue.
    The other note on the power tilt is that it adds length to the aft side of the outboard mounting bracket this will conflict with the duel bailing plugs on the Alaskan Ranger boats with the short shaft transom. The Solution is to order your boat with the long shaft transom option and use the long shaft outboard with the power tilt. This raises the outboard up 5 inches and fixes the conflict with the duel drain plugs.

    Jim King


    Alaska Series Inflatable Boats,
    The Toughest Bottoms in the Business,
    River Rafts, Catarafts, Inflatable Kayaks,
    Inflatable Canoes, Inflatable Sport Boats,
    Inflatable Jet Boats, Tenders and Dinghies.
    WWW.alaskaseries.com
    (907)248-2900
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    Member patrickL's Avatar
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    All good advice here. When I was talking about our boats for work, we only put our motors on once and remove them once a year. Its a major pain with the 40hp motors. The Etec is especially heavy at 250lbs for a 40hp. Honda was like 212lbs and the Yamaha 198lbs. Still alot of weight for a single guy to move around. The Honda 30 was manageable but I wouldn't want to take it very far.

    Another thing about heavy motors. It always seems like the heavier motors get damaged when we move them around. Scratches, cracked cowling, etc. They're so heavy its tough to be careful when moving them around.

  18. #18
    Member Lone Wolf1's Avatar
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    Smile

    I've had an old Zodiac MkIII 15.5' for years. I used to run an old Evinrude 30hp 2-stroke that pushed her around well with some serious loads. A few years ago I replaced it with a 30hp 4-stroke short-shaft Tohatsu. It's a lot better on gas, and still does well. It does not, however, have as much thrust power as the old Evinrude. It's slower to get a "hole shot" up on step, and it's a little heavier. Having said that, my wife and I have taken it everywhere and really loaded her down on some bear hunts (see photo). The Tohatsu 30 is definitely enough motor, and right at the upper weight limit of my willingness to manhandle on/off the boat. We usually put it on once per season to trailer it, so that's not too big an issue. Good luck with your search...
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  19. #19
    Member sbiinc's Avatar
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    I had a Mark III that I originally used with a 40hp prop and was scared to open it up, the boat would just about come out of the water while empty...

    I moved down to a 25hp 2-stroke Yamaha after seizing up the old motor and actually got the zodiac on step with near 1800lbs in it, counting the 4 people sitting above the pile of gear even though two had to shift their weight so far forward they were near hanging in front of the bow.

    Since I've bought another inflatable raft (Zodiac knockoff) and a few years ago borrowed a 15hp for a bear trip to use on the zodiac and found with 4 people and camp gear aboard it wasn't near enough to get on step... just my little bit of experience to aid your choice.

    PS my 25 is really nice kicker for the boat on my avatar and isn't too bad to wrestle around and switch over to the raft when I bring it along.

    B

  20. #20
    Member AK_Kid's Avatar
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    Drop the extra loot and go Kenai legal. When you take me dipnetting, I'll split gas.

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