finger

A finger is a narrow, short pier that projects perpendicularly from a main dock or wharf. It serves as a berthing point for a single vessel or, in some configurations, two smaller craft moored on opposite sides. The finger typically ranges from 40 to 150 feet long and 20 to 40 feet wide, depending on the size of ships it is designed to accommodate.

Fingers are the most space-efficient berthing arrangement in modern marinas and commercial harbors. Unlike a straight dock that requires a vessel to occupy linear waterfront, fingers allow multiple ships to tie up perpendicular to a main pier, multiplying the number of berths without expanding the overall footprint. Each finger is usually served by its own set of shore power, water, and fuel lines, making it economical to add or modify individual finger piers as demand changes.

Construction and Positioning

Fingers are built on pilings, dolphins, or floating pontoons, depending on water depth, bottom conditions, and tidal range. Fixed fingers use driven steel or concrete piles; floating fingers move with the tide and are more forgiving of debris and ships drifting during storms. Each finger typically has a pile-driving frame or guide that allows it to slide vertically while remaining aligned with the main dock structure. Fenders, usually made of rubber or foam, protect both the pier and the vessel hulls from collision damage during berthing.

The name derives directly from the visual resemblance: a main dock is the hand, and the perpendicular projections are fingers. This terminology is standard across the shipbuilding, port operations, and recreational boating industries. Fingers are sometimes called slip piers or slip docks when reserved for a single vessel, though finger is the more precise term for the structure itself.

Maintenance is focused on pile condition, fender integrity, and tie-off hardware. Corrosion of steel piles in salt water is managed through cathodic protection systems or coating regimens. Fingers used in high-traffic commercial ports see greater wear and require more frequent inspection of warping posts, cleats, and electrical connections than those in sheltered marinas.