Stainless Steel Flag Pole Base AISI316 – Deck Mount Socket (14mm & 20mm)

Display your colors with confidence using our stainless steel flag pole base designed for boat decks and gunwales. Fabricated from AISI 316 stainless steel, this flag pole socket provides a secure mounting point for your yacht’s ensign or courtesy flags while seamlessly blending with other high-quality deck hardware. The base is extremely robust: its one-piece cast construction and thick walls ensure it can withstand constant stress from wind and movement, keeping your flag staff upright and steady even when cruising at speed or in choppy conditions.

We offer two size variants to accommodate the most common marine flagpole diameters:

• 14mm Inner Diameter Base: Fits flag masts of 14mm diameter (typically about 0.55 inches). This size is often used with flag poles around 400mm (40cm) in length, which are suitable for small to medium boats (e.g., 4–6m vessels) flying a standard sized national flag or courtesy flag (often around 30×20cm flag dimensions).
• 20mm Inner Diameter Base: Fits flag masts of 20mm diameter (about 0.78 inches). This pairs with slightly thicker flag poles usually about 600mm (60cm) long, ideal for larger boats (6–10m or more) that use a bigger ensign or club burgee (flag sizes roughly 45×30cm or larger). The thicker pole and base provide extra rigidity needed for a larger flag on a yacht or motorboat.

Each base has a flared socket that holds the bottom of the flagpole at an approximately 15-degree angle, which is a common rake for flag poles on boats. This gentle backward tilt ensures the flag streams nicely behind the boat rather than straight up, improving visibility and appearance. It also helps the flag clear any stern railings or obstacles. The base’s interior is smooth and accurately machined to the specified diameter, allowing you to insert and remove the flag pole easily while minimizing any wobble. A small through-hole or set screw at the side of the socket (if provided on this model) allows you to secure the pole by tightening a screw against it, preventing the pole from turning or lifting out inadvertently (for example, if a strong gust hits the flag). (Note: Many flag pole bases include a side screw or pin – if included, use it to lock the pole in place.)

The mounting flange of the base measures about 85–91mm in length (depending on model) and ~40–45mm in width, with a slight curvature that can sit on a flat or mildly curved surface. It features three countersunk mounting holes for flush installation of screws or bolts. The typical arrangement is two screws on one side of the socket and one on the opposite side (triangular pattern), which ensures a very firm attachment to the deck or transom and prevents rotation or loosening of the base under load. When properly through-bolted with backing washers or plates (recommended for fiberglass decks), this base can take considerable force – including the flag whipping in strong winds or someone accidentally grabbing the flagpole.

Our flag pole base comes with a brilliant polished finish, matching the gleam of chrome or stainless steel fittings on your vessel. This mirror finish not only looks prestigious, reflecting your commitment to quality, but also serves a practical purpose: it’s easy to keep clean and offers maximum resistance to pitting and corrosion. Rain, UV exposure, and salt will not dull this base’s appearance. A quick rinse and wipe-down will keep it shining for years, maintaining the upscale look of your boat’s stern or mast.

Use & Installation:
Mount the base on a horizontal surface at or near the stern (such as the top of the transom, swim platform, or a dedicated flag staff mount point on the aft deck). Ensure there is clearance for the flag to fly without snagging. Install with the angled socket leaning toward the aft. Use the included stainless screws (or better, use through-bolts with locknuts) to fasten the base securely. A bedding compound (marine sealant) under the flange is recommended to seal any screw holes and to cushion between the base and the deck, preventing water intrusion. Once mounted, insert your flag pole and tighten the side screw (if present) to lock the pole. Attach your flag’s halyard or clips to the pole’s eyelets – usually, a flagpole will have an eye or finial at top and a cleat or ring at bottom to secure the flag. With the base and pole in place, your flag will be prominently and securely displayed.

This AISI316 flag staff base is not only functional but also an upgrade in style and quality compared to common zinc or aluminum bases. It will not corrode or leave rust streaks on your deck, even if left in place year-round. Whether you’re displaying the national ensign, a yacht club burgee, or a courtesy flag of a country you’re visiting, this base ensures your flag flies true. It’s a subtle but important detail that demonstrates pride in your vessel and attention to marine tradition.

Mariners know that a well-mounted flag at the stern is a sign of a well-found boat. By using our stainless flag pole base and matching flagpole, you equip your boat with a reliable, attractive, and long-lasting solution for flag display. It’s an essential piece of deck hardware for any boat owner who wants to fly flags with dignity and security, from small motorboats to luxury yachts.