Bow eye (U-bolt) | A4 | M8230

Bow eye for boats and mooring in A4 / AISI 316 stainless steel is intended for use in demanding marine environments where high corrosion resistance and mechanical strength are required. The product is used as a fixed attachment point in the boat's bow for mooring lines, chains, or hooks. The design is adapted to absorb tensile forces from mooring and towing, and to distribute the load against the surface. It is suitable for installations where long service life and reliable function under varying loads are critical. To obtain the inner dimensions, you can use the center-to-center (cc) dimension on the drawing and subtract the material thickness (D).

AREA OF USE

The product is used in marine equipment, boats, docks, and trailer installations. It is intended for applications where a fixed and secure attachment point is required in the bow, for example, for mooring, winching, or boat transport. The bow eye allows for secure connection to shackles, hooks, or straps and is dimensioned to handle tensile loads in the longitudinal direction. The choice of material provides resistance to saltwater, moisture, and chemically aggressive environments.

TECHNICAL SPECIFICATIONS

Product type: Fitting
Product family: Bow eye
Material grade: A4
Strength class: Not specified
Standard: Not specified
Diameter: Not specified
Design: Eye with mounting plate or threaded attachment
Surface finish: Untreated
Environment: Marine
Delivery unit: Piece

FREQUENTLY ASKED QUESTIONS (FAQ)

What characterizes a bow eye in acid-proof stainless steel (A4 / AISI 316)?

A bow eye (bow bolt) is a heavy-duty attachment point specifically designed for marine loads and permanent mounting in the boat's hull:

• Secure anchoring in the bow: Serves as the boat's primary attachment point for mooring lines, locking chains, winch cables from boat trailers, or tow lines.

• Even force distribution: The design is threaded through the hull and secured on the inside with washers and nuts. This distributes high tensile forces over a larger hull area and prevents point loading in fiberglass or wood.

• Calculation of inner dimensions: To quickly calculate the eye's free inner dimension, take the center-to-center (cc) measurement from the drawing and subtract the material thickness.

Why is acid-proof stainless steel A4 (AISI 316) the only right choice in marine environments?

Hull-mounted fittings are constantly exposed to harsh conditions where material failure can lead to serious incidents:

• Maximum protection against saltwater: A4 steel (1.4401 / AISI 316) contains molybdenum, which provides superior protection against corrosion, crevice corrosion, and pitting in brackish water, harsh saltwater, and humid marine environments.

• High mechanical strength: Withstands strong and sudden pull-out forces from waves, wind, or jerks in the mooring without deforming or suffering from fatigue cracks.

• Long service life without maintenance: Retains its strength and shiny surface for decades without risk of rust stains on the hull.

How do you mount a bow eye correctly for a watertight and strong installation?

1. Drill and countersink the holes: Drill the holes in the bow with exact precision based on the bow eye's cc dimension. Slightly bevel the hole edges in the gelcoat/fiberglass to prevent stress cracks in the surface layer.

2. Seal carefully: Apply plenty of marine sealant (e.g., polyurethane or MS polymer) around the threads and under the external contact surface to ensure a completely watertight seal.

3. Use reinforcement washers on the inside: Install heavy-duty A4 hull washers or a backing plate on the inside of the hull together with acid-proof locking nuts (A4) to provide maximum contact surface against the hull.