You don't get any reaction or additional thrust from spraying at the water, but there could be a reason to "trim out" your boat by adjusting the vector of the nozzle outlet.
Why not plumb the outlet through the transom under the water line? You'd keep your shallow draft and it would be a lot more efficient than just spraying water backwards in the air. I'm genuinely curious, because I have several large electric centrifugal pumps and I've been considering trying something similar with one of them, just more performance oriented.
He said that one of his design criteria was not to have anything in the water or on the bottom of the boat because of going over rocks common in the river that he frequents for fishing. My design has the jets in the water, but those were his design criteria.
love it,doing a similiar build in the uk,im using 2 pumps as you are but running the outlets 2 into 1 and then out the back of the boat,using stainless tube for the outlet (welded) hoping it stays together! great project keep up the good work.
I love the build, are you using a stator to straighten out the flow of the water exit your nozzles.? Every jet pimp uses one as it directs the energy of the flow in the direction you want ( rather than spraying in a big fan). I believe the sweet spot for a jet pump to eject the water is right at the water line. Under the water you lose thrust . If you look at A mokai they have their jet pump nozzle in the water until you take off then it is sitting at the waterline in the wake created by the boat. I’m no expert on jet pumps but I have built several,versions of a jet powered paddleboard and like you have also had to learn by trial and error the best configuration for max speed/power. I’m still working on that btw….. it seems every time you fix a problem you create 2 new ones. I’m looking forward to seeing the improvements you make along the way. It may not be possible with the configuration you have there but if you can get toe flow to your pumps to come in at a more gentle angle you would have a lot more power. Those 90 degree turns from the bottom of the hull up then over and a another 90degree into the pump has to be slowing the water flow down and also adding turbulence to the flow. It will create a lot of cavitation on the impeller which will cause premature wear on the bearings and impeller. Not something you need to,address in the short term but for long life and reliability once you have made the other improvements you plan on doing, I’d want to eliminate the 90 degree turns in your intake as much as possible. You might want to consider relocating the intakes to right under the pumps ( like a jet outboard does) that might be all you need to do to improve intake efficiency. That’s a lot to digest Sorry I keep thinking of my own experiences and I’d like to save you some of the mistakes I made. Good luck with the build Cheers Frank
I actually have a similar idea for adding propulsion to my canoe. I looked at various small outboards, gas and electric and thought, hey, I have the Predator 2-inch pump that puts out a ton of water. Why not try using that, incorporating 2" PVC fitting and then reducers to dual water jets for balance in propulsion? I was wondering if anyone had done something similar, and here you are. My jets will be in the water, but I'm less concerned about rocks. Nice experiment - and thanks for sharing.
Hi guy that is a pretty cool ! J I am a boatbuilder and we are currently building a 65 ft glass bottom boat with 3 water jets tol look at the shipwrecks in Georgian Bay We built several others in the past ! Have a great day !
Thanks Nathan!!! I'm just getting started. THIS IS ONLY THE BEGINNING!!! Please subscribe and share with anybody who'd be interested. Glad you liked it.
Are you limited by the engine rev limit? I am looking in to doing this with 212cc (6.5 hp) engine. But it has a big world of aftermarket parts to make up to 15 hp for another $300ish. So power goes up and revs out to 8k rpms
Thanks for the comment/question OutOfWork Outdoors! If the engine ran faster I would bet I'd get more flowrate and more speed. If I could come up with $600 more to throw at this build perhaps I will do it.
Very cool,.... you would have increase HP 4x to get any speed with this set up. When you trim a jet out board up so water is spraying up in the air, it hardly moves. Seems thats what you have here. I do like the intake. Cheap shallow jet boat YES. NO reverse noway. Like your determination and will keep watching.
Amazing work. Keep it up! I wanted to ask you if there is any cavitation happening in the pumps? I want to modify my boat to jet drive with the help of a big centrifugal water pump powered by a 16Hp petrol engine.
Awesome man I am a carpenter but I have seen a guy making boats from fiberglass and foam sheets. I fish a river that on low tide a canoe with a trolling motor is not capable of traversing. This jet idea maybe what I am looking for!
Thanks for the comments Jim! You should try it. It's not fast, but it is cheap and very functional. Also very hard to damage a pump that's designed to suck "trash, mud, sand, etc. Would you consider subscribing? Or sharing this with a friend?
@ D Red, thanks for the suggestion! This has come up a lot, and is a counterintuitive concept. I've made a few videos explaining. ua-cam.com/video/HgQTKWpNgQQ/v-deo.html
That's an ingenious design! I'm wondering if you scale up to a larger boat with the same engine, same hull and everything, if it will actually end up being faster or not. One thing that I noticed was the reverse. You don't have one. Also, the flow of water is restricted in your design due to the size of intake pipe verses the many holes. You are restricting the flow by about half because of all that metal blocking the flow. I would think that if you had more water coming in than the size of your pipe than that would increase the power.
Thanks Robert! I did measure the "open area" of all the little intake holes, and it's equivalent to a 3" hole (the same size as the inlet). I do agree that it's a lot of turbulent flow, and if I removed the little holes, and just cut it out it would go faster.
Just like every other jet boat! Moving the water the smallest distance possible is the most efficient method! If your happy listening to those loud thing and barley be on plane more power to ya! Personally id have picked up a sub 1000$ jetski and had something that actually got up to speed! Instead of spending all that money and getting poor results..!! You could have achieved much better results using 1 212 engine and an sps longtail kit and been money ahead speed ahead simplicity ahead and still be able to go more places
![Lp. Сердце Вселенной #60 РОЖДЕНИЕ ЛОЛОЛОШКИ [Финал] • Майнкрафт](http://i.ytimg.com/vi/YoR0pAV9FVQ/mqdefault.jpg)
Nozzle in water would make this a hit project right off the bat!
No you would be wasting thrust, the nozzle has to be out of the water for maximum thrust. Look at any jet boat design or jetski.
Would it not be more effective to have the outlets turned down towards the water?
You don't get any reaction or additional thrust from spraying at the water, but there could be a reason to "trim out" your boat by adjusting the vector of the nozzle outlet.
@@greenlizardusa3105 ah but you are wrong grasshopper.......ua-cam.com/video/C9jGKaiZIcQ/v-deo.html
Wouldn't they perform better submerged? Out the back??
@@greenlizardusa3105 You are right. Newton's Third Law says it all.
Why not plumb the outlet through the transom under the water line? You'd keep your shallow draft and it would be a lot more efficient than just spraying water backwards in the air. I'm genuinely curious, because I have several large electric centrifugal pumps and I've been considering trying something similar with one of them, just more performance oriented.
Dont get me wrong...love the project....your thinking outside the box!
Thanks Garry! That’s the way my brain works. Always thinking of other ways to do things. Even if just for the fun of it!
@@greenlizardusa3105 good thing we aren't neighbors.....no telling what we build.....I love fabrication!
Agreed! might end up like colin furze!!!
just don't understand,,, why wouldn't you put the jet nozzle into the water?
He said that one of his design criteria was not to have anything in the water or on the bottom of the boat because of going over rocks common in the river that he frequents for fishing. My design has the jets in the water, but those were his design criteria.
love it,doing a similiar build in the uk,im using 2 pumps as you are but running the outlets 2 into 1 and then out the back of the boat,using stainless tube for the outlet (welded) hoping it stays together! great project keep up the good work.
Put the existing nozzles under the water line
Yes, the water output would push a lot harder against water, than air. This is bizarre that he got this far, but no farther... Hmm.
If you discharge the outflow under water wouldn’t you greatly increase efficiency?
It’s actually counterintuitive. Check out some of my “Here’s the Proof” videos or the one I made for the Veritasium science communication contest.
I love the build, are you using a stator to straighten out the flow of the water exit your nozzles.? Every jet pimp uses one as it directs the energy of the flow in the direction you want ( rather than spraying in a big fan). I believe the sweet spot for a jet pump to eject the water is right at the water line. Under the water you lose thrust . If you look at A mokai they have their jet pump nozzle in the water until you take off then it is sitting at the waterline in the wake created by the boat.
I’m no expert on jet pumps but I have built several,versions of a jet powered paddleboard and like you have also had to learn by trial and error the best configuration for max speed/power. I’m still working on that btw….. it seems every time you fix a problem you create 2 new ones.
I’m looking forward to seeing the improvements you make along the way.
It may not be possible with the configuration you have there but if you can get toe flow to your pumps to come in at a more gentle angle you would have a lot more power. Those 90 degree turns from the bottom of the hull up then over and a another 90degree into the pump has to be slowing the water flow down and also adding turbulence to the flow. It will create a lot of cavitation on the impeller which will cause premature wear on the bearings and impeller. Not something you need to,address in the short term but for long life and reliability once you have made the other improvements you plan on doing, I’d want to eliminate the 90 degree turns in your intake as much as possible.
You might want to consider relocating the intakes to right under the pumps ( like a jet outboard does) that might be all you need to do to improve intake efficiency.
That’s a lot to digest Sorry I keep thinking of my own experiences and I’d like to save you some of the mistakes I made.
Good luck with the build
Cheers Frank
I actually have a similar idea for adding propulsion to my canoe. I looked at various small outboards, gas and electric and thought, hey, I have the Predator 2-inch pump that puts out a ton of water. Why not try using that, incorporating 2" PVC fitting and then reducers to dual water jets for balance in propulsion? I was wondering if anyone had done something similar, and here you are. My jets will be in the water, but I'm less concerned about rocks. Nice experiment - and thanks for sharing.
whats new on the jet boat build?
Hi guy that is a pretty cool ! J
I am a boatbuilder and we are currently building a 65 ft glass bottom boat with 3 water jets tol look at the shipwrecks in Georgian Bay
We built several others in the past !
Have a great day !
Thanks Carl! That’s awesome!!
That is so badass, how does this channel not have more views
Thanks Nathan!!! I'm just getting started. THIS IS ONLY THE BEGINNING!!! Please subscribe and share with anybody who'd be interested. Glad you liked it.
Have you experimented with having the intake just below the waterline at the bow to increase efficiency? What is your top speed compared to the canoe
Great question. I made a video on this topic!
ua-cam.com/video/HgQTKWpNgQQ/v-deo.html
Speed is similar or slightly slower than canoe.
Are you limited by the engine rev limit? I am looking in to doing this with 212cc (6.5 hp) engine. But it has a big world of aftermarket parts to make up to 15 hp for another $300ish. So power goes up and revs out to 8k rpms
Thanks for the comment/question OutOfWork Outdoors! If the engine ran faster I would bet I'd get more flowrate and more speed. If I could come up with $600 more to throw at this build perhaps I will do it.
Would you consider subscribing to support?
Great video!
Thanks John!
Very cool,.... you would have increase HP 4x to get any speed with this set up. When you trim a jet out board up so water is spraying up in the air, it hardly moves. Seems thats what you have here. I do like the intake. Cheap shallow jet boat YES. NO reverse noway. Like your determination and will keep watching.
Thanks Johnny Fish! If your haven't already, would you Subscribe?
William, that's awesome!👍👍Liked and Subscribed!
Awesome thank you!
Amazing work. Keep it up!
I wanted to ask you if there is any cavitation happening in the pumps?
I want to modify my boat to jet drive with the help of a big centrifugal water pump powered by a 16Hp petrol engine.
What a mad lad! I love it.
Awesome man I am a carpenter but I have seen a guy making boats from fiberglass and foam sheets. I fish a river that on low tide a canoe with a trolling motor is not capable of traversing. This jet idea maybe what I am looking for!
Thanks for the comments Jim! You should try it. It's not fast, but it is cheap and very functional. Also very hard to damage a pump that's designed to suck "trash, mud, sand, etc. Would you consider subscribing? Or sharing this with a friend?
@@greenlizardusa3105 I did subscribe
Solid, thanks Jim!
If you had the output in the water it would work a lot better
@ D Red, thanks for the suggestion! This has come up a lot, and is a counterintuitive concept. I've made a few videos explaining. ua-cam.com/video/HgQTKWpNgQQ/v-deo.html
ua-cam.com/video/a8r5bHJ4FlI/v-deo.html
ua-cam.com/video/Nj1fF7YmMqA/v-deo.html
👍
Thanks!
That's an ingenious design! I'm wondering if you scale up to a larger boat with the same engine, same hull and everything, if it will actually end up being faster or not. One thing that I noticed was the reverse. You don't have one. Also, the flow of water is restricted in your design due to the size of intake pipe verses the many holes. You are restricting the flow by about half because of all that metal blocking the flow. I would think that if you had more water coming in than the size of your pipe than that would increase the power.
Thanks Robert! I did measure the "open area" of all the little intake holes, and it's equivalent to a 3" hole (the same size as the inlet). I do agree that it's a lot of turbulent flow, and if I removed the little holes, and just cut it out it would go faster.
Genius!!!!
Thanks Stacey!!
If they are in the water it will be faster. Trust me
Do you mean the outlets?
ua-cam.com/video/HgQTKWpNgQQ/v-deo.html
Also this one is a super basic "proof" of why above versus below.
ua-cam.com/video/a8r5bHJ4FlI/v-deo.html
Just like every other jet boat! Moving the water the smallest distance possible is the most efficient method! If your happy listening to those loud thing and barley be on plane more power to ya! Personally id have picked up a sub 1000$ jetski and had something that actually got up to speed! Instead of spending all that money and getting poor results..!! You could have achieved much better results using 1 212 engine and an sps longtail kit and been money ahead speed ahead simplicity ahead and still be able to go more places
👍
Thanks irwoody2! What did you think?
@@greenlizardusa3105 that me and my buddy have been wanting to put together a powered canoe and this looks like it
You should totally do it! If you're not already, would you consider subscribing? Make a video and share it here if you do make a powered canoe.
Here's a link to my current canoe build. ua-cam.com/video/GM5B4PAtUSA/v-deo.html