Inflatable boat operation often requires the installation of an outboard motor, but standard solutions do not always meet the needs of experienced water engines in terms of power or reliability. A homemade transom on a inflatable boat becomes the ideal solution when the factory transom-board seems too fragile or needs to be replaced. A properly manufactured stop allows you to safely use more powerful power units without fear for the integrity of the cylinders and seams.
The process of creating such a piece requires accurate angle calculation, selection of quality materials and strict adherence to assembly technology. Design errors can lead to a shift in the center of gravity, the roll of the boat or, in the worst case, to the loss of the engine while driving. In this article, we will discuss in detail all the steps, from choosing plywood to the final painting to your car. prairie He served for years.
Design features and types of transom boards
Before you start cutting materials, you need to decide on the type of design that will be most effective for your boat model. There are several main types of stops, each of which has its own advantages depending on the operating conditions and specifications of the vessel. Understanding these differences will help to avoid fatal errors in the design.
The classic trans board is a solid sheet of moisture-resistant plywood that is inserted between the sides in the aft section. It relies on inflatable tubes or special stops, transmitting the traction force of the engine to the entire width of the stern. prairie, which is attached exclusively to cylinders by means of slings or belts, without touching the floor.
More complex designs can include adjustable angle of inclination, which allows you to compensate for the differential of the boat under different loads. Also popular are composite versions, where the central part is made of plywood and the side ears are made of lighter material for weight loss. outboard You plan to use it.
It is important to consider that a homemade design should perfectly repeat the geometry of the stern of your boat. The wrong angle of the transom will lead to the fact that the boat will either burrow its nose or, conversely, overly bully it, which will reduce speed and handling.
Selection of materials: plywood, fasteners and impregnation
The basis of any reliable transom is a material that can withstand constant contact with water, vibration and weight of the engine. The most common and time-tested solution is aviation or boat plywood brand. FSFThis material has increased moisture resistance due to the phenolformaldehyde glue used in gluing layers of veneer.
Plywood thickness is directly dependent on the engine power and the width of the boat. For engines up to 5 hp, 12-15 mm thickness is usually sufficient, whereas for more powerful units (10-15 hp) you will need a sheet thickness of 18-21 mm. FCIt is only permissible under ideal sealing, but the risk of stratification remains high over time.
When buying plywood, carefully examine the ends of the sheet: they must be tightly compressed without visible voids and stratifications, even the presence of microscopic gaps between the layers of the veneer will become a place for water to enter.
To strengthen the design and protect the edges, aluminum corners or stainless steel linings are often used. Fixing elements such as bolts and nuts must be made of stainless steel AISI 304 or AISI 316 to avoid corrosion in salt water, and ordinary ferrous metal, even when painted, will not survive in an aggressive aquatic environment for long.
The final touch of the materials is the choice of impregnation. Modern epoxy resins and special yacht varnishes create a monolithic protective layer that prevents swelling of wood. You can't save on the chemistry of protection, because you can't replace the soaked transom in the middle of the pond.
Step-by-step instructions for the manufacture of transmutants
The fabrication process starts with precise measurements and drawings, and you have to measure the distance between the insides of the cylinders in the aft and the height from the bottom to the expected top edge of the transom, and from that data you create a pattern of cardboard that you try on on to the boat to test the geometry.
☑️ Preparation for manufacture
Once the template is approved, plywood is cut, and the best way to cut the material is with a jigsaw jigsaw with a small-toothed file to minimize chipping at the edges, and all the ends immediately after the cut should be sanded with 80-100 grain sandpaper, eliminating all irregularities and burrs.
The next step is impregnation and pasting, and the wooden base is covered with several layers of epoxy, allowing each layer to dry completely. For maximum strength, many craftsmen paste the transom with fiberglass, creating a kind of fiberglass cocoon, which greatly increases the life of the product.
⚠️ Warning: When working with epoxy resins and hardeners, be sure to use a respirator and gloves. The pairs of components can cause severe airway irritation and allergic skin reactions.
The final step is to install fasteners. If the design involves removable elements or adjustment, bolt holes are drilled into the plywood, and the holes are also carefully sealed so that moisture does not enter the structure of the tree through the fastener channel.
Methods of fixing and adjusting the angle of inclination
The anchoring of the homemade transmuner is a critical point in determining the safety of the entire structure. There are two main methods of fixation: hard reinforcement in cylinders and a combined method using bottom stop. The first option is more common for boats with inflatable floor, where rigid communication with the floor is not possible.
When the slats are rigid, the slats are inserted between the sides and fixed by belts or slings passing through special rings on cylinders. It is important that the pressure is distributed evenly throughout the width of the board. To do this, soft linings of porous rubber or foam are often put on the edges of the transom, which also protect the cylinders from rubbing.
How to calculate the angle of inclination of the transom?
The standard angle of deviation of the transom vertical from perpendicular to bottom is in the range of 0-15 degrees. The exact angle is selected experimentally: if the boat's nose is lifted when moving, the angle is reduced, if it burrows, increase.
Adjustment of the angle of inclination (different) is carried out using gaskets or special mechanisms, if they are provided by the design. The correct angle ensures the optimal position of the engine's lower unit relative to the surface of the water, which affects the efficiency of the screw and the speed of the vessel. Adjustment of the transom This is especially important when changing the type of cargo or the number of passengers.
In some cases, especially on hard-bed boats, the bottom edge of the transom can be hoisted on the floor, which creates an additional foothold and relieves the load on the stern cylinders, but this requires perfectly flat flooring and precise height calculations so that the inflatable elements do not damage the deformation of the bottom under load.
Wood protection and anti-corrosion treatment
The durability of your product depends on the quality of the finishing work, and even the most moisture-resistant plywood will absorb moisture sooner or later if it is not properly protected, and the processing process involves primer, basic painting and the finishing lacquer layer.
The primer is a great epoxy compound that penetrates deep into the pores of the tree and seals them. After drying the primer, the surface is grinded with fine sandpaper (grain 220-240) to remove the pile. Then applied paint designed for marine applications, resistant to ultraviolet and salt water.
| Type of coating | Resistance to water | Resistance to UV | Difficulty of application |
|---|---|---|---|
| Oil paint | Low. | Medium | Low. |
| alkyd enamel | Medium | High. | Medium |
| Epoxy resin | Very high. | Low (yellowish) | High. |
| Yacht lacquer | High. | High. | Medium |
Particular attention should be paid to the places where the motor attaches, where the paint quickly wears away from vibration and contact with the metal of the bracket, in these areas it is recommended to use additional protective linings made of rubber or plastic, or regularly update the lacquer coating.
The quality of the transom is not just an aesthetic, it's a necessity. The water that gets inside the plywood expands when it freezes and tears the material from the inside, making the transom unusable in one season.
Operational safety and maintenance
A homemade transom requires regular inspection and maintenance, especially after an intense season of operation. Before each release, check the integrity of the anchorages, the absence of cracks in the tree and the condition of the protective coating. Any suspicious changes in the structure of the material should be immediately corrected.
Keep the boat with the set transcenza should be in a dry, ventilated room. If the transgran is removable, it is better to dismantle it and store it in a horizontal position to avoid deformation under its own weight.
⚠️ Warning: Never leave a powerful motor hanging on a transom while standing on water or storing a boat on land, creating a constant bending stress that can cause the structure to collapse suddenly.
Periodically check the tightening of bolt joints, as vibration from the engine can weaken even reliably fixed nuts. Using growers or fixing compounds for threading (anaerobic sealants) will help keep the joints intact.
What to do if the squirrel starts to creak?
Screeching usually occurs because the wood is rubbing against the cylinders or the attachments are loosened. Grease the contact areas with silicone lubricant and tighten all bolt joints. If the creak is left, check for microcracks.
Frequently Asked Questions (FAQ)
Can I use regular birch plywood instead of FSF?
Use regular plywood FC This is only possible as a last resort and with perfect, multilayered epoxy treatment on all sides, including the ends. However, the risk of stratification and swelling remains high, especially with frequent contact with water. FSF Or bakelite plywood.
What is the maximum power of the motor will withstand a homemade transom?
The capacity of the transom depends on its thickness, width of the boat and quality of manufacture. For a standard inflatable boat with a width of 130-140 cm, the safe limit is usually considered a motor with a capacity of 5-8 hp. Increased power requires strengthening the structure, the use of thicker plywood (from 21 mm) and additional stiffness ribs, as well as consulting with the boat manufacturer.
Do I need to take off the transom for the winter?
Yes, the removable transom is better removed, so that the boat cylinders can be deformed at pressure points under the board's own weight for a long time, and dry storage will extend the life of the wooden structure.
How do you know if the angle of the transom is chosen incorrectly?
If the boat is heavily nose-drained and poorly controlled when it goes out for planing, the angle of inclination is probably too large (nose upwards). If the nose burrows into the water, creating a high wave, and the engine is overloaded, the angle should be reduced. The optimal position is when the bottom of the boat is parallel to the surface of the water when moving.