Owners of fiberglass boats and boats constantly face the risk of damage to the hull when docking or moving in shallow water. kielgard It's not just an accessory, it's a vital piece of design that extends the life of the boat, and even experienced captains are not immune to unforeseen contact with a concrete slab or sharp rocks on the bottom.
That is why the installation of high-quality keel guard This element takes the brunt of touching the bottom, saving the expensive fiberglass hull from cracks and holes. Glass plastic when struck against a stone is prone to the formation of microcracks in the gelcoat, which are eventually saturated with water, leading to the stratification of the body.
In this article, we will take a look at everything from the choice of profile material to the nuances of its sticking, you will learn why cheap options are often more expensive to operate and how to properly prepare the surface for maximum adhesion.
Purpose and design features of the keel guard
The main function of this element is to mechanically protect the bottom and bottom of the sides, and structurally it is a profile that is mounted around the perimeter of the boat or only in the most vulnerable places. Depreciation impact occurs due to the elastic properties of the material from which the profile is made.
Unlike metal boats, where a blow often results in a dent, fiberglass can get through damage. kielgard It distributes the impact energy over a larger area, reducing the point pressure on the body. Modern models often have complex geometry with internal stiffness ribs.
It is important to understand that in addition to protection, this element acts as a buffer when mooring. board The boat does not scratch the mooring walls, maintaining a presentable appearance, but do not rely on the keel guard as the main element for repelling obstacles, its task is to mitigate accidental touches.
⚠️ Note: The use of a keel guard does not give the right to deliberately ram obstacles or go ashore at high speed. The design is designed to quench the inertia of the privatny contacts, not to constant impact loads.
Materials of manufacture: comparison and selection
The market offers several basic types of materials, each with unique specifications, depending on the operating conditions of the vessel and the owner's budget. PVC (polyvinyl chloride).
- 🔵 PVC profile: It has high wear resistance and perfectly holds the shape, but requires special glue for installation.
- 🟢 Rubber (EPDM): Excellent elasticity and resistance to ultraviolet light, but can be deformed during prolonged parking under load.
- 🟡 Polyurethane: Maximum strength and durability, however, has a higher cost and is difficult to handle.
When choosing a material, you should pay attention to its stability to saltwater Cheap analogues can swell or lose elasticity after the first season of active operation. profile retains its properties in the temperature range from -40 to +60 degrees.
The table below will help you compare the key specifications of popular materials used to protect the case.
| Parameter | PVC | EPDM rubber | Polyurethane |
|---|---|---|---|
| Term of service | 5-7 years | 7-10 years | 10+ years |
| Elasticity | Medium | High. | Low. |
| Resistance to UV | Good. | Great. | Great. |
| Price. | Medium | Low. | High. |
Secrets of Durability of Materials
The most durable profiles have internal reinforcement with fabric, which prevents the material from stretching under load. When buying, tap on the profile: a deaf sound often indicates a low density of the material.
Surface Preparation: Critical Stage
The installation quality is 90 percent dependent on the proper preparation, the fiberglass must be absolutely clean, fat-free and dry, any dust or trace of oil will cause the plastic to be completely clean. adhesion The glue will be broken.
The first step is to thoroughly wash the area of the installation using detergents. solvent Do not use acetone on colored gelcoats without a preliminary test, as it can dissolve the pigment.
If you have an old keel guard on the case, removing it requires care. Heating with a building hair dryer helps soften the old glue, but do not overheat the fiberglass above 80 degrees.
☑️ Preparation for installation
Installation technology and glue selection
Installation of the keel guard is a process that requires patience and accuracy, and special polyurethane or MS-polymer sealants, such as glues, are used to fix it. Sikaflex or 3M 5200Conventional silicone for this purpose is not suitable, as it does not withstand constant dynamic loads.
The adhesive is applied to the inside of the profile in a zigzag strip or dotted, depending on the manufacturer's recommendation. Once pressed to the board, it is important to lock the element until the initial grasping, you can use paint tape or temporary stops.
Special attention should be paid to the joints of the sections of the profile. If the boat has a complex bypass shape, the profile can be cut into parts. Docking elements Often come with quality profiles.
⚠️ Warning: Never pull the rubber profile when you install it. Once installed, it may shrink and the adhesive will be severed from the inside due to the stress of the material.
Apply glue at an air temperature not lower than +10 ° C. Cold glue lies in lumps and does not provide a uniform layer, which is critical for the tightness of the seam.
Corner elements and transom protection
The most vulnerable areas are the nose and the zygomatic corners, and this is where the most frequent disturbances or moorings occur. corner-layerThey repeat the geometry of the body.
The nasal keel guard needs to be carefully installed, because it's the zone that experiences the maximum water pressure during the course, the profile must fit tightly around the bend without forming voids, and in some cases, you need to trim the profile at an angle for perfect fit.
Protecting the transom is also important, especially for outboard boats, where it is easy to damage the bottom of the transom when you recline the motor or maneuver at the berth. Trants keel guard It is a reinforced pad, often with a metal core inside.
Properly installed nose keel guard reduces water resistance at high speeds, as smoothes the sharp edges of the body and improves hydrodynamics.
Repair and protection services
Even the strongest keel guard wears out over time; deep cuts or detachments require immediate intervention; ignoring minor damage can cause water to fall under the profile and begin to break down fiberglass.
You can use special remixes based on epoxy resins or polyurethane to repair small cuts, and if the profile is unstuck over a large area, it needs to be completely dismantled, cleaned of old glue and glued back. Repairs It should be carried out in dry weather.
Regular maintenance is to inspect the condition of the fastener (if any) and the integrity of the adhesive seam. Once a season, it is recommended to check the density of the profile along the entire length.
- 🔍 Check the profile for cracks and scuffs.
- 🧼 Wash the keel guard along with the case, removing algae and dirt.
- 🛠️ If you find a detachment, immediately clean and glue the area.
⚠️ Warning: Do not use aggressive solvents or hard brushes to clean the keel guard, which can damage the top protective layer of the material and accelerate its aging.
lifehack for glue testing
If you're in doubt about whether the glue holds, try to tamper with a thin spatula carefully, and if you hear the characteristic crackling of the tear and you see the glue on both surfaces, the adhesion is good, and if the profile is coming away clean, you need to overload.
Frequently Asked Questions (FAQ)
Can I put a keel guard on an old paint coating?
It is strongly discouraged: the glue must be in direct contact with the fiberglass (gelcoat), the paint or antifowling may not withstand the load and come off with the profile, all coatings in the gluing area must be removed to a clean material.
How long does the keel guard glue dry?
The initial grip time is 2 to 6 hours depending on temperature and humidity, full polymerization and maximum strength gain takes 24 to 72 hours, and you can't operate the boat before that time.
Do I need to drill the body to install a keel guard?
In 95% of cases, only adhesive is sufficient. Mechanical fasteners (shock cutters) are rarely used, mainly on very large boats or when installing metal profiles. For fiberglass boats, additional perforation of the hull is undesirable.
How to remove an old keel guard without damaging the body?
Use a building hair dryer to heat the profile to 60-70 degrees to soften the glue. Carefully trim the adhesive layer with a fishing line or a special knife. Remove the glue residue mechanically, trying not to damage the gelcoat.