Dock & Mooring Lines
Docking & Mooring Guide
Dock Lines, Mooring Lines & Fenders Guide
Learn how to choose dock lines, mooring lines, spring lines, fender lines, rope accessories, and fenders for safer tie-ups at slips, docks, pilings, mooring buoys, and transient stops.
Quick Rule
Shop Double-Braided Lines
Use the right line size, protect every chafe point, and set spring lines so the boat can move without hitting the dock.
This guide is general boating guidance. Confirm line ratings, cleat capacity, marina rules, tides, weather, and vessel-specific requirements before leaving the boat unattended.
Quick Answers
Line Size
Common Dock Line Starting Points
| Boat Length | Common Line Diameter | Typical Use |
|---|---|---|
| Under 20 ft | 3/8 in | Small boats in protected slips |
| 21-34 ft | 1/2 in | Common recreational dock line size |
| 35-45 ft | 5/8 in | Larger cruisers and heavier loads |
| 46-60 ft | 3/4 in | Large boats or exposed conditions |
Size up for heavy displacement, exposed docks, storms, strong wake, rough pilings, or commercial use.
Length
How Long Should Dock Lines Be?
Bow and stern lines are often around two-thirds of boat length as a starting point. Spring lines are commonly close to the boat's length or longer so they can run at useful angles.
Fixed docks, tides, pilings, rafting, and storm prep may require longer lines and more chafe protection.
Nylon
Popular for dock lines because it stretches and absorbs shock from wake, wind, and surge.
Polyester
Good UV and abrasion performance with lower stretch. Useful where controlled movement is important.
Floating Rope
Useful for safety, tenders, and visible temporary lines, but not always the right dock-line material.
Dock Setup
Use Bow, Stern, and Spring Lines Together
A secure dock setup usually uses bow and stern lines to hold the boat near the dock and spring lines to control forward and backward movement. The boat should have enough give to absorb wake and tide, but not enough movement to strike the dock or neighboring boats.
Bow lineControls the bow and keeps the front of the boat from wandering away from the dock.
Stern lineControls the stern and keeps the boat aligned alongside the dock.
Forward springLimits backward movement.
Aft springLimits forward movement.
Fenders
Fenders Protect the Hull, Lines Hold the Boat
Fenders should be placed where the boat may contact the dock, piling, wall, or another boat. They do not replace properly set lines.
Placement
Place Fenders Before You Need Them
Rig fenders before entering a slip or approaching a fuel dock. Adjust height for the dock edge, pilings, freeboard, and expected wake or tide changes.
Carry extra fenders for rafting, locks, unfamiliar docks, or changing docking plans.
Inspection
When to Replace Dock Lines
Replace dock lines when strength is uncertain or visible damage appears. Permanent dock lines age faster than lines stored clean and dry.
Chafe or cutsDeep abrasion, broken yarns, exposed core, or damage at eyes and chocks.
Heat or overloadFlat, glazed, melted, shiny, or stiff areas from heavy load or friction.
UV damageBrittle, crunchy, powdery, or badly faded fibers.
Unknown historyReplace after severe storm loading, hard surge, or questionable prior use.
FAQ
Docking & Mooring Questions
What is the difference between dock lines and mooring lines?
Dock lines usually secure a boat to a dock, pier, piling, or another boat. Mooring lines are usually heavier-duty lines for mooring buoys, mooring fields, permanent berths, or longer-term securing.
What size dock lines do I need?
As a starting point, many recreational boats use 3/8 inch for under 20 feet, 1/2 inch for 21 to 34 feet, 5/8 inch for 35 to 45 feet, and 3/4 inch for 46 to 60 feet. Adjust for boat weight, exposure, and hardware.
Are nylon or polyester lines better?
Nylon is usually preferred for dock lines because it stretches and absorbs shock. Polyester has strong UV and abrasion resistance with lower stretch.
Can dock lines be too tight?
Yes. Lines that are too tight can shock-load cleats, prevent the boat from rising and falling, and fail during wake or tide changes.
Ready to Set Up Your Dock Lines?
Shop Dock Lines, Mooring Lines, Fenders & Accessories
Use the collection page or search by line type, diameter, material, length, fender setup, chafe protection, or storage accessory.
Seachoice 42910 Solid Braid Nylon -White-3/16 X 1000
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A strong, firm, uniformly round rope. Works exceptionally well in blocks and on winches. Does not flatten under load. Has elasticity that allows it...
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Twisted Nylon Rope, White, 5/16" x 600'
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Manufactured from 100% filament nylon fibers. Has great elasticity properties and the ability to absorb sudden shock loads. Excellent resistance to...
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Seachoice Twisted Braid Polypropylene Spool, Yellow, Floats. X 600 Ft., 100% Polypropylene
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600 Feet of Floating Polypropylene Line. Ready for Whatever the Water Throws at It.The Seachoice 3/8" x 600 Ft. Twisted Braid Polypropylene Spool i...
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CABO Floating Rope - 6mm (15/64") Diameter - 30m (98.4 ft) Spool - Orange
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CABO Floating Rope - High-Visibility OrangePremium buoyant polypropylene rope designed specifically for marine safety applications. This high-visib...
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CABO Fender Line - Double Braided Polyester - 12mm (1/2") x 3m (9.8 ft) - Black - with Loop
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CABO Double Braided Fender Line with Pre-Spliced LoopPremium double-braided polyester fender line designed for secure and reliable fender attachmen...
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CABO Fender Line - Double Braided Polyester - 12mm (1/2") x 3m (9.8 ft) - Navy Blue - with Loop
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CABO Double Braided Fender Line with Pre-Spliced LoopPremium double-braided polyester fender line designed for secure and reliable fender attachmen...
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CABO Fender Line - Double Braided Polyester - 10mm (3/8") x 2m (6.6 ft) - Black - with Loop
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CABO Double Braided Fender Line with Pre-Spliced LoopPremium double-braided polyester fender line designed for secure and reliable fender attachmen...
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CABO Fender Line - Double Braided Polyester - 10mm (3/8") x 2m (6.6 ft) - Navy Blue - with Loop
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CABO Double Braided Fender Line with Pre-Spliced LoopPremium double-braided polyester fender line designed for secure and reliable fender attachmen...
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CABO Fender Line - Double Braided Polyester - 8mm (5/16") x 2m (6.6 ft) - Black - with Loop
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CABO Double Braided Fender Line with Pre-Spliced LoopPremium double-braided polyester fender line designed for secure and reliable fender attachmen...
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CABO Fender Line - Double Braided Polyester - 8mm (5/16") x 2m (6.6 ft) - Navy Blue - with Loop
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CABO Double Braided Fender Line with Pre-Spliced LoopPremium double-braided polyester fender line designed for secure and reliable fender attachmen...
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Parallel Connector for Fender Baskets - 2 Pack - Fender Basket Linking Hardware
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Parallel Connector for Fender Baskets - 2 PackHeavy-duty parallel connectors designed to link fender baskets side-by-side, creating an expandable m...
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Connector & Rail Support Set for Fender Baskets - Complete Mounting Hardware Kit
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Complete Connector & Rail Support Set for Fender BasketsComprehensive mounting hardware set designed for secure installation of fender baskets ...
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OCEAN Heavy Duty Fender H9 - 28cm x 109cm (11" x 43") - Black - Reinforced Marine Fender
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OCEAN Heavy Duty Fender H9 - 28cm x 109cm (11" x 43") - BlackExtra heavy-duty marine fender designed for larger vessels and commercial applications...
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OCEAN Heavy Duty Fender H8 - 22cm x 104cm (8.7" x 41") - Black - Reinforced Marine Fender
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OCEAN Heavy Duty Fender H8 - 22cm x 104cm (8.7" x 41") - BlackExtra heavy-duty marine fender designed for larger vessels and commercial application...
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OCEAN Heavy Duty Fender H7 - 28cm x 76cm (11" x 30") - Black - Reinforced Marine Fender
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OCEAN Heavy Duty Fender H7 - 28cm x 76cm (11" x 30") - BlackExtra heavy-duty marine fender designed for larger vessels and commercial applications....
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OCEAN Heavy Duty Fender H6 - 22cm x 76cm (8.7" x 30") - Black - Reinforced Marine Fender
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OCEAN Heavy Duty Fender H6 - 22cm x 76cm (8.7" x 30") - BlackExtra heavy-duty marine fender designed for larger vessels and commercial applications...
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OCEAN Heavy Duty Fender H2 - 14cm x 50cm (5.5" x 20") - Black - Reinforced Marine Fender
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OCEAN Heavy Duty Fender H2 - 14cm x 50cm (5.5" x 20") - BlackExtra heavy-duty marine fender designed for medium to larger vessels and commercial ap...
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OCEAN MAGNUS Inflatable Fender - 24" x 66" (61cm x 168cm) - Black - Heavy-Duty Marine Fender
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OCEAN MAGNUS Inflatable Fender - 24" x 66" (61cm x 168cm) - BlackExtra-large heavy-duty inflatable fender designed for large yachts, commercial ves...
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OCEAN MAGNUS Inflatable Fender - 24" x 58" (61cm x 147cm) - Black - Heavy-Duty Marine Fender
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OCEAN MAGNUS Inflatable Fender - 24" x 58" (61cm x 147cm) - BlackExtra-large heavy-duty inflatable fender designed for large yachts, commercial ves...
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OCEAN MAGNUS Inflatable Fender - 24" x 42" (61cm x 107cm) - Black - Heavy-Duty Marine Fender
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OCEAN MAGNUS Inflatable Fender - 24" x 42" (61cm x 107cm) - BlackExtra-large heavy-duty inflatable fender designed for large yachts, commercial ves...
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OCEAN MAGNUS Inflatable Fender - 18" x 45" (46cm x 114cm) - Black - Heavy-Duty Marine Fender
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OCEAN MAGNUS Inflatable Fender - 18" x 45" (46cm x 114cm) - BlackHeavy-duty inflatable fender designed for large yachts and commercial vessels. The...
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OCEAN MAGNUS Inflatable Fender - 18" x 42" (46cm x 107cm) - Black - Heavy-Duty Marine Fender
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OCEAN MAGNUS Inflatable Fender - 18" x 42" (46cm x 107cm) - BlackHeavy-duty inflatable fender designed for large yachts and commercial vessels. The...
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Rope Thimble for Ø1" (Ø24mm) Rope - Nylon PA - White
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Premium Rope Thimble - Nylon PA for Ø1" (Ø24mm) RopeThis professional-grade nylon PA rope thimble is designed to protect rope eyes from chafe and w...
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Rope Thimble for Ø7/8" (Ø22mm) Rope - Nylon PA - White
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Premium Rope Thimble - Nylon PA for Ø7/8" (Ø22mm) RopeThis professional-grade nylon PA rope thimble is designed to protect rope eyes from chafe and...
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Rope Thimble for Ø7/8" (Ø20mm) Rope - Nylon PA - White
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Premium Rope Thimble - Nylon PA for Ø7/8" (Ø20mm) RopeThis professional-grade nylon PA rope thimble is designed to protect rope eyes from chafe and...
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Rope Thimble for Ø3/4" (Ø18mm) Rope - Nylon PA - White
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Premium Rope Thimble - Nylon PA for Ø3/4" (Ø18mm) RopeThis professional-grade nylon PA rope thimble is designed to protect rope eyes from chafe and...
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Rope Thimble for Ø5/8" (Ø16mm) Rope - Nylon PA - White
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Premium Rope Thimble - Nylon PA for Ø5/8" (Ø16mm) RopeThis professional-grade nylon PA rope thimble is designed to protect rope eyes from chafe and...
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Rope Thimble for Ø1/2" (Ø12mm) Rope - Nylon PA - White
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Premium Rope Thimble - Nylon PA for Ø1/2" (Ø12mm) RopeThis professional-grade nylon PA rope thimble is designed to protect rope eyes from chafe and...
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Rope Thimble for Ø3/8" (Ø10mm) Rope - Nylon PA - White
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Premium Rope Thimble - Nylon PA for Ø3/8" (Ø10mm) RopeThis professional-grade nylon PA rope thimble is designed to protect rope eyes from chafe and...
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Rope Thimble for Ø5/16" (Ø8mm) Rope - Nylon PA - White
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Premium Rope Thimble - Nylon PA for Ø5/16" (Ø8mm) RopeThis professional-grade nylon PA rope thimble is designed to protect rope eyes from chafe and...
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Rope Thimble for Ø1/4" (Ø6mm) Rope - Nylon PA - White
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Premium Rope Thimble - Nylon PA for Ø1/4" (Ø6mm) RopeThis professional-grade nylon PA rope thimble is designed to protect rope eyes from chafe and ...
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Rope Thimble for Ø3/16" (Ø5mm) Rope - Nylon PA - White
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Premium Rope Thimble - Nylon PA for Ø3/16" (Ø5mm) RopeThis professional-grade nylon PA rope thimble is designed to protect rope eyes from chafe and...
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Rope Thimble for Ø5/32" (Ø4mm) Rope - Nylon PA - White
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Premium Rope Thimble - Nylon PA for Ø5/32" (Ø4mm) RopeThis professional-grade nylon PA rope thimble is designed to protect rope eyes from chafe and...
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