• Welcome to Jetboaters.net!

    We are delighted you have found your way to the best Jet Boaters Forum on the internet! Please consider Signing Up so that you can enjoy all the features and offers on the forum. We have members with boats from all the major manufacturers including Yamaha, Seadoo, Scarab and Chaparral. We don't email you SPAM, and the site is totally non-commercial. So what's to lose? IT IS FREE!

    Membership allows you to ask questions (no matter how mundane), meet up with other jet boaters, see full images (not just thumbnails), browse the member map and qualifies you for members only discounts offered by vendors who run specials for our members only! (It also gets rid of this banner!)

    free hit counter

Lateral Thrusters High Speed Video Completely Out Of Water

JetBoatPilot

Event Sponsor
Event Sponsor
Vendor
Messages
3,135
Reaction score
3,392
Points
362
Location
Panama City, Fl
Boat Make
Yamaha
Year
2016
Boat Model
Other
Boat Length
19
Watch this video to see how the Lateral Thrusters get completely out of the water at high speeds. This means no loss in top end speed and no additional loads and forces on the part which would shorten life span and increase risk of submerged object impact.

 

Scottintexas

Jetboaters Admiral
Staff member
Messages
5,807
Reaction score
6,396
Points
482
Location
Corinth, TX (DFW)
Boat Make
Yamaha
Year
2007
Boat Model
AR
Boat Length
23
Love the videos ! Great view point
 

KyleWade14

Jet Boat Addict
Messages
120
Reaction score
43
Points
122
Location
Washington, OK
Boat Make
Yamaha
Year
2014
Boat Model
SX
Boat Length
21
Wow that is pretty awesome. I would have thought the jet would be more underwater.
 

fraserjr

Jet Boat Junkie
Messages
307
Reaction score
201
Points
147
Location
Fairfax, VA
Boat Make
Yamaha
Year
2016
Boat Model
242 Limited S E-Series
Boat Length
24
@JetBoatPilot appreciate all of the great videos on the Lateral Thrusters. One thing that would help me would be a "steering/directional" diagram for different situations for a twin engine boat. For example:

Move the boat laterally to the right - Example setting: Wheel hard right, starboard engine forward detent, port engine netural
Move boat back and to the left - Example setting: Wheel straight, starboard engine neutral, port ending reverse detent

I think that would really help me visualize how I can move the boat as compared to what I can do today without Lateral Thrusters.
 

1WetBoat

Jetboaters Commander
Messages
585
Reaction score
574
Points
197
Location
Tampa
Boat Make
Yamaha
Year
2021
Boat Model
AR
Boat Length
25
I think unintentionally this video also shows where the underwater LED's would be at while underway along with transducers. I know a lot of the LED's require them to be submerged to prevent overheating.
Great video Will.
 

seanmclean

Jetboaters Admiral
Messages
2,792
Reaction score
3,814
Points
307
Location
Medford, NJ
Boat Make
Yamaha
Year
2017
Boat Model
Limited S
Boat Length
24
I think unintentionally this video also shows where the underwater LED's would be at while underway along with transducers. I know a lot of the LED's require them to be submerged to prevent overheating.
Great video Will.
Helping me with transducer placement, too!
 

ruztew

Jetboaters Lieutenant
Messages
254
Reaction score
202
Points
167
Location
32408
Boat Make
Yamaha
Year
2015
Boat Model
SX
Boat Length
19
My mind is blown, I assumed the jets were under the water when underway....
 

Sbrown

Jetboaters Captain
Messages
980
Reaction score
1,029
Points
202
Location
Easton, Pa
Boat Make
Yamaha
Year
2017
Boat Model
AR
Boat Length
24
A lot of people think that thrust is generated by the jet of water pushing against the water around it when actually thrust is generated by a pressure differential inside the pump. Which is also why some of the claims I've seen made about certain add-on equipment make absolutely no sense from a physics standpoint.
 
Last edited:

2kwik4u

Jetboaters Fleet Admiral
Messages
7,374
Reaction score
9,427
Points
532
Location
Georgetown, IN
Boat Make
Yamaha
Year
2017
Boat Model
AR
Boat Length
19
My mind is blown, I assumed the jets were under the water when underway....
I bet most people do. They can be underwater, but don't have to be.

Jets (anything with a nozzle really) don't work by "pushing" on the water behind you (as Jet aircraft don't "push" on the air either. They instead trade momentum for movement.

Do this thought exercise in your head. Stand in a small john boat holding a really heavy object (lets say a 36in tube TV). Now, throw that object out the back of the boat. What happens? The boat moves forward based on the interaction between the relatively high momentum of the TV, and the relatively low force required to move the boat forward. NOW.......do the same thing with a very very high number of very light things (water droplets in our case of a jet boat). Same results.

The jets are essentially throwing high amounts of momentum out of the back of the boat in exchange for the force to move the boat forward.

I'll try to dig up my notes from Fluid Dynamics when I get home and post the equations that make this work. It was completely fascinating to me when I learned the first time!

A lot of people think that thrust is generated by the jet of water pushing against the water around it, when actually, thrust is generated by a pressure differential inside the pump. Which is also why some of the claims I've seen made about certain add-on equipment make absolutely no sense from a physics standpoint.
You beat me to it :D
 

Renod

Jet Boat Junkie
Messages
181
Reaction score
369
Points
132
Location
Grosse Ile, MI
Boat Make
Yamaha
Year
2018
Boat Model
242 Limited S E-Series
Boat Length
24
I'll try to dig up my notes from Fluid Dynamics when I get home and post the equations that make this work. It was completely fascinating to me when I learned the first time!
Very cool. Just please remember to use small, simple words for some of us!
 

Cobra Jet Steering LLC

Jetboaters Admiral
Vendor
Messages
5,865
Reaction score
5,348
Points
452
Location
Florida
Boat Make
Yamaha
Year
2021
Boat Model
Other
Boat Length
Other
The basics as we all should understand, prop boats pull thus the name screw for the prop.
However jet propelled boats push , now air is compressible but water is not thus comparing a airplane to a boat totally different animals and to take it one step further the lateral thrust device takes away some of the reverse thrust exiting the bottom of the nozzle and redirects it to one side or the other to change the direction of the back of the boat so your own statement claims incorrectly that this won't work !
Just like my mega fangs capture more of the very same reverse thrust exiting the nozzle from the very same place the side thrusters take their thrust from , but rather than bleed off some of that reverse thrust I focus it capturing more of it as useable directed thrust for stopping and for real reverse steering.
Same thrust just using it differently .
Now lets look at a sea doo reverse bucket that captures the thrust from the nozzle and redirects it in a way so that the boat turns in reverse completely opposite from a Yamaha boat. So it all works from the jet thrust being redirected in numerous different ways to create different results. . And undisputedly I might add. So Not rocket science actually
 

scokill

Jetboaters Admiral
Messages
1,576
Reaction score
1,184
Points
272
Location
Rowlett, TX
Boat Make
Yamaha
Year
2008
Boat Model
AR
Boat Length
23
I've been gone awhile but seems like a lot posts on the latest dohickeys.
 

AZ Native

Jet Boat Junkie
Messages
209
Reaction score
233
Points
137
Location
Phoenix, Arizona 85044
Boat Make
Yamaha
Year
2013
Boat Model
Limited S
Boat Length
24
Seeing this video may be the coolest revelation I've experienced since buying my first jet boat 2 years ago. Obviously I never stuck my head under the back of the boat at full speed to see what happens, but wow, I never expected that. I know Will had a different objective in mind while filming this, but the general educational value caught my interest. I had no idea how this worked, I'm a consumer who usually only cares that it does work. I'm going too assume however, that low speed maneuvering uses completely different principles since the jets are underwater and they must act like a hose nozzle turned up full blast in a pool pushing the hose around. In that case we really are pushing the boat?
Now my really stupid question. If the jets are completely out of the water, what the hell makes the boat turn if they're not pushing the boat??
BTW my new term to impress my grown kids is "Fluid Dynamics". It just sort of roles off the tongue. I hope they don't ask me what it means. :confused:
 

Cobra Jet Steering LLC

Jetboaters Admiral
Vendor
Messages
5,865
Reaction score
5,348
Points
452
Location
Florida
Boat Make
Yamaha
Year
2021
Boat Model
Other
Boat Length
Other
 

swatski

Jetboaters Fleet Admiral 1*
Messages
12,806
Reaction score
18,566
Points
822
Location
North Caldwell, NJ
Boat Make
Yamaha
Year
2016
Boat Model
AR
Boat Length
24
So - FWIW - here is one of my favorite jet boat pics - that (I think) @Williamsone46 posted some time ago - showing a 2015+ 240/242 hull/stern/jets at planning speeds:


Pretty cool!

--
 

Peelz

Jetboaters Lieutenant
Messages
677
Reaction score
479
Points
167
Location
SE IA
Boat Make
Glastron
Year
2004
Boat Model
SX
Boat Length
17
awesome product aside, what a sweet viewpoint.
 

Sbrown

Jetboaters Captain
Messages
980
Reaction score
1,029
Points
202
Location
Easton, Pa
Boat Make
Yamaha
Year
2017
Boat Model
AR
Boat Length
24
Seeing this video may be the coolest revelation I've experienced since buying my first jet boat 2 years ago. Obviously I never stuck my head under the back of the boat at full speed to see what happens, but wow, I never expected that. I know Will had a different objective in mind while filming this, but the general educational value caught my interest. I had no idea how this worked, I'm a consumer who usually only cares that it does work. I'm going too assume however, that low speed maneuvering uses completely different principles since the jets are underwater and they must act like a hose nozzle turned up full blast in a pool pushing the hose around. In that case we really are pushing the boat?
Now my really stupid question. If the jets are completely out of the water, what the hell makes the boat turn if they're not pushing the boat??
BTW my new term to impress my grown kids is "Fluid Dynamics". It just sort of roles off the tongue. I hope they don't ask me what it means. :confused:
Honestly, I've held back responding to this thread because I'm trying to avoid arguments. But I can't not answer your question either. In the simplest terms, all of the force that makes your boat move happens inside the pump. The reason it turns when you change the angle of the nozzles is due to something called "thrust vectoring" which simply means that when you change the angle of the center of the low pressure area (the water escaping the high pressure of the pump), the center of the high pressure area (inside the pump opposite the nozzle) changes as well. And for the record, boat propellers, airplane propellers, helicopter rotors, aircraft wings and our jet pumps, all work on the same physics principles and to a certain extent, yes, it actually is rocket science. It really works off of two simple principles. 1: Any gas or liquid will flow from a high pressure area to a low pressure area. 2: All actions have an equal and opposite reaction. As an answer to your last question, yes the pumps are pushing the boat, just the jet of water is not pushing the boat directly. You could put your boat 20 feet in the air, and if you feed your jets water, the boat will move forward, turn, etc. Hell, you could put the boat in a vacuum and it would still work if you fed the jets water.
 

swatski

Jetboaters Fleet Admiral 1*
Messages
12,806
Reaction score
18,566
Points
822
Location
North Caldwell, NJ
Boat Make
Yamaha
Year
2016
Boat Model
AR
Boat Length
24
Honestly, I've held back responding to this thread because I'm trying to avoid arguments. But I can't not answer your question either. In the simplest terms, all of the force that makes your boat move happens inside the pump. The reason it turns when you change the angle of the nozzles is due to something called "thrust vectoring" which simply means that when you change the angle of the center of the low pressure area (the water escaping the high pressure of the pump), the center of the high pressure area (inside the pump opposite the nozzle) changes as well. And for the record, boat propellers, airplane propellers, helicopter rotors, aircraft wings and our jet pumps, all work on the same physics principles and to a certain extent, yes, it actually is rocket science. It really works off of two simple principles. 1: Any gas or liquid will flow from a high pressure area to a low pressure area. 2: All actions have an equal and opposite reaction. As an answer to your last question, yes the pumps are pushing the boat, just the jet of water is not pushing the boat directly. You could put your boat 20 feet in the air, and if you feed your jets water, the boat will move forward, turn, etc. Hell, you could put the boat in a vacuum and it would still work if you fed the jets water.
Yep. It's all good ol' Bernoulli's effect.
Just like strong wind lifting roof off building.

--
 

adrianp89

Jetboaters Admiral
Messages
5,270
Reaction score
4,290
Points
382
Location
Tampa Bay, FL
Boat Make
Yamaha
Year
2021
Boat Model
252SE
Boat Length
25
Honestly, I've held back responding to this thread because I'm trying to avoid arguments. But I can't not answer your question either. In the simplest terms, all of the force that makes your boat move happens inside the pump. The reason it turns when you change the angle of the nozzles is due to something called "thrust vectoring" which simply means that when you change the angle of the center of the low pressure area (the water escaping the high pressure of the pump), the center of the high pressure area (inside the pump opposite the nozzle) changes as well. And for the record, boat propellers, airplane propellers, helicopter rotors, aircraft wings and our jet pumps, all work on the same physics principles and to a certain extent, yes, it actually is rocket science. It really works off of two simple principles. 1: Any gas or liquid will flow from a high pressure area to a low pressure area. 2: All actions have an equal and opposite reaction. As an answer to your last question, yes the pumps are pushing the boat, just the jet of water is not pushing the boat directly. You could put your boat 20 feet in the air, and if you feed your jets water, the boat will move forward, turn, etc. Hell, you could put the boat in a vacuum and it would still work if you fed the jets water.
So you're telling me if I can recycle the water from the jets back into the jets... and add wings.. I can fly with my boat? @swatski is this on your mod list yet?
 
Top