CALIFORNIA HUMBOLDT • GULF OF MAINE • CELTIC SEA • NORTH SEA DEEPWATER

Offshore Floating Wind Towage Corridor Guide

Navigation passages, bollard pull tug configurations, metocean weather windows ($H_s \le 2.5m$), and Coast Guard safety zones for towing fully integrated 15MW to 20MW floating wind turbines from coastal marshaling ports to deepwater mooring fields.

Select Floating Wind Towage Corridor

Inspect required ocean bollard pull, transit speeds, bar crossing hazards, and seasonal wave regimes.

Active Region:

TOTAL OCEAN TOW DISTANCE 28.5 Nautical Miles Tow Speed: 2.5–3.5 knots (~9.5 hrs)

MIN CHANNEL WATER DEPTH 14.6 Meters (48 ft) Humboldt Bar Dredged Channel

REQUIRED BOLLARD PULL 220T Total BP 1x 150T Lead Tug + 2x 70T Escorts

WEATHER WINDOW LIMIT Hs ≤ 2.2m | Wind ≤ 18kt Zero transit during swell period Tp > 12s

Detailed Passage Plan & Navigational Geometry

Departs Humboldt Bay Samoa Peninsula marshaling quay via the North Bay shipping channel. Navigates the jettied entrance channel across the Humboldt Bar, requiring strict slack water timing and high-tide clearance over the outer bar shoal. Once past the whistle buoy RW “HB”, courses 285° True towards the Humboldt Wind Energy Area (WEA) deepwater lease block (water depth 600m to 1,000m).

Critical Chokepoint 1: Humboldt Bar Jettied Entrance (Channel Width: 500 ft)

Critical Chokepoint 2: Shelf Break Transition (200m to 800m Bathymetry Drop)

Tug Towing Configuration: Arrowhead Tow Formation with 900m Synthetic Pennant

Metocean Limits & Maritime Regulatory Governance

Pacific Northwest long-period groundswells ($T_p > 14s$) induce pitch and roll resonance in 15MW floating substructures, creating high bending moments at the tower-to-substructure flange. Operations mandate an unbroken 24-hour calm weather window certified by third-party oceanographic forecasting.

Significant Wave Height Limit: Hs ≤ 2.2m (Maximum Hmax ≤ 3.8m)

Wind Velocity Limit: 10-Minute Mean Wind ≤ 18 knots (20.7 mph)

Security Escort Zone: USCG 500m Moving Safety Zone with Patrol Cutter

MWS Certification, Regulatory Authorizations & Towage Timeline

Permitted Towing Seasons

May 1 – September 30 (Summer Calm Window)

Pacific winter storm curfews restrict open ocean towing between October and April.

Authorizing Agencies

USCG Sector Humboldt Bay / BOEM Pacific

DNV Certificate of Approval (CoA) issued by Marine Warranty Surveyor prior to tow.

Fisheries & Wildlife Coordination

Protected Species Observer (PSO) on Lead Tug

Continuous visual/PAM monitoring for humpback whales and marine mammals along tow route.

Related Offshore Energy Logistics Modules

→ SPMT Loadout Manual → Mooring Tension Calc → Port Quayside Bearing Audit → Marine Dispatch