Marine OS

Reference

Marina & boating glossary

Plain-English definitions of the terms you meet around docks, marinas, and passage planning: what a transient slip is, slip versus berth, mooring fields, shore power, and the rest of the waterfront vocabulary.

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A

Air draft
The height of a boat above the waterline, from water to the tallest fixed point. It decides which bridges you clear, the vertical twin of draft.

B

Berth
A designated place where a vessel is kept: in marinas often used interchangeably with slip, though berth can also mean alongside a wall or pontoon. In Europe, berth is the common word; in the US, slip.
Bilge
The lowest inside part of the hull where any water aboard collects, kept dry by bilge pumps.
Breakwater
A structure, fixed or floating, that shelters a harbor or marina basin from waves.
Bulkhead
A retaining wall along the waterfront that holds back land and lets boats lie alongside; replacing one is among the biggest capital costs a marina faces.

C

Chandlery
A shop selling boat gear and supplies, often found at larger marinas.
Cleat
The T-shaped fitting on docks and decks that lines are made fast to.

D

Dock freeboard
The height between the dock surface and the water. Low freeboard eases boarding for small boats; high fixed docks suit bigger vessels and big tide ranges use floating docks instead.
Dockage
The service, and the fee, for keeping a boat at a dock. Transient dockage is short-stay; seasonal or annual dockage is a contract.
Dockmaster
The person who runs a marina's docks day to day: slip assignments, arrivals, fuel, and the dock crew. Compare harbormaster, who typically has authority over a whole harbor, often as a public official.
Dockominium
A slip you own like a condominium rather than rent: deeded ownership of the slip plus fees for shared facilities.
Draft
How deep a boat sits in the water, keel to waterline. Your draft plus safety margin sets the minimum water you can float in.
Dry stack (rack storage)
Boats stored ashore on multi-level racks and launched by forklift on request. Common for outboard powerboats; sold as a service much like a slip.

F

Fairway
The clear channel between rows of slips that boats use to maneuver in and out.
Fender
The cushions hung between hull and dock to prevent damage. Calling them bumpers marks you as new; everyone understands anyway.
Float plan
A short document left with someone ashore describing the boat, crew, route, and return time, so a search starts fast if you are overdue. See our float plan template.
Floating dock
Docks that ride up and down with the tide on pilings or anchors, keeping dock freeboard constant. Fixed docks stay put and the step up or down changes with the tide.

G

GPX
The universal file format for exchanging waypoints, routes, and tracks between navigation apps and chartplotters.
Gunwale
The upper edge of a boat's side, pronounced "gunnel".

H

Harbormaster
The official responsible for a harbor as a whole: moorings, traffic, and regulations. A marina's equivalent role is the dockmaster.
Haul-out
Lifting a boat from the water for storage, inspection, or repair, usually with a travel lift or crane. Insurance policies often ask where and how often a boat is hauled.
Haul-out pad
The reinforced area of a boatyard where hauled boats are blocked and stored, built to take the point loads of stands and keels.

I

ICW (Intracoastal Waterway)
The protected inside route along the US East and Gulf coasts, measured in statute miles from Mile 0 at Norfolk. See our ICW trip planning guide.

K

Knot
One nautical mile per hour. A boat doing 6 knots covers 6 nautical miles in an hour; saying "knots per hour" is the classic landlubber tell.

L

Liveaboard
Someone who lives on their boat full time. Marinas that allow it usually charge a liveaboard fee and cap the number of liveaboard slips.
LOA (length overall)
The full length of a boat including pulpits and swim platforms. Marinas bill by LOA, not by the length on the registration, and slips are sized by it.

M

Magenta line
The charted line marking the recommended ICW route. Treat it as guidance, not gospel: shoaling moves faster than charts.
Mooring
Securing a boat to a fixed point other than a dock, most often a mooring ball attached to a permanent anchor. Cheaper than a slip, no walk-ashore access.
Mooring ball
The floating buoy you pick up and tie to on a mooring. Under it: a pendant, chain, and a heavy anchor or block that outholds any anchor you carry.
Mooring field
An organized area of moorings laid out and managed by a harbor, town, or marina, usually rented nightly or seasonally. The affordable middle ground between anchoring and a slip.

N

Nautical mile
1.852 kilometers, about 1.15 statute miles: one minute of latitude. All sea distances are measured in it. See our sailing distance calculator guide.

P

Pile / piling
The vertical posts driven into the seabed that docks are built on and boats tie off to.
Pump-out
Emptying a boat's sewage holding tank at a dockside or mobile pump-out station. Legally required disposal method in no-discharge zones.

R

Rafting (rafting up)
Boats tying alongside each other rather than to the dock, common at crowded events and some transient walls.
Rode
The anchor line: rope, chain, or both, connecting anchor to boat. Scope is the ratio of rode paid out to depth.

S

Sea trial
The on-water test drive of a boat, standard before a purchase closes.
Shore power
Electricity supplied to a boat at the dock through a shore power cord, typically 30 or 50 amp in the US. Marinas meter or flat-rate it; bigger boats care about pedestal amperage.
Slip
An individual parking space for a boat in a marina, usually between finger docks or pilings. A boat kept there is "in a slip"; the everyday US word for a berth.
Slip vs berth
Functionally the same thing: an assigned spot for a boat. US usage says slip, European and superyacht usage says berth, and berth also covers alongside spots that are not slips.
Snowbird
A cruiser who migrates south each fall and north each spring, the seasonal heartbeat of the ICW and Florida marinas.
Spring line
Docklines run diagonally fore or aft that stop a boat surging forward and back in the slip.

T

Tender
The small boat (dinghy) used to get to and from a larger boat at anchor or on a mooring.
Transient slip
A slip rented short term, a night to a few weeks, to visiting boats, as opposed to seasonal or annual slips. Transient dockage is usually priced per foot per night. Marinas manage it with transient reservation systems.
Travel lift
The mobile gantry crane with slings that hauls boats out of the water and moves them around the yard.

V

VHF
The marine radio band. Channel 16 is the international hailing and distress channel; marinas commonly stand by on 16 and work a designated channel.

W

Waypoint
A saved position used to build routes. A route is an ordered list of waypoints; a track is a recording of where you actually went.
Wet slip
A slip in the water, said to distinguish from dry stack storage ashore.
Winterization
Preparing a boat and its systems for freezing temperatures: draining water, antifreeze, and shrink wrap territory. A core boatyard revenue season.

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