Sea-Dog Line Deck Fill Plate Keys

Sea-Dog Line Deck Fill Plate Keys: The Right Tool for Every Fill Cap

A deck fill plate key is one of those small but mission-critical pieces of gear that every boater needs on board. Without the right key, opening or servicing a fuel, water, or waste fill cap can quickly become a frustrating ordeal — especially when you're at the fuel dock with a line of boats waiting behind you. Sea-Dog Line has long been recognized as a trusted manufacturer of marine hardware, and their lineup of deck fill plate keys reflects that same commitment to practical, well-built solutions designed for real-world boating.

A Range of Keys to Match Any Fill Cap

Sea-Dog Line offers deck fill plate keys in several configurations, so you can find exactly the right tool whether you're working with their own fills or another brand's caps. Their lineup includes:

• Universal Deck Fill Key (Stainless Steel, Stamped): Designed to fit all Sea-Dog fuel fills as well as most others on the market, this stamped 304 stainless steel key is the go-to choice for boaters who want maximum compatibility. It fits deck fill caps with hole widths of 1-1/16" and 1-3/16", with an overall length of 4" and width of 2-3/4".
• Cast Stainless Deck Fill Key (351399-1): A more refined cast stainless option, with 1-3/16" center-to-center of lugs, ideal for pairing directly with Sea-Dog's cast stainless deck fill cap family.
• Nylon Deck Plate Key (357399-1): Made of black nylon, this lightweight, corrosion-immune option is a smart backup key or budget-friendly choice for boats where weight and simplicity take priority. It fits all cast stainless Sea-Dog deck fill caps as well as many other brands'.
• PLUGMATE™: An injection-molded polycarbonate/machined design that adds a modern, durable alternative for boaters who want a non-metallic, long-lasting option.

More Than Just a Key

What sets Sea-Dog's flagship Universal Deck Fill Key apart from a bare-bones tool is its thoughtful multi-function design. Also included on the key is a shackle key, bottle opener, and a straight blade screwdriver, plus 5/16" hex head and 7/16" hex head wrenches. That means a single compact piece of stainless steel handles a surprising number of common on-the-water tasks. It is constructed of corrosion-resistant stamped 304 stainless steel — a necessity in the harsh salt, sun, and spray environment of the marine world.

Built for the Marine Environment

Whether you choose stainless or nylon, Sea-Dog Line deck fill plate keys are engineered to survive aboard a boat. Stainless steel options resist rust and corrosion in saltwater, while the nylon key provides a lightweight, non-scratching alternative that won't corrode under any conditions. Sea-Dog designs their keys with broad compatibility in mind, so one key can often handle multiple fill caps across different fluid types — fuel, water, waste, and more — simplifying what you need to keep on board.

If you're stocking up on marine plumbing hardware, Sea-Dog Line's deck fill plate keys are a natural companion to their broader lineup of deck fills and caps. Explore the full Sea-Dog Line brand catalog or browse all deck fill plate keys to find the right fit for your vessel.