HydroJet Pro
Well-Known Member
- Messages
- 11
- Reaction score
- 2
- Points
- 62
- Boat Make
- Yamaha
- Year
- 2008
- Boat Model
- SX
- Boat Length
- 21
I've been reading that there is some confusion about how our product works.
We designed our system to provide effective steering at the most crucial times. At the same time, we did extensive testing to ensure we did not remove the jet boat feel and handling characteristics.
Here is how we did it:
Unlike propelled boats, jet boats require constant thrust for steering. The lower the thrust, the harder is to control. Because there is no keel, the boat spins around its center of mass. The further away the nozzles are from it, the bigger the moment and the easier the boat will turn.
The effectiveness of our fins is also dependent on the type of the flow across them. There’s 2 types of regimes when it comes to fluid flow:
·Laminar flow: where the motion of the particles of the fluid is very orderly with all particles moving in straight lines parallel. When an object is placed in laminar flow, it will disturb the particles in the flow. This will increase the pressure in front of said object and reduce it behind. In this case, the generated pressure difference will create a side force on our fins helping you turn your watercraft.
·Turbulent flow: is a flow regime where the particles are already disturbed, and are constantly sustaining a chaotic property changes. In other words, because the flow is already disturbed, the effect an object can have on it is very small. The more intense the turbulent flow that our fins will encounter, the less they will help you turn.
The effectiveness of the side force created by the fins is dictated by the amount of perpendicular area to the incoming flow. The more of the fin area that faces the flow, the bigger the exerted force will be, increasing the turning moment of your boat.
Effectiveness with regards to position and speed
Reverse
Because while on reverse the fins will always see laminar flow, they provide maximum effectiveness. In this position, the fins work essentially as individual rudders, increasing the handling immensely while backing.
Idle
At very slow speeds, < 2 knots, the flow over the fins is also entirely laminar, indicating a 100% effective area. Slow maneuvering will mostly occur at this range, and it is at this range that our fins perform at their best.
Forward
Between 3 and 6 knots, our fins are still observing laminar flow. It is in this range that boats operate in marinas, around anchored boats and while navigating through multiple PWC’s. The aided steering is still highly effective.
Above 6 knots, our fins begin allowing your jetboat to steer through the water using the natural thrust vectoring from the jets as the turbulent flow (drag bucket) increases behind the boat. The faster the boat moves the more turbulent the flow will be. For speeds higher than 10 knots the flow observed by the fins will be entirely turbulent and only the integrated thrust vectoring from your nozzle with turn your boat. At this stage, our system is completely out of the way, letting you experience the true jet boat feel without any training wheels or limitations.
Let me know if have any questions or comments! I'd be happy to explain our product further.
We designed our system to provide effective steering at the most crucial times. At the same time, we did extensive testing to ensure we did not remove the jet boat feel and handling characteristics.
Here is how we did it:
Unlike propelled boats, jet boats require constant thrust for steering. The lower the thrust, the harder is to control. Because there is no keel, the boat spins around its center of mass. The further away the nozzles are from it, the bigger the moment and the easier the boat will turn.
The effectiveness of our fins is also dependent on the type of the flow across them. There’s 2 types of regimes when it comes to fluid flow:
·Laminar flow: where the motion of the particles of the fluid is very orderly with all particles moving in straight lines parallel. When an object is placed in laminar flow, it will disturb the particles in the flow. This will increase the pressure in front of said object and reduce it behind. In this case, the generated pressure difference will create a side force on our fins helping you turn your watercraft.
·Turbulent flow: is a flow regime where the particles are already disturbed, and are constantly sustaining a chaotic property changes. In other words, because the flow is already disturbed, the effect an object can have on it is very small. The more intense the turbulent flow that our fins will encounter, the less they will help you turn.
The effectiveness of the side force created by the fins is dictated by the amount of perpendicular area to the incoming flow. The more of the fin area that faces the flow, the bigger the exerted force will be, increasing the turning moment of your boat.
Effectiveness with regards to position and speed
Reverse
Because while on reverse the fins will always see laminar flow, they provide maximum effectiveness. In this position, the fins work essentially as individual rudders, increasing the handling immensely while backing.
Idle
At very slow speeds, < 2 knots, the flow over the fins is also entirely laminar, indicating a 100% effective area. Slow maneuvering will mostly occur at this range, and it is at this range that our fins perform at their best.
Forward
Between 3 and 6 knots, our fins are still observing laminar flow. It is in this range that boats operate in marinas, around anchored boats and while navigating through multiple PWC’s. The aided steering is still highly effective.
Above 6 knots, our fins begin allowing your jetboat to steer through the water using the natural thrust vectoring from the jets as the turbulent flow (drag bucket) increases behind the boat. The faster the boat moves the more turbulent the flow will be. For speeds higher than 10 knots the flow observed by the fins will be entirely turbulent and only the integrated thrust vectoring from your nozzle with turn your boat. At this stage, our system is completely out of the way, letting you experience the true jet boat feel without any training wheels or limitations.
Let me know if have any questions or comments! I'd be happy to explain our product further.
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