Tools & fastening

For the installation and repair of fittings, brackets, equipment, covers, railings, interior fittings, electrical/pump installation, and rigging/deck fittings—anywhere a connection needs to be permanent, vibration-resistant, and corrosion-resistant.

Self-tapping screws form their own threads in thin material (sheet metal, thin-walled fittings). Wood screws are designed for wood and wood-like materials (superstructures, interior fittings). Machine screws are screwed into an existing thread or secured with a nut/threaded plate—typically used for load-bearing fittings, engine/propulsion parts, and permanent connections.

A2 is often sufficient for many applications in dry indoor areas or protected environments. A4 is usually the more robust choice in salty environments (splash water, deck, exterior fittings). Contact corrosion (material mix) and the design are also important: stainless steel in aluminum without a barrier, for example, can cause problems.

Washers distribute the load, protect surfaces, and prevent heads/nuts from sinking into the material. With FRP, sandwich panels, and soft materials, washers and backing plates significantly increase the durability of the joint and reduce cracking and “tearing out.”

Rivets are useful when you cannot provide support from the back or need a quick, flat connection (e.g., thin sheets, profiles). Screws are better when the connection needs to be regularly removable, when high loads with defined preload are required, or when you can work with backing plates/nuts.

Important factors include material selection (e.g., Monel or seawater-resistant variants depending on the application), correct drilling, a clean fit, and—if necessary—sealant to prevent moisture from penetrating sandwich/FRP structures. Be mindful of material compatibility to avoid contact corrosion.

With correct sizing, clean contact surfaces, appropriate washers, and suitable fasteners: lock nuts, split pins, threadlocker (medium-strength/high-strength depending on the application), and wire locks if necessary. Use spring washers only where necessary—they are not always the best solution for stainless steel. Regular inspections are advisable for safety-critical parts.

TORX is often the best practical choice: good power transmission, less “wearing out,” and often easier to loosen after years of use. Hex is also good, but requires clean tools and tends to round off more easily when exposed to dirt or salt. Phillips is the most sensitive to high torque.

The screw should provide sufficient thread engagement but not be unnecessarily long (risk of collision/injury, corrosion on the protruding end). For nuts: sufficient thread engagement (rule of thumb: at least “1× diameter” of thread engagement). For wood: sufficient screw-in depth without splitting the material—pre-drilling helps.

Drill holes cleanly, seal edges if necessary (moisture protection), distribute loads via washers/backing plates, and seal openings with a suitable sealant. This prevents water ingress and long-term damage (softening of the sandwich core, delamination).

They secure plug-in or movable connections against accidental loosening. Split pins are typically used to secure bolts, shackle bolts, or axles—especially where vibration or movement occurs. Important: correct diameter, corrosion-resistant design, and safe ends (no sharp edges).

Common: incorrect material (corrosion), lack of load distribution (no washers/counterplates), poorly drilled holes, insufficient sealing at penetrations, incorrectly applied threadlocker, or a design that promotes contact corrosion. Better: plan carefully, check material compatibility, and regularly inspect critical connections.