Dock & Gangway

Dock & Gangway Construction

Engineered for Puget Sound's tidal range, wave action, and long-term marine performance — fixed piers, floating docks, and aluminum gangways designed for Whidbey Island waterfront properties.

Why Dock Construction in Puget Sound Demands Specialized Engineering

Puget Sound presents one of the most demanding marine construction environments on the West Coast. A tidal range of 14-plus feet, strong reversing currents, persistent Pacific swell, biofouling from mussels and barnacles, and corrosive saltwater exposure all impose structural and material requirements that generic contractor experience cannot adequately address.

Dock and gangway systems must accommodate the full tidal cycle — float levels, gangway angles, and anchor pile loads all shift dramatically between high and low tide. A structure engineered only for mid-tide conditions will fail prematurely or become unsafe at tidal extremes. Sound Slope and Shoreline designs every system to perform across the full tidal envelope.

Washington State and Puget Sound regulatory agencies impose strict permitting requirements on in-water structures, including review by the Army Corps of Engineers, Washington Department of Fish and Wildlife, and the Department of Ecology. Navigating this permitting process is a core part of our project delivery — not an afterthought.

14+ ft

Tidal range Sound Slope and Shoreline engineers every dock system to accommodate — from substrate to float elevation.

Dock & Gangway Systems We Build

Sound Slope and Shoreline constructs a full range of dock and gangway configurations for residential and commercial waterfront properties on Whidbey Island and throughout Puget Sound. Each system is engineered to the specific tidal, substrate, and use conditions of the site.

Aluminum gangway at low tide on Puget Sound

Aluminum Gangways

Lightweight, corrosion-resistant aluminum gangways engineered with the correct slope, width, and handrail geometry for the full tidal range. Available in fixed and adjustable configurations.

Fixed pile pier at Whidbey Island

Fixed Piers

Pile-supported fixed piers for protected coves and low-wave-energy sites. Designed around substrate conditions and load requirements, with decking selected for traction, durability, and regulatory compliance.

Floating dock system in calm saltwater cove

Floating Docks

High-density polyethylene or aluminum-frame floating dock sections anchored to pin piles or spuds. Float systems track the tide smoothly and are sized for the vessel type, mooring loads, and site exposure.

Boat ramp at waterline low tide

Boat Ramps

Concrete or aluminum boat launch ramps engineered for substrate stability, anti-slip surface texture, and the tidal elevation range required for year-round vessel launching.

Custom commercial dock with finger piers aerial view

Custom Commercial Configurations

Multi-slip finger pier layouts, commercial float systems, and barge tie-up facilities designed to the vessel complement, operational load, and permitting envelope of commercial waterfront operations.

Materials & Standards

Built to Outlast the Marine Environment

Material selection and construction standards are what separate a dock that lasts a decade from one that lasts a generation. In Puget Sound's salt, current, and biofouling environment, every fastener, frame member, and surface material must be specified for marine service — not adapted from terrestrial construction.

Aluminum Framing: Marine-grade 6061-T6 aluminum alloy is our primary structural framing material for gangways and float frames. Aluminum's corrosion resistance, high strength-to-weight ratio, and weldability make it the correct choice for structures subject to continuous tidal immersion and salt spray.

Composite Decking: We use UV-stabilized composite decking profiles engineered for marine applications — dimensionally stable, slip-resistant, and maintenance-free compared to treated timber. Decking profiles are selected for the load class and occupancy of each structure.

Hardware and Fasteners: Every connector, bolt, chain, and cleat is specified in 316-grade stainless steel or hot-dip galvanized steel appropriate to the immersion zone. We do not substitute interior or exterior hardware for marine applications — hardware failure in a tidal structure is a safety issue, not a maintenance inconvenience.

Aluminum gangway frame welding and marine-grade hardware detail

Completed Projects

Project Portfolio

A selection of completed dock and gangway projects across Whidbey Island and Puget Sound — ranging from residential floating dock replacements to custom commercial float systems. Each entry notes the site location and primary scope of work.

Residential aluminum gangway and floating dock at high tide

Residential Floating Dock — South Whidbey

Aluminum gangway and float replacement on a protected cove. Full tidal range accommodation, composite decking, marine-grade hardware.
Fixed pile pier with composite decking at Whidbey Island

Fixed Pile Pier — Oak Harbor Waterfront

Pile-supported fixed pier with composite deck surface. Substrate engineering and shoreline permit coordination.
Two-section floating dock aerial view in calm inlet

Two-Section Float System — Penn Cove

Dual-section aluminum-frame floating dock with spud-pile anchoring and aluminum gangway.
Aluminum gangway mid-construction framing and welded connections

Gangway Fabrication — Custom Residential Build

Custom aluminum gangway fabrication showing structural framing, gusset welds, and handrail connections prior to installation.
Completed boat ramp with aluminum skiff launching

Boat Launch Ramp — Freeland Waterfront

Concrete and aluminum launch ramp engineered for tidal elevation range and anti-slip surface. Year-round vessel launching.
Commercial multi-finger float system with vessels moored

Commercial Float System — Langley Harbor

Multi-slip finger pier float system with commercial mooring hardware, permitting coordination, and barge-access layout.

Frequently Asked Questions

Dock & Gangway Questions Answered

Waterfront property owners planning a dock project typically have questions about permitting, cost drivers, and how a dock system is engineered to handle Puget Sound conditions. The most common questions are addressed below.

  • What permits are required to build a dock in Washington State?

    Most docks and piers in Puget Sound require a Hydraulic Project Approval (HPA) from the Washington Department of Fish and Wildlife, a Shoreline Substantial Development Permit or Shoreline Exemption from the local jurisdiction, and in many cases a Section 404/Section 10 permit from the Army Corps of Engineers. Some projects also require a water quality certification from the Department of Ecology. Sound Slope and Shoreline coordinates permitting as part of project delivery — we are experienced with the regulatory agencies and documentation requirements specific to Whidbey Island and Island County.

  • How does a floating dock accommodate tidal variation?

    A floating dock rises and falls with the tide, remaining at the water surface regardless of tidal stage. It is connected to fixed anchor piles or spud poles via guide brackets that allow vertical movement while restraining lateral drift. The gangway connecting the dock to the fixed shore structure is hinged at both ends to accommodate changes in angle as the tide moves the float up and down. We engineer the gangway length and hinge geometry to maintain a safe walking angle across the full local tidal range.

  • What is the expected service life of a new dock system?

    A properly engineered aluminum-frame dock system with composite decking and marine-grade hardware, correctly installed and maintained, should provide 30 or more years of service. Timber deck systems require more frequent inspection and replacement of decking elements. Annual inspection and periodic cleaning of hardware are the primary maintenance requirements. We provide maintenance guidance specific to your dock system and site conditions at project closeout.

  • Can an existing dock be upgraded rather than fully replaced?

    In many cases, yes. If the pile foundation is sound and the framing is structurally adequate, it is often economical to replace the decking surface, upgrade hardware, and add or replace the gangway rather than reconstruct the entire structure. Sound Slope and Shoreline performs condition assessments on existing dock systems to determine the most cost-effective path to a safe, code-compliant, long-service structure.

  • Does my dock need to comply with ADA accessibility requirements?

    Commercial docks and those associated with public access facilities are generally subject to ADA accessibility requirements, including gangway slope limits, handrail specifications, and surface texture standards. Residential private docks are typically not subject to ADA, but many residential clients request accessible design for household members or guests with mobility considerations. We design to the applicable standard for the project type and flag accessibility considerations during the design phase.

Get Started

Ready to Plan Your Dock or Gangway Project?

Sound Slope and Shoreline brings specialized marine construction expertise, local regulatory knowledge, and direct field experience to every dock and gangway project on Whidbey Island. Contact our team to discuss your site conditions, scope, and permitting requirements — and to receive a project-specific assessment.