Small boats are always risky, and even the most reliable boat can lose their buoyancy when punctured or depressurized. boat-side Water engines often underestimate the importance of backup air volume, relying on regular sections, but the statistics of water incidents suggest otherwise. The increase in buoyancy allows the vessel to stay afloat even when the cockpit is completely flooded, keeping the crew dry and allowing for self-return to shore.
In this article, we will discuss how to calculate the required volume, choose the right material and conduct installation without compromising the performance of the vessel, you will learn how inflatable outriggers differ from rigid pontoons, and why standard factory solutions may not be suitable for extreme conditions. Correct configuration The additional capacity is able to turn an ordinary boat into an unsinkable boat, ready for any tests by a storm or oncoming wave.
Before we start purchasing materials or welding structures, we need to understand the physics of the process and the requirements of GIMS. Miscalculation can lead to a shift in the center of gravity, roll on board or complete loss of controllability. We will look at proven techniques and technical solutions used by rescue professionals and experienced fishermen.
Why you need additional tanks: physics and safety
The main purpose of the installation of additional volumes is to create a guaranteed buoyancy reserve that exceeds the weight of the vessel, equipment and crew. According to the basic principles of hydrostatics, 1 liter of displaced water holds 1 kg of cargo, but for safety this ratio must be much higher. Standby buoyancy It should be such that even a fully watered boat keeps the sides above the water at least 10-15 centimeters.
There's a common misconception that the foam inside the boards solves the problem completely. polystyrene filler It's good, but it takes up useful space and can get moisture over time, losing its properties. inflatable tubes installed outside or inside the shell provide dynamic protection that you can't get with static materials. They act as buffers that quench the shocks of waves and prevent water from scooping through the side.
In addition, additional cylinders often serve as outriggers, significantly improving the stability of the vessel, which is critical for fishing while standing or catching large fish, when the roll can become fatal. Expanding the dimensions by means of side tanks allows you to safely install more powerful engines without fear of a transom pit.
⚠️ Attention: Installing additional tanks changes the boat's sailing. In strong side winds, a vessel with large inflatable sides can become unstable on the course, requiring constant steering adjustment.
It is also important to consider that when a boat is rolled over, additional cylinders can act as an airbag, preventing the boat from completely turning upside down (keel up) if they are positioned correctly, which gives valuable time to the crew to evacuate or try to roll.
Types of additional cylinders: design choice
The boating market offers several basic types of solutions to increase buoyancy, and each has its own specifications. PVC Or a metal/plastic boat, and understanding the differences will help you avoid unnecessary costs and installation problems.
The first type is outrigger They are elongated cylinders that are mounted on brackets, and their main advantage is their versatility and ease of dismantling, and in calm weather, they can be blown away and removed, reducing water resistance and improving speed.
- 🚤 Universality: Suitable for most types of boats from 3 to 6 meters.
- 🎈 Easiness: in a deflated state, they practically do not occupy space and do not weigh the boat during transportation.
- 🛡️ Defense: They serve as a buffer when mooring, protecting the sides from impacts on the pier or other boats.
- 💰 Cost: It is usually cheaper than hard analogues.
The second type is rigid inserts or sealed blocks of composite materials, which are more commonly used on metal boats and boats as built-in structural elements. pontoon They're not afraid of punctures, but they require a lot of mounting and they take up a fixed volume, and inflatable boats, they don't really use this because of their weight.
A third option is additional inflatable sections that are integrated into the design of the boat itself (such as removable inflatable bottoms or additional stringer cylinders), a solution often offered by PVC boat manufacturers as an option, which perfectly repeat the contours of the hull, but increase the overall weight and time of preparation for descent.
When choosing a material for inflatable elements, you should pay attention to the density of the fabric and the number of layers. PVC density of 750-900 g/m2 Thinner materials may not withstand prolonged contact with water and mechanical stress in the environment.
Calculation of required volume and buoyancy reserve
The most critical step before you buy or manufacture is math. You can't just attach some cylinders hoping for the best. Formula for calculation You need to know the full weight of the boat, the maximum weight of the crew, the weight of the engine, fuel and equipment.
The total weight must be multiplied by the stock factor, which for small craft is recommended to be 1.5 or even 2.0 for increased safety. The resulting value in kilograms is numerically equal to the required volume of displaced water in liters (or cubic decimeters), from this volume is subtracted the buoyancy of the regular cylinders of the boat (if they are sealed) and the foam filler.
For example, if a motorized boat and two anglers weighs 400 kg, then for confident holding on the water you need a buoyancy reserve of about 600 liters (400 × 1.5). If regular cylinders provide 400 liters, then additional ones should give at least another 200 liters. It is better to always take with a margin, since the real density of water may vary, and the condition of the rubber deteriorates over time.
It is also important to consider weight-weighting. Additional cylinders should not overload the nose or stern. If the bulk is placed in the nose, the boat will burrow in the wave; if in the stern, there will be a different per transom, which is dangerous when running on full gas. The ideal solution is to evenly distribute the additional volume along the sides.
⚠️ Attention: Never calculate buoyancy back to back. Always leave a minimum of 30% of the margin above the calculated values to compensate for the loss of pressure in cylinders when the temperature drops at night.
Materials and components for self-manufacturing
If you decide to make additional cylinders yourself or upgrade, you will need quality. reinforced PVCThe use of car cameras or awning fabric is not recommended, as they do not have the necessary tensile strength and resistance to marine environment (salts, oils, UV radiation).
To glue cylinders, you need a two-part polyurethane adhesive designed specifically for PVC materials. A conventional "moment" or rubber adhesive will not ensure leakage under pressure and load, and you will also need high-pressure valves (type Bravo or similar petal), a belt for strengthening the seams and a solvent for degreasing.
- 🧵 Fabric: PVC boat 5-layer, density of at least 850 g / m2.
- 🔩 Furniture: Brass or plastic valves, reinforced D-rings for fastening.
- 🧪 Chemistry: Glue for PVC (two-component), degreasing, activator.
- ✂️ Tool: The scissors (for the scissors), the scissors, the scissors.
An important element is bracket For PVC inflatable boats, special transom plates or straps are used under the bottom. For metal boats, brackets are better welded or mounted on bolts through sealing pads, so as not to disturb the integrity of the board. The bracket metal must be stainless (AISI 304/316) or painted with powder paint.
Don't forget. kitIt's always on board, and even the strongest materials can be affected by a sharp hook or a branch, and the remix should include flaps of fabric, glue and a sealed degreaser.
Step-by-step instructions for installation and fastening
The installation process depends on the type of boat, but the general principles remain the same: the main rule is the reliability of the mounting. The tearing of the cylinder at speed can lead to a sharp roll and rollover. Below is a guide for installing inflatable outriggers on a PVC boat or light boat.
First, you need to mark the mounting places on the sides. The distance from the water to the bottom of the cylinder in a calm state should be 10-15 cm. If you lower it will increase the resistance of water, higher it will reduce the effectiveness of protection against splashes and unrest. The fasteners should cover the cylinder and pass under the bottom of the boat or be attached to the beams.
Then the fixation is made. Belts. You need to be evenly tightened, without skewing, use carbines with a locking mechanism to prevent spontaneous unbuttoning. If the boat is metal and the brackets are welded, the welding sites should be thoroughly cleaned and treated with anticort before painting.
Once installed, be sure to test in shallow water. Inflate the cylinders to working pressure and rock the boat. Check if the belts rub against sharp corners, if they clamping the valves. Make sure that access to the pump valves remains free.
⚠️ Attention: When mounted on a metal boat, avoid contact of aluminum brackets with copper-containing antifouling coatings or steel without insulation to prevent electrochemical corrosion.
Maintenance and leakproofness testing
Additional cylinders require regular maintenance, especially if they are operated in salt water or under the scorching sun, after each foray they must be washed with fresh water, removing salt, sand and dirt. The accumulation of contaminants in the folds of the material accelerates the destruction of the polymer structure.
The leakproofness test is done visually (inflated in the sun) and with soap solution. Pay special attention to the joints and the places of valve insertion. If you notice that cylinders have to be pumped more often than usual, then there is a micropuncture or looseness of the valve.
Store additional cylinders should be deflated (if they are removable) in a dry, dark place at a temperature of -20 to +40 degrees. Do not leave them inflated for a long time outside the boat - this creates excess tension of the fabric and shortens the service life.
| Parameter | Inflatable outriggers | Hard pontoons. | Foam filling |
|---|---|---|---|
| Weight. | Low. | Highly | Medium. |
| Risk of puncture | Highly | Missing. | Missing. |
| Impact on speed | Medium (inflated form) | High. | Missing. |
| Difficulty of installation | Low. | High. | Medium |
| Price. | Affordable | High. | Low. |
Frequently Asked Questions (FAQ)
Can I use car cameras as additional cylinders?
It's not recommended. Auto tires are not designed to be in long-term contact with water, sun and aggressive environments. They break down quickly from UV light, have low tensile strength, and can burst when hit by a wave, leaving you without a buoyancy margin at the most inopportune moment.
What pressure should be in the additional cylinders?
The optimum working pressure is usually 0.2-0.25 atm (about 3-4 psi). It is dangerous to pump cylinders, especially in hot weather, since when heated in the sun, the pressure inside will increase sharply, which can lead to rupture of the seams. Undominated cylinders will be too soft and worse to perform a protective function.
Do I need to re-register the boat after installing additional cylinders?
If the installation of additional inflatable tubes does not change the load capacity and passenger capacity specified in the boat's ticket, and does not change the design features (for example, the length of the waterline or the type of engine), re-registration is usually not required.
How to repair a puncture in an additional balloon on a pond?
For emergency repairs, use a patch from the remix, degrease the puncture site, apply glue, wait for time (according to the glue instructions), and tightly press the patch. If there is no special glue, you can temporarily use a sealant or even chewing gum (as a temporary solution) to reach the shore, but full repair is mandatory.