Smallest Jet Outboard?

[msawyer]

Hello all..


I'm planning on buying a 16 ft inflatable for hunting/exploring and I would like to put an outboard jet with a tiller (or long tiller). I would like to be able to pack the boat and motor into a float plane - A Yamaha 40 hp jet weights nearly 300 pounds but is a well regarded jet motor. Does anyone have any advice of a smaller/lighter jet outboard for use on a small inflatable? Also, do any of the experience "small" jet boaters have any advice about the smallest motor (hp) that would allow a 16 ft inflatable, two guys, 10 days gear and possible a moose to head back upstream on a 10 kmh current (for example). Thanks in advance for your thoughts/advice/input.

[wildcatter]

A 16 ft inflatable is not a small boat and you need at least a 40-60 HP outboard.
With 40 you would be pretty slow, even more so if loaded with gear and a moose.
Yamaha has jet drive outboards from 40 HP to 150 HP.

[Keta1969]

You will be disappointed by trying to go minimum hp on a jet. 2 guys 10 days gear and a moose is a load. Have only been on one jet boat trip with a few different boats but it was readily apparent that having reserve hp was the way to go.

[chinook150]

40 HP is barely enough for 2 large men with packs and river current. I am not sure you would be able to add a moose.

[emerson]

Tohatsu 50/35 weighed 196 lbs. I used it on an 18’ Crestliner. It’s still boating around Smithers.

[Ride Red]

Hello all..


I'm planning on buying a 16 ft inflatable for hunting/exploring and I would like to put an outboard jet with a tiller (or long tiller). I would like to be able to pack the boat and motor into a float plane - A Yamaha 40 hp jet weights nearly 300 pounds but is a well regarded jet motor. Does anyone have any advice of a smaller/lighter jet outboard for use on a small inflatable? Also, do any of the experience "small" jet boaters have any advice about the smallest motor (hp) that would allow a 16 ft inflatable, two guys, 10 days gear and possible a moose to head back upstream on a 10 kmh current (for example). Thanks in advance for your thoughts/advice/input.

Start with a list of everything you’ll be taking including you and your buddy, then do the math on weight. Most people are surprised at what kind of weight they’ll end up with, then figure out what horsepower you’ll need to move the load. I have a firefish and just short trips with 4 of us, extra fuel, food, gear etc makes all the difference in the world. Then you start looking at necessities vs wants for the trip to lighten your load.

[bigredchev]

Don’t forget how much spare fuel you will pack.




is it more efficient to have a smaller lighter engine running at max load vs. A bigger/ heavier engine running in at peak efficiency and working easier?

[Blockcaver]

We used a 20 HP Merc 2-stroke jet (derated to 15 HP jet I believe) on a fairly small raft in Alaska on a brown bear hunt on a river a few years ago. Obviously it was an older obsolete motor that wasn't too heavy for one guy to move around and fly in via Super Cub. It pushed two of us up river rather well...without camp or a moose in the raft.

I've fished on the Thompson River in a raft with a Yamaha 40/30 jet. That thing would fly with just two of us on board. But as mentioned, it is heavy and stayed on the raft frame full time. Wouldn't want to have to load and move it in a Beaver.

Sorry, I don't know either of the raft lengths, but both were relatively small...certainly not 16' long, likely more in the 12' range.

[butthead]

i had a 12ft inflatable with 30 hp for scuba diving
2 guy @ 160 lbs
4 tanks 2 weight belts and all the other stuff you
took with u.
it worked well on the ocean but a river id like more power
would be in your favor

[theoutdoorsman]

With the boat/gear mentioned a 50/35 two stoke is probably the bare minimum. With any jet bound excursion power, fuel, and weight of said fuel and power will always be a hard balance to keep. Adding float plane transportation and your're into a losing battle. Unless you're flying around in a twin otter your best bet is go 60/40 4 stoke and forget about the plane or run a 12-14ft inflatable with a 20hp 2 stoke and keep a pak raft to tow a moose in (not on step) once you're successful. There is a reason most guys that hunt with jet boats are running 18ft + armoured boats with 350's.

[fuzzybiscuit]

You don’t want to have to load a 40hp Yamaha into a plane and a 16’ inflatable is pretty big to be using as a portable.

I have had three 25hp Merc 2-strokes with jets and presently have a factory one I just picked up last fall. I wouldn’t want to be lugging around a motor much bigger than that. They are fine on a 1448 aluminum Jon or 12-14’ inflatable but it wouldn’t push any more than that.

To be honest, inflatables and jets don’t always work well together. Most inflatables end up catching a lot of air which ends up getting into the pump causing them to cavitate badly. On a 2-stroke that will cause a loss of power and possibly liner damage. On a 4-stroke you could float a valve and cause engine damage on top of the loss of power and liner damage on the 2-stroke,

I wouldn’t own another inflatable that I was planning to use a jet on unless it had a built in tunnel that funnelled water into the pump. The Alaskan Jet Ranger and Solar brand boats are the only two I know of with a tunnel.

[Drillbit]

I run a 14 sled with a Yamaha 60/40 4 stroke. The 50/30 honda before it wasn't enough for power.

I would hate to have to load that into a plane.

[Samsquantch]

Mercury made a factory 20 at the jet up until 2006 from what I know. They are perfect for a 16 foot inflatable but with spare fuel and two guys with ten days of gear I doubt you would get on plane going in or loaded with critter coming out.

[albravo2]

It sounds like a lot of fun... fly in then boat upriver.

Count on needing a Beaver and even that might take two trips on the way out if you kill a big critter. I wouldn't want to try and load a 300# engine into a 185.

[msawyer]

Thanks Emerson... do you where one could buy such a motor and would you recommend the motor?

[msawyer]

Thanks to everyone... All good information and/or advice... Ummmm.... back to the drawing board!

[emerson]

I ran the 18’ Crestliner with the 50-35. Day hunts with 3 guys were no problem. Longer hunts with 2 guys packing like a sheep hunt would be ok too. Only had 1 time 2 big guys and 5yr old quartered bull moose, no planing. I would debone it all and expect planing at WOT only if I had big distance to go. I always planned for 2 trips if we got lucky. The boat weighed 660#+batt, fuel etc. Stainless impeller and new wear ring cut my fuel use by 35%, probably because stainless was 10thou clearance and aluminum 30thou. I would use an inflatable with a tunnel and the same motor I used but pack like you are carrying everything on your back. Expect 2 flights out and budget for it.

[BC Cruiser]

I agree smallest jet outboard I would go to is a mercury 25 hp at the jet (factory jet) with a 1448 MV Jon. I’ve used both this and the Alaskan jet ranger (which worked fine, but experience cavitation).

[tyreguy]

Fly in a prop motor with you, more efficient than a jet and you're landing on a lake i assume or something at least with some water in it.


Thanks to everyone... All good information and/or advice... Ummmm.... back to the drawing board!

[emerson]

Fly in a prop motor with you, more efficient than a jet and you're landing on a lake i assume or something at least with some water in it.
Using a prop sure cuts weight well, if you aren’t running shallow.

[puddlejumper]

Hello all..


I'm planning on buying a 16 ft inflatable for hunting/exploring and I would like to put an outboard jet with a tiller (or long tiller). I would like to be able to pack the boat and motor into a float plane - A Yamaha 40 hp jet weights nearly 300 pounds but is a well regarded jet motor. Does anyone have any advice of a smaller/lighter jet outboard for use on a small inflatable? Also, do any of the experience "small" jet boaters have any advice about the smallest motor (hp) that would allow a 16 ft inflatable, two guys, 10 days gear and possible a moose to head back upstream on a 10 kmh current (for example). Thanks in advance for your thoughts/advice/input.

There are a number of options. Maybe run a representative stream on google earth first, determine if any really rocky areas, long shallow areas etc, something that you might be thinking of exploring. You may be able to get away with a short leg prop in the 20-25hp range with a prop protector that will push that boat up the river with your load. leave the kitchen sink at home. With the additional weight of a moose you may have to make a couple of extra trips. There are simple prop protectors that wrap around the propeller or one that encases the skeg and prop and comes in different sizes based on hp. Don't lock in the motor, go slow and easy, but forward, allow it to drag over the rocks, you will have to be on and off the throttle but have control of the boat. A spare prop would help as well.

WRT to your question, I probably wouldn't go less than a 40/30hp Jet on the 16' inflatable. I had a 30 on a 14 inflatable and it worked fine, sometimes seemed bit heavy for the boat (have a video somewhere and will share when I find it). Just as a reference, a 25hp jet on a 14' Jon boat will get up on plane in seconds with about 500lbs including persons in the boat and doesn't slow down against the current. Also for space and weight, look into bladder fuel tanks opposed to jerry cans. Once empty they take up little space.

Hope that helps a bit.

[knothead]

I thought my rotopax were expensive, those bladder fuel tanks are about twice the price for a 5gal.

[knothead]

By the way I use rotopax to carry extra fuel on my jet boat, they fit nicely in the gunnels on my boat so take up no floor space.

[fuzzybiscuit]

Here’s a 20hp Merc 2-stroke with a prop guard on the 13’ Titan I posted previously. It flys and the light motor bounces up when it hits a rock with no damage.

https://i.postimg.cc/Jz2n3SbT/BB844-CAD-0-C31-4213-BF5-A-D057153975-A4.jpg (https://postimg.cc/fVYDD2qX)

https://i.postimg.cc/PqvqSKyd/2-F29-C19-E-8-D73-43-EB-8-CD6-DF1983-E29-C08.jpg (https://postimg.cc/94VVMdsk)

https://i.postimg.cc/xT9c9vfP/94-FA62-F7-76-F3-488-F-91-D9-C54-D4-FE820-A3.jpg (https://postimg.cc/qgZkLCCt)

[canishunter22-250]

Here’s a 20hp Merc 2-stroke with a prop guard on the 13’ Titan I posted previously. It flys and the light motor bounces up when it hits a rock with no damage.

https://i.postimg.cc/Jz2n3SbT/BB844-CAD-0-C31-4213-BF5-A-D057153975-A4.jpg (https://postimg.cc/fVYDD2qX)

https://i.postimg.cc/PqvqSKyd/2-F29-C19-E-8-D73-43-EB-8-CD6-DF1983-E29-C08.jpg (https://postimg.cc/94VVMdsk)

https://i.postimg.cc/xT9c9vfP/94-FA62-F7-76-F3-488-F-91-D9-C54-D4-FE820-A3.jpg (https://postimg.cc/qgZkLCCt)

Great looking guards. I've got similar homemade ones for a 20 and 30 hp and use them with my 12 and 14 foot zodiacs. Got a 16 ft too and even the 30 is underpowered for it. I've got a Yamaha 40 for it which works great but really pushing the brink of being 'portable'. My wife and I can barely lift it to get it on the transom. Not going in any planes!