Sea-Dog supplies marine deck-fill hardware as complete fill assemblies, separate slotted caps, operating keys and emergency plugs. These components do different jobs. This comparison uses five exact manufacturer part numbers to help match the correct gas-marked hose fill and compatible replacement hardware.
Three different deck-fill component types
351320-1 is a gas-marked stainless hose deck fill from Sea-Dog's earlier catalog. It joins a 1½-inch hose; it is not just the top cap.
351390-1 is the threaded slotted cap and chain for 1½-inch Sea-Dog hose fills. The 351399-1 stainless and 357399-1 nylon items are separate keys.
357390-1 is a nitrile/Buna rubber emergency plug. It is not a substitute for installing a correct, serviceable deck-fill cap permanently.
Sea-Dog hose-fill and replacement-part comparison
The 351390-1 cap uses a 1⅞-inch outside diameter and a 12 NPSM straight thread according to Sea-Dog. Those details should not be transferred to two-inch or pipe-type fill systems.
| MPN | Component | Material | Purpose | Identifying fit |
|---|---|---|---|---|
| 351320-1 | Gas hose deck fill | 316 stainless steel | Complete fill assembly | Gas marking; 1½-in hose |
| 351390-1 | Slotted cap and chain | 316 stainless steel | Replacement cap | Sea-Dog 351320–351323 hose fills |
| 351399-1 | Stainless deck-fill key | 316 stainless steel | Opening slotted caps | 1 3/16-in centre-to-centre holes |
| 357390-1 | Emergency deck-fill plug | Nitrile/Buna rubber | Temporary emergency plug | Check exact fill opening |
| 357399-1 | Nylon deck-fill key | Black nylon | Opening slotted caps | Multi-spacing key; verify cap |
351320-1 is documented in Sea-Dog's earlier catalog; newer manufacturer tables show other variants. Confirm the body marking and exact part before ordering. The nylon key's individual pin spacings should be checked against the actual cap.
Installation, fuel marking and maintenance checks
Verify the intended fuel or water line, hose diameter, cap thread, seal and mounting flange. Sea-Dog specifies three #10 flat-head fasteners for the 351320 series. Marine fuel-fill installations require proper bonding under applicable regulations and the manufacturer instructions.
Sea-Dog's 351390-1 cap belongs to the 351320–351323 hose-fill family. Its 12 NPSM straight thread is not the same as the larger pipe-type or two-inch hose-fill cap systems. Always confirm the exact fitting family and closure.
Do not use the emergency plug as a permanent repair. Follow the vessel manufacturer's safety procedures when working with fuel or waste connections.
Sea-Dog deck fills, keys and replacement caps
Select a component below to check product details and availability.
Sea-Dog 351320-1
Earlier-catalog gas-marked fill body for 1½-inch hose, not a loose replacement cap.
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Sea-Dog 351390-1
1⅞-inch cap, 12 NPSM straight thread, supplied with attachment chain; not a two-inch hose or pipe-fill cap.
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Sea-Dog 351399-1
Cast stainless key for Sea-Dog stainless fill caps with matching hole spacing.
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Sea-Dog 357390-1
Emergency-use plug; do not treat it as a permanent cap replacement without the correct application.
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Sea-Dog 357399-1
Lightweight nylon key for compatible slotted deck-fill caps; match the pin spacing.
View part details and availabilityOther Sea-Dog marine deck hardware
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