Jet nozzles for boat motors

Description of water jet attachments for outboard motors

A jet nozzle is a pump-like device that greatly increases the efficiency of marine engines.

Principle of operation

In fact, a water jet engine and a propeller operate according to the same scheme. The pump blades, like the propeller blades, under acceleration push water from the bow of the tray to its stern.

The differences are that this entire process occurs in a pipe located inside the vessel, and not under its bottom, and a stream of water under pressure splashes out from the nozzle located above the water.

To make turns, the nozzles are directed in the desired direction. To force the boat to slow down or move backwards, change the direction of the nozzle to the opposite, using a special damper.

Where is it used?

Water jet engines can be used on such water transport as:

• Jet skis;
• Sports boats;
• Rescue boats. They have to maneuver around people, so in order to avoid injury, they use water jet engines.
• Firefighting vessels;
• Tourist ships;
• Patrol boats;
• Military boats;

As you can see, the scope of application of a water-jet engine is quite wide. Motor attachments are designed to turn a regular motor into a water jet.

Advantages

Water jet nozzles, like the engines themselves, have a lot of advantages. Below are the advantages of nozzles and motors, as their advantages also apply to nozzles:

• The biggest plus is that it is possible to move through shallow water, since there are no protruding blades. Also, this mechanism allows you to “climb” directly onto a gentle bank, and using reverse gear you can go back. This function is often used by patrol and rescue vessels;
• Water cannons are safe. As already written, rescue ships use this so as not to injure people during maneuvers close to them;
• The working parts of the mechanism are protected from debris. This function is used by fishermen who fish in places where mud and algae accumulate;
• Smooth moves;
• Easy descent into the water and back;

And now about the advantages of the attachments themselves:

• The entire kit consists of 6 parts that are very easy to assemble;
• No bevel gear;
• Efficiency does not decrease when sand is sucked in;
• Easy to install.

Minuses

• The first disadvantage that catches your eye is the price. Water jets are much more expensive than screw engines. The same applies to attachments;
• If a person is accustomed to the steering mechanism, steering a boat with a water jet will be a very difficult task for him;
• If the ship stands still, the channels become overgrown, and this will significantly affect the speed.
• Cleaning the channels is problematic;
• Power is lost due to friction of water in the channel.
• Large transverse dimensions;
• KDM is practically two times lower than on screw engines.

Description and design details

A jet nozzle is a mechanism installed on an outboard motor, which is an alternative to a propeller; it operates on the principle of a centrifugal pump, in which water, when the impeller blades rotate, enters the hull from the bow and is pushed out in the opposite direction, thereby imparting acceleration ship. The water jet nozzle may have its own design features. But they all have the following nodes.

The water intake with a grate is a load-bearing power part, and is also of great importance in the hydrodynamics of the water jet. There are several rules for making this element:

1. Summary of details. Should allow water to flow continuously into the housing, so it should not be steep.
2. "Lip" or leading edge. Must have a hydrodynamic profile.
3. Cross-section of the catchment and lip. They should be the same size and blend smoothly into a circle in front of the impeller blades.

Impeller or "impeller" - designed to convert energy from the engine by rotating the blades and pushing water. These nodes can have several types of design:

1. Axial. They are characterized by high values ​​of the stop when moving at low speed. They are distinguished by ease of manufacture and low efficiency; they are mainly used on low-speed devices.
2. Axis-diagonal. They produce high efficiency during operation, thereby operating effectively at different speeds.
3. Diagonal, as well as screw. More complex to manufacture and technically advanced parts capable of delivering maximum efficiency. They are installed on devices operating at high speeds and make it possible to develop high speeds.

These units are made of stainless steel, as well as alloys of non-ferrous metals. For production, the precision casting method is used; welded elements are less commonly used.

The straightening apparatus is important in the operation of the water jet; it is designed to direct the stream of outgoing water. Execution options:

1. Blade compression - the advantage of this type is the ability to reduce the size of the water jet. The blades in this version simultaneously serve as a nozzle.
2. Slotted - used quite rarely, mainly for water cannons on large ships. They are rarely used for mounted engines due to the large loss of efficiency.

Nozzle - designed to form a water jet and by pressing it and creating jet thrust. Depending on the diameter of the nozzle, the installation power can vary by up to 50%. Many manufacturers combine the straightening apparatus directly with the nozzle, this makes it possible to reduce the size of the structure.

Reversible steering unit - there are many options for this element, each manufacturer has its own methods, but all of them must meet the basic requirements:

1. Steering the vessel should be carried out without significant effort.
2. Power must be used efficiently.
3. Ensuring good controllability when maneuvering and moving at different speeds.

1. Rotary nozzle.
2. Rotating nozzle.
3. Reversible flap.
4. Rudder in the flow.

A drive is used to control this unit. Depending on the power of the power plant, it can be made in several versions:

1. Hydraulic. Used for units greater than 250 horsepower.
2. Mechanical. For engines up to 150 horsepower.
3. Electromechanical. It can be used for installation on mechanisms with low and medium power.

Stern tube seals, as well as bearing units - taking into account the operating features of the water jet, are mainly equipped with rolling bearings. A mechanical seal is used as sealing connections.

Advantages and disadvantages

The use of a water jet nozzle in various operating conditions has positive and negative aspects. The poles are as follows:

1. Rotating parts are located inside the housing, which ensures their protection.
2. Possibility of operation in shallow water and in conditions of large accumulation of objects on the water.
3. Safety for people and animals.
4. A high-quality and correctly selected device allows you to develop high speeds.
5. The speed of maneuvers, braking and turning.
6. The motor life is higher than that of a screw engine.
7. There is no need to select a propeller for different operating conditions and boat load.

The disadvantages include:

1. The transverse size is larger than that of a propeller.
2. Most of these units significantly lose power. These losses can reach 30% when driving at low speeds.
3. There are features of ship control, they are related to the design and operating principle.
4. High cost of products supplied by well-known global manufacturers.

Outboard motor attachments

Attachment for outboard motors, suitable for both beginners and experienced users of boats with a motor. The attachment increases the power of the outboard motor by about 35-40 percent.

The use of such a nozzle provides:

• Engaging reverse gear when the boat is moving at full speed;
• Easy maintenance, sometimes you need to spray with waterproof lubricant;
• High cross-country ability;

In general, these attachments are intended for use on outboard motors. The only bad thing is the price, both for the nozzle and for its repair.

Jet nozzles for outboard motors

A water jet attachment is a device that allows even a beginner to convert an ordinary outboard motor into a full-fledged water jet in an hour or two. Essentially, this is a centrifugal pump, which, with the help of impeller blades (impeller), draws water into the engine through a water intake and pushes it out under pressure in the direction opposite to the movement of the boat.

Pros of water jet nozzles:

• The ability to engage reverse at full speed forward, giving a powerful braking effect.
• No shifting in the gearbox means no wear on the mechanism.
• Easy maintenance. Periodically (every 10-12 hours) injection with a special waterproof lubricant is required.
• Safety of people in the water near the boat (discussed above).

Disadvantages of water jet nozzles:

• According to various estimates, after installing the nozzle, the output power will drop by 20-30%.
• Quite expensive and troublesome repair.

Popular models of water jet attachments for outboard motors

The attachments are ideal for all popular brands of outboard motors, as well as their Chinese copies. You need to choose the nozzle wisely to avoid manipulation with trance build-up.

Below are the brands of the most popular attachments for outboard motors:

As you can see, the scope of application of a water-jet engine is quite wide. Motor attachments are designed to turn a regular motor into a water jet.

You can find an attachment for any outboard motor. The company has attachments for motors of any power, manufacturer and year of manufacture. True, the nozzles of this company are very expensive, which is a significant disadvantage;

Suzuki

These attachments are produced in Taiwan. The assembly is quite good, stainless steel is used. The downside is that the model range is limited to attachments for only four stroke engines.

Yamaha

Often there are low-quality attachments, but the price for them is not as high as for Outboard Jets.

"Crucian carp"

From the name it is immediately clear in which country these attachments are produced. Moreover, the product is quite good and very convenient. The entire kit can be assembled in 5-10 minutes. They are also not very expensive.

Mercury

The company produces outboard motors for boats. But they also produce attachments. Their prices are average, more expensive than Suzuki, but cheaper than Outboard Jets.

There are also similar companies whose activities include the production of various equipment:

• Nissan;
• Honda;
• Mariner;
• Johnson;
• Evinrude;
• Force;
• Chrysler;
• Tohatsu;

In general, the choice of attachments is quite large and everyone has the right to decide for themselves what to put on their motor. But your best bet would be to choose a nozzle from Outboard Jets.

Review of popular models of water jet attachments for outboard motors

Jet nozzles can be installed on an outboard motor from any well-known company absolutely without any problems: Yamaha, Honda, Tohatsu, Suzuki and many Chinese clones that are exact copies of well-known world brands. An important note: with the correct selection of a jet nozzle, manipulations with extending the transom under the outboard motor can be avoided. A correctly installed nozzle only lowers into the water to the height of the nozzle!

Particularly popular are the products of such companies as:

• Outboard Jets, USA manufacturer. A virtually unlimited selection of attachments for outboard motors, regardless of the manufacturer, year of manufacture, or power. Approximate price tag: 100,000-150,000 rubles.
• Yamaha, manufacturer Taiwan. Perhaps distrust of the manufacturer influenced the price: 50,000-80,000 rubles. Although we note that there are no more complaints about the products of Taiwanese companies than others.
• Suzuki, again made in Taiwan. Quite a high quality build. Impeller made of stainless steel. Price tag: 50,000-80,000 rubles.
• “Karas”, manufacturer Russia, Krasnoyarsk. Installs and removes in 10-15 minutes. Depending on the materials, price: 40,000-50,000 rubles.

To summarize all of the above, it is worth noting: the main reason for the ambiguous attitude towards water-jet engines lies in their low speed and low power in comparison with a propeller. Despite the clearly outstanding positive qualities, which we have listed repeatedly, all other things being equal, the water cannon will remain a loser. Its destiny, in our opinion, is parallel coexistence with propeller-rudder systems, but in the foreseeable future it will not be able to replace them.

Applicable to Russian realities, water-jet attachments are the best option, because purchasing and installing a full-fledged water-jet engine is not a pleasure for every wallet.

Prices

Prices for jet nozzles for outboard motors depend on the region and specific suppliers. On average, their price ranges from 40 to 150 thousand rubles.

• Outboard Jets – 100-150 thousand rubles;
• Yamaha - 50-80 thousand rubles;
• Suzuki – 50-80 thousand rubles;
• Crucian carp - 40-50 thousand rubles;

In general, a water jet attachment for an outboard motor is not a cheap pleasure. Plus, we must not forget about repairs, which will also take a significant toll on your wallet.

Reviews

About two years ago I bought an American nozzle. I bought it second hand (it’s expensive in the store), but it serves faithfully and has never failed me. Grade:

Basil

When installing a nozzle from Suzuki, the efficiency dropped significantly, I won’t blame the nozzle, maybe there’s something wrong with the boat. Grade:

Paul

I recently bought a nozzle from Outboard Jets, fortunately there is no limit, but I still have to pay for the loan for a whole year. Grade:

Victor

I'm a patriot (I just didn't have enough money for Outboard Jets) and that's why I bought a "crucian carp", but it's a good thing. Our fellows did their best. Grade:

Gennady

I recommend Outboard Jets to everyone, you won't find better attachments. This company has proven itself for a long time. Grade:

Michael

Water jet engines are a good and useful thing, but they are unlikely to replace propeller engines. However, water jet attachments are becoming increasingly popular every day.

Positive differences and disadvantages

The water jet outboard motors used have the following advantages:

• a significant increase in the speed and maneuverability of the boat due to jet propulsion;
• the boat’s ability to move in shallow water (at a depth of up to 15 cm), which is difficult for a conventional propeller;
• hiding the propellers in the pipe can significantly reduce the likelihood of failure of the propulsion unit due to algae, debris, etc. getting into it;
• reduced vibration and smooth running at high speeds;
• It is possible to use a water cannon as a pump for pumping liquid.

In addition to speed, the safety of using the boat increases, because
all propellers are closed and injury to people from the operating propeller is excluded. Along with the advantages, there are several disadvantages that may affect the desire to purchase and install a water jet on your boat, namely:

• the power of a water jet is less than the power of a conventional boat motor, the reason is that the diameter of the impeller of the water jet is smaller than the diameter of a conventional propeller; the increasing turbulence in the pipe also affects the power;
• steering a boat with a water jet is much more difficult than a conventional motorboat with a propeller; it will take some time to get used to it;
• after installing a water-jet propulsion system, the weight of the boat will increase significantly, because it itself is quite heavy, the weight of the water entering the pipe will also be added;
• the cost of water cannons greatly exceeds the prices of conventional propulsion engines with a propeller, at least 1.5 times.

For lovers of water travel and active recreation on the water, the above disadvantages cannot have a decisive influence, because the speed, agility and safety advantages they gain are more important. For this reason, the question of which is better, a water-jet propulsion system or an outboard propulsion system, does not arise before them. A boat on which a water jet is installed travels a greater distance with less time.

Characteristics of the Kalmar and Yamaha 30 HWCS models

The appearance of the Squid water cannon on the market gave lovers of water travel the opportunity to travel faster and further, because... unlike its predecessors, it is four-stroke. It was designed as a device for boats with a transom of 25 - 45 cm. Its engine power is 2.5 horsepower, the speed is 8 - 15 km/h depending on the load of the craft, and the operating life before overhaul is 650 hours. Weight is only 9.5 kg, which is very valuable during operation. The design allows it to be installed on transoms, as well as on transomless boats.

Its device is simple and does not require special knowledge from the user; it is enough to be able to use an outboard motor. The shape allows it to be stored in a vertical position without supporting devices, this is very important for four-stroke engines, and outboard motors are no exception.

Installation of the Squid is possible on watercraft with a carrying capacity of no more than 350 kg (including the weight of the boat itself). At maximum load, the speed will be no less than 8 km/h. The Kalmar water jet is a convenient and powerful water jet unit, easy to operate, suitable for all lovers of fishing and tourism. Russian-made water cannons are presented on the market not only by Kalmar and its modifications, but also by such models as Stalker and others.

Yamaha 30 is a motor for an outboard boat; it belongs to the group of two-stroke motors with power from 2 to 30 horsepower. The models are compact, light weight, high performance and reliable. Almost any model of Yamaha engine can be adapted for a water cannon.

Water jets for PVC boats

You can make a water jet for a PVC boat with your own hands; almost any boat motors are suitable for this; models with a power of 15 to 20 horsepower are best suited. You can find almost any type of engine you need on sale, it all depends on your needs, preferences and budget. The less a boat motor installed on such a craft weighs, the better. Experts advise using imported engines. The kit for making a water cannon for a PVC boat includes the following tools and materials:

• the actual boat motor;
• engine diagram;
• fittings;
• gearbox;
• flange;
• hub;
• welding machine;
• drainage pan;
• input filter;
• glue.

When creating a water jet for a PVC boat, you need to take into account all the operating points that can affect the final result. All parts must be selected, their sizes calculated and determined. In order to cope well with such a task, you need to be properly prepared and have drawings.

There are many articles and guides on this topic both on the Internet, on forums, and in printed periodicals devoted to issues of this specific nature. Boat engines that are converted into a water jet with your own hands are a source of pride for their owners.

On many portals and forums devoted to the creation, design, and improvement of equipment, there are tips on how to use a similar device from a jet ski under a water cannon on a boat, installing it on a boat.

Water jet nozzles

Suspended water cannons or water jet attachments are a more budget-friendly option. This is a set of components that is installed where the gearbox and propeller are attached, and a regular motor turns into a water jet. Different boat motors require their own types of attachments.

When installing a motor to which such an attachment is attached, it is installed 15 cm lower than a motor with a conventional propeller, so that water gets under the water cannon. It would be even better to add a support for the motor to the transom - a built-on transom, with it the use of a water jet attachment is more convenient.

Water jet nozzles can be used as a water jet on a boat - a cauldron. These boat models are made of duralumin, are very light and fast, so the use of powerful water jet models is undesirable, because... can simply lead to the boat capsizing during sharp maneuvering. But a boat - a cauldron with a low-power water cannon or a water-jet attachment installed on it - becomes even faster. Thus, a water jet attachment or suspended water jet is a cheaper analogue.