Choosing a swimming means for fishing or resting on the water often becomes a compromise between cost, dimensions and driving performance. katabaidThe inflatable catamaran is a unique solution that combines the stability of a wide platform and the ease of transportation inherent in inflatable boats. Unlike the classic monoholistic models, this design allows you to feel confident even in strong lateral excitement, making it a favorite among owners of sites in large reservoirs.
Use of use motor-bodied The ability to install a full-fledged outboard motor of medium power turns a quiet rowing boat into a fast vessel capable of plane with a payload. However, the design of the catamaran imposes its own requirements for weight distribution and the choice of attachments, the neglect of which can lead to undesirable consequences on the water.
In this article, we will discuss in detail the nuances of the choice of transom boards, the specifics of balancing the vessel and the features of operating PVC catamarans in different weather conditions. Understanding the physics of the movement of a two-hull vessel will help you avoid common mistakes and maximize the potential of your boat.
Design features of PVC catamarans
The design is based on two inflatable tubes connected by a rigid or soft frame, which is the distance between the cylinders, called the "Space of the cylinders". clearanceThe wider the cylinders are, the harder it is to flip the catamaran, but it also increases the sailing and resistance of the water when moving.
The engine uses a tray board that can be integrated into the frame or attached to the rear of the cylinders. transumeration They have power limitations, whereas rigid aluminum or steel frames allow you to install more powerful engines. When choosing a model, note the presence of reinforced linings at the mounting points of the transom.
⚠️ Warning: Never exceed the manufacturer's recommended engine power. Overloading the transom board on a catamaran can cause it to tear off along with the engine, since the center of gravity is above the waterline, and the roll at a sharp start is much stronger than that of a conventional boat.
The material for the manufacture of cylinders is usually reinforced PVC For catamarans designed for the motor, it is recommended to choose fabrics with maximum density and an additional protective layer against abrasion, since the vibration from the engine is transmitted to the entire structure.
Advantages and Disadvantages of Two-Shield Inflatable Vessels
The main advantage of catamarans is their sluggishness Even if one of the cylinders is fully punctured, the vessel will remain afloat and able to operate, although the speed will drop significantly, a critical safety factor for those who go on the water alone or far from shore.
But there's a downside to this, and the two-hull circuit creates more water resistance at low speeds than a narrow inflatable boat. planing It requires more power, and exiting it occurs at a higher speed, which increases fuel consumption.
- 🚀 High stability allows you to stand up in full height for fishing or changing gear, even on the wave.
- 🎣 The large usable area of the cockpit is convenient for accommodating a few fishermen and a large amount of equipment.
- 🌊 Comfortable cruising on the associated and side wave - pitching is felt less than on monohole boats.
And we also need to keep in mind the wind drift, because the high landing and the wide construction make the catamaran sensitive to lateral wind, and when mooring or anchoring, you need to take this into account and use anchors of sufficient weight or a combined anchor system.
To reduce wind drift on PVC catamarans, it is recommended to use an underwater wing or an additional floating anchor, especially when trolling or on the current.
Choosing an inflatable catamaran motor
The selection of the power plant is a key stage in the preparation for the season, the power of the engine depends on the load capacity and design of the transom board. 5-9.9 hp This is enough to bring a boat with two passengers to plane.
The use of electric motors on catamarans has its own peculiarities: due to the wide stern, standard mounts may not be suitable, elongated bars or special brackets are required. In addition, the weight of the battery placed on the transom can disrupt the differing, so the battery is better placed in the bow or in the center on the bottom.
| Catamaran class | Recommended power (hp) | Maximum speed (km/h) | Fuel consumption (L/h) |
|---|---|---|---|
| Small (up to 3 m) | 2.5 – 5.0 | 15 – 20 | 1.0 – 1.5 |
| Medium (3.2 – 3.6 m) | 5.0 – 9.9 | 25 – 35 | 1.5 – 2.5 |
| Large (from 3.8 m) | 9.9 – 15.0 | 35 – 45 | 2.5 – 4.0 |
| Expeditionary | 15.0 – 20.0 | 40 – 50 | 4.0 – 6.0 |
When installing a gasoline engine, it is important to monitor the tilt angle of the lower unit. Because of the flat bottom between the cylinders, water can be captured with improper differentiation, leading to cavitation and loss of traction. transom-angle It should be done experimentally on the water.
Secrets of fuel economy on a catamaran
To save fuel, keep the boat in close to planing mode, but do not go into yaw mode. The optimal speed for long transitions is 80% of the maximum. Also keep the bottom and cylinders clean: algae fouling or dirt increase resistance to 15%.
Rules for installation of the transom board and hangings
Installation of a transom is an operation that requires maximum care. If a removable board is used, it should be fixed with special slings or metal locks that prevent spontaneous opening.
For rigid frames integrated into the structure, you need to regularly check the condition of the fasteners. Vibration from the motor can unwind even tight bolts. Use growers or a locking sealant for threaded joints.
⚠️ Warning: Check the integrity of the slings of the slingboard before each outing, and weakening the mounts on the move can cause the boat to shift its center of gravity and roll sharply, which is dangerous for those in the boat.
The height of the engine also plays a role, and on catamarans, the lower unit often has to be raised higher than on conventional boats to avoid being overwhelmed by the wave between the cylinders, but too high a lift will cause water intake to suffocate and the engine to overheat.
☑️ Check before installing the engine
Operation and management on water
Drive a catamaran for an outboard motor is different from control of a conventional boat. Because of the wide hull, the vessel has a great turn inertia. Maneuvering in narrowness requires earlier turn and careful operation of the gas.
When moving against the wave, the catamaran behaves softer than a narrow boat, but when moving obtrusively towards the wave, unpleasant pitching is possible. Experienced boaters recommend changing course or speed in such cases to find a resonance at which pitching is minimal.
Special attention should be paid differentiationIf the engine is too heavy, the stern may squat and the nose will topping up, which not only makes the sight worse, but also makes the vessel unstable to yaw, in which case you need to move the load (anchor, battery, things) to the bow.
- ⚓ When mooring to the pier, approach slowly, using inertia, as it is more difficult to brake a wide catamaran.
- 🌬️ In high winds, try to keep your nose or stern to the wind when you stop, so that sailing has minimal impact on demolition.
- 🔄 Turn 180 degrees perform at low speed with active operation of the engine, so as not to lose control.
Remember, inflatable tubes are sensitive to temperature changes, on a hot sunny day, the pressure inside can rise, and vice versa, fall when you go out into cold water, and regular pressure monitoring is the key to the long-term service of the material.
The main rule of safety on a catamaran is the even distribution of cargo and passengers.
Maintenance and storage
After each release, especially on salt water bodies, the catamaran must be rinsed with fresh water, and salt and dirt, falling into the folds of the material and on the metal elements of the frame, cause corrosion and destruction of the structure of PVC.
Drying before packaging is mandatory. Even a little moisture inside a rolled-up cylinder can lead to mold and an unpleasant odor that is almost impossible to remove. It is better to dry the product in the shade, avoiding direct sunlight, which accelerates the aging of plasticizers.
When stored in winter, it is recommended to slightly lower the cylinders to compensate for the expansion of air when the temperature changes in the room. The optimal storage temperature is from +5 to +20 degrees Celsius.
⚠️ Warning: Do not store catamaran near heaters or open fire sources, and avoid contact with sharp objects and chemically aggressive liquids (gasoline, solvents), which can instantly destroy the material of cylinders.
Regularly inspect the joints and valves, the appearance of small bubbles or stratifications is a signal for immediate repair, using quality glue and patches of the same material as the boat, ensures leakage.
How to properly fold the catamaran
First, blow the cylinders to a state of elasticity, then fold the frame. Cylinders twist from the valves to the transom, releasing air. Avoid sharp clamps on the folds, this shortens the life of the product.
Frequently Asked Questions (FAQ)
Can I install a 15 hp engine on a catamaran designed for 9.9 hp?
Theoretically, you can, if the transombboard can withstand the weight and the pressure, and the frame design allows it, but it will upset the balance, make the boat too sharp to drive and can cause the transom to break, and it can be a violation of the registration rules of small craft if the power exceeds the passport.
Which PVC material is better for a motor catamaran: 750 or 900 g/m2?
For motor catamarans, especially if you plan to actively operate, transport heavy loads or use on rocky shores, it is definitely better to choose a fabric density. 900–1100 g/m2It's more resistant to abrasion, puncture, and it's better at keeping its shape under load.
Do I need to register an inflatable catamaran in GIMS?
Registration is required if the weight of the equipped vessel (with an engine and a minimum set of equipment) exceeds 200 kg OR the power of the installed engine exceeds 8 kW (about 10.8 hp). If your engine is more powerful than 10 hp, registration is required regardless of the weight of the boat.
How to deal with cavitation on a catamaran at full load?
Cavitation often occurs due to the wrong angle of the inclination of the lower unit or too deep landing of the transom. Try to change the angle of inclination of the engine with a ramp or redistribute the load in the boat, raising the nose. Also check if the propeller blade is damaged.
Can I use an electric motor on a PVC catamaran in winter?
You can use an electric motor, but lithium-iron-phosphate (LiFePO4) batteries don't tolerate charging in the cold, and conventional lead-acid batteries lose capacity. The motor itself and the cylinders are cold tolerated normally, but PVC becomes stiffer, so careful pumping and operation is required.