Dock Washers
What are Dock Washers?
Dock washers are heavy duty, large diameter flat washers designed to spread load over a wide area and resist pull-through in demanding builds. They are thicker than standard flat washers and commonly paired with structural bolts for outdoor and marine work.
What are dock washers used for?
- Spreading clamp force on timber, pilings, and plate steel
- Reducing pull-through on oversized or weathered holes
- Stabilizing connections exposed to movement and impact
- Providing a broad bearing surface for long lasting joints
Dock washers vs fender washers what is the difference?
Both offer a large outside diameter. Dock washers are typically thicker and built for structural loads and outdoor exposure. Fender washers focus on coverage with thinner stock for sheet metal and light duty repairs.
What size dock washer do I need? inch and metric
- Match the nominal size to the bolt or rod, for example 1/2 in or M12
- Verify the inner diameter clears the shank without excess play
- Select an outside diameter that fully covers the hole with margin
- Choose a thickness that resists cupping under structural torque
- Available in common inch and metric ranges to pair with US and metric hardware
Which material should I choose
Hot dip galvanized steel
Thick zinc coating suited to docks, piers, and outdoor structures. Pair with hot dip galvanized bolts and nuts.
316 stainless steel
Premium corrosion resistance for marine and chemical exposure. Ideal near saltwater and splash zones.
304 stainless steel
General purpose corrosion resistance for light coastal and outdoor service where loads are moderate.
Zinc plated steel
Economical for dry interiors. Not recommended for long term wet exposure.
Installation tips for dock washers
- Use clean, flat bearing surfaces so the washer seats evenly
- Place the washer under the rotating component to protect the surface
- Tighten to the fastener’s recommended torque and re-check after initial set in wood
- Match finishes across the joint to limit galvanic corrosion in wet areas
Applications
- Dock and pier construction with treated lumber and structural steel
- Marine and coastal infrastructure exposed to spray and weather
- Outdoor framing, sign supports, and heavy equipment mounting
- Repairs where enlarged holes need a wide, stiff bearing surface
Best practices and selection tips
- Use 316 stainless near saltwater and hot dip galvanized for rugged outdoor structural connections
- Confirm clearance so the outside diameter does not interfere with flanges or channels
- Add a locking method for vibration when required, such as a lock washer or threadlocker
FAQs about Dock Washers
It spreads load across a wide area and helps prevent pull-through in heavy duty joints, especially in timber and plate connections.
Dock washers are thicker and intended for structural loads and harsh environments. Fender washers are generally thinner and used for coverage on sheet materials and light repairs.
Match the washer to the bolt size, confirm the inner diameter fits the shank, and select a large outside diameter and sufficient thickness to resist cupping under torque.
316 stainless offers the highest corrosion resistance near saltwater. Hot dip galvanized steel is a durable choice for outdoor structural work when paired with galvanized hardware.
They improve seating and load spread but do not lock by themselves. Add a locking feature or threadlocker when vibration is expected.
Yes. Choose the corresponding metric size, such as M10 or M12, and verify inner diameter and thickness for your load.
Docks and piers, coastal infrastructure, outdoor framing, and heavy equipment mounts that need a wide, stiff bearing surface.
Tighten gradually and re-check after the first load cycle since treated lumber can compress over time.
Yes. Keep stainless with stainless and galvanized with galvanized to reduce galvanic corrosion in wet conditions.